Study On Controllable Chemical Reaction Of Polypropylene In Reactive Extrusion

The reaction rule of polypropylene by reactive extrusion was studied in a specific designed extruder in this paper. Modified PP product were analyzed by using kinds of methods in order to obtain PP modified rules, to develop high melt strength, ultra toughness, and high liquidity polypropylene and specific PP-R, and to improve process and mechanics properties. So the application scope of PP can be extended.In high melt strength domain, a wrong formula that used widely to calculate the melt strength was found. In my study, three modified methods and many monomers were used to research the change of PP. It was found that DVB coupling with PP enhanced melt strength greatly. When DVB is 1% and DCP 0.04%, the melt strength of modified PP is more than ten times than raw material. Torque experiments by Haake Rheometer show torque change in reaction, and the original and ending time are confirmed. Using WAXD and DSC, P-crystal can be found in DVB coupling modified PP, therefore, PP product possesses excellent properties. Besides, gel content is only 3.7%, this can't influence the process and reprocess properties.Experiments about controllable degradation and toughening use different POE, PP and DCP scale by reactive extrusion. The results show that PP degradation occurred becauses of DCP, and liquidity was improved, so the process properties of PP also increased. At the same time, DCP induced PP and POE coming into being mini-crosslinking, therefore, mechanics properties are enhanced mechanics properties experiments at different temperature show that impact resistance and breaking elongation of modified PP at room temperature were improved greatly. The results show that POE is effective for PP at room temperature, but as temperature decreasing, effects of POE become weak, at -30℃, POE will do nothing for toughening.The controllable degradation rules of PP-R by reactive extrusion were also studied in the paper, and already researched the best processing condition. By changing DCP dosage, the effects on PP-R degradation reaction were carefully studied with different temperature of the first zone of extruder. Then, mechanics properties experiments show that PP-R degradation product is much better than common PP. So it possesses widely applied value.