Synthesis of soluble poly(vinylene carbonate) by redox-initiated RAFT process in microemulsion and its aminolysis yielding snow-white polymethylol

Abstract

The radical polymerization of vinylene carbonate (VCB) above 40 C yields lightly colored and partially soluble polymers by common procedures. Herein, we describe a redox-initiated room temperature micro-emulsion process for the living polymerization of a VCB yielding polymer, which is entirely soluble in DMF, in the presence of a RAFT agent. Despite the polymerization following first order kinetics, the molecular weight-time plot exhibited a sudden rise at the beginning; however, a slow but linear increment was noticed after that, which is typical for a RAFT polymerization in a micro-emulsion. This procedure yielded entirely soluble polymers and the gel permeation chromatograms (GPC) implied an almost constant polydispersity index (PDI: 1.2) within 20-88% conversion range. The process was determined to be living as demonstrated by a chain extension with styrene, yielding a diblock copolymer with nearly double molecular weight. The livingness of the process was confirmed by synthesizing a chain extension of the polymer with styrene using a photo-iniferter technique. Nearly double molecular weight of the resulting polymer within 24 h of irradiation implied the formation of vinylene carbonatestyrene block copolymers. It was demonstrated that the VCB homopolymer readily dissolves in ammonia solution (25%) at room temperature and a snow-white precipitate of the aminolysis product, polymethylol, is observed within a few minutes. Polymethylol is known to be insoluble in common solvents, including water, due to the intermolecular hydrogen bridging. Surprisingly, the polymer was determined to dissolve in 80% phosphoric acid to give optically clear solutions, which were stable for over one week at room temperature. 1 H NMR spectrum of this polymer in D 3 PO 4 indicated a pure polymethylol structure.

On the photopolymerization of mevalonic lactone methacrylate: exposing the potential of an overlooked monomer

“…Controlled radical polymerization is very useful when low dispersities and/or block copolymer formation are required. [32][33][34] In this part, we employ a dithiobenzoate RAFT agent for the synthesis of PMevL as described in the Experimental section. Unlike the free-radical photopolymerization, the RAFTmediated/controlled analogue (RPMevL) was terminated in 10 hours (instead of 16 hours) and after purification resulted in a pale pink colored powder, which indicates the presence of RAFT end-groups on the resulting polymer chains (still dormant polymer chain).…”

“…Controlled radical polymerization is very useful when low dispersities and/or block copolymer formation are required. [32][33][34] In this part, we employ a dithiobenzoate RAFT agent for the…”

Cryo‐3D Printing of Hierarchically Porous Polyhydroxymethylene Scaffolds for Hard Tissue Regeneration

“…Pioneered by Newman and Addor during the 1950s, high molecular weight PHM (see Figure ) is readily available by the free radical polymerization of vinylene carbonate (VCA) followed by the hydrolysis of the resulting polyvinylene carbonate (PVCA). [ 39–45 ]…”

“…Since PHM resembles polysaccharides, it is expected to be biocompatible and holds promise regarding its medical applications. [ 45,46 ] Particularly, PHM exhibits high hydrophilicity due to the high number of hydroxyl groups, which could have a beneficial effect on cell cultivation, as the polymer can be assumed to have good wettability with aqueous cell culture solutions. Albeit PHM is insoluble in water, water functions as a PHM plasticizer lowering the glass temperature of dry PHM from 134 to 39 °C.…”

“…Pioneered by Newman and Addor during the 1950s, high molecular weight PHM (see Figure 1) is readily available by the free radical polymerization of vinylene carbonate (VCA) followed by the hydrolysis of the resulting polyvinylene carbonate (PVCA). [39][40][41][42][43][44][45] Since PHM resembles polysaccharides, it is expected to be biocompatible and holds promise regarding its medical applications. [45,46] Particularly, PHM exhibits high hydrophilicity due to the high number of hydroxyl groups, which could have a beneficial effect on cell cultivation, as the polymer can be assumed to have good wettability with aqueous cell culture solutions.…”