ISSN:
1042-7147
Keywords:
Thermotropic
;
Relaxations
;
Coefficient of linear thermal expansion
;
Tensile modulus
;
Orientation
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
A molecular laminate model is used to explain the properties of unoriented and oriented films of poly(p-phenylene-2,5-didodecyloxyterephthalate) cast from solution. In oriented films the two different crystal modifications, A and B, give rise to room temperature tensile moduli of 15 and 30 GPa respectively. The packing (in clusters) of the side chains in modification A, leading to a glass-like transition in the side-chain regions around -40°C, is largely responsible for this difference. Oriented films of modification A and B have coefficients of thermal expansion of +0.3×10-5 and -1× 10-5 K-1 respectively. It is concluded that the properties of this class of polymers can be adjusted in a systematic way.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pat.1994.220050928
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