Experimental determination of the elastic modulus of crystalline regions of some aromatic polyamides, aromatic polyesters, and aromatic polyether ketone

Abstract

The elastic modulus El of the crystalline regions parallel to the chain axis was measured by X-ray diffraction for aromatic polyamides, i.e., Kevlar 49, 29, HM-50, aromatic polyesters, i.e., Ekonol, Vectran, and aromatic polyether ketone, i.e., poly(ether ether ketone) (PEEK). The values of El for these polymers were obtained as follows; El (Kevlar 49, 29)=156 GPa, El (Ekonol)=130 GPa, El (Vectran)=126 GPa, and El (PEEK)=71 GPa. Except for PEEK, El of these polymer are very high and the ratio of the specimen modulus (Yl) to El is close to unity. These El values were discussed from molecular structure and conformation in the crystalline regions. The molecular structure and conformation which are required for high modulus and high strength polymers were discussed from the value of El. © 1987 The Society of Polymer Science, Japan. All rights reserved.