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Studies on a terephthalic acid and dihydroxydiphenyl sulfone liquid crystalline copolymer and its composites with different thermoplastics
Author(s) -
Khan Khurram A.,
Kahraman Ramazan,
Hamad Esam Z.,
Ali Shaikh A.,
Hamid Syed H.
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970425)64:4<645::aid-app3>3.0.co;2-n
Subject(s) - materials science , composite material , differential scanning calorimetry , ultimate tensile strength , compression molding , copolymer , thermoplastic , polystyrene , polymer , scanning electron microscope , polycarbonate , glass transition , terephthaloyl chloride , phase (matter) , condensation polymer , thermotropic crystal , polymer chemistry , liquid crystalline , chemistry , mold , physics , organic chemistry , thermodynamics
A liquid crystalline polymer (LCP) was synthesized by an interfacial polycondensation reaction at room temperature from terephthaloyl chloride and p,p ′‐dihydroxydiphenyl sulfone. The LCP synthesized was so stable and molecularly rigid that it did not show any phase transition until it degraded at about 320°C. Composites of the LCP with polycarbonate (PC), polystyrene (PS), and sulfonated polystyrene (SPS) were formed by compression molding at a temperature at which the thermoplastic matrix was in the melt state. They were thermally analyzed by differential scanning calorimetry. Tensile specimens were cut from the compression‐molded plates, and mechanical tests were performed. The morphology of the material systems was studied by performing scanning electron microscopy analysis on cryogenically fractured specimens. For LCP/PS and LCP/SPS systems, a sharp two‐phase morphology was formed, which suggested poor interfacial adhesion. The tensile strength of both systems decreased with LCP addition. The LCP/PC system also revealed a two‐phase morphology; however, the interfaces between the LCP domains and the PC matrix were not so well defined, showing better interfacial adhesion than the two previous systems studied. Stronger bonding between the LCP and PC resulted in a significant improvement in the mechanical behavior of PC by LCP addition. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 645–652, 1997