Study On The In-situ Alloy Of Polypropylene With Polyethylene Induced By Ethylene Plasma

A self-designed Dielectric barrier discharge (DBD) device was made in this study. Ethylene plasma can be polymerized at atmospheric pressure using the device.At first, Ethylene plasma was used to treat the Polypropylene (PP) film surface and Polyethylene (PE) film surface under the different treating conditions. DPPH method was used to determine the concentration of free radicals on the treated PP and treated PE surface. Combining the calculation of surface contact angle and surface tension, the results show that PP surface is activated more easily and it is in the treatment time of 10 min and treatment voltage of 41V that the radical content has reached the maximum value. The surface elements content as well as oxygen-containing groups after plasma treated were characterized by X-ray photoelectron spectroscopy (XPS). At the same time, Fourier transform infrared spectroscopy (FTIR) was used to research the treated thin PP film. Scanning electron microscopy (SEM) was used to characterize the morphology of the treated surface. The results showed there were many sediments of Ethylene plasma in PP surface with etching phenomenon. Wide-angle X-ray diffraction (WAXD) was used to characterize the melted treated PP film. The diffraction peak at (20=16.08°) appeared in the WAXD of the treated PP, and not appeared in the WAXD of PP. This phenomenon showed Ethylene plasma may induce β crystal. The sediments of Ethylene plasma deposited in the inorganic materials surface were characterized by FITR and XPS.The self-designed device was used to combine with the mixer. The melted PP can be treated by the Ethylene plasma. A new method was applied to prepare in-situ alloy of PP with PE modified by Ethylene plasma. For comparison, PP/PE blends of the same proportion as PP/PE alloys were prepared. SEM was used to characterize the morphology of the PP/PE alloys and PP/PE blends. The results showed the miscibility between PP and PE was improved to some extent. Small angle X-ray scattering (SAXS) was used to study the alloy’s structure by calculating the interfacial layer thickness. The results correlated well with the results obtained by SEM. WAXD observed that β-form in alloy can been induced. The sediment exhibited that it may be the accelerating agent or nucleating agent of β crystal. This phenomenon needs to intensive research.