close

Вход

Забыли?

вход по аккаунту

?

bk-2017-1251.ch011

код для вставкиСкачать
Chapter 11
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Nanocellulose: Common Strategies for
Processing of Nanocomposites
Marcos Mariano and Alain Dufresne*
Univeristy Grenoble Alpes, CNRS, Grenoble Institute of Engineering,
LGP2, F-38000 Grenoble, France
*E-mail: alain.dufresne@pagora.grenoble-inp.fr.
There has been an explosion of interest in the use of biomass
as a source of renewable energy and materials. One focus
of this activity has followed from the recognition that, by
suitable chemical or mechanical treatments, it is possible
to produce materials with dimensions in the nanometer
range from many naturally occurring sources of cellulose.
Cellulose-based materials are carbon neutral, sustainable,
recyclable, and nontoxic; they thus have the potential to be
truly green nanomaterials with many useful and unexpected
properties. The potential of these nanoparticles has been proved
for special functional nanomaterials but it is as a biobased
reinforcing nanofiller that they have attracted significant
interest. Impressive mechanical properties and reinforcing
capability, abundance, low weight, and biodegradability of these
nanoparticles make them ideal candidates for the processing of
polymer nanocomposites. However, as for any nanoparticle,
the main issue is related to their homogeneous dispersion within
a polymeric matrix. This entry describes the main issues and
challenges associated with the processing of nanocellulose
reinforced polymer nanocomposites.
© 2017 American Chemical Society
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Introduction
It is undeniable and well accepted that the development of new materials
changed the world during the last century. Materials that are able to combine better
conductivity and flexibility and, at the same time are light weight has allowed the
growth of many technologies that are today a part of life as we know it. With a
broad range of applications and characteristics, polymeric materials are probably
the most remarkable class of materials developed during this period. There are no
doubts that they revolutionized the way as we prepare, store and transport virtually
all the products available for consumption.
Despite the development of such a broad range of materials, some polymers
cannot present the optimal properties for specific applications. As a way to
overcome these limitations, the use of polymer as matrix for the creation of
composites became widespread. The presence of a rigid filler can improve
several properties of the material such as chemical, mechanical, barrier and
swelling properties. However, today we are aware that it is necessary to deal with
problems related to the discard of the first generation of polymers. Since they
are mostly petroleum-sourced, issues of non-biodegradability and recyclability
limitations became a major concern during the last decades. As a solution,
the utilization of biopolymers has been offered as a way to replace traditional
materials. Produced by living organisms, renewable and abundant, many of
these so-called “green polymers” are readily biodegradable and their production
is not petroleum-dependent. These renewable resources are replenished by the
environment over relatively short periods of time. Furthermore, these polymers
can also be used for the preparation of composites. In this case, we are able to
create fully biobased composites by their combination with biodegradable fillers.
In the last years, these green composites became more advanced.
Technological and scientific research now go towards these sustainable materials
as we become witnesses of nanotechnology growth. Aiming to obtain more
advanced, light weight and powerful devices, the development of polysaccharide
nanoparticles can be combined with biopolymers to produce eco-friendly
nanocomposites. As principal candidate for the development of this kind of green
nanofiller, cellulose has gained huge attention in this miniaturization process
of advanced nanomaterials. Since the first publications about the subject, in
the middle of 90’s, several research groups started to dedicate special attention
to this topic. This interest is justifiable since cellulose is the most abundant
polymer on earth and possesses very promising properties. Natural cellulose
based composites have been used as engineering material for thousand of years
and, still today, cellulose is largely present in our lives in textile and paper.
Fortunately, the current technology provides us the tools to observe the microand nano-scale hierarchical structure of this material and find out the source of
its functionality, flexibility and strength. Looking closer, the structure of a plant
itself is a nanocomposite. As described by Sain and Oksman (1), the backbone
of plants is composed mostly of cellulose, a polymeric carbohydrate that is, at its
core, organized as nanofibers.
The advancing of cellulose nanofiber technology is remarkable. In the
beginning of the last decade, only 2% of world cellulose production (estimated to
204
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
1.5 x 1012 annual tons in 2005) were dedicated to producing fibers and cellulose
derivatives, such as regenerated cellulose and cellulose esters. The major part
of the production was destined for the paper industries (2). Since 2015, this
scenario started to change in terms of commercial purposes. Some companies
have commercialize nanocellulose (including nanofibrils and nanocrystals) on
a large scale, and can produce tons per day (3). This is a huge advance for a
material that can be considered as a feedstock for industrial applications. Today,
ten years have passed since the publication of “Cellulose Nanocomposites” in
ACS Symposium Series (4). During this time, research on nanocellulose has
traveled a long road. New interests, perspectives and challenges can be found in
literature, always supported by a growing number of publications. Here, we try
to summarize some important concepts and recent breakthroughs with a focus on
the processing of cellulose based nanocomposites.
Cellulose Structure and Nanocellulose Obtainment
Since we are describing the use of nanocellulose or cellulose nanomaterials in
nanocomposite preparation, it is important to describe some characteristics of these
nanoparticles that are essential during processing. The classical representation of
plant hierarchical structure is represented in Figure 1.
Figure 1. Plant hierarchical structure. Reproduced with permission from ref.
(5). Copyright 2012 Elsevier.
205
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Elementary nanofibrils (CNF) are the building blocks of this structure.
Subsequently with removal of lignin and other secondary materials (e.g.
hemicelluloses, waxes and trace components) from pristine fiber, these fibrils
can be isolated as nanoparticles. Normally this is done by the application of
mechanical and enzymatic treatments, which induces the defibrillation of the
microfiber structure. Several techniques are available to assist in obtaining
these individualized nanofibers, including 2,2,6,6-tetramethylpiperidine-1-oxyl
(TEMPO)-mediated oxidation as a way to facilitate the separation of the fibrils,
reducing the necessary time and energy (6, 7).
In turn, individual CNF are composed of amorphous and crystalline
cellulosic domains. The disruption of the amorphous phase, normally performed
using strong acids, allows the isolation of rod-like crystalline domains, called
cellulose nanocrystals (CNC), which are extremely strong and lightweight
crystalline nanoparticles. Due to their highly crystalline structure and nanometric
dimensions, these particles can present Young’s modulus values in the range of
100-150 GPa combined with a high specific surface area in the range of several
hundred m2g-1 (8).
The isolation conditions used in obtaining these nanoparticles strongly
affect their surface and bulk properties along with the cellulose source. Several
publications are dedicated to describing the influence of the preparation conditions
on the final surface properties, thermal stability, polymorphism and dimensions
of the nanoparticles. Some of these properties will be discussed in this chapter.
The possibility of obtaining particles with different properties is a quite
interesting topic, which can bring valorization of residual or unexplored biomass.
Different plants can present a large range of cellulose contents and nanocrystalline
dimensions. While cellulose content in wood reaches between 40–50% (half
in nanocrystalline and half in amorphous form), other sources such as bacterial
cellulose (or even cotton) consist of more than 90% cellulose (with varied
crystalline content), that makes the preparation of cellulose with high purity easy.
However, several reasons (e.g. local production, specific crystalline dimensions,
short treatment time, etc) can serve as motivation for the obtainment of cellulose
nanoparticles from sources that are richer in lignin (e.g. sisal, soy hulls, capim
dourado, etc). The production of nanocellulose and the isolation of lignin can
be combined and used as a way to obtain versatile nanoparticles and aromatic
chemical reagents from these materials, increasing the valorization of this biomass
(9, 10).
