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Morphology and physical properties of poly(butylene terephthalate)
Author(s) -
Chang EngPi,
Slagowski Eugene L.
Publication year - 1978
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/app.1978.070220315
Subject(s) - materials science , glass transition , composite material , amorphous solid , nucleation , scanning electron microscope , relaxation (psychology) , dynamic mechanical analysis , glass fiber , fracture (geology) , modulus , polymer , crystallography , thermodynamics , chemistry , psychology , social psychology , physics
Liquid nitrogen‐quenched PBT samples produce much larger spherulites of an optic axis orientation different from the of the air‐cooled samples. Optical and scanning electron microscopy show that glass fibers in the glass‐reinforced PBT sample nucleate the growth of well‐defined spherulites along the glass fiber axis. Fracture studies at temperatures below and above the T g indicate, respectively, brittle and ductile interspherulite boundary fracture. From dynamic mechanical studies, three transitions designated by α (flow transition), β ( T g ), and γ (secondary relaxation) are observed. The magnitudes of the β and γ transitions are larger for the more amorphous quenched sample than the air‐cooled sample, suggesting their amorphous phase origin. Addition of glass fibers raises the dynamic modulus and flow temperature, but suppresses the γ transition without significantly affecting the melting and glass transition temperatures.