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A comparative study of semi‐2 and full interpenetrating polymer networks based on poly( n ‐butyl acrylate)/polystyrene
Author(s) -
Widmaier J. M.,
Sperling L. H.
Publication year - 1982
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/app.1982.070270927
Subject(s) - polystyrene , miscibility , materials science , acrylate , interpenetrating polymer network , polymer chemistry , photopolymer , divinylbenzene , polymer , acrylic acid , phase (matter) , copolymer , swelling , chemical engineering , composite material , chemistry , monomer , organic chemistry , styrene , engineering
Sequential poly( n ‐butyl acrylate)/polystyrene (PnBA/PS) semi‐2 and full IPN's of various compositions were made by UV photopolymerization. Acrylic acid anhydride and divinylbenzene were used as labile and permanent crosslinkers, respectively, for the rubbery phase and the plastic phase. After IPN formation, network I was selectively decrosslinked. After extracton of polymer I, the remaining PS network II was characterized by swelling measurements and examined by scanning electron microscopy. It was found that crosslinked PnBA affects the formation of the second network more than uncrosslinked PnBA does. A porous phase formed by an aggregate of spherical polystyrene domains was observed. The experimental domain diameter was in good agreement with previous theoretical values. The dynamic mechanical properties of full IPN's, decrosslinked IPN's, and semi‐2 IPN's were also studied. A significant level of molecular mixing was found for full IPN's of midrange compositions. The major difference between the full IPN's and the decrosslinked IPN's is that the glass transitions of the respective polymers become more pronounced in the latter case, with a deeper valley between them. With the destruction of the crosslink sites, there is no longer a forced miscibility of the interlocked phases, which are, in fact, thermodynamically incompatible.