The Study Of Preparing High-Melt-Strength Polypropylene With Twin Screw Extruder

The increasing melt-strength of Polypropylene method,equipment condition,material formula,processing conditions and product application in industrial application of preparing high melt-strength of Polypropylene was studied with the improving twin screw extruder in batch in this paper.Experiments show that the prepared high melt strength polypropylene has good use effect and meets industrial needs.The test found that the best barrel temperature setting for preparing high melt strength polypropylene is: 180,180,185,185,185,185,190,185,180 °C(from zone 1 to zone 9);The addition of antioxidant in sector 4 will cause the reaction monomer DVB to escape from the feeding port and reduce the melt strength of the product,while closing the feeding port in the fourth zone is conducive to the extrusion reaction,and adding antioxidant directly to the premix is beneficial to improve the melt strength of the product,and the optimum dosage of antioxidant is 0.3%.Different types of PP will significantly affect the melt strength of the product.Block copolymerized polypropylene(PP-B)is easier to prepare products with high melt strength than homopolypropylene(PP-H).The lower the screw speed is,the more favorable the extrusion reaction is;the DHBP initiator is more convenient and effective to use than DCP,and its optimum dosage is 0.035%.Improving the vacuum rate of the exhaust section can effectively remove the odor in the product and improve the quality of the product.The melt strength of the prepared product is more than 10 times higher than that of the raw material PP(MFR method),but too high melt strength will cause too much crosslinking of PP,which affects the post-processing application of the product,so all aspects of performance should be considered.The test results of various physical properties of the high melt strength polypropylene product show that its oxidation induction period reaches 16 minutes,and the product has good thermal stability.The properties and notched and unnotched impact strengths at different temperatures did not change significantly,indicating that while improving the melt strength of the product,its mechanical properties were not affected.Using the best conditions to produce high melt strength polypropylene in small batches,the industrial application test shows that adding 5% high melt strength polypropylene to the PP-H casting film material will solve the problem of easy occurrence in the past film production process.The problem of film rupture can ensure that the produced casting film has no odor,the film maintains high transparency,and the tensile strength of the film is increased by 10%,indicating that the high melt strength polypropylene prepared in this work has a good industrial application effect.