The Study On Polypropylene Materials With High Transparency And Low Temperature Resistant And High Toughness

Polypropylene (PP) is a kind of cheap materials, which has a good performance compared with other polymer materials. Polypropylene has an outstanding chemical property, and it has a good strength and stiffness. So PP is widely used in material fields, such as the biological medical field, automotive materials field. However, The application of PP is limited because of its low impact resistance, high rate of molding shrinkage and high brittleness.In this paper we used two types(T30s, EPD60R) polypropylene as the matrix resin,and polypropylene were melted with ethylene octene copolymer (POE) and styrene ethylene butylene styrene block copolymer (SEBS), ethylene acetate ethylene copolymer (EVA) and low density polyethylene (LDPE) polymer in an extruder to prepare two materials with good mechanical properties, high transparency. The research results are as follows:(1)We used orthogonal design to find out the processing technology of preparing polypropylene:The injection temperature was 200?,220?, 230?,210?, The injection pressure was 20MPa, 10MPa, 10MPa; The injection time was 12s;The cooling time was 18s, The pressure was 20MPa,40MPa,40MPa; The pressure time was 30s; The injection speed was 30%,20%,20%.(2)The T30s type polypropylene were used as matrix resin, the study found that when the content of POE, LDPE, EVA were 10 phr and 5phr, 10 phr, The PP/POE, PP/LDPE and PP/EVA blends had the best mechanical properties and transparency; The transmission rate was 83.7%, the haze was 27.1%, the fracture elongation, impact strength in low temperature and tension strength was 338.6%,20.6kJ/m2,23.0MPa with addition of 10phr POE.(3)DSC showed that SEBS can effectively reduce the crystallization of PP/POE, PP/LDPE, PP/EVA blends.The crystallization temperature were reduced too. TGA studies showed that SEBS can decreased the temperature of thermal decomposition. X-ray diffraction and polarized microscope study showed that, SEBS can refine the grain size, prevent crystallization of PP; When the content of SEBS was 12phr, low-temperature impact strength, elongation at break and tensile strength was 22.0kJ/m2,420.0%,21.3MPa, and the transmission rate was 89.5%, the haze was 26.1%.(4) The EPD60Rtype polypropylene were used as matrix resin. DSC showed that SEBS can effectively reduce the crystallization of PP/SEBS blends.The crystallization temperature were reduced too. TGA studies showed that SEBS can decreased the temperature of thermal decomposition. X-ray diffraction and polarized microscope study showed that SEBS can refine the grain size, prevent crystallization of PP;When the content of SEBS was 80phr, the elongation fracture increased to 642.4%, the tensile strength decreased to 14.0MPa, the transmittance increased from 86.4% to 90.0%, the haze decreasd from 19.0% to 14.2%, the hardness decreased from 81HD to 38HD, the low-temperature impact strength was 27.0kJ/m2', the preparation of PP/SEBS materials can be comparable to the hardness of 90A soft PVC.