Preparation And Characterization Of Linear Polydicyclopendiene And Its Derivatives

C5 resource is a by-product of ethylene industry mainly congsisting of isoprene, 1,3-pentadiene and dicyclopentadiene. With the rapid development of petrochemical industry, C5 resource is attracting extensive attention. PDCPD, which is formed through ROMP of DCPD, has excellent thermal performance. The study on the preparation of PDCPD and its derivatives is an approach for improvement of product-addition value of DCPD products, which is also significant for the utilization of C5 resource.Currently, the prodiction of PDCPD employed certain selective binary catalytic systems instead of well-defined catalysts. It has been demonstrated that the main advantages of the well-defined catalysts compared to the binary catalytic ones are the relatively high catalyst stability, the elimination of co-catalyst or activators, and the lack of side reactions resulting from the high Lewis acidity of the older systems. What's more, with most of the catalytic systems, the polymerization is very fast and gives crossed-linked PDCPD. The crosslinked structure of PDCPD can bring difficulties to the production,application and recycling, that's why we tried to prepared linear PDCPD and its derivatives.The methods for controlling polymerization rate in the ROMP of DCPD using Grubbs' 1st generation catalyst were studied. It has been found that the Grubbs' 1st generation catalyst was sensitive to oxygen and water. We can control the polymerization rate by controlling the temperature, catalyst concentration and the triphenyl phosphine concentration. Then the structure of PDCPD was also characterized by infrared spectroscopy. It showed that the ROMP reaction occurred mianly in the norbornene-type double bonds from DCPD. The cyclopentene-type double bonds should also be involved by ROMP reaction or olefin addition reaction.Scientists tried to develop new catalytic system to get linear PDCPD,though with little success. Herein research thinking to get linear PDCPD derivative is to selectively inactivate the cyclopentene-type double bond of DCPD. The acetoxy group was introduced to the active methylene of the DCPD. As an electron-withdrawing group, the acetoxy group has a large stabilizing effect on the rings by reducing the reactivity of the double bonds and increasing steric hindrance of the reactions. Then linear acetoxy-substituted PDCPD, Poly(AcO-DCPD), were prepared by ROMP of AcO-DCPD involving selectively ring-opening of norbornene-type ring. The microstructures of the Poly(AcO-DCPD) were analyzed by 1H NMR and 13 C NMR and proved to be linear. Poly(AcO-DCPD) showed good solubility in common solvents. The Tg of the Poly(AcO-DCPD)s range from 136? to 159?, which are much higher than that of Linear PDCPD(53?). The thermal stability of Poly(Ac O-DCPD)s, by comparison, is bad. Because its onset degradation temperatures is around 220? due to the acetoxy groups. Then the Poly(AcO-DCPD) was prepared into Poly(HO-DCPD) by converting acetoxy into hydroxyl. Poly(HO-DCPD) has better thermal stability, but can be only dissolved in DMSO,which should be the results of the physical crosslinking occurs due to hydrogen-bonding interaction.