官能团化POSS及多臂星形聚酯的合成与表征

Preparation and Characterization of Functionalized POSS Derivatives and Multi-arm Star-shaped Polyesters

利用八乙烯基多面体齐聚倍半硅氧烷(OVPOSS)与2-巯基乙醇、1-巯基甘油或半胱胺盐酸盐发生高效的"巯基-烯"点击化学反应,制备了表面分别含有8个或16个羟基以及8个氨基的3种POSS衍生物POSS-8OH、POSS-16OH和POSS-8NH2,采用核磁共振波谱(1H-, 13C-NMR)和傅里叶变换红外光谱(FTIR)详细表征了它们的化学结构.随后,利用POSS-8OH和POSS-16OH中的羟基分别引发ε-己内酯(ε-CL)和2-乙氧基-2-氧代-1,3,2-二氧磷杂环戊烷(EOP)进行开环聚合,成功合成了疏水性八臂和十六臂星形聚己内酯(POSS-8PCL和POSS-16PCL)以及亲水性八臂星形聚磷酸酯(POSS-8PEEP).利用FTIR、1H-NMR、13CNMR、凝胶渗透色谱(GPC)和热失重分析(TGA)表征了星形聚酯的化学结构、分子量和分子量分布以及热稳定性.

A set of functional POSS derivatives and star-shaped POSS-cored polyesters are presented. Three POSS derivatives POSS-8OH, POSS-16OH and POSS-8NH2 are prepared by thiol-ene "click" reaction of octavinyl polyhedral oligomeric silsesquioxane(OVPOSS) with 2-mercapto-ethanol, 1-thioglycerol and cysteamine hydrochloride. Their chemical structures are confirmed by 1H-NMR, 13C-NMR, and FTIR analyses. Subsequently,POSS-8OH and POSS-16OH are used to initiate the ring-opening polymerization(ROP) of ε-caprolactone(ε-CL)and 2-ethoxy-2-oxo-1,3,2-dioxaphospholane(EOP), resulting in hydrophobic 8-arm(POSS-8PCL) and 16-arm(POSS-16PCL) star-shaped poly(ε-caprolactone), as well as hydrophilic 8-arm star-shaped poly(ethyl ethylene phosphate)(POSS-8PEEP). Three star-shaped POSS-8PCL with different arm lengths are synthesized by changing the feed ratio of the monomer to initiator. As a demonstration, the chemical structure of POSS-8PCL-2 is confirmed by using FTIR, 1H-NMR and 13C-NMR analyses. TGA test indicates that the initial decomposition temperature and decomposition mode are influenced by the molecular weights of POSS-8PCL. In order to compare the thermal stability of star-shaped PCL with a POSS core or an organic core, tripentaerythritol(TPE) is used to initiate the ROP reaction of ε-CL to give eight-arm PCL(TPE-8PCL) with an organic core. TGA test demonstrates that inorganic POSS core has better support to maintain melt stability of 8-arm star-shaped PCL than organic TPE core. The chemical structure and molecular weight information of POSS-16PCL are characterized by FTIR, 1H-NMR and 13C-NMR analyses, as well as GPC test. TGA analysis shows that the initial decomposition temperature is around 200 ℃, the decomposition behavior also displays an apparent two-stage mode, and the residue derived from POSS segment is about 3.6% at 700 ℃. Finally, POSS-8OH is used to initiate the ROP reaction of EOP to obtain POSS-8PEEP. The chemical structure and molecular weight information of POSS-8PEEP are confirmed by FTIR, 1H-NMR and GPC analyses. Furthermore, TGA analysis demonstrates that the thermal stability of POSS-8PEEP is weaker than star-shaped PCL and the initial decomposition temperature is decreased to about 100 ℃. The decomposition of POSS-8PEEP shows a more apparent multi-stage mode and about 19.8% residue is left at 700 ℃. This work reports a facile method for the preparation of functional POSS derivatives and star-shaped POSS-cored polymers.