ISSN:
0098-1273
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Oriented fibers of poly(pentamethylene terephthalate) will crystallize in one of two phases. In one phase (designated α), which is preferred in the unstressed fiber at room temperature, the chain is contracted from its chemical repeat length. In the other (designated β), induced by tension, it is nearly fully extended. The structural analysis of both forms is described. The unit cells of both phases are triclinic. The parameters of the α phase are a = 4.7 Å, b = 5.8 Å, c = 24.7 Å, α = 112°, β = 94°, γ = 105°. For the β phase they are a = 5.0 Å, b = 5.8 Å, c = 28.2 Å, α = 126°, β = 74°, γ = 120°. The methylene sequence is all trans in the β phase but, surprisingly, in the α phase, three of its bonds are near the eclipsed conformation. The other surprising feature is the departure from planarity of one of the terephthaloyl residues in the β phase. These, and other features of the structures are compared with those of other chemically similar materials, both monomeric and polymeric.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1978.180161208
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