Synthesis Of Multifunctional Core-shell Silicone Modifier And Its Application In Plastic Modification

Recently,the polymer materials with functional performance by physical or chemical modification method have been one of the development directions.Among them,the toughening modification of polymer materials is an important aspect.Compared with common modifiers of the rigid particles,rubber elastomer and thermoplastic elastomer,the core-shell polymer is suitable for the polymer toughening as it possesses the advantages of other modifiers and can effectively increase the toughness of the polymer while has little effects on the strength.Therefore,the material with high performance can be obtained.The core-shell organic silicon modifier has excellent low-temperature toughness,good ultraviolet aging resistance,heat resistance,and not only improves the toughness of the plastic while maintain its rigidity,but also endows the material with special properties,which is beneficial for the performance improvement of modified plastics.In this work,the core-shell organic silicon modifier with organic silicon core and polyacrylate shell was successfully synthesized by the emulsion polymerization,it showed special properties when incorporating the weather resistance groups by adjusting the polymer structure.The obtained core-shell organic silicon modifiers were applied to the preparation of weather resistance of polycarbonate?PC?material,low noise of acrylonitrile-butadiene-styrene copolymer?ABS?material,free-spraying of PC composite and flame-retardant wood plastic of polyvinyl chloride?PVC?material.Effects of the structure of the core-shell organic silicon modifier on the plastics properties were systematical studies.Meanwhile,the relationship between structure and performance of the organic silicon modifier was also established.The work aims at extending the applications of organic silicon modifier,and providing solutions and ideas for the development of new type of organic silicon products and modified plastics.The research contents and results are listed as following:?1?The core-shell organic silicon and acrylate polymer?poly?D4-MMA-BA??emulsion was successfully synthesized by the core-shell emulsion polymerization using octamethyl cyclotetrasiloxane?D4?and?-methacryloxypropyl trimethoxysilane?KH-570?as core monomers,and butylacrylate?BA?,methyl methacrylate?MMA?and acrylic acid?AA?as shell monomers.By the optimization of the technological conditions,effects of the proportion of organic silicon monomer and core-shell monomer ratio on the monomer conversion,latex particle size,morphology,gel rate,film-forming and toughness properties were investigated,and were characterized by the Fourier infrared spectrum?FTIR?,dynamic light scattering instrument?DLS?and transmission electron microscopy?TEM?.FTIR showed that the target product was successfully synthesized.When the mass ratio of the D4 to KH-570 and core monomers to the shell monomers were 41.5/3.5 and 5/4,respectively,the obtained poly?D4-MMA-BA?possessed monomer conversion higher than 98%and gel rate lower than 0.5%.Meanwhile,the poly?D4-MMA-BA?showed good film-forming property and toughness.Thermo-gravimetric?TG?indicated that the poly?D4-MMA-BA?had good heat resistance with a high initial decomposition temperature?>300??.TEM showed that the prepared latex particles had core-shell structure with particle size of about 150 nm.?2?The core-shell modifier was prepared using spray drying process.The obtained poly?D4-MMA-BA?modifier,silicone lubricant,polyethylene wax and ethylene bis stearamide were used as modifiers for the preparation of the low noise ABS material.Effects of the lubricants on the friction noise of the ABS material were studied based on the friction coefficient tester and a self-designed noise tester.Compared with other lubricants,the polyethylene wax could improve the friction performance of the surface and reduced the?F,thereby reducing stick-slip phenomenon and friction noise.When the polyethylene wax content was 4%,the friction noise of the material was only 58 d B.It was because that the lubricant of polyethylene wax would migrate to the surface to form a layer of low surface energy material,which not only reduced the surface tension of the material,but also made the dynamic and static friction coefficient and?F of the ABS decreased.This would prevent the occurrence of the stick-sliding phenomenon,which improve the friction noise of the material.The introduction of the poly?D4-MMA-BA?modifier could effectively improve the toughness and thermal stability of ABS,but had negative effects on the tensile strength.Meanwhile,the poly?D4-MMA-BA?modifier could reduce the friction coefficient of material,improve the wear resistance and lower the friction noise.However,it had limited effects on the improvement of the?F.The materials were then tested and characterized by the friction tester,noise tester,FTIR and scanning electron microscope?SEM?to study the key factors and mechanism of friction noise.Results showed that the friction noise of ABS material was mainly generated by the stick-sliding phenomenon,and the friction noise of the material from the relative sliding related to the?F that was the key factor for reducing the friction noise.?3?The microspheres of the aluminum packaged