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Improved toughness in HIPS obtained from different styrene/butadiene‐graded block copolymers through modification of the polydispersity index of the PS block
Author(s) -
Morales Graciela,
Díaz de León Ramón,
Acuña Pablo,
Flores Flores Rodolfo,
Montalvo Robles Antonio
Publication year - 2006
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20591
Subject(s) - materials science , copolymer , dispersity , polybutadiene , polystyrene , natural rubber , composite material , volume fraction , styrene , polymer chemistry , particle size , styrene butadiene , polymerization , phase (matter) , polymer , chemical engineering , chemistry , organic chemistry , engineering
The polymerization of styrene in the presence of graded block copolymers with a polystyrene/polybutadiene composition of 40/60, 30/70, and 20/80 and with a polydispersity index ( M w / M n ) in the polystyrene block varying from 1.1 to 1.6 was studied. As the polydispersity index of the polystyrene block increases, an improvement of up to 50% in the Izod impact toughness of the produced high‐impact polystyrene was achieved. The rubber particle morphology type, the size, and the volume fraction of the rubber phase particles could be modified through changes in the composition of the graded block copolymer. The changes that occurred in the rubber phase were mainly generated by the variation in the interfacial tension between the phases, and this variation was principally attributed to an increase in the polydispersity index of the polystyrene block in the precursor copolymer. POLYM. ENG. SCI., 46:1333–1341, 2006. © 2006 Society of Plastics Engineers