Cellulose is a polysaccharide composed of D-glucopyranose (C6H11O5) rings
linked through β(1,4) bonds. With a high number of hydroxyl groups, cellulose
chains are able to form hydrogen bonds with neighboring molecules. These
bonds are responsible for keeping the chains packed together and for controlling
the formation of the fiber microstructure. Crystalline domains are supposed to
present around 7.2 -OH/nm2 on their surface (11), which, combined with their
large surface area, are responsible for the properties of chemical reactivity and
hydrophilicity of these nanomaterials.
According to TAPPI definition (TAPPI WI3021), CNF are particles that
possess diameters (d) between 5-30 nm and lengths (L) such that the aspect ratio
L/d is higher than 50. Due to the presence of amorphous regions, these particles
206
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
are somewhat flexible and have high surface area. This combination of properties
makes these particles perfect candidates for producing materials capable of
absorbing water, and creating gels and suspensions with high viscosity. When
obtained from bacteria, these nanoparticles can be easily applied in biomedicine
(12). Due to their strength and stiffness, CNC are used as nanofiller in the
preparation of rigid materials. Defined as particles with diameters (d) ranging
from 3 to 10 nm and L/d > 5, these rod-like nanoparticles can form a very rigid
3D network of percolated nanoparticles, that is able to provide outstanding
mechanical properties in different polymeric matrices. Once extracted from
the original structure of the fiber, these particles can offer new features, not
only based on different aspect ratios but also polymorphism, surface charge and
thermal stability due to the presence of sulfate groups inserted during cellulose
hydrolysis with H2SO4 (13, 14).
The use of harsh or mild conditions during sulfuric acid hydrolysis also
effects the level of particle sulfation and, as a consequence, the thermal resistance
of the obtained nanoparticles. While some treatments, such as TEMPO oxidation,
can be used as a way to increase cellulose reactivity and, in some cases, its thermal
resistance, others tend to cause early degradation of the external cellulose chains
of the nanoparticle (15, 16). The use of other acids seems to not induce early
thermal degradation of cellulose, but cannot provide the negative charge present in
the sulfate SO3- group, that results in electrostatic stability for CNC suspensions.
Normally performed with strong acids, the hydrolysis of the amorphous phase
can also modify the structure of isolated crystalline particles. It seems that,
besides the insertion of sulfate groups, strong acids can also cause a swelling of
the crystalline regions resulting in a polymorph conversion of cellulose (17–19).
Under moderate conditions, these particles are normally elongated rod-like
particles able to keep the original cellulose I crystalline structure. Although, some
experimental conditions can cause a conversion from cellulose I to cellulose II.
Some works describe this conversion when using acid (20) and mechanical (21)
treatments, generating a mix of nanoparticles with both polymorphs or even a
predominant distribution of cellulose II round-like particles. By choosing the
adequate cellulose source and chemical/mechanical treatment, it is possible to
control some of the aspects mentioned above. While CNF are broadly used in
food packaging and for control of permeability (5, 22), CNC are more popularly
used to improve the mechanical properties (23). Of course, these applications are
not exclusive to one or another cellulosic nanomaterial, but can take advantage of
its principal characteristics.
207
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
208
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Table 1. Examples of nanoparticles isolated by using different methodologies
Source
Form
Obtention
Method
Onset Thermal
Degradation (°C)
Polymorph
Ref.
Bacterial cellulose
CNF
HCl hydrolysis
-
Iα
(24)
Bacterial cellulose
CNF
Filtration
-
-
(25)
Microfibrillated Cellulose
CNF
Commercial Sample
-
I
(26, 27)
Paper pulp
CNF
Supermass colloider
-
-
(28)
Softwood
CNF
Shear Homogenization
246
I
(29)
Sonication/ Homogenization
-
-
(30)
Iα
(24)
Sugar pulp
CNF
Wood
CNF
Commercial Sample
-
Bamboo
CNC
H3PO4, HCl
H2SO4, CH3COOH/HNO3
250 - 320
I
(31)
Bacterial cellulose
CNC
H2SO4 hydrolysis
-
-
(32)
Cotton
CNC
H2SO4 hydrolysis
224
I and II
(33)
Cotton
CNC
H2SO4 hydrolysis
128 – 270
I
(13)
Kenaf bast fiber
CNC
H2SO4 hydrolysis
120 - 280
I
(34)
Lyocellfibers
CNC
Ammonium persulfate
-
II
(35)
MCC*
CNC
Water/Temperature
300
I
(36)
Ramie
CNC
H2SO4 hydrolysis
-
-
(37)
Sisal
CNC
H2SO4 hydrolysis
145
I
(15)
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Form
Obtention
Method
Onset Thermal
Degradation (°C)
Polymorph
Ref.
Wood
CNC
TEMPO/Sonication
-
II
(19)
Wood
CNC
H2SO4 hydrolysis
-
I and II
(20)
Wood
CNC
Ball-milling
-
I and II
(21)
Wood
CNC
N2H4/ H20
-
II
(38)
MCC means Microcrystalline Cellulose.
209
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
*
Source
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
For instance, it was reported by Rusli et al. (39) that the use of HCl or H2SO4
to prepare CNC modifies the mechanism of stress transfer between a polymeric
matrix and the obtained nanoparticles. It seems that due to the presence of
negative charges on the surface of the nanoparticle, H2SO4-hydrolyzed CNC can
increase stress transfer. This is of importance since it is as a biobased nanofiller
for mechanical reinforcement that such nanoparticles have attracted significant
interest. Table 1 shows some examples of different cellulose nanomaterials
that can be obtained through the application of different methodologies for
nanoparticle isolation.
Preparation of Nanocomposites
The preparation of nanocomposites based on cellulosic nanomaterials is a
broad topic that is well explored in literature by a large number of publications.
Until the middle of 2000’s, most of these publications dealt with preparation of
new materials in a liquid medium, exploring film casting/evaporation. In the last
10 years, the number of publications exploring melt processing has increased
significantly. Also, the use of alternative techniques such as layer-by-layer (LbL)
assembly, electrospinning and resin transfer molding is now investigated (40).
This is a natural consequence of the search for methodologies that can be applied
at industrial scale. Since processing techniques influence the final properties of
the nanocomposites (e.g. dispersion, distribution and alignment of the filler),
investigation of different preparation routes became one of the major targets of
research in the area (40).
Influence of Aggregation
The huge specific surface area of nanomaterials is one of their main assets
but is also responsible for the greatest challenges during the preparation of
these materials: aggregation. Nanostructures have an exponentially increasing
natural tendency to aggregate, which is not different for cellulose nanoparticles.
Moreover, the self-association of cellulose nanoparticles is exacerbated by
the omnipresence of hydroxyl groups on their surface, which leads to particle
interaction and the formation of new interparticle H bonds. To avoid it, well
controlled processing conditions are very important. The distance between CNCs
in a film swelled by water was calculated to be between 1.2 to 1.6 nm (e.g. 4 to
6 layers of water molecules), that shows how close these particles can be packed
together in a final stage or processing (41).
The polar cellulose surface is a drawback during the preparation of
nanocomposites with non-polar polymers or dispersion in non-polar solvents.
