Removal of Trithiocarbonyl End Group of RAFT-Polymerized Poly(stearyl acrylate) and Effect of the End Group on Thermal and Structural Properties

Abstract

The effect of a long alkyl end group on the thermal and structural properties of RAFT (reversible addition-fragmentation chain transfer)-polymerized poly(stearyl acrylate) (PSA) was investigated. RAFT-polymerized PSA was prepared using 2-cyano-2-[(dodecylsulfanylthiocarbonyl) sulfanyl] propane (CDTP) with long alkyl group as a chain transfer agent and azobisisobutyronitrile (AIBN) as an initiator. The RAFT polymerization resulted in the polymerized structure having trithiocarbonyl (TTC) at one end and isobutyronitrile at the other end. RAFT-polymerized PSA was prepared with two different molecular weights. The TTC end group was replaced by isobutyronitrile using radical reaction with AIBN through optimization of the conditions, which resulted in isobutyronitrile at both ends. The effect of the end group on the thermal and structural properties was investigated using differential scanning calorimetry and X-ray diffraction, and the results indicated that the long alkyl group from TTC lowers the melting point and semi-crystalline structure in the case of low molecular weight PSA.

Comprehensive studies of continuous flow reversible addition–fragmentation chain transfer copolymerization and its application for photoimaging materials

“…Therefore, the copolymer was subjected to terminal group removal by the reaction with an excess of the thermal radical generator, that is AIBN. [76][77][78][79] The extent of the modification reaction was traced through UV/ vis absorption spectroscopy (Fig. S19 †), 80,81 and the typical degree of removal was higher than 0.98 without any significant side reactions such as chain coupling (Fig.…”

Direct Measurement of Polymer-Chain-End-to-End Distances by Using RAFT Chain Transfer Agent as the FRET Acceptor

“…The relationship between the FRET efficiency and polymer DP was included in the insets of Figure A,B, showing that increasing the DP results in a lower FRET efficiency. To further confirm that the quenching of An fluorescence emission is due to the presence of dithiobenzoate end-group, the CTA moiety was removed from a PMMA sample (molecular weight: 4100 Da) using a radical-based method. , The disappearance of the absorption peak signal between 440 and 600 nm in UV–vis spectroscopy confirmed the successful removal of the dithiobenzoate (Figure S7). Subsequently, fluorescence measurement of An-functionalized PMMA was performed for samples with the absence of CTA (after the removal of RAFT end-group), showing a nearly complete recovery (∼98%) of the An emission intensity in Figure S8.…”

Materiomically Designed Polymeric Vehicles for Nucleic Acids: Quo Vadis?

“…For ATRP, the advent of ARGET ATRP , and iron-based ATRP alleviates the challenge of copper removal. For RAFT, a plethora of end-group modification approaches have been reported to impart additional functionality to RAFT polymers and to remove the thiocarbonate functionality. − In the miniaturized synthetic workflows depicted in Figure B–D, hundreds of polymers can be processed in multiwell plates with minimal equipment needs, generating large libraries of homopolymers, statistical copolymers and block copolymers in a simple and economical fashion . However, the intervening purification steps required for the complete removal of deoxygenation aids such as enzymes, metals, and small molecules, are not fully compatible with high-throughput modes of operation .…”