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

Abstract

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.

Incorporating Hydrophobic Cellulose Nanocrystals inside Latex Particles via Mini‐Emulsion Polymerization

“…Fonseca et al. [ 18,60 ] showed that PSAs from MEP and CEP have different microstructure, and therefore different viscoelastic properties. They found that MEP resulted in lower molecular weight (MW) polymer due to the lower polymer concentration, on average, in the polymerizing particles.…”

“…They found that MEP resulted in lower molecular weight (MW) polymer due to the lower polymer concentration, on average, in the polymerizing particles. [ 60 ] PSAs produced via MEP showed superior tack and peel strength, which was attributed to their higher entanglement density, i.e., the ratio of polymer molecular weight divided by the entanglement molecular weight ( M w / M e ). [ 18 ] Our results similarly showed higher tack and peel strength for PSAs synthesized via MEP compared to CEP at 0 wt% CNC loading (Figure 5A,B).…”

Synthesis of high‐solid‐content, acrylic pressure‐sensitive adhesives by solvent polymerization

“…Some investigations have been carried out to study the influence of the CTA and the polymer molecular characteristics on the adhesion performance of the resulting PSAs . For example, Ravindra et al .…”

In situsynthesis and properties of hydrogenated rosin/polyacrylate composite miniemulsions-based pressure sensitive adhesives

“…In situ synthesis and properties of hydrogenated rosin/polyacrylate composite miniemulsions-based pressure sensitive adhesives 1…”

“…[1][2][3][4] However, some technical problems still need to be solved with further effort, for example, the usage of the surfactant and the monomer containing carboxyl groups lead to the latex films' low resistance to water, the adhesion properties of polyacrylate emulsions especially for the nonpolar materials such as polyolefin are relatively poor. [5][6][7] Therefore, the application of the polyacrylate emulsions is restrained at a certain degree.…”