Increased Onset Temperature of Expansion in Thermally Expandable Microspheres from Combination of Crosslinking Agents
2011 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 121, no 1, 369-375 p.Article in journal (Refereed) Published
Free-radical suspension polymerization was used to synthesize thermally expandable microspheres (TEMS) in which a poly(acrylonitrile-co-methacrylonitrile) shell encapsulates isooctane. TEMS were prepared with 1,4-butanediol dimethacrylate (BDDMA), in combination with 1,4-butanediol divinyl ether (BDDVE), diallyl carbonate (DAC), or allyl methacrylate, as crosslinkers. It was found that a significant increase in the onset temperature of expansion (T-start) could be obtained when a combination of BDDMA and BDDVE or DAC was used, compared to when only BDDMA was used as crosslinker. The expansion capacity of the TEMS was excellent when BDDMA and DAC were combined. One benefit of the increased T-start was demonstrated when poly(vinyl chloride)-plastisols containing TEMS could be cured at higher temperatures without premature expansion. The differences in expansion obtained with different combinations of crosslinkers originate from the difference in reactivity of the vinyl-functionalities of the crosslinkers, which regulate the incorporation of the crosslinker into the polymer and thereby, the mechanical properties of the microsphere shell.
Place, publisher, year, edition, pages
2011. Vol. 121, no 1, 369-375 p.
core-shell polymers, blowing agents, crosslinking, radical polymerization
IdentifiersURN: urn:nbn:se:kth:diva-11980DOI: 10.1002/app.33585ISI: 000289353700045ScopusID: 2-s2.0-79953705069OAI: oai:DiVA.org:kth-11980DiVA: diva2:291746
FunderSwedish Research Council, 2003-4573Swedish Research Council, 2004-605
QC 20110211 Uppdaterad från Submitted till Published 201105092010-02-032010-02-032011-05-09Bibliographically approved