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Model-filled polymers. II. Stability of polystyrene beads in a polystyrene matrix

✍ Scribed by K. Gandhi; M. Park; L. Sun; D. Zou; C. X. Li; Y. D. Lee; J. J. Aklonis; R. Salovey

Book ID
105338307
Publisher
John Wiley and Sons
Year
1990
Tongue
English
Weight
466 KB
Volume
28
Category
Article
ISSN
0887-6266

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✦ Synopsis

Abstract

Thermomechanical degradation, as a result of mixing at 175°C during the preparation of polystyrene composites containing monodisperse (0.45μm) crosslinked polystyrene beads, often leads to a uniform decrease in rheological properties on increasing the concentration or on reducing the crosslink density of the beads. The extent of such degradation depends on the molecular weight of polystyrene and on the crosslink density of the polystyrene beads. Scission fragments from decomposed beads may induce free radical degradation of the polystyrene matrix. Degradation during mixing of the beads and the matrix is suppressed by mixing crosslinked beads in a polystyrene solution, and removing the solvent, or by melt mixing after adding 0.2% BHT. Polystyrene beads and composites show thermally induced weight loss on heating above 330°C in nitrogen or above 250°C in air. Networks of increased crosslink density are of enhanced thermal stability on heating in the absence of shear.

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