Attraction between the surfaces of neighboring nanofillers can be much stronger
than between the filler and the non-polar medium/surface. To overcome this
limitation and avoid aggregation, different physical and chemical procedures can
be adopted. For example, surface modification can be used to provide new steric
or electrostatic properties on particle surfaces (42). Many routes are available
to perform surface modification (e.g. creation of new covalent bonds) through
210
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
chemical reaction, by inserting functional non-polar groups or polymers, or by
adsorbing surfactants on the nanoparticle surface through electrostatic interactions
(43). Independently of the chosen approach, the general purpose is to control
(decrease) the surface energy of the nanoparticle, fitting it to a broader number
of chemical environments.
Aggregation decreases the surface area of the nanoparticle and reduces
filler-polymer interactions, causing effects that can be harmful to nanocomposites,
independent of the targeted final application of the material. For example, the
presence of well-dispersed nanofiller can increase barrier properties of polymeric
materials, by increasing the tortuosity of the matrix, along with the presence of
crystalline particles that act as impenetrable domains for the solvent (or gas)
molecules. The presence of aggregates induces the formation of voids and holes
into the structure of the nanocomposite, making the diffusion of small molecules
easier. In the same way, aggregation prevents the formation of a percolating
network of individual particles and decreases the mechanical properties of the
material (44). Also, during hot processing, the presence of aggregates increases
thermal degradation of the cellulosic materials and damages the structure of the
composite (45).
Common Processing Methodologies
As described in the last section, the most common processing methods used
for the preparation of cellulose based nanocomposites include traditional film
casting/evaporation and extrusion/injection molding, besides more specific or
alternative techniques.
Since the forces and parameters involved in these methodologies are
completely different, it will deeply affect the organization and integrity of the
filler, besides modifying the matrix structure. Roughly, these different processing
techniques can be grouped as solvent-based and melt-processing techniques, as
illustrated in Figure 2.
Figure 2. Flowchart of some popular processing methodologies applied for the
preparation of cellulose nanocomposites.
211
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Solvent-Based Processing
As a result of the disintegration process of cellulose macrostructure, cellulosic
nanoparticles are usually obtained as an aqueous suspension. It makes sense,
since water medium can help to swell cellulose pristine fibers and facilitate the
destruction of its structure, saving energy, chemicals and time. At this stage, a
drying step would induce irreversible aggregation of cellulose nanoparticles and
lost of the nanoscale.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Casting/Evaporation
As reported by Favier et al. (46–48), the first publications dealing with
cellulose reinforced nanocomposites were based on casting/evaporation of an
aqueous mixture of CNC and elastomeric matrix in latex form. Never-dried
aqueous dispersion of CNC was therefore used. These publications attributed
the outstanding mechanical reinforcement that was obtained by the addition of
CNC to the formation of a percolating network of the particles. Theoretically, the
obtainment of this network occurs for a critical volume content (φc) corresponding
to the percolation threshold, which directly depends on the aspect ratio (L/d) of
individual particles, as described by Equation I (47).
This equation shows the importance of the source from where the particles
are obtained and hydrolysis conditions since long nanorods can provide
the construction of the percolating network at a lower volume fraction of
nanoparticles. This 3D nanoparticle network can only be obtained under specific
experimental conditions, as a result of the slow evaporation of the solvent. The
evaporation of the solvent, that normally takes hours, allows the progressive
organization and interaction among the nanoparticles (based on the construction
of new H bonds). Until now, these systems based on elastomers are still used as
model systems to study the maximum reinforcement potential of particles coming
from different sources. A common example is natural rubber (NR) as a matrix,
used to investigate the influence of volume fraction and filler aspect ratio on the
mechanical properties (49, 50).
The maximum reinforcement obtained seems to mainly depend on the
filler aspect ratio. In fact, it is usually reported that longer nanoparticles can
provide better mechanical reinforcement, while shortest nanoparticles can present
better results for barrier properties. Also, some have found that nanocomposites
containing long CNC particles need a smaller volume fraction of particles to reach
the percolation threshold and, for some of these systems, the casting methodology
induces sedimentation of the filler resulting in a gradient of particles in the
thickness of the obtained film (51). This means that one of the faces of the film
has a higher concentration of nanoparticles, which can cause anomalous behavior
(e.g. unexpected increase of elongation) (51, 52).
212
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Nowadays, the use of the casting/evaporation technique is not limited to a
water medium and has already expanded beyond aqueous dispersion of polymers
or are water-soluble polymers. This means that alternative preparation methods
were adapted for these systems. Chemical modification of the nanofiller can
increase filler-polymer interactions and avoid aggregation. However, some
increase the particle-particle distance if large chains are attached to the nanofiller
surface. This prevents the formation of a percolating network. As an alternative,
the particles (normally CNC) can be transferred from water to acetone and, in
sequence, to a desirable organic solvent. Some common examples are DMF
(53), pyridine (54), toluene (55) and chloroform (56), increasing considerably
the number of polymeric systems that can be used to produce nanocomposites by
casting/evaporation.
Template Approach
An interesting method, explored in a few works, was the construction of a
CNC network prior to the solvent evaporation. Though laborious, Capadona et al.
(57) used a slow solvent exchange process from water to a non-solvent to create a
nanocellulose gel. Then, the gelled nanofiber scaffold was imbibed with a polymer
(by its immersion directly in a solution of the desired polymer). Processing of
nanocomposites have been traditionally limited by a maximum volume fraction of
nanoparticles due to a significant increase in viscosity caused by high-aspect-ratio
fillers. The advantage of the template method is the possibility of creating even
neat cellulose films from the precursor gel, with unlimited nanofiber content.
Annamalai et al. (58) prepared nanocomposites using this approach
and compared ensuing systems to nanocomposites obtained by traditional
casting/evaporation methodology. The mechanical properties of materials
prepared by this template approach followed the predicted storage modulus (E′)
values described by the percolation theory, what corroborates the formation of
a 3D percolating structure of particles. However, the final values of E′ were
higher for materials prepared by simple casting/evaporation. Recently, a similar
approach was used to create tough and stretchable hydrogels (59).
LbL Assembly and Electrospinning
Also using CNC suspension in a suitable liquid, the LbL technique is based on
the alternating deposition of different layers, normally performed by dipping the
film in different solutions. Cellulose nanomaterials can be used as a reinforcing
phase, in association with other nanoparticles (60).
Mechanical and barrier properties of the final material are controlled by the
final number of deposited layers and their thickness. Some work has used CNC in
the construction of LbL materials with the intention of controlling O2 permeability,
improving electrical and mechanical properties, as well as some surface studies
about material roughness and Young modulus (61–63).
213
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Also based on the use of nanocelluse suspensions, electrospinning is
now a popular way to prepare materials for biomedical and pharmacological
applications (64, 65). As advantages, this technique can allow the development
of micro/nanofibers with very high surface area-to-volume ratio. Electrospinning
is a fiber production method which uses electric force to draw charged threads
of polymer solutions or polymer melts up to fiber diameters in the order of some
hundred nanometers. The use of nanocellulose can provide significant mechanical
reinforcement to the produced fibers, besides increasing its electrical conductivity
(66, 67).
Melt Processing
The use of melt processing for the preparation of cellulose based
nanocomposites is a quite new subject with increasing number of publications
in the last 5 to 10 years compared to solvent-based methods. Besides industrial
interest and a short processing time (minutes, against hours in the case of
casting/evaporation), this approach is also interesting since temperature is used
to soften the polymer matrix and no solvent is involved, resulting in greener
methodology.
