Research On Ethyl Ether As The Impregnating Agent Assisting The Graft Modification Of PP With Maleic Anhydride

In this paper, diethyl ether was used as impregnated swelling agent to swelling PP and inserting monomers into the PP matrix under normal temperature and pressure conditions and sub-critical condition, respectively. Swelling agent was subsequently removed, then the grafted products were obtained by the thermal free radicals reaction. The effect of the solvent content, monomer concentration, PP particle size, swelling temperature, swelling time on PP swelling degree and monomer impregnation was studied. The influences of some factors on grafting reaction also were studied, such as monomer and initiator concentration, reaction time and temperature, etc. Finally, the two impregnated swelling methods were compared, and the products were characterized.The studies showed that PP could be swellinged in the normal temperature and pressure ether or sub-critical diethyl ether, at the same time small molecules can be inserted into PP microporous. This method can eliminate the influence of the internal diffusion, so that the grafting reaction was controlled by the reaction instead of diffusion. Under the conditions that impregnated agent dosage was 10 mL, impregnated swelling temperature was 28 ℃, w(MAH): w(PP)=6%,when the impregnated swelling time was 40 min, the biggest swelling degree was 12.50%; when the impregnated swelling time was 10 h, the biggest monomer impregnation amount was 1.26%. The solid phase grafting reaction was performed under the optimal conditions of swelling. The maximum grafting rate and grafting efficiency obtained were 1.05% and 17.49%, respectively, under the following conditions: reaction temperature was 100 ℃, reaction time was 2 h, w(BPO): w(PP)=0.3%, w(MAH): w(PP)=6%, particle size were 10 mesh-12 mesh. The results of solid phase grafting PP which is assisted by sub-critical diethyl ether were as follows: impregnating agent dosage was 10 mL, impregnated swelling temperature was 70 ℃,w(MAH): w(PP)=8%, the maximum swelling degree and monomer impregnation amount obtained were13.69% and 1.88%,respectively, under the conditions that impregnated swelling time was 40 min and 2 h. Under the optimal conditions that swelling solid phase grafting reaction was performed,when the reaction temperature was 100 ℃, reaction time was 2 h, w(BPO): w(PP)=0.3%, w(MAH): w(PP)=6% particle size were 10mesh-12 mesh, the grafting rate was 1.54% and the grafting efficiency was 25.63%.Since sub-critical ethyl ether compared to the normal temperat ure and pressure ethyl ether has more excellent swelling and monomer impregnating feature, so PP impregnated by sub-critical ethyl ether spent less time to achieve swelling conditions, moreover, had higher grafting percentage and grafting efficiency under the same solid grafting conditions.The products were characterized by FTIR, water contact angle and MFR measurement which showed that MAH had been grafted onto PP successfully and po larity of PP had been improved. All the products of two ways which assists grafting reaction of PP reduced contact angle of PP. The grafting products of PP with assistant of sub-critical ethyl ether had the better polarity and thermal stability than another one, and the appearance of test samples and MFR were more likely properties of pure PP.