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Polybutadiene/polystyrene interpenetrating polymer networks
Author(s) -
Curtius A. J.,
Covitch M. J.,
Thomas D. A.,
Sperling L. H.
Publication year - 1972
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.760120205
Subject(s) - polybutadiene , materials science , polystyrene , polymer , polymer science , composite material , expanded polystyrene , polymer chemistry , copolymer
Interpenetrating polymer networks (IPN's) of polybutadiene (PB) and polystyrene (PS) were prepared using both random (containing 36% cis, 55% trans, and 9% 1,2 vinyl) PB and high‐cis PB. For both series, a wide range of PB/PS compositions were synthesized. Using samples stained with osmium tetroxide, electron microscope studies revealed an irregular cellular structure of a few hundred Ångstrom diameter with the first component, PB, making up the cell walls. The size of the cells was found to depend on the PB crosslink density for the random materials. Modulus‐temperature data revealed two distinct glass transitions, confirming the microscopy finding of two phases. However, the transition temperature and transition slope varied with composition, and with the microstructure of the polybutadiene, giving evidence of significant molecular mixing. Stress‐strain data on the IPN's showed that materials rich in PB behave like self‐reinforced elastomers. Charpy impact resistance experiments on materials rich in PS indicated values of 5 ft‐lb/in. of notch, which compares well with graft‐type polyblends of similar PB/PS composition. The results were interpreted in the light of the recent theoretical work of Bragaw, who considered the importance of the distances between domain boundaries with respect to crack acceleration mechanics. Although the IPN's considered herein exhibited somewhat less than the predicted optimum phase dimensions, the arrangement of the domains is different from ordinary impact resistant plastics.