First, it is important to note that high temperature mixing of the rigid
cellulose filler and polymeric matrix is possible because cellulose does not present
classical thermal behavior of semicrystalline polymers. In other words, cellulose
nanoparticles do not become soft at high temperatures since their Tg and Tm
values cannot be observed for these materials. Some extrapolations indicate a
possible Tg value for cellulose in a range from 220 to 250°C and, based on that,
a melting temperature of 430°C (2). These values are normally above cellulose
degradation temperature, especially in nanocellulose form (Table 1). With some
limitations, many examples of materials produced by in situ polymerization,
extrusion, injection-molding, and resin transfer molding at high temperatures can
be found elsewhere (68–70).
All these methods are highly appealing because they can be applied at
industrial scale. However, since no solvent is present during processing, it means
that nanocellulose usually needs to be solvent-free, i.e. in the dry state, even if
water-assisted extrusion methods exist. In this case, simple methods based on just
mixing the dried nanocellulose powder and polymer pellets have demonstrated
to be inefficient due to particle aggregation in the cellulose powder, which
is not reversible during processing (71). Furthermore, with solvent methods,
some systems can present heterogeneities attributed to incompatibility between
cellulose and most of polymeric matrices, that makes nanoparticles difficult to
disperse.
As discussed by Reid et al. (41), even the presence of solvent is not
necessarily enough to ensure cellulose nanoparticle dispersion, and external
energy may be necessary to overcome Van der Waals forces that are keeping the
particles together. In the absence of solvent, other ways should be used to keep the
nanoparticles apart and avoid aggregation prior to the processing. The principal
approaches to preparing nanocomposites with well-dispersed filler are based on
chemical modification and preparation of masterbatches. Several examples of
214
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
chemical modification of the nanocellulose surface can be found in the literature
for nanocomposites prepared by extrusion, for example. As advantages, not
only the improvement of particles dispersion is reported, but also a reduction in
nanoparticle thermal degradation. The introduction of silane groups, surfactants
and even polymerization of new groups on the particle surface have been reported
(72–75). More simply, the use of a masterbatch is based on the preparation of
a concentrated mixture of nanocellulose in polymer. Following this technique,
a film, normally prepared by casting, can be prepared from a suspension of
nanoparticles and the polymer in a suitable solvent, that allows the polymeric
chains to coat the nanoparticles. This creates a mechanical barrier that avoids
nanoparticle aggregation and low thermal degradation (54, 76, 77).
The presence of secondary chains on the surface of the nanoparticles can
be a problem when casting/evaporation preparation is used, since it prevents the
formation of a percolating nertwork. This is not significant for melt processing
because this percolation phenomenon of particles is generally not possible using
this approach. The short preparation time requested to prepare the composites at
high temperatures also limits the interactions between the particles. In addition,
during melt processing, high shear forces are imposed to the sample and cause
the orientation of the particles, trapped within the polymeric chains after cooling
of the material (78). Recently, an attempt was made to reorganize the particles,
based on their diffusion coefficient inside the polymer melt, but without success
(79). As a consequence, a higher volume fraction of particles should be used to
obtain similar results than for cast/evaporated materials (80).
Many properties of melt processed materials are also impacted by the indirect
effect of the processing conditions or by the simple presence of the nanoparticles.
Some processing conditions (e.g. screw speed during extrusion, temperature,
humidity content, etc) can affect the nanocomposite structure. Modification of
polymer’s molecular weight and quality of dispersion are the most relevant ones
(81), which are effected by the combination of the stress imposed on the sample
and high temperatures. In that sense, it seems that hot-pressing is less aggressive
on the sample than injection-molding or extrusion.
Crystallinity
Since melt processing is performed in conditions that should cause polymer
melting, cooling conditions will affect the final properties of the obtained
nanocomposite. Thermal treatments of polymers are known to generate a “thermal
history” which affects the organization of polymeric chains and crystal structure.
Besides the thermal history of the matrix, nanocellulose can also modify the
crystal structure of the polymer. Due to its small dimensions and large surface area,
these particles can have a large nucleation effect on the polymer. It can increase
the crystallinity of and alter the polymer structure. Some studies showed that the
presence of CNC particles can increase the crystallinity of thermoplastic polymers
and modify the activation energy of crystallization (79, 82–85). This effects seems
to be even more significant if a reduction of polymer molecular weight occurs
during extrusion (54).
215
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
216
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Table 2. Examples of some properties obtained for nanocomposites prepared by different methods
Preparation
Form
Matrix
Permeability
coeficient
P/Po (%)
Mechanical
reinforcement E/Eo
Crystallinity variation
(χ-χo)
ref
LbL
CNC
PET
0.06†
-
-
(86)
LbL
CNC
Resins
-
6.9
-
(87)
Electrospinning
CNC
PVA
-
3.7
2.0 %
(38)
Electrospinning
CNC
PCL
-
1.6
3.0 %
(88)
Electrospinning
CNF
SPI
-
7.6
-
(89)
Casting/Evaporation
CNF
PLA
1.10*
1.8
- 5.0 %
(90)
Casting/Evaporation
CNC
Gelatin
0.60*
1.3
-
(91)
Casting/Evaporation
CNC
Starch
0.74‡
25.0
-
(92)
Casting/Evaporation
CNC
PLA
1.10†
1.2
3.4 %
(93)
Casting/Evaporation
CNC
PMMA
-
3.4
-
(94)
Casting/Evaporation
CNC
PVA
-
1.3
6.4 %
(95)
Casting/Evaporation
CNC Tara Gum
0.33†
3.4
-
(96)
Casting/Evaporation
CNF
PU
-
2.4
6.7 %
(97)
Casting/Evaporation
CNC
CNF
0.33†
1.3
-
(98)
Casting/Evaporation
Extrusion
Roller Blade
CNC
PVAc
-
1.5
1.3
1.5
-
(81)
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
217
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Preparation
Form
Matrix
Permeability
coeficient
P/Po (%)
Mechanical
reinforcement E/Eo
Crystallinity variation
(χ-χo)
ref
Extrusion
CNF
PLA
-
1.0
- 5.0 %
(99)
Extrusion
CNC
PA 6
-
1.5
- 1.0 %
(76)
0.76†
1
19.2 %
(100)
Extrusion
CNC PLA/PHB
Extrusion/Injection
CNC
PBAT
-
1.5
7.2 %
(101)
Melt Mixer
CNC
PLA/
Lignin
-
-
34.2 %
(102)
Where Po, Eo and χo are the initial values of the respective properties and P, E and χ the final ones. † Coefficients: Oxygen barrier ‡ water activity *
Water vapour barrier Abbreviations: PA 6 (Polyamide 6); PBAT (Poly(butylene adipate-co-terephthalate); PET (Polyethylene terephthalate); PHB
(Polyhydroxybutyrate ); PLA (Polylactic acid); PMMA (Polymethyl methacrylate ); PU (Polyurethane); (Polyvinyil alcohol); PVAc (Polyvinyl acetate);
SPI (Soybean protein isolate).
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
As a consequence, the modification of matrix properties is directly related to
the behavior of the nanocomposite. Permeability, mechanical properties and light
transmittance are examples of properties that are strongly influenced by the amount
of crystalline domains present in the matrix. Table 2 shows a compilation of
some results obtained for the mechanical and barrier properties of nanocomposites
preparated by different techniques.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
Conclusions and Perspectives
Nanomaterials can be prepared from cellulose using different strategies.
