Preparation And Properties Of MAPHE Functionalized Polyolefin

Polyolefin is one of the most commonly used polymer plastics due to its outstanding physical and chemical properties.However,polyolefin has its inherent drawbacks,such as poor hydrophilicity,low surface energy,poor miscibility with polar polymers,and lack of chemical functionalities,which have restricted its even wider applications.In the present work,we report the solid-phase grafting of 1-methyl acrylamide-2-phenyl acetic acid（MAPHE）onto polypropylene（PP）and high density polyethylene（HDPE）assisted by an aqueous suspension to improve their performance.In this study,the monomer MAPHE was synthesized by the reaction of methyl acryloyl chloride with phenylglycine.The functionalized PP and HDPE was prepared by using styrene（St）as comonomer,DMF as the solvent of monomer,benzoyl peroxide（BPO）as initiator.The effects of different reaction conditions on the grafting degree were investigated for the optimum conditions of polyolefin graft modification.Effects of the ratioes of two monomers,the monomers concentration,the amounts of initiators,the reaction time and the amounts of the interface agent on grafting degree were investigated to obtain PP-g-MAPHE/St with a higher grafting degree.Effects of the ratioes of two monomers,the monomers concentration and the catalyst of CeCl₃·7H₂O on grafting degree were investigated to obtain HDPE-g-MAPHE/St with a higher grafting degree.The grafting copolymer PP-g-MAPHE/St was characterized by Fourier transform infrared（FTIR）spectroscopy,FTIR microscopic imaging,differential scanning calorimetry（DSC）and polarized optical microscopy（POM）.The FTIR spectrum of the grafting copolymer confirmed the successful grafting of MAPHE onto the PP molecular chain.The DSC results showed that the crystallization temperature of PP-g-MAPHE/St increased about15¹6℃more than that of the virgin PP,and the melting temperature decreased about 6⁷℃.Isothermal crystallization process showed that the crystallization process of the main phase of the sample and Avrami equation matched.Nonisothermal crystallization process showed that the crystallization peak temperature（T_P）of the sample shifted to the lower temperature with the increasing of cooling rate,and the exothermic peak width becomed larger.POM micrographs revealed that the size of the PP spherulites significantly decreases after the solid-phase grafting.The polarity was improved according to the test of water contact angle.The grafting copolymer HDPE-g-MAPHE/St was characterized by the same test method for.The FTIR spectrum of HDPE-g-MAPHE/St confirmed the successful grafting of MAPHE onto the HDPE molecular chain.The DSC results showed that the effect of grafting on T_m and T_c of HDPE was not obvious.POM micrographs revealed that the size of the HDPE spherulites significantly decreased after the solid-phase grafting.Contact angle test results showed little change of hydrophilic effect on HDPE.The contact angle test results showed that the effect of grafting on hydrophilic of HDPE was not obvious.