Flow birefringence and flexibility of the molecules of copolymers of para- and meta-aromatic polyamides

✍ Scribed by V.N. Tsvetkov; N.V. Pogodina; L.V. Starchenko

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 565 KB
• Volume: 17
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(81)90144-0

✦ Synopsis

Flow birefringence (FB) of solutions of poly-p-phenyleneterephthalamide (PpPhTPhA!, polym-phenyleneisophthalamide (PmPhIPhA) and 13 of their copolymers, with various compositions, has been investigated. The number S of monomer units in a Kuhn segment was determined for all samples from the experimental values of the shear optical coefficient An/At. Molecular models for homo-and copolymers were considered. On the basis of these models, an equation expressing the dependence of the chain flexibility parameter I/S on copolymer composition Z was derived. Good agreement between the experimental dependence of I,S on Z and the theoretical value confirms the additivity of the structural and deformation mechanisms of flexibility in polymer chains.

A characteristic feature of aromatic polyamides is a sharp difference in the equilibrium rigidity of their molecules depending on the type (para [1,2] or meta [3]) of phenyl rings into the polymer chain. (m molar parts) and terephthalic dichloroanhydridc CIOC --~ COCI (n-m molar parts). Thus. copolynlers of the type "EHN ~-NHOC ~ CO]'~-HN @ NHOC ~ CO -]-n-m