Precision Synthesis of Bio-Based Acrylic Thermoplastic Elastomer by RAFT Polymerization of Itaconic Acid Derivatives

• Published in: Macromolecular rapid communications. 2014-01, Vol.35 (2), p.161-167
• Main Authors: Satoh, Kotaro, Lee, Dong-Hyung, Nagai, Kanji, Kamigaito, Masami
• Format: Article
• Language: English
• Subjects: Acrylates - chemical synthesis; Applied sciences; block copolymerization; Block copolymers; Elastomers - chemistry; Exact sciences and technology; itaconic acid derivative; living polymerization; Magnetic Resonance Spectroscopy; Organic polymers; Physicochemistry of polymers; Polymerization; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Reproducibility of Results; Succinates - chemistry; thermoplastic elastomer
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201300638

Bio‐based polymer materials from renewable resources have recently become a growing research focus. Herein, a novel thermoplastic elastomer is developed via controlled/living radical polymerization of plant‐derived itaconic acid derivatives, which are some of the most abundant renewable acrylic monomers obtained via the fermentation of starch. The reversible addition–fragmentation chain‐transfer (RAFT) polymerizations of itaconic acid imides, such as N‐phenylitaconimide and N‐(p‐tolyl)itaconimide, and itaconic acid esters, such as di‐n‐butyl itaconate and bis(2‐ethylhexyl) itaconate, are examined using a series of RAFT agents to afford well‐defined polymers. The number‐average molecular weights of these polymers increase with the monomer conversion while retaining relatively narrow molecular weight distributions. Based on the successful controlled/living polymerization, sequential block copoly­merization is subsequently investigated using mono‐ and di‐functional RAFT agents to produce block copolymers with soft poly(itaconate) and hard poly(itaconimide) segments. The properties of the obtained triblock copolymer are evaluated as bio‐based acrylic thermoplastic elastomers. Controlled/living radical polymerization of naturally‐derived itaconic acid derivatives, such as N‐aryl itaconimide and dialkyl itaconate, is investigated with RAFT agents. Their sequential copolymerization using a difunctional RAFT agent leads to ABA‐type triblock copolymer consisting of hard outer N‐aryl itaconimide (A) and soft middle dialkyl itaconate (B) segments, which would be a novel bio‐based thermoplastic elastomer.