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Core–shell particles to toughen epoxy resins. I. Preparation and characterization of core–shell particles
Author(s) -
Lin KingFu,
Shieh YeowDer
Publication year - 1998
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19980906)69:10<2069::aid-app18>3.0.co;2-x
Subject(s) - materials science , glycidyl methacrylate , ethylene glycol dimethacrylate , emulsion polymerization , polymer chemistry , epoxy , methacrylate , polymerization , glass transition , composite material , methyl methacrylate , butyl acrylate , particle size , shell (structure) , chemical engineering , methacrylic acid , polymer , engineering
A two‐stage, multistep soapless emulsion polymerization was employed to prepare various sizes of reactive core–shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA) copolymerizing with various concentrations of glycidyl methacrylate (GMA) as the shell. Ethylene glycol dimethacrylate (EGDMA) was used to crosslink either the core or shell. The number of epoxy groups in a particle of the prepared CSP measured by chemical titration was close to the calculated value based on the assumption that the added GMA participated in the entire polymerization unless it was higher than 29 mol %. Similar results were also found for their solid‐state 13C ‐NMR spectroscopy. The MMA/GMA copolymerized and EGDMA‐crosslinked shell of the CSP had a maximum glass transition temperature ( T g ) of 140°C, which was decreased with the content of GMA at a rate of −1°C/mol %. However, the shell without crosslinking had a maximum T g of 127°C, which decreased at a rate of −0.83°C/mol %. The T g of the interphasial region between the core and shell was 65°C, which was invariant with the design variables. The T g of the BA core was −43°C, but it could be increased to −35°C by crosslinking with EGDMA. The T g values of the core and shell were also invariant with the size of the CSP. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2069–2078, 1998