Effect of morphology on mechanical and rheological properties of butyl acrylate–methyl methacrylate multiphase polymers

Abstract

SYNOPSISPolymers of butyl acrylate-methyl methacrylate with different morphologies were synthesized by emulsion polymerization. Four types of polymers were obtained copolymer, coreshell, three layer, and a core-shell with a copolymer layer of variable composition (gradient). The effect of the morphologies on the mechanical and rheological properties of these polymers was studied. It was found that when the same overall composition was used the properties of the polymer can be varied from those of rigid plastic to those of an elastomeric material. It was also found that increasing the content of butyl acrylate (BA) improves the mechanical properties and the presence of a copolymer zone improves the impact resistance of the material.

Effect of the MMA content on the emulsion polymerization process and adhesive properties of poly(BA‐co‐MMA‐co‐AA) latexes

“…Emulsion acrylic copolymers have enjoyed the fastest growth and the biggest share of the PSA market in commercial applications 2, 3. Among acrylic polymers making for PSAs, long‐alkyl acrylates, such as poly( n ‐butyl acrylate), poly(BA),4–15 and poly(2‐ethyl hexyl acrylate), poly(2‐EHA)2, 4, 15–21 are generally used. However, because these kinds of acrylic PSAs comprise polymers that have high entanglement molecular weight ( M e ) values,22 low glass‐transition temperature ( T g ) values, and medium to low molecular weights, this may present a problem in PSA label converting and high temperature printing, and some types of crosslinking must be provided to yield shear holding power 15, 22–26.…”

“…To achieve this purpose, a PSA is usually a copolymer of an inherently tacky polymer (used to provide adhesion) with a higher T g polymer used to increase modulus. Copolymerization of acrylic ester with other monomers, such as methyl methacrylate (MMA),2, 7, 9–14, 16–21 styrene (St),1, 6, 29 and vinyl acetate (VAc)4, 8 is used to vary the chemical and physical properties of the adhesives. However, the increase in polymer modulus by the inclusion of higher T g polymer is often at the expense of the essential adhesion properties.…”

“…In the past work, the shear resistance of poly( n ‐butyl acrylate) was low,30 even incorporation of inorganic filler, silica,31 and chain transfer agent, CTA in the compositions 5, 32, 33. It is well‐known that the copolymerization of BA with MMA will increase the glass transition temperature, and enhance the shear resistance of acrylic polymers 7, 9–14, 34. In spite of their commercial importance, less work has been dedicated to systematically synthesize the controlled composition and structure for the copolymerization of BA with different MMA contents by semicontinuous emulsion polymerization and influence of the composition on the adhesive properties of PSAs 9, 11, 14, 35–37.…”