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Syndiotactic polystyrene‐ b ‐atactic polypropylene block copolymer alloy as a compatibilizer for syndiotactic polystyrene/isotactic polypropylene blends
Author(s) -
Chen Rui,
Wu Qing,
Zhu Fangming,
Lin Shangan
Publication year - 2003
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.12334
Subject(s) - tacticity , materials science , polystyrene , copolymer , polypropylene , polymer chemistry , composite material , polymer blend , polymerization , polymer
A polymeric alloy (SP–A) containing syndiotactic polystyrene (sPS), atactic polypropylene (aPP), and about 66 wt % sPS‐ b ‐aPP diblock copolymer, was prepared by the sequential feed of monomers in the presence of the half‐titanocene Cp*Ti(OBz) 3 (where Cp* is C 5 Me 5 and Bz is PhCH 2 ), modified methylaluminoxane, and external triisobutylaluminum. The effects of the SP–A alloy as a compatibilizer for sPS and isotactic polypropylene (iPP) blends were evaluated. The blending of sPS and iPP, with and without SP–A, was performed in a single‐screw miniextruder with a side channel that allowed the continuous recycling of materials. The influence of SP–A on the mechanical and thermal properties of the immiscible sPS/iPP blends was investigated over a range of composition. The presence of the SP–A alloy resulted in a significant improvement of the impact strength of the blends compared with that of pure sPS and their pure blends. This improvement was particularly obvious in the sPS/iPP (90/10 wt %) blend containing 5 wt % SP–A. Morphological analysis of the impact‐fractured surface of the ternary blends indicated that the sPS‐ b ‐aPP diblock copolymer contained in the SP–A alloy acted as an efficient compatibilizer by decreasing the dispersed‐phase iPP particle size, improving the interfacial adhesion, and generating a stable microphase‐separated state. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1596–1605, 2003