Study On The Preparation And Properties Of In-Situ Chlorinated Graft Modified CPVC And Blending Modified CPVC

The reaction process of PVC in-situ chlorinated graft method had been studied to graft some different monomers, in addition, the mechanical and rheological properties of graft polymer and blend of CPVC/LCPE (Low chlorinated polyethylene).Kinds of monomers were employed to modify CPVC by the method of in-situ chlorinated graft. It was found that the CPVC modified by St had the outstanding property. The mechanism of PVC in-situ chlorinated graft Styrene (St) and the reaction condition were debated, as well as the influence of monomer amount, reaction temperature, and chlorine content for mechanical property. A equation of the release velocity of HC1 with the concentration of Cl₂ and RH had been built. The results showed that the yield strength of modified CPVC reached the maximum of 69MPa, which was 17% higher than that of unmodified CPVC, but the vicat softening temperature decreased when St amount was about 10 parts and the reaction temperature was 120 ℃ and the chlorine content was about 60%; The yield strength and vicat softening temperature of CPVC and modified CPVC were both increased with the increase of chlorine content.When study the rheological properties of the modified CPVC, it was turned up that CPVC and the modified CPVC were pseudo-plastic fluids. The shear rate of modified CPVC was higher than CPVC and the melt apparent viscosity was lower at the same shear stress. In the temperature range of 190²00℃, the viscosity of modified CPVC decreased with the increasing of temperature, but the relationship did not accord with Arrhenius equation. The heat-stability was improved by this method. St and Butyl Acrylate (BA) were the ideal choice.The mechanism and rheological properties of blend (CPVC/LCPE) were discussed. It has been covered that the yield strength of blend had unobvious change, when the amount of LCPE was less than 5 phr. When CPVC was mixed with LCPE which chlorine content were 5.2% and 6.7%, the tenacity of CPVC enhanced distinctly. CPVC and the blend were pseudo-plastic fluids, and the blend had a more clear pseudoplasticity. The fluidity of blend was especially finer with 5 phr LCPE. The swell ratio of the blend augmented with the increasing of chlorine content of LCPE, and so...