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Development of a New Type of Polyamide.

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through the U O P Olex-Pacol process or the Phillips’
metathetic process, the above route to alcohols is worthy
of interest.
Lecture at Frankfurt on June 3,1971
Development of a New Type of Polyamide
By Gerhard Bier‘*’
Until recently only purely aliphatic polyamides, such as
perlon, nylon 6,6, nylon 11, etc., have been produced for
thermoplastic processing techniques. Completely aromatic polyamides like polymetaphenyleneisophthalamide
(raw material of NOMEX fibers) or aliphatic-aromatic
polyamides like that formed from hexamethylenediamine
and terephthalic acid (m. p. 370 “C) cannot be processed
thermoplastically in practice.
Preliminary work by R. Gabler was taken up at Dynamit
Nobel and a polyamide was subsequently synthesized from
a branched-chain aliphatic hexamethylenediamine and
terephthalic acid and tested for possible applications. The
polyamide (which has been given the trade name TROGAMID T@)is amorphous and has a glass transition temperature of about 150°C. It can readily be processed by thermoplastic techniques. The influence of the aromatic component, of the methyl side chain, and of the carboxamide
group on crystallinity and glass transition temperature was
studied in detail with the aid of model compounds. It was
found, inter alia, that for a constant formula weight the
positions of the carboxamide groups have a considerable
effect on the glass transition temperature. In spite of the
amorphous nature of the polymer a high degree of structural order must exist for almost all the carboxamide groups
are linked by hydrogen bonds. Above the glass transition
temperature the number of NH groups not participating
in hydrogen bonding rapidly increases.
TROGAMID T@ischaracterized by a high tensile strength
and dimensional stability as well as resistance to tracking
currents, resistance to attack by chemical reagents, resistance to cracking when subjected to a pulsating compression and by transparency. These properties, in conjunction
with the low shrinkage in processing, make TROGAMID
T@suitable for uses in the automobile industry and for
electronics and electrical engineering, filter manufacture,
the dairy industry, watch- and clockmaking, production
of umbrellas, and measurement and control engineering.
Examples include shock absorber pistons, switch knobs,
casings for high performance switchgear, caps for ends of
cables, transparent filter units, parts for milking machines,
filter cups, watch glasses, umbrella frames, and flowmeters
for gases and liquids.
Lecture at Stuttgart on November 11, 1971 [VB 325 IE]
German version. Angew Chem 84,69 (1972)
Dr. G. Bier
Dynamit Nobel A G
521 Troisdorf (Germany)
Angew. Chem. internat. Edit. 1 Vol. I 1 (1972) 1 No. 1
BY Watther Burchnrd“’
[VB 321 IE]
German version : Angew. Chem. 84,37 (1972)
[*I
New Aspects of the Structure of Randomly Branched
Macromolecules
In contrast to unbranched chain molecules little is known
about the structure of randomly branched macromolecules.
The reason may be seen in the difficulties resulting from the
large width of the molecular weight distributions ( M , / M ,
ca. 100-150) and the extreme variety of isomeric structures.
The current practice of approximating the physical properties by results obtained for fixed structures (star and
comb polymers) holds out of relatively little promise because these structures are probably not representative of
the randomly branched chain molecules.
The difficulties can be largely overcome by two techniques
novel to polymer science:
1) Branched molecules can be regarded as “trees”. After
choice of an arbitrary chain element as root, the resulting
tree exhibits practically all the characteristics of a family
tree which can be unequivocally divided up into different
generations. From this results a clear system of ordering
and numbering.
2) Methods common in the statistical treatment of population growth processes (demographic methods) can be
applied to these “trees”. Particular mention should be made
in this context of the generating functions which have
properties similar to a Fourier transformation of a probability distribution. The advance in the treatment of randomly branched structures results essentially from two
properties of generating functions:
a) Straightforward differentiation of the generating functions with respect to the auxiliary variable yields physically
meaningful average values that are accessible to measurement and cover both molecular-weight and isomer distributions.
b) The generating functions can be boxed into one another
in the form o f a cascade (lst, 2nd, 3rd ... generation); structures of trees are thereby reproduced which are characteristic of the branched molecules.
In this way it was possible to calculate for a number of
branching types the weight- and number-average molecular weights as well as the z-averages of the mean square
radius of gyration and of the particle scattering factor for
light scattering. The linear chain is always included in the
cascade process as a limiting case. Details were given of
measurements on alternating copolymers of decamethylene
glycol and benzene-1,3,5-triacetic acid as well as of measurements on star molecules having glycogen as nucleus.
Lecture at Marl o n November 3, 1971 [VB 324 IE]
German version: Angew. Chem. 84,69 (1972)
[*] Doz.Dr. W. Burchard
Institut fur makromoiekulare Chemle der Universitat
78 Freiburg, Stefan-Meier-Strasse 31 (Germany)
63
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