Influence of Crosslinking on the Characteristics of Thermally Expandable Microspheres Expanding at High Temperature
2010 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 118, no 2, 1219-1229 p.Article in journal (Refereed) Published
Free-radical suspension polymerization was used to synthesize thermally expandable microspheres (TEMS); in this process, a poly(acrylonitrile-co-methacrylonitrile) shell encapsulated isooctane. Different amounts of dimethacrylate, diacrylate, or divinyl ether functional crosslinker were added to investigate the effects on the crosslinking density of the polymer and the expansion properties of the TEMS. The optimum amount of crosslinker was found to be approximately 0.05-0.1 mol %. However, a significantly better expansion could be obtained with 1,4-butanediol dimethacrylate as a crosslinker, compared to 1,4-butanediol divinyl ether or 1,4-butanediol diacrylate. From monitoring the conversion of monofunctional analogues by gas chromatography, we suggest that the differences in expansion obtained with different crosslinkers, originated from the difference in the reactivity of the radicals in the system toward the vinyl functionalities of the crosslinkers. This regulated the incorporation of the crosslinker into the polymer and, thereby, the mechanical properties of the microsphere shell.
Place, publisher, year, edition, pages
2010. Vol. 118, no 2, 1219-1229 p.
blowing agents, core-shell polymers, crosslinking, radical polymerization
IdentifiersURN: urn:nbn:se:kth:diva-11979DOI: 10.1002/app.32301ISI: 000280748400069ScopusID: 2-s2.0-77956246293OAI: oai:DiVA.org:kth-11979DiVA: diva2:291732
QC 20101022. Uppdaterad från Submitted till Published (20101022).2010-02-032010-02-032010-10-22Bibliographically approved