Study On The Preparation And Application Of Silicon-propylene Compatibilizer

Polymer blending technology can combine the advantages of a variety of polymer materials into that of one composite material to achieve complementary functions.Thermoplastic polyurethane?TPU?has high elasticity,and has the characteristics of easy processing,wear resistance,oil resistance,and aging resistance of thermoplastics.Methyl vinyl silicone rubber?VMQ?is a kind of polymer elastomer with both inorganic and organic properties.It has excellent resistance to high and low temperature,weather resistance and other properties.Blending the TPU and VMQ together,the composite material with complementary performance could be achieved.However,due to the large differences in the polarity of TPU and VMQ,the composite material tends to produce macroscopic phase separation during direct mixing,resulting in poor application of interface strength.It is difficult to solve the above problems by changing the shear stress or the temperature of the kneading.In order to avoid the phase separation phenomenon and obtain the ideal blending effect,compatibilizer is generally introduced.In this experiment,an organosiloxane-grafted acrylate copolymer compatibilizer?K81?was prepared by emulsion polymerization,and some of the process conditions and recipes in the synthesis process were investigated,and the optimum conditions and recipes were determined.The compatilizer K81 and the purchased compatilizer K80 were added to the TPU/VMQ blend system in different proportions.The compatibilizer's compatibilizing effect on the system were investigated,including water resistance,heat resistance,and mechanical properties.The main experimental results are as follows:?1?Using MM,D₄,KH-570 as the main organic silicon monomer,the emulsion containing polysiloxane molecules was synthesized.Using MMA,BA,EGDMA,etc.as main acrylate monomer,they were successfully grafted onto the polysiloxane molecule to produce PSiO-BA-MMA with LIPI structure.The optimum reaction time for the polymerization of organosilicon monomers to form a polysiloxane emulsion is 2.5 h.PSiO-BA-MMA emulsion was synthesized by grafting polysiloxane onto acrylate monomers,the optimum polymerization time is 2h.The optimal addition amount of emulsifier?catalyst?DBSA is 2%,the silicon-propylene ratio is 5:5,and the ratio of butyl acrylate?BA?and methyl methacrylate?MMA?is 3:4,dimethacrylic acid.Ethylene glycol?EGDMA?is 0.3%of the total monomer.Under the above conditions,the produced emulsion has an uniform particle size distribution,a stable emulsion state,a milky white solid after the emulsion breaking,and is easily crushed,which facilitates the addition of processing experiments.?2?The TPU,VMQ and compatibilizer were ternary blended together.It was found that,the compatibility of the system was best when the K80 and K81 were 6wt%and 4wt%,respectively.The static contact angles of the materials are 109°and 113°,respectively.The hydrophobicity of the composite material is the best.The mechanical property are also improved to that maximum.The tensile strength and elongation at break increased from10.3 MPa to 12.5 MPa,and 660%to 741%respectively when k81 content was 4 wt%.In contrast,when the same tensile strength value was reached,k80 was added 1.5 times as much as k81,and the elongation at break was only increased to 703.85%.The dynamic thermo-mechanical analysis of k80 and k81 blends showed that,the two damping peaks appeared when k80 content was 6 wt%,the peak temperature was-109.5 and-14.8?,the peak deviation was the largest,and the compatibility between TPU and VMQ was the best.When k81 content was 4 wt%,the two damping peak temperatures of the blend were-109.9 and-14.2?,respectively.The peak deviation was the largest,and the compatibility between TPU and VMQ was the best.In summary,the compatibilizer?K81?synthesized in the experiment can effectively improve the compatibility of the TPU/VMQ system and is a good compatibilizer for this system.