They display high stiffness and are lightweight making them ideal candidates
for the preparation of polymer nanocomposites. Casting-evaporation from an
aqueous (or at least polar) medium is the most suited processing method, since it
preserves the dispersion state of the nanoparticles in this medium and the surface
hydroxyl groups lead to unexpected mechanical properties. This slow wet process
gives the highest mechanical performance materials compared to other processing
techniques. Indeed, during liquid evaporation strong interactions between
nanoparticles can develop and promote the formation of a strong percolating
network through H-bonding. This strategy is probably well adapted for niche
applications.
However, if industrial and large scale manufacturing of cellulose nanomaterial
reinforced polymer nanocomposites is the final target, melt processing is
definitively the most interesting technique, since the final product can be easily
shaped by extrusion, injection-molding, blow-molding or compression-molding,
but it is also the most challenging. Issues of self-aggregation and thermal
degradation are usually identified as the main challenges, but different strategies
have been proposed to limit these phenomena. Nevertheless, the mechanical
properties of ensuing materials are always disappointing and far from the
expectations if compared with percolated nanoparticles. It mainly results from
the orientation of the nanoparticles but also from their inevitable coating (to avoid
self-aggregation upon drying), which alters or limits access to surface hydroxyl
groups, and prevents a H-bonded percolated structure. The new challenge
probably consists of restoring this percolating network after shaping of the
product.
References
1.
2.
3.
Sain, M.; Oksman, K. In Cellulose Nanocomposites, Sain, M.; Oksman, K.,
Ed.; ACS Symposium Series 938, American Chemical Society: Washington,
DC, 2006; pp 2−8.
Dufresne, A. Nanocellulose - From Nature to High Performance Tailored
Materials; Walter de Gruyter GmbH: Berlin/Boston, 2012.
Miller, J. Nanocellulose, State of the Industry, 2015.
http://
www.tappinano.org/media/1114/cellulose-nanomaterials-production-stateof-the-industry-dec-2015.pdf (accessed March 17, 2017).
218
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
4.
5.
6.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
Oksman, K.; Sain, M. Cellulose Nanocomposites; ACS Symposium Series
938, American Chemical Society: Washington, DC, 2006.
Lavoine, N.; Desloges, I.; Dufresne, A.; Bras, J. Microfibrillated cellulose
- Its barrier properties and applications in cellulosic materials: A review.
Carbohydr. Polym. 2012, 90, 735–764.
Saito, T.; Nishiyama, Y.; Putaux, J.-L.; Vignon, M.; Isogai, A. Homogeneous
suspensions of individualized microfibrils from TEMPO-catalyzed oxidation
of native cellulose. Biomacromolecules 2006, 7, 1687–1691.
Henriksson, M.; Henriksson, G.; Berglund, L. A.; Lindström, T. An
environmentally friendly method for enzyme-assisted preparation of
microfibrillated cellulose (MFC) nanofibers. Eur. Polym. J. 2007, 43,
3434–3441.
Mariano, M.; El Kissi, N.; Dufresne, A. Cellulose nanocrystals and related
nanocomposites: review of some properties and challenges. J. Polym. Sci.,
Part B: Polym. Phys. 2014, 52, 791–806.
Shuai, L.; Amiri, M. T.; Questell-santiago, Y. M.; Héroguel, F.; Li, Y.;
Kim, H.; Meilan, R.; Chapple, C.; Ralph, J.; Luterbacher, J. S. Formaldehyde
stabilization facilitates lignin monomer production during biomass
depolymerization. Science 2016, 354, 329–333.
Bras, J.; Viet, D.; Bruzzese, C.; Dufresne, A. Correlation between stiffness
of sheets prepared from cellulose whiskers and nanoparticles dimensions.
Carbohydr. Polym. 2011, 84, 211–215.
Khoshkava, V.; Kamal, M. R. Effect of surface energy on dispersion and
mechanical properties of polymer/ nanocrystalline cellulose nanocomposites.
Biomacromolecules 2013, 14, 3155–3163.
Lin, N.; Dufresne, A. Nanocellulose in biomedicine: current status and future
prospect. Eur. Polym. J. 2014, 59, 302–325.
Lin, N.; Dufresne, A. Surface chemistry, morphological analysis and
properties of cellulose nanocrystals with gradiented sulfation degrees.
Nanoscale 2014, 6, 5384–5393.
Bandera, D.; Sapkota, J.; Josset, S.; Weder, C.; Tingaut, P.; Gao, X.; Foster, E.
J.; Zimmermann, T. Influence of mechanical treatments on the properties of
cellulose nanofibers isolated from microcrystalline cellulose. React. Funct.
Polym. 2014, 85, 134–141.
Mariano, M.; Cercená, R.; Soldi, V. Thermal characterization of cellulose
nanocrystals isolated from sisal fibers using acid hydrolysis. Ind. Crops
Prod. 2016, 94, 454–462.
Roman, M.; Winter, W. T. Effect of sulfate groups from sulfuric acid
hydrolysis on the thermal degradation behavior of bacterial cellulose.
Biomacromolecules 2004, 5, 1671–1677.
Kovalenko, V. I. Crystalline cellulose: structure and hydrogen bonds. Russ.
Chem. Rev. 2010, 79, 231–241.
Kim, N.-H.; Imai, T.; Wada, M.; Sugiyama, J. Molecular directionality in
cellulose polymorphs. Biomacromolecules 2006, 7, 274–280.
Hirota, M.; Tamura, N.; Saito, T.; Isogai, A. Water dispersion of cellulose
II nanocrystals prepared by TEMPO-mediated oxidation of mercerized
cellulose at pH 4.8. Cellulose 2009, 17, 279–288.
219
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
20. Flauzino Neto, W. P.; Putaux, J.-L.; Mariano, M.; Ogawa, Y.; Otaguro, H.;
Pasquini, D.; Dufresne, A. Comprehensive morphological and structural
investigation of cellulose I and II nanocrystals prepared by sulphuric acid
hydrolysis. RSC Adv. 2016, 6, 76017–76027.
21. Nge, T. T.; Lee, S.-H.; Endo, T. Preparation of nanoscale cellulose
materials with different morphologies by mechanical treatments and their
characterization. Cellulose 2013, 20, 1841–1852.
22. Saini, S.; Sillard, C.; Belgacem, M. N.; Bras, J. Nisin anchored cellulose
nanofibers for long term antimicrobial active food packaging. RSC Adv.
2016, 6, 12422–12430.
23. Siqueira, G.; Abdillahi, H.; Bras, J.; Dufresne, A. High reinforcing capability
cellulose nanocrystals extracted from Syngonanthus nitens (Capim Dourado).
Cellulose 2010, 17, 289–298.
24. Sacui, I. A.; Nieuwendaal, R. C.; Burnett, D. J.; Stranick, S. J.; Jor, M.;
Weder, C.; Foster, E. J; Olsson, R. T.; Gilman, W. Comparison of the
properties of cellulose nanocrystals and cellulose nanofibrils isolated from
bacteria, tunicate, and wood processed using acid, enzymatic, mechanical,
and oidative methods. ACS Appl. Mater. Interfaces 2014, 6, 6127–6138.
25. Juntaro, J.; Ummartyotin, S.; Sain, M.; Manuspiya, H. Bacterial cellulose
reinforced polyurethane-based resin nanocomposite: A study of how ethanol
and processing pressure affect physical, mechanical and dielectric properties.
