PET-RAFT copolymerization of vinyl acetate and acrylic acid
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ORIGINAL RESEARCH
PET‑RAFT copolymerization of vinyl acetate and acrylic acid Wei Wang1,2 · Wan‑Yun Xie1,2 · Guo‑Xiang Wang1,2 · Wenyuan Xu1,2 · Enxiang Liang1,2 Received: 7 June 2020 / Accepted: 15 September 2020 © Iran Polymer and Petrochemical Institute 2020
Abstract Photoinduced electron transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization of vinyl acetate (VAc) and acrylic acid (AA) was successfully realized in methanol at room temperature under blue LED (420 nm, 6 mW/ cm2) irradiation with xanthate as RAFT agent and fac-[Ir(ppy)3] as the photocatalyst. The well-defined copolymers of poly(VAc-co-AA) with controlled molecular weights (Mn,GPC) and polydispersity index (PDI) were successfully obtained. The polymerization revealed the behaviors of controlled/living polymerization, which was verified by the observed linear relationship of ln([M]0/[M]t) with respect to irradiation time and that of the experimental molecular weights (Mn,GPC) with respect to monomer conversion. GPC curves showed a single peak and shifted to high molecular weights with increasing the irradiation time. The reactivity ratios of VAc and AA were 0.043 and 1.181, respectively in this system. The effect of the amount of fac-[Ir(ppy)3] on PET-RAFT polymerization was investigated. The monomer conversion increased with increasing the amount of fac-[Ir(ppy)3] and the PDI decreased with the increase in the amount of fac-[Ir(ppy)3]. The temporal controllable PET-RAFT polymerization of vinyl acetate (VAc) and acrylic acid (AA) was achieved. The structure of synthesized poly(VAc-co-AA) was characterized by nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC), respectively. The extended experiments of poly(VAc-co-AA) with fresh AA was conducted under the irradiation of blue LED, and the results demonstrated that this extension polymerization displayed controlled polymerization behavior. The mechanism was explained in this study. Keywords PET-RAFT · VAc · AA · Photo-induced · Copolymerization
Introduction Poly(vinyl alcohol) (PVA) is a kind of non-toxic water-soluble polymer with good film-forming property, and PVA film has good solvent, wear resistance, tensile strength and oxygen resistance [1, 2]. By now, PVA has been widely applied in the field of cosmetics, printing, textile and agriculture [3]. PVA needs to be first dissolved in water at 90 °C when it was processed and produced downstream products, but this Wei Wang and Wan-Yun Xie are the first authors. * Guo‑Xiang Wang [email protected] 1
Key Laboratory of Hunan Province for Advanced Carbon‑Based Functional Materials, Hunan Institute of Science and Technology, Yueyang 414006, People’s Republic of China
School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, People’s Republic of China
2
process required higher energy consumption and longer dissolution time. Therefore, the development of soluble PVA, such as copolymerization of other monomers, began to attract more
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