Preparation Design And Performance Study Of PP/PLA Functional Hybrid Composite Material

Polypropylene has increased its output year by year due to its excellent performance and wide range of uses.However,because it is a synthetic plastic,it cannot be biodegraded and limits its application.This study explores the preparation of biodegradable polylactic acid and polypropylene.The composite film with complementary advantages and the addition of functional nano-filler make it have the properties of anti-UV aging,electromagnetic shielding and so on,and can be used as packaging materials for high-precision instruments.The first part of this paper uses polypropylene as the matrix and green degradable polylactic acid as the dispersed phase to prepare the composite film by melt mixing.And through testing,the best ratio of the two is 80/20,the optimum process parameters are mixing time:8 mins;maleic anhydride addition:0.8 wt%;screw rotation speed:130 rpm.In the second part,PP/PLA/TiO2 composite film was prepared by adding nano titanium dioxide as UV block agent.When the addition ratio of nano-TiO,was 1wt%,the tensile strength and elastic modulus of the composite film were 30.60 Mpa and 1868.35Mpa,respectively.The crystallization rate and water barrier properties are improved,the UV transmittance is 0%,and the tensile strength retention after UV irradiation is close to 90%.In the third part,the carbon nanotube film(buckypaper)was first prepared by suction filtration,then the buckypaper was used as the interlayer,and the PP/PLA/TiO2 composite film was prepared by hot pressing to prepare the sandwich structure BP/PP-PLA-TiO2 composite film.Backypaper has a good reinforcing effect on PP/PLA/TiO2 composite film.When the thickness of buckypaper is 90?m,the tensile strength and elastic modulus are increased by 119%and 11%,respectively,compared with PP/PLA/TiO2 composite film.In addition,the addition of buckypaper enhances the crystallinity and thermal stability of the film.Electromagnetic shielding effectiveness(EMI SE)of BP/PP-PLA-TiO2 composite film can reach an average of 40 dB or more in the frequency range of 0-3 GHz when the thickness of the bucky paper is 90?m.