Preparation Of Epoxy And Amino Functional Silicone Microspheres And Its Application In PC

Polymer-silica hybrid materials have emerged since the 1970s.Due to its excellent properties,such as polymer's flexibility,excellent processability,low cost,high strength and high temperature resistance,it is favored by researchers.Among the organic-inorganic hybrid materials,polysilsesquioxane microspheres have become one of the most popular organic-inorganic hybrid materials due to their unique thermal,optical and mechanical properties.In the application of silicone microspheres,surface modification of functional groups is often required.Till now,the traditional preparation process is cumbersome and high cost.Therefore,in this paper we developed a simple,efficient and low cost method to prepare functional group coating silicone microspheres.And then the functinal group coating silicone microspheres were dispersed into polycarbonate by twin-screw extruder to prepare light diffusing materials?LDMs?.The properties and structure of LDMs are also studied.In this thesis,phenyltrimethoxysilane?PTHS?,?-glycidoxypropyltrimetho--xysilane?KH560?,3-aminopropyltriethoxysilane?KH550?as the raw materials,ammonia as the catalyst were used to prepare silicone microspheres.Polyphenylsilsesquioxane microspheres?PPSQ?were successfully prepred.And PPSQ was then coated with epoxy and amino functional groups using KH560 and KH550.Si²⁹ NMR,SEM?FTIR?TG?DSC methods were used to characterize the structure and properties of prepared microspheres.Then the prepared silicone microspheres were dispersed into polycarbonate?PC?by twin-screw extruder to prepare light diffusing materials?LDMs?.The structure and properties of light diffusing polycarbonates were systematically studied.The interfacial properties of silicone microspheres and PC were studied,the mechanism of dispersibility in polycarbonates of silicone microspheres was also explored.The transmittance and haze of light scattering materials were studied.The effects of the size and loading of silicone microspheres on light diffusing properties were also investigated.The results are shown below:?1?The PPSQ microspheres were prepared uder base catalysis by one-step process.We successfully prepared silicone microspheres with a particle size of0.5¹.8?m.The organosilicone monomers hydrolyzed and condensed into nuclei in a very short period of time and grew rapidly.The reaction system was basically stable after 60min and microspheres were not grown up.In the seeding polymerization for preparing epoxy or amino functional group coating silicone microspheres,KH560or KH550 aqueous were used..The addition of KH560/550 would reduce the final organosilicone microspheres yield.The more the addition of the KH560/550,the more the final organosilicone microspheres yield reduced.Far too many loading of KH560or KH550 would even to lead agglomeration.The structure of pure PPSQ microsphere and epoxy and amino groups coating microspheres were also studied.It was also found that although the three kinds of silicone microspheres are all prepared from trifunctional monomers throughhydrolysis and polycondensation under the catalysis of ammonia,the PPSQ microspheres have a planar trapezoidal structure,however the KH560 or KH550 polymerization products have a crosslink structure.The silicone microspheres coated with expoxy or amino group have better solvent resistance,higher refractive index comparing to PPSQ.However The addition of KH560/550 would reduce the microspheres thermal stability.The more the addition of the KH560/550,the more the organosilicone microspheres thermal stability reduced.?2?Silicone microspheres were used to prepare PC based light scattering materials.The structure and properties of prepared LDMs were studied.The results show that the well dispersion of silicone microspheres in PC is mainly decided by the viscosity rather than the interface compatibility.They have similar effect on light diffusing properties for these three kinds of silicone microspheres.When the particle size of light scattering particles is constant,the haze of light scattering materials will increase with the increasing of the concentration of light scattering particles in LDMs,and the transmittance change little.When the light scattering particles with different particle size were added into the light scattering material,the haze of light scattering material increases obviously and the transmittance varies little as size increases.When the epoxy group coatingsilicone microspheres with diameters of 0.50?m and 1.38?m were loaded in LDMs by 1 phr,The transmittance of crresponded 2mm thickness PC diffusing plate was 85.1%and 85.3%,and the haze was 29.1%and 53.8%respectively.All these were benefitful to solve the contradiction between haze and transmittance of LDMs.The particle size of organic silicon microspheres has little effect on the impact properties of LDMs,but they have a certain effect on the dynamic thermal mechanical properties of LDMs.The storage modulus of light scattering materials have an upward trend with the increase of particle size of the added microspheres.When the particle size of the added microsphere is 0.50?m and1.84?m,the storage modulus of the cresponding composites is 1935MPa and2070MPa,respectively.In addition,the addition of silicone microspheres can significantly improve the thermal stability of LDMs.