利用膦腈碱(t-BuP4)为催化剂在室温下催化甲基丙烯酸烯丙酯(AMA)的进行基团转移聚合(GTP)反应,制备含悬垂双键的线型聚合物,并通过核磁(1 H NMR)、红外(FTIR)、凝胶渗透色谱(GPC)等对其进行分析和表征。结果表明t-BuP4催化AMA的GTP反应1h内,单体转化率就接近100%;聚合反应是通过AMA上的甲基丙烯酸酯双键进行,烯丙基双键不参与聚合反应;所得聚合物Mark-Houwink常数为0.75;使用极性溶剂更有利于加强聚合反应的可控性。
Phosphazene base,t-BuP2,was employed to catalyze the proton transfer polymerization(PTP)of 2-hydroxyethyl acrylate(HEA),and PTP was further combined with ring-opening polymerization(ROP)to exploit a new type of hybrid copolymerization.The studies on homopolymerization showed that t-BuP2 was a particularly efficient catalyst for the polymerization of HEA at room temperature,giving an excellent monomer conversion.Throughout the polymerization,transesterification reactions were unavoidable,which increased the randomness in the structures of the resulting polymers.The studies on copolymerization showed that t-BuP2 could simultaneously catalyze the hybrid copolymerization via the combination of PTP and ROP at 25°C.During copolymerization,HEA not only provided hydroxyl groups to initiate the ROP ofε-caprolactone(CL)but also participated in the polymerization as a monomer for PTP.The copolymer composition was approximately equal to the feed ratio,demonstrating the possibility to adjust the polymeric structure by simply changing the monomer feed ratio.This copolymerization reaction provides a simple method for synthesizing degradable functional copolymers from commercially available materials.Hence,it is important not only in polymer chemistry but also in environmental and biomedical engineering.
