Study On Preparation And Property Of Polydicyclopentadiene/Montmorillonite Nanocomposite

Polydicyclopentadiene (hereinafter referred to as PDCPD) is a type of engineering plastic which possesses excellent mechanical properties. At present, it has been sollen in USA,Japan and Europe, but only studied in lab in China, no products in domestic market. There are no reports about research on its nanocomposite. The experiments were carried out with Reaction Injecting Molding (hereinafter referred to as RIM) to prepare PDCPD/Montmorillonite (hereinafter referred to as MMT) nanocomposite via polymerizing in situ. The MMT is dispersed in the polymer matrix in the form of filling. Catalytic system and factors of affecting on properties of the material has been studied.DCPD polymerization is Ring-Opening Metathesis Polymerization of cyclic olefin. Traditional Ziegler-Natta catalytic system has been applied as solicitation system. WCl₆ and alkyl aluminum as two-component initiator are mostly adopted. WCl₆ is solid powder and is sensitive to water and oxygen. In order to solve the instability of WCl₆ in the air, many types of ligands such as para-tertiary butyl phenol,2,6-di(tert-butyl)-4-methyl phenol, 2-hydroxyl-4-n-octoxybenzophenone and so on have been selected to react with WCl₆ to form a kind of relatively stable complex compound catalysts. Their catalytic activity has been studied. The results indicate that all of the catalysts using many kinds of ligand complex compound have high reactive activity, they are suitable to the reaction requires of this experiment. The complex compound formed by para-tertiary butyl phenol and and WCl₆ is used as main catalyst system in this experiment.It is an available method that nanocomposite can be made by using MMT as carrier to support W catalytic system to catalyze DCPD polymerization. Inorganic MMT and organic MMT are applied as carrier, which prepares supported catalyst system. The results which have been proved by X-ray diffraction, SEM and TEM indicate that organically modified MMT can act as a good carrier for the WCl₆/t-BuArOH complex compound, whereas the nonmodified inorganic MMT can only adsorb the catalyst on its surface and precipitate, with instable solution formed.The activity of catalytic system after catalyst supported on MMT has reduced, but it is benefit to control the reaction rate. The experiment results indicate that the best properties of PDCPD/MMT nanocomposite is obtained when the mass fraction of MMT is 3.5%, n(DCPD)/n(W) is 1500:1, n(Al)/n(W) is (8～9): 1, and the temperature is 70℃.In addition, DCPD is solid at room temperature. DCPD should be altered its character in order to apply to the production conditions. The freezing point of DCPD after hot polymerization can reduce to 18℃. In a word, the temperature of hot polymerization should be controlled at 145℃, the reaction time is about 6h. It is advantageous to satisfy production and reduce the production costs.