Copolymers with hyperbranched architecture
The copolymers were synthesised using a free radical polymerisation (strathclyde method) in emulsion technique. Divinyl benzene was used as brancher which acted as comonomer and 1-dodecanethiol was used as chain terminating agent. A linear copolymer from methyl methacrylate and butyl acrylate was also synthesised for comparison.
Lower viscosity at equivalent solid content
The hyperbranched architecture was established from spectroscopic and rheological measurements. The gel permeation chromatography showed all hyperbranched copolymers were low molecular weight with lower polydispersity index (PDI) compared to the linear grade. They were more spherical and achieved lower viscosity (yet higher solubility, >90%) than the linear grade (<50%) which was mostly open ended. Lower viscosity at equivalent solid content made the hyperbranched polymers a potential binder for adhesive and coatings applications.
The study is published in: Journal of Applied Polymer Science, Volume 134, Issue 42, November 5, 2017