Importance of film morphology on the performance of thermo-responsive waterborne pressure sensitive adhesives

• Published in: European polymer journal Vol. 98; pp. 63 - 71
• Main Authors: Mehravar, Ehsan, Gross, Michael A., Agirre, Amaia, Reck, Bernd, Leiza, Jose R., Asua, José M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-01-2018; Elsevier BV
• Subjects: Adhesive properties; Adhesives; Blend; Core-shell; Crystal structure; Crystallinity; Emulsion polymerization; Mechanical properties; Miniemulsion polymerization; Morphology; Pressure sensitive adhesives; Temperature-responsive behavior; Temperature-responsive behavior; Blend; Miniemulsion polymerization; Mechanical properties; Crystallinity; Adhesive properties; Pressure-sensitive adhesives; Core-shell
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2017.11.004

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•Semicrystalline hard core-soft shell pressure sensitive adhesives (PSAs) were synthesized by miniemulsion polymerization.•Performance of core-shell PSAs was compared with other PSAs prepared by blending soft and hard latexes.•Better adhesive and mechanical properties were observed for the blend adhesives.•Crystalline domains provided strong temperature-responsiveness to the blend adhesives.•Differences in performance of core-shell and blend PSAs were attributed to the differences in film morphologies.
Temperature responsive pressure sensitive adhesives (PSAs) are of interests in many applications due to the possibility of removing strong adhesives by moderate heating. In this work, semicrystalline poly(octadecyl acrylate) obtained by miniemulsion polymerization is used as a key component of the thermal responsiveness. Comparison of the adhesive performance of crystalline hard core-soft shell PSAs with other PSAs of the same overall composition and similar molar mass distributions but prepared by blending soft and hard latexes shows that the arrangement of the phases in the film play a key role in performance of the PSAs. Good adhesive performance and thermal responsiveness is only achieved when the crystalline domains are dispersed in a continuous soft phase containing entangled nanogels. Interestingly, this morphology is achieved with blends, but no with core-shell dispersions. The reasons for this difference are investigated.