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Rubber modification of unsaturated polyester resin with core–shell rubber particles: Effect of shell composition
Author(s) -
Ahmadi M.,
Moghbeli M. R.,
Shokrieh M. M.
Publication year - 2012
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.23154
Subject(s) - materials science , natural rubber , composite material , polyester , scanning electron microscope , elastomer , butyl acrylate , particle (ecology) , methyl methacrylate , methacrylate , izod impact strength test , ultimate tensile strength , copolymer , polymer , oceanography , geology
Poly(butyl acrylate)/poly(vinyl acetate‐ co ‐methyl methacrylate) PBA/P(VAc‐ co ‐MMA) core–shell rubber particles with various shell compositions, i.e., VAc/MMA weight ratios, were used to toughen unsaturated polyester. The morphology and surface‐free energy of the rubber particles were determined by transmission electron microscopy (TEM) and contact angle measurements, respectively. The effect of shell structure on the dispersion state of rubber particles inside the unsaturated polyester resin was studied by scanning electron microscopy and TEM. Increasing MMA units in the shell changed the particle dispersion state from small agglomerates or globally well‐dispersed particles to large aggregates in the cured‐resin matrix. For the blends that contain 5 wt% rubber, the highest un‐notched impact toughness, stress‐intensity factor ( K IC ), and fracture energy ( G IC ) were observed for the blend containing PVAc shell particles. The results showed that by increasing the particle level from 5 to 10 wt%, the highest K IC and G IC values were obtained for the blend containing rubber particles with VAc/MMA (80/20 wt/wt) copolymer shell. The crack‐tip damage zone in the neat and rubber‐modified unsaturated polyester resins was observed by means of transmission optical microscopy. In addition, using PVAc shell particles exhibited a minimum reduction in the volume shrinkage and tensile properties of the rubber‐modified resin. POLYM. ENG. SCI., 52:1928–1937, 2012. © 2012 Society of Plastics Engineers