Influence of Particle Nucleation in Pressure Sensitive Adhesive Properties: Miniemulsion versus Emulsion Polymerization

• Published in: Macromolecular symposia Vol. 271; no. 1; pp. 83 - 93
• Main Authors: Fonseca, Gabriela E, McKenna, Timothy F, Dubé, Marc A
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Weinheim Wiley-VCH Verlag 01.09.2008; WILEY-VCH Verlag; WILEY‐VCH Verlag; WILEY
• Subjects: 2-ethyl hexyl acrylate; Applied sciences; Concentration (composition); Copolymerization; Droplets; Emulsion polymerization; Exact sciences and technology; methyl methacrylate; miniemulsion polymerization; Nucleation; Organic polymers; Peel strength; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; pressure sensitive adhesives; Shear strength; Sol gel process; Ionomer; Terpolymer; Acrylic acid copolymer; Adhesivity; Thiol; Alkyl acrylate copolymer; Radical terpolymerization; Oil water emulsion; Non ionic surfactant; Experimental study; Methyl methacrylate copolymer; Property processing relationship; Anionic surfactant; Tack; Chain transfer; Surface properties; Radical copolymerization; Comparative study; Pressure sensitive adhesive
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/masy.200851109

Miniemulsion polymerization is a promising approach to produce and tailor pressure sensitive adhesives (PSAs). In this paper, a systematic comparison of the adhesive properties of latexes produced by miniemulsion and conventional emulsion polymerization is presented. Specifically, the influence of the total surfactant concentration, chain transfer agent concentration and chemical composition on the final adhesive properties of the polymer 2-ethyl hexyl acrylate/methyl methacrylate/acrylic acid was discerned using a 2³ factorial design for each polymerization method. In addition to the adhesive properties (i.e., loop tack, peel strength and shear strength), molecular weight distribution, particle size distribution (PSD) and glass transition temperature were analyzed. The results show that under the conditions used in this work, it is possible to produce PSAs using miniemulsion polymerization, a process wherein monomer droplet nucleation is the dominant particle nucleation mechanism. The use of a miniemulsion polymerization process, as opposed to the conventional emulsion technique, produced several differences such as larger particles sizes and narrower molecular weight distributions. Focusing on the PSA films that exhibited adhesive rather than cohesive failure, the PSA films generated via miniemulsion polymerization displayed higher values of loop tack and peel strength compared to those produced via conventional emulsion polymerization. Shear strength results were strongly dependent on the amount of gel content and sol molecular weight for both cases.