WHOLLY-AROMATIC COPOLYESTERS CONTAINING IPA, 2.6-NDA, TPA, CLHQA AND PABA MONOMERS

The crystallinities, thermal properties, liquid crystal properties and rheologic properties of two series of the aromatic copolyesters are studied. One of them is composed of IPA, 2,6-NDA, CLHQA, PABA and. the other composed of TPA, 2.6-NDA, CLHQA, IPA. The results show that the crystallinities of the aromatic copolyesters are relatively low and the melting point of the copolyesters decreases with an increase of the unsymmetrical contents. These two series of aro- matic copolyesters are both suitable for the conventional melt spinning process and have a good fiber forming property and a good thermal stability. The viscosities of aromatic copolyester melts are greatly affected by the shear rate, hence the so-called" thinning under shearing" phe- nomenon. The melts have a rather high viscosity flow activation energy and a relatively low elasticity.