可逆交联瓶刷状聚己内酯的合成及性能

Design,Synthesis and Characterization of Reversible Crosslinked Bottlebrush Polycaprolactone

通过原子转移自由基聚合(ATRP)得到聚甲基丙烯酸羟乙酯(PHEMA),以PHEMA的羟基为引发剂通过开环聚合得到了瓶刷状聚己内酯。通过凝胶渗透色谱和核磁共振波谱确定聚合物的结构,证明成功合成了瓶刷状聚己内酯且分子量分布较窄(PDI<1.22)。将得到的瓶刷状聚己内酯与二苯基甲烷二异氰酸酯(MDI)进行交联得到了一系列含有动态共价氨酯键的可逆交联瓶刷状聚己内酯网络。通过傅里叶变换红外光谱仪、差示扫描量热仪、动态力学热分析仪、万能拉伸机等对交联后的聚合物进行了结构表征和性能分析。交联后的聚合物断裂伸长率随臂长的增加显著提高,最高可达344.4%;材料表现出明显的应力松弛行为,符合阿伦尼乌斯公式规律。材料破碎后仍可热压成型,拉伸强度和断裂伸长率均可恢复至80%以上。

Poly(hydroxyethyl methacrylate)(PHEMA)was synthesized via atom transfer radical polymerization(ATRP).Bottlebrush polycaprolactone was acquired by ring-opening polymerization using the hydroxyl team of PHEMA as initiator.The shape of the polymer was decided by gel permeation chromatography and nuclear magnetic resonance spectroscopy.It is proved that the bottlebrush-like caprolactone was efficiently synthesized with a slender molecular weight distribution(PDI<1.22).A collection of reversible cross-linked bottlebrush-like polycaprolactone networks containing dynamic covalent urethane bonds have been acquired by way of crosslinking the received bottlebrush-like polycaprolactone with diphenylmethane diisocyanate(MDI).The crosslinked polymer was characterized and analyzed by FT-IR,DSC,DMA and common tensile machine.The elongation at break of the crosslinked polymer extends appreciably with the amplify of arm length,up to 344.4%.The fabric suggests apparent stress rest behavior,which conforms to the Arrhenius formula.The tensile strength and elongation at break of the cloth can be restored to greater than 80%after warm pressing.