Carbohydr. Polym. 2012, 87, 2464–2469.
26. Li, M.-C.; Wu, Q.; Song, K.; Lee, S.; Qing, Y.; Wu, Y. Cellulose
nanoparticles:
structure-morphology-rheology relationships.
ACS
Sustainable Chem. Eng. 2015, 3, 821–832.
27. Li, M.-C.; Wu, Q.; Song, K.; Qing, Y.; Wu, Y. Cellulose nanoparticles as
modifiers for rheology and fluid loss in bentonite water-based fluids. ACS
Appl. Mater. Interfaces 2015, 7, 5006–5016.
28. Nechyporchuk, O.; Belgacem, M. N.; Pignon, F. Rheological properties of
micro-/nanofibrillated cellulose suspensions: Wall-slip and shear banding
phenomena. Carbohydr. Polym. 2014, 112, 432–439.
29. Zhao, J.; Zhang, W.; Zhang, X.; Zhang, X.; Lu, C.; Deng, Y. Extraction
of cellulose nanofibrils from dry softwood pulp using high shear
homogenization. Carbohydr. Polym. 2013, 97, 695–702.
30. Agoda-Tandjawa, G.; Durand, S.; Berot, S.; Blassel, C.; Gaillard, C.;
Garnier, C.; Doublier, J.-L. Rheological characterization of microfibrillated
cellulose suspensions after freezing. Carbohydr. Polym. 2010, 80, 677–686.
31. Zhang, P. P.; Tong, D. S.; Lin, C. X.; Yang, H. M.; Zhong, Z. K.; Yu, W.
H.; Wang, H. Effects of acid treatments on bamboo cellulose nanocrystals.
Asia-Pac. J. Chem. Eng. 2014, 9, 686–695.
32. Hirai, A.; Inui, O.; Horii, F.; Tsuji, M. Phase separation behavior in aqueous
suspensions of bacterial cellulose nanocrystals prepared by sulfuric acid
treatment. Langmuir 2009, 25, 497–502.
33. Yue, Y.; Zhou, C.; French, A. D.; Xia, G.; Han, G.; Wang, Q.; Wu, Q.
Comparative properties of cellulose nano-crystals from native and
mercerized cotton fibers. Cellulose 2012, 19, 1173–1187.
220
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
34. Kargarzadeh, H.; Ahmad, I.; Abdullah, I.; Dufresne, A.; Zainudin, S.
Y.; Sheltami, R. M. Effects of hydrolysis conditions on the morphology,
crystallinity, and thermal stability of cellulose nanocrystals extracted from
kenaf bast fibers. Cellulose 2012, 19, 855–866.
35. Cheng, M.; Qin, Z.; Liu, Y.; Qin, Y.; Li, T.; Chen, L.; Zhu, M. Efficient
extraction of carboxylated spherical cellulose nanocrystals with narrow
distribution through hydrolysis of lyocell fibers by using ammonium
persulfate as an oxidant. J. Mater. Chem. A 2014, 2, 251–258.
36. Novo, L. P.; Bras, J.; Garcia, A.; Belgacem, M. N.; Curvelo, A. A. S.
Subcritical water: a method for green production of cellulose nanocrystals.
ACS Sustainable Chem. Eng. 2015, 3, 2839–2846.
37. Peresin, M. S.; Habibi, Y.; Zoppe, J. O.; Pawlak, J. J.; Rojas, O. J. Nanofiber
composites of polyvinyl alcohol and cellulose nanocrystals: manufacture and
characterization. Biomacromolecules 2010, 11, 674–681.
38. Kolpak, F. J.; Blackwell, J.; Litt, M. H. Morphology of cellulose regenerated
from hydrazine solution. J. Polym. Sci. Polym. Lett. Ed. 1977, 15, 655–658.
39. Rusli, R.; Shanmuganathan, K.; Rowan, S. J.; Weder, C.; Eichhorn, S. J.
Stress transfer in cellulose nanowhisker composites - Influence of whisker
aspect ratio and surface charge. Biomacromolecules 2011, 12, 1363–1369.
40. Oksman, K.; Aitomäki, Y.; Mathew, A. P.; Siqueira, G.; Zhou, Q.;
Butylina, S.; Tanpichai, S.; Zhou, X.; Hooshmand, S. Review of the recent
developments in cellulose nanocomposite processing. Composites, Part A
2015, 83, 2–18.
41. Reid, S. M.; Villalobos, M.; Cranston, E. D. Cellulose nanocrystal
interactions probed by thin film swelling to predict dispersibility. Nanoscale
2016, 8, 12247–12257.
42. Araki, J. Electrostatic or steric? - preparations and characterizations of
well-dispersed systems containing rod-like nanowhiskers of crystalline
polysaccharides. Soft Matter 2013, 9, 4125–4141.
43. Moon, R. J.; Martini, A.; Nairn, J.; Simonsen, J.; Youngblood, J. Cellulose
nanomaterials review: structure, properties and nanocomposites. Chem. Soc.
Rev. 2011, 40, 3941–3994.
44. Lemahieu, L.; Bras, J.; Tiquet, P.; Augier, S.; Dufresne, A. Extrusion of
nanocellulose-reinforced nanocomposites using the dispersed nano-objects
protective encapsulation (DOPE) process. Macromol. Mater. Eng. 2011,
296, 984–991.
45. Quiévy, N.; Jacquet, N.; Sclavons, M.; Deroanne, C.; Paquot, M.; Devaux, J.
Influence of homogenization and drying on the thermal stability of
microfibrillated cellulose. Polym. Degrad. Stab. 2010, 95, 306–314.
46. Favier, V.; Chanzy, H.; Cavaillé, J.-Y. Polymer Nanocomposites Reinforced
by Cellulose Whiskers. Macromolecules 1995, 28, 6365–6367.
47. Favier, V.; Canova, G. R.; Shrivastava, S. C.; Cavaillé, J.-Y. Mechanical
percolation in cellulose whisker nanocomposites. Polym. Eng. Sci. 1997,
37, 1732–1739.
48. Favier, V.; Canova, G. R.; Cavaillé, J.-Y.; Chanzy, H.; Dufresne, A.;
Gauthier, C. Nanocomposite materials from latex and cellulose whiskers.
Polym. Adv. Technol. 1995, 6, 351–355.
221
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
49. Rippel, M. M.; Galembeck, F. Nanostructures and Adhesion in Natural
Rubber: New Era for a Classic. J. Braz. Chem. Soc. 2009, 20, 1024–1030.
50. Dufresne, A. In Rubber Nanocomposites: Preparation, Properties and
Applications; Thomas, S.; Stephem, R., Eds.; John Wiley & Sons (Asia) Pte
Ltd., 2010; pp 113−144.
51. Flauzino Neto, W. P.; Mariano, M.; Da Silva, I. S. V.; Silvério, H. A.;
Putaux, J.-L.; Otaguro, H.; Pasquini, D.; Dufresne, A. Mechanical properties
of natural rubber nanocomposites reinforced with high aspect ratio cellulose
nanocrystals isolated from soy hulls. Carbohydr. Polym. 2016, 153,
143–152.
52. Bras, J.; Hassan, M. L.; Bruzesse, C.; Hassan, E. A.; El-Wakil, N. A.;
Dufresne, A. Mechanical, barrier, and biodegradability properties of bagasse
cellulose whiskers reinforced natural rubber nanocomposites. Ind. Crops
Prod. 2010, 32, 627–633.
