One-Step Synthesis of Thermally Curable Hyperbranched Polymers by Addition–Fragmentation Chain Transfer Using Divinyl Monomers

Abstract

Free radical bulk and solution polymerizations of a divinyl monomer, ethylene glycol dimethacrylate (EGDMA), in the presence of methyl 2-(bromomethyl)acrylate as an addition–fragmentation chain transfer agent were investigated to synthesize thermally curable hyperbranched polymers by a one-step reaction. Soluble polymers were obtained up to high conversion of EGDMA, and the molecular weight and molecular weight distribution of the polymers increased with increasing EGDMA conversion. 1H NMR and MALDI-MS analyses revealed that the soluble polymers were obtained after the consumption of a considerable amount of the pendant methacryloyl groups, and one polymer chain contained a number of end groups indicating the formation of hyperbranched polymers. The isolated hyperbranched polymers underwent thermal curing above 110 °C without curing agents, and the polymers having a large number of pendant methacryloyl groups resulted in a significant increase in glass transition temperature, i.e., from around room temperature to above 210 °C.

Photocuring of Radically Polymerizable Hyperbranched Polymers Having Degradable Linkages

“…The products were purified by reprecipitation in hexane and the precipitates were dried under vacuum for 24 h in the ice bath. The formation of hyperbranched polymer was confirmed by combined analysis of 1 H NMR and GPC as described in our previous report [6]. at 117 ºC for 24 h, 30 mg) was dissolved in the 5 mL of tetrahydrofuran (THF) solution containing Bu 3 P (56 mmol/L) as a reductant and the mixture was stirred at room temperature for 6 h. The GPC elution curve of the reaction mixture is shown in Fig.…”

“…We recently reported the one-pot synthesis of the hyperbranched polymers by radical homopolymerization of divinyl monomers in the presence of an addition-fragmentation chain transfer (AFCT) agent [6].…”

Synthesis of hyperbranched polymers and their applications in analytical chemistry

“…In addition, Wu and co-workers 5 reported the synthesis of a new series of hyperbranched polytriazoles containing perfluoroaromatic rings by click chemistry under copper catalysis. 51 By virtue of its great feasibility, the CuAAC reaction has proven effective for various material construction applications, involving small molecules, 10 linear polymers, HBPs, and other nanoscale or macroscopic materials. The resulting products have been widely applied in different areas.…”

“…[59][60][61] The thiol−ene click reaction has been used industrially since the 1970s, but has recently been used to prepare many types of dendrimers and hyperbranched polymers because of the rapid, robust, and efficient nature of the reaction. [62][63][64] For instance, Ramakrishnan and co-workers reported a novel route for the synthesis of peripherally "clickable" hyperbranched 10 polyethers by click reaction. 65 The method was based on selfcondensation of a specifically designed AB 2 -type monomer, bearing two propargylbenzyl ether groups and one hydroxyl group, and yielded a hyperbranched polyether bearing numerous peripheral allyl groups.…”

“…Besides, the applications of HBPs in analytical chemistry fields such as sample pretreatment and immunosensors are also briefly summarized. 10 …”