The Mechanical Properties of Epoxy Composites Filled with Rubbery Copolymer Grafted SiO2

Polymers

Jianing Gao¹  Junting Li³  Brian C. Benicewicz³  Su Zhao²  Henrik Hillborg² 

[1] Department of Materials Science & Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA;ABB Corporate Research, Forskargränd 7, 72226 Västerås, Sweden;Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA;

关键词: toughened epoxy;    rubbery interlayer;    nanocomposites;    RAFT polymerization;   

DOI  :  10.3390/polym4010187

来源: mdpi

【 摘 要 】

This study demonstrated a method for toughening a highly crosslinked anhydride cured DGEBA epoxy using rubbery block copolymer grafted SiO₂ nanoparticles. The particles were synthesized by a sequential reversible addition-fragmentation chain transfer (RAFT) polymerization. The inner rubbery block poly(n-hexyl methacrylate) (PHMA) had a glass transition temperature below room temperature. The outer block poly(glycidyl methacrylate) (PGMA) was matrix compatible. A rubbery interlayer thickness of 100% and 200% of the particle core radius was achieved by grafting a 20 kg/mol and a 40 kg/mol PHMA at a graft density of 0.7 chains/nm² from the SiO₂ surface. The 20 kg/mol rubbery interlayer transferred load more efficiently to the SiO₂ cores than the 40 kg/mol rubbery interlayer and maintained the epoxy modulus up to a loading of 10 vol% of the rubbery interlayer. Both systems enabled cavitation or plastic dilatation. Improvement of the strain-to-break and the tensile toughness was found in both systems. We hypothesize that plastic void growth in the matrix is the primary mechanism causing the improvement of the ductility.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.