53. Trifol, J.; Plackett, D.; Sillard, C.; Hassager, O.; Daugaard, A. E.;
Bras, J.; Szabo, P. A comparison of partially acetylated nanocellulose,
nanocrystalline cellulose, and nanoclay as fillers for high-performance
polylactide nanocomposites. J. Appl. Polym. Sci. 2016, 133, 43257.
54. Mariano, M.; El Kissi, N.; Dufresne, A. Melt processing of cellulose
nanocrystal reinforced polycarbonate from a masterbatch process. Eur.
Polym. J. 2015, 69, 208–223.
55. Gousse, C.; Chanzy, H.; Excoffier, G.; Soubeyrand, L.; Fleury, E. Stable
suspensions of partially silylated cellulose whiskers dispersed in organic
solvents. Polymer 2002, 43, 2645–2651.
56. Xu, W.; Qin, Z.; Yu, H.; Liu, Y.; Liu, N.; Zhou, Z.; Chen, L. Cellulose
nanocrystals as organic nanofillers for transparent polycarbonate films. J.
Nanoparticle Res. 2013, 15, 1562.
57. Capadona, J. R.; Van den Berg, O.; Capadona, L. A..; Schroeter, M.;
Rowan, S. J.; Tyler, D. J.; Weder, C. A versatile approach for the processing
of polymer nanocomposites with self-assembled nanofibre templates. Nat.
Nanotechnol. 2007, 2, 765–769.
58. Annamalai, P. K.; Dagnon, K. L.; Monemian, S.; Foster, E. J.; Rowan, S.
J.; Weder, C. Water-responsive mechanically adaptive nanocomposites based
on styrene–Butadiene rubber and cellulose nanocrystals - processing matters.
ACS Appl. Mater. Interfaces 2014, 6, 967–976.
59. Yang, J.; Zhang, X.-M.; Xu, F. Design of cellulose nanocrystals templateassisted composite hydrogels: insights from static to dynamic alignment.
Macromolecules 2015, 48, 1231–1239.
60. Wu, C.-N.; Saito, T.; Fujisawa, S.; Fukuzumi, H.; Isogai, A. ultrastrong and
high gas-barrier nanocellulose/clay-layered composites. Biomacromolecules
2012, 13, 1927–1932.
61. Shariki, S.; Liew, S. Y.; Thielemans, W.; Walsh, D. A.; Cummings, C. Y.;
Rassaei, L.; Wasbrough, M. J.; Edler, K. J.; Bonné, M. J.; Marken, F. Tuning
percolation speed in layer-by-layer assembled polyaniline–nanocellulose
composite films. J. Solid State Electrochem. 2010, 15, 2675–2681.
62. Cranston, E. D.; Eita, M.; Johansson, E.; Netrval, J.; Salajkov, M.; Arwin, H.;
Wågberg, L. Determination of Young’s modulus for nanofibrillated cellulose
222
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
63.
64.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
multilayer thin films using buckling mechanics. Biomacromolecules 2011,
12, 961–969.
Cranston, E. D.; Gray, D. G.; Rutland, M. W. Direct surface force
measurements of polyelectrolyte multilayer films containing nanocrystalline
cellulose. Langmuir 2010, 26, 17190–17197.
Muller, D.; Silva, J. P.; Rambo, C. R.; Barra, G. M. O.; Dourado, F.; Gama, F.
M. Neuronal cells’ behavior on polypyrrole coated bacterial nanocellulose
three-dimensional (3D) scaffolds. J. Biomater. Sci. Polym. Ed. 2013, 24,
1368–1377.
Costa, L. M. M.; de Olyveira, G. M.; Cherian, B. M.; Leão, A. L.;
de Souza, S. F.; Ferreira, M. Bionanocomposites from electrospun
PVA/pineapple nanofibers/Stryphnodendron adstringens bark extract for
medical applications. Ind. Crops Prod. 2013, 41, 198–202.
Gabr, M. H.; Phong, N. T.; Okubo, K.; Uzawa, K.; Kimpara, I.; Fujii, T.
Thermal and mechanical properties of electrospun nano-celullose reinforced
epoxy nanocomposites. Polym. Test. 2014, 37, 51–58.
Thunberg, J.; Kalogeropoulos, T.; Kuzmenko, V.; Hägg, D.; Johannesson, S.;
Westman, G.; Gatenholm, P. In situ synthesis of conductive polypyrrole
on electrospun cellulose nanofibers: scaffold for neural tissue engineering.
Cellulose 2015, 22, 1459–1467.
Müller, D.; Cercená, R.; Gutiérrez Aguayo, A. J.; Porto, L. M.; Rambo, C.
R.; Barra, G. M. O. Flexible PEDOT-nanocellulose composites produced by
in situ oxidative polymerization for passive components in frequency filters.
J. Mater. Sci. Mater. Electron. 2016, 27, 8062–8067.
Raquez, J.-M.; Murena, Y.; Goffin, A.-L.; Habibi, Y.; Ruelle, B.; DeBuyl, F.;
Dubois, P. Surface-modification of cellulose nanowhiskers and their use
as nanoreinforcers into polylactide: A sustainably-integrated approach.
Compos. Sci. Technol. 2012, 72, 544–549.
Reis, M. O.; Zanela, J.; Olivato, J.; Garcia, P. S.; Yamashita, F.;
Grossmann, M. V. E. Microcrystalline cellulose as reinforcement in
thermoplastic starch/poly(butylene adipate-co-terephthalate) films.
J.
Polym. Environ. 2014, 22, 545–552.
de Menezes, A. J.; Siqueira, G.; Curvelo, A. A. S.; Dufresne, A. Extrusion
and characterization of functionalized cellulose whiskers reinforced
polyethylene nanocomposites. Polymer 2009, 50, 4552–4563.
Oliveira Taipina, M.; Ferrarezi, M. M. F.; Yoshida, I. V. P.; Gonçalves, M. D.
C. Surface modification of cotton nanocrystals with a silane agent. Cellulose
2013, 20, 217–226.
Siqueira, G.; Bras, J.; Dufresne, A. New pprocess of chemical grafting of
cellulose nanoparticles with a long chain isocyanate. Langmuir 2010, 26,
402–411.
Nagalakshmaiah, M.; El Kissi, N.; Dufresne, A. Ionic compatibilization
of cellulose nanocrystals with quaternary ammonium salt and their melt
extrusion with polypropylene. ACS Appl. Mater. Interfaces 2016, 8,
8755–8764.
223
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
75. Trovatti, E.; Carvalho, A. J. F.; Ribeiro, S. J. L.; Gandini, A. Simple green
approach to reinforce natural rubber with bacterial cellulose nanofibers.
Biomacromolecules 2013, 14, 2667–2674.
76. Corrêa, A. C.; Morais Teixeira, E.; Carmona, V. B.; Teodoro, K. B. R.;
Ribeiro, C.; Mattoso, L. H. C.; Marconcini, J. M. Obtaining nanocomposites
of polyamide 6 and cellulose whiskers via extrusion and injection molding.
Cellulose 2014, 21, 311–322.
77. Nicharat, A.; Sapkota, J.; Weder, C.; Foster, E. J. Melt processing of
polyamide 12 and cellulose nanocrystals nanocomposites. J. Appl. Polym.
