The Study Of PP/EPEDM/TALC Composite Materials Microcellular Foam Injection Molding

Because of the advantages of good mechanical properties and recycling,PP was widely used in our daily life. However, as a semicrystalline polymer, PP had low melt strength,which was bad to form uniform and dense bubble, the application of PP microporous products was greatly limited. In order to improve bubble morphology and mechanical properties of PP microporous products and promote the application of PP microporous products, the influence of additives(EPDM, talcum and PP-g MAH)and injection molding process on the properties of microporous products was studied. And the main research contents were as follows.The influence of EPDM, talcum and PP-g-MAH on the bubble morphology and mechanical properties of microcellular PP composite material products and macroscopic was revealed, the results showed that, when the EPDM content was21%, bubble diameter was the smallest, bubble density was the largest, and compared with the solid products, mechanical performance degradation ratio was the least; and compared to PP/EPDM microporous products,when the talcum content was4%, the foaming effect of microporous PP/EPDM/talc products was superior to the former, with bubble diameter decreasing by41%and bubble density increasing by42%, meanwhile the various mechanical properties were improved;1%PP-g-MAH improved the bubble pattern of microporous PP/EPDM/talc composites products and promoted the ascension of mechanical properties.The influence of injection molding process on the microstructure,mechanical properties and weight loss rate of microporous PP/EPDM/talc composites was studied through the system experiment research, the results showed for that, as the melt temperature increasing, bubble diameter firstly decreased and then increased, meanwhile bubble density showed the trend of at first decreasing and then increasing; with the increase of injection speed and the cooling time, bubble diameter showed the trend of decreasing and bubble density showed the trend of increasing; with the increase of melt and back pressure, bubble diameter showed the trend of decreasing, and bubble hole density showed the trend of at first decreasing after increasing. Compared with other molding process factors, plasticizing amount determined the amount of weight loss rate of microporous products. In addition, when cell morphology was improved and the amount of weight loss rate increased, the impact strength would increase, but the tensile strength and flexural strength increased first and then decreased. Meanwhile, the influence degree of the mechanical properties and relevant process optimization was studied through orthogonal experiment, and the result was found that, while the advantages of impact strength was maintained, low injection speed, melt temperature and cooling time, high melt amount and back pressure was good to improve the overall performance.