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Effect of syndiotactic polystyrene on the crystallization behavior of isotactic polypropylene/syndiotactic polystyrene blends with and without β ‐nucleating agent
Author(s) -
Zhang Ronghua,
Li Robert Kwok Yiu
Publication year - 2013
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.4378
Subject(s) - tacticity , polystyrene , nucleation , crystallization , materials science , polypropylene , polymer chemistry , polyamide , polymer blend , chemical engineering , composite material , polymer , polymerization , chemistry , organic chemistry , copolymer , engineering
Blends of isotactic polypropylene ( PP ) and syndiotactic polystyrene ( sPS ) with and without β ‐nucleating agent were prepared using a twin‐screw extruder at 290 °C. Blends of PP / sPS with β ‐nucleating agent mainly show β crystalline form, irrespective of high (20 °C min −1 ) or low (2 °C min −1 ) previous cooling rates. This suggests that the cooling rates have little effect on the polymorphic composition of PP in PP / sPS blends. The effect of sPS on the crystallization of PP is compared with that of polyamide 6 ( PA6 ). The increase in crystallization temperature of PP is smaller in the presence of sPS than in the presence of PA6 ; the fold surface free energy of PP / sPS is larger than that of PP / PA6 blends. These results reveal that compared with PA6 , sPS has much weaker α ‐nucleation effect on the crystallization of PP . The weak α ‐nucleation effect of sPS is attributed to the high lattice mismatch between PP and sPS crystals.