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Modification of porous suspension‐PVC particles by stabilizer‐free aqueous dispersion polymerization of absorbed acrylate monomers
Author(s) -
ShachCaplan M.,
Narkis M.,
Silverstein M. S.
Publication year - 2002
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.166
Subject(s) - materials science , polymerization , monomer , acrylate , chemical engineering , polymer chemistry , dispersion polymerization , polymer , suspension polymerization , butyl acrylate , dynamic mechanical analysis , particle (ecology) , composite material , oceanography , engineering , geology
The present study describes modification of porous PVC particles by polymerization of a monomer/crosslinker/peroxide solution absorbed within the PVC particles. The modifying crosslinked polymers include butyl acrylate (BA) crosslinked with ethylene glycol dimethacrylate (EGDMA) and ethylhexyl acrylate (EHA) crosslinked with EGDMA. The monomer solution is blended with the PVC particles by dry‐blending. The monomer absorbed particles are then polymerized in a stabilizer‐free aqueous dispersion‐polymerization. The modified semi‐IPN PVC particles have better stability than the neat PVC particles in packed columns for absorption of halo‐organics from water, etc. The modified semi‐IPN PVC particles are melt processable and thus have the potential of being interesting and useful modified rigid PVC materials. The modified PVC particles characterization includes polymerization yield, non‐extractables and porosity measurements and also morphology and dynamic mechanical behavior (DMTA). PBA and PEHA polymerization has shown high yield levels. The high conversion of BA and EHA within the particle, is partly due to their low solubility in water. The levels of non‐extractable fractions found are indicative of low chemical interaction between the polyacrylate/PVC phases in the particle. The modified PVC particle's porosity levels indicate that BA and EHA partly polymerize within the PVC particles' bulk and partly in the pores as crusts covering the PVC pore surfaces. This finding is supported by SEM observations of unetched and etched freeze fractured surfaces. Higher crosslinking levels of the polyacrylate modification promote compatibility with the PVC particles' bulk. DMTA measurements show two loss modulus peaks for the 0.5%EGDMA blends in the glass transition temperature region, suggesting imcompatibility. However, at 5%EGDMA a single transition is found exhibiting enhanced compatibility owing to the high degree of crosslinking, which prevents phase separation. Copyright © 2002 John Wiley & Sons, Ltd.