by poly?D4-MMA-BA?were successfully prepared by the centrifugal spray drying after process optimization using aluminum silver paste as metallic material and the core-shell poly?D4-MMA-BA?as the packaged material.The obtained microspheres were adopted for the preparation of the free-spraying PC metallic material,which would prevent the occurrence of the flow mark and increase the low-temperature toughness of the composite.The dispersion of aluminum microspheres in PC and the effects of the microspheres content on the mechanical properties,appearance of flow mark,thermal stability and melt flow were also studied,and were characterized by the TG,differential scanning calorimetry?DSC?,SEM and the element analysis?EDS?.It showed that curing reaction of poly?D4-MMA-BA?occurred and the aluminum was successfully packaged by poly?D4-MMA-BA?polymer,forming the microspheres or flake morphology.The aluminum microsphere could greatly improve the impact strength of the PC,especially the low temperature impact strength.Compared with the PC/Al composite,the impact strength and the low temperature impact strength of the PC/aluminum microsphere increased by 47.2%and48.8%,respectively.The packaged of aluminum powder with poly?D4-MMA-BA?could obviously destroy the lamellar structure of the orientation of aluminum powder,thereby improving the weld line and flow mark on the composite.?4?A light stabilizer compound of 2-?2'-propionyloxy-5'-methylphenyl?benzotriazole?AMB?was synthesized by the esterification of the 2-?2'-hydroxy-5'-methylphenyl?benzotriazole?UV-P?with acryloyl chloride?AC?,and the AMB was then copolymerized with the acrylate and silicone monomers to prepare the silicone modifier of the core-shell poly?D4-MMA-BA-AMB?with light stability.The poly?D4-MMA-BA-AMB?was used as the light stabilizer and added into the PC to prepare the PC composite with high toughness and weather resistance.Effects of the AMB monomer on the conversion and polymerization stability,and the toughening and photostabilizing effects of the poly?D4-MMA-BA-AMB?on the PC were studied.Meanwhile,the aging mechanism of the AMB was explored.The prepared multifunctional modifier and the PC composite were characterized by FTIR,nuclear magnetic resonance spectroscopy?¹H-NMR?,TG,TEM,DLS and ultraviolet absorption spectroscopy.The target product of AMB was synthesized and the poly?D4-MMA-BA-AMB?modifier with core-shell structure were successfully prepared using the emulsion polymerization.It showed that the AMB possessed good ultraviolet absorption property by the chain scission of producing benzotriazole?UV-P?.The incorporation of the AMB had negative effects on the polymerization stability while improved the thermal stability of the modifier.The obtained poly?D4-MMA-BA-AMB?modifier could effectively absorb the ultraviolet rays.Although the addition of the poly?D4-MMA-BA-AMB?modifier had a negative effect on the tensile strength of the PC,it could greatly improve the low temperature notched impact strength,toughness performance and yellowness performance of PC products after UV irradiation.Compared with the silicone modifier,the modifier of the poly?D4-MMA-BA-AMB?had better anti-ultraviolet irradiation property.The PC/poly?D4-MMA-BA-AMB?composite had higher retention of tensile strength and impact strength and less color change after 1000 h of ultraviolet irradiation in comparison with that of the PC/poly?D4-MMA-BA?composite.Moreover,the PC/poly?D4-MMA-BA-AMB?had better aging resistance after water boiling than the composite of PC/poly?D4-MMA-BA?/UV-P.?5?The core-shell modifier of the poly?D4-MMA-BA-AMB?was added into the PVC wood-plastics material to improve the weather resistance,flame retardancy and toughness,and the effects of the poly?D4-MMA-BA-AMB?on the flame retardant,mechanical properties and anti-aging performance of the composite were investigated.The products were characterized and tested by the cone calorimeter instrument,optical microscope,chromatic aberration tester and aging test box.Results showed that the poly?D4-MMA-BA-AMB?could improve the notched impact strength of PVC-WPC,and possessed higher toughening effect than that of other organic silicon modifiers.The PVC-WPC with excellent flame retardant performance and weather resistance could be obtained by adjusting mass ratio of the white wood powder,modifier and molybdenum trioxide?Mo O₃?.The optimal ratio of the PVC-WPC was:5%white wood powder,2.5%silicone modifier and 1.5%Mo O₃.The complex of the poly?D4-MMA-BA-AMB?and Mo O₃into the PVC-WPC could reduce the smoke release and heat release rate,and increase the rate of carbon residue and the dense of the forming carbon layer,resulting in the excellent flame-retardant properties of material.Meanwhile,the incorporation of the poly?D4-MMA-BA-AMB?could also improve the weather resistance of the PVC-WPC.When the poly?D4-MMA-BA-AMB?content was 3.5%,the PVC-WPC showed excellent weather resistance and the appearance of the composite had no obvious color change after 1000 hours of accelerated aging.Moreover,the poly?D4-MMA-BA-AMB?increased the melt viscosity of the PVC-WPC during the extrusion process.When the poly?D4-MMA-BA-AMB?content was2.5%,the PVC-WPC possessed good mechanical properties and appropriate pore size through the optimization of the foaming process.