Sci. 2016, 132, 42752.
78. Nagalakshmaiah, M.; Pignon, F.; El Kissi, N.; Dufresne, A. Surface
adsorption of triblock copolymer (PEO–PPO–PEO) on cellulose
nanocrystals and their melt extrusion with polyethylene. RSC Adv. 2016, 6,
66224–66232.
79. Mariano, M.; El Kissi, N.; Dufresne, A. Structural reorganization of CNC in
injection-molded CNC/PBAT materials under thermal annealing. Langmuir
2016, 32, 10093–10103.
80. Alloin, F.; d’Aprea, A.; Dufresne, A.; El Kissi, N.; Bossard, F.
Poly(oxyethylene) and ramie whiskers based nanocomposites: Influence of
processing: extrusion and casting/evaporation. Cellulose 2011, 18, 957–973.
81. Sapkota, J.; Kumar, S.; Weder, C.; Foster, E. J. Influence of processing
conditions on properties of poly (vinyl acetate)/cellulose nanocrystal
nanocomposites. Macromol. Mater. Eng. 2015, 300, 562–571.
82. Camarero-Espinosa, S.; Boday, D. J.; Weder, C.; Foster, E. J. Cellulose
nanocrystal driven crystallization of poly(D,L-lactide) and improvement of
the thermomechanical properties. J. Appl. Polym. Sci. 2015, 132, 41607.
83. Vestena, M.; Gross, I. P.; Pires, A. T. N. Nanocomposite of poly(lactic acid)/
cellulose nanocrystals: Effect of CNC content on the polymer crystallization
kinetics. J. Braz. Chem. Soc. 2016, 27, 905–911.
84. Pei, A.; Zhou, Q.; Berglund, L. A. Functionalized cellulose nanocrystals as
biobased nucleation agents in poly(L-lactide) (PLLA) - crystallization and
mechanical property effects. Compos. Sci. Technol. 2010, 70, 815–821.
85. Gray, D. G. Transcrystallization of polypropylene at cellulose nanocrystal
surfaces. Cellulose 2007, 15, 297–301.
86. Li, F.; Biagioni, P.; Finazzi, M.; Tavazzi, S.; Piergiovanni, L. Tunable green
oxygen barrier through layer-by-layer self-assembly of chitosan and cellulose
nanocrystals. Carbohydr. Polym. 2013, 92, 2128–2134.
87. Kumar, S.; Hofmann, M.; Steinmann, B.; Foster, E. J.; Weder, C.
Reinforcement of stereolithographic resins for rapid prototyping with
cellulose nanocrystals. ACS Appl. Mater. Interfaces 2012, 4, 5399–5407.
88. Zoppe, J. O.; Peresin, M. S.; Habibi, Y.; Venditti, R. A.; Rojas, O. J.
Reinforcing poly(ε-caprolactone) nanofibers with cellulose nanocrystals.
ACS Appl. Mater. Interfaces 2009, 1, 1996–2004.
89. Chen, G.; Liu, H. Electrospun cellulose nanofiber reinforced soybean protein
isolate composite film. J. Appl. Polym. Sci. 2008, 110, 641–646.
224
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Downloaded by CITY UNIV OF HONG KONG on October 25, 2017 | http://pubs.acs.org
Publication Date (Web): October 23, 2017 | doi: 10.1021/bk-2017-1251.ch011
90. Abdulkhani, A.; Hosseinzadeh, J.; Ashori, A.; Dadashi, S.; Takzare, Z.
Preparation and characterization of modified cellulose nanofibers reinforced
polylactic acid nanocomposite. Polym. Test. 2014, 35, 73–79.
91. Santos, T. M.; Souza Filho, M. D. S. M.; Caceres, C. A.; Rosa, M. F.;
Morais, J. P. S.; Pinto, A. M. B.; Azeredo, H. M. C. Fish gelatin films as
affected by cellulose whiskers and sonication. Food Hydrocoll. 2014, 41,
113–118.
92. da Silva, J. B. A.; Pereira, F. V.; Druzian, J. I. Cassava starch-based films
plasticized with sucrose and inverted sugar and reinforced with cellulose
nanocrystals. J. Food Sci. 2012, 77, N14–N19.
93. Espino-Pérez, E.; Bras, J.; Ducruet, V.; Guinault, A; Dufresne, A.;
Domenek, S. Influence of chemical surface modification of cellulose
nanowhiskers on thermal, mechanical, and barrier properties of poly(lactide)
based bionanocomposites. Eur. Polym. J. 2013, 49, 3144–3154.
94. Liu, H.; Liu, D.; Yao, F.; Wu, Q. Fabrication and properties of transparent
polymethylmethacrylate/cellulose nanocrystals composites.
Bioresour.
Technol. 2010, 101, 5685–5692.
95. Fortunati, E.; Puglia, D.; Luzi, F.; Santulli, C.; Kenny, J. M.; Torre, L. Binary
PVA bio-nanocomposites containing cellulose nanocrystals extracted from
different natural sources: Part I. Carbohydr. Polym. 2013, 97, 825–836.
96. Ma, Q.; Hu, D.; Wang, L. Preparation and physical properties of tara gum
film reinforced with cellulose nanocrystals. Int. J. Biol. Macromol. 2016,
86, 606–612.
97. El Miri, N.; Abdelouahdi, K.; Barakat, A.; Zahouily, M.; Fihri, A.;
Solhy, A.; El Achaby, M. Bio-nanocomposite films reinforced with cellulose
nanocrystals: Rheology of film-forming solutions, transparency, water
vapor barrier and tensile properties of films. Carbohydr. Polym. 2015, 129,
156–167.
98. Bardet, R.; Reverdy, C.; Belgacem, N.; Leirset, I.; Syverud, K.; Bardet, M.;
Bras, J. Substitution of nanoclay in high gas barrier films of cellulose
nanofibrils with cellulose nanocrystals and thermal treatment. Cellulose
2015, 22, 1227–1241.
99. Herrera, N.; Mathew, A. P.; Oksman, K. Plasticized polylactic acid/cellulose
nanocomposites prepared using melt-extrusion and liquid feeding:
Mechanical, thermal and optical properties. Compos. Sci. Technol. 2015,
106, 149–155.
100. Arrieta, M. P.; Fortunati, E.; Dominici, F.; López, J.; Kenny, J. M.
Bionanocomposite films based on plasticized PLA–PHB/cellulose
nanocrystal blends. Carbohydr. Polym. 2015, 121, 265–275.
101. Mariano, M.; Chirat, C.; El Kissi, N.; Dufresne, A. Impact of cellulose
nanocrystal aspect ratio on crystallization and reinforcement of poly(butylene
adipate-co-terephthalate). J. Polym. Sci., Part B: Polym. Phys. 2016, 54,
2284–2297.
102. Gupta, A.; Simmons, W.; Schueneman, G. T.; Mintz, E. A. Lignin-coated
cellulose nanocrystals as promising nucleating agent for poly(lactic acid). J.
Therm. Anal. Calorim. 2016, 126, 1243–1251.
225
Agarwal et al.; Nanocelluloses: Their Preparation, Properties, and Applications
ACS Symposium Series; American Chemical Society: Washington, DC, 2017.
Документ
Категория
Без категории
Просмотров
14
Размер файла
592 Кб
Теги
1251, 2017, ch011
1/--страниц
Пожаловаться на содержимое документа