Studies On Preparation And Properties Of Polycarbonate/inorganic Nanocomposite

In recent years,the multi-functionalization and high performance of polymer has been the hot field of polymer materials research and application.The filling nanoparticles in polymer is of great significance in terms of developing the new type of composite materials.In this dissertation,the research began from the molten salt assisted preparation of well-dispersed ZrO₂ nano particles and adopted the methods of coupling agent and the graft modification of polymer to modify the surfaces of nanoparticles.PC nanocomposites were prepared via the melting blending method.The mechanical properties,dynamic mechanical properties of PC nanocomposites as well as its thermal stability and UV light resistance were also studied.Meanwhile,a new transparent organic-inorganic hybrid was prepared via the Sol-Gel processing.The PC/hybrid composite mechanical properties and optics properties were also primarily explored.(1) The preparation and characterization of the well-dispersed,small diameter ZrO₂The well-dispersed,small diameter ZrO₂ was prepared via reverse microemulsion system and chemical sedimentation respectively assisted by molten salt to calcine the precursor.The influencing rules of the crystalline structure and dispersibility of nano-sized ZrO₂ were also studied from the following aspects of different reaction conditions,calcination temperature and mode.According to the variety of conductance,the stabilized Triton X-100/span85/yclohexane/hexyl alcohol/water could be synthesized by the method of reverse microemulsion and could provide micro-reactor for the preparation of nanoparticles.In the chemical sedimentation system,the agglomeration of outcomes could be prevented with the addition of surfactant during the course of sedimentation, azeotropic distillation through which to desiccate precursor.The dispersibility of outcomes could obviously be improved by the above two methods through which the precursor was obtained and calcined by molten salt with a certain amount of LiNO₃. Thus the well-dispersed small-diameter spherical cubic-crystalline nanopaticles ZrO₂ were synthesized with optimizing processing.The last phase also discussed about the mechanism of molten salt calcination's influence upon the dispersibilty of outcomes.(2) The surface modification of nano-ZrO₂ and the preparation and characterization of PC/ZrO₂ nanocomposites.The surface organic modification of nano zirconia was studied and the research was focused on the following two methods:silane coupling agent 3-(trimethoxydilyl) propylmethacrylate(KH-570) grafting modification and the modification of poly(ethylene terephthalate)(PET) graft polymerization.The preceding two methods all belong to the chemical modifications.The modified products,the surfaces of ZrO₂ were analyzed by FT-IR,TGA,XPS,TEM and contact angle test,respectively.The PC/ZrO₂ nanocomposites were prepared via melting blending.At the same time,their properties of mechanics,dynamic mechanics and thermal stability were examined.Results showed that the fill of nanoparticles was able to promote storage modululoss,loss modulus and the thermal dispersiblity of composites.With respect to the mechanical property,filling nanoparticles could increase the bending strength and modululoss.When blended with original ZrO₂,the notched impact strength and the tensile property of nanocomposites would be both weakened.However,these properties would present the tendency of changing from high to low as a result of gradual filling of ZrO₂-KH570 and ZrO₂-g-PET.The SEM photos of fractured surface of notched-impact showed that the modified nanoparticles dispersed in PC homogeneously and had preferable interfacial interactions so as to improve the toughening and strengthening.The result of filling ZrO₂-g-PET was better than that of filling ZrO₂-KH570.The max value of impact strength of filling ZrO₂-g-PET was 10% higher than that of ZrO₂-KH570.Meanwhile,the relationships of three types of nanoparticles with PC interfaces were analyzed half quantitatively by introducing the formula of TPT.Value B reflected the property of interface:ZrO₂-g-PET＞ZrO₂-KH570＞Original ZrO₂ and ZrO₂-g-PET had the best interfacial property.(3) The surface modification of nano-TiO₂ and the preparation and characterization of PC/TiO₂ nanocomposites.The original TiO₂ and the modified TiO₂ which included TiO₂-KH570 and TiO₂-g-PET were melting blended with PC to prepare PC/TiO₂ composites.Their properties of mechanics,dynamic mechanics,thermal stability and UV light resistance were equally examined.The result demonstrated that the obtained PC/TiO₂ nanocomposites varied in all of the properties of mechanics,dynamic mechanics and thermal stability.The modified nanoparticles could promote those comprehensive properties effectively within a certain amount of fill contents while too much fill contents would form the agglomeration which led to weaken the mechanics at last. However,the nanocomposites blended with TiO₂ displayed the favorable property of UV light resistance.After UV light radiation 240h,the keeping rate of mechanical properties of PC/TiO₂ nanocomposites was obviously higher than that of the neat PC.(4) The preparation of P(MMA-MSMA)/titania/zirconia hybrid materials by Sol-Gel processing and the primarily application in PC.A new transparent hybrid P(MMA-co-MSMA)/TiO₂/ZrO₂ was prepared via Sol-Gel processing and blended with PC resin and thus PC/hybrid composites was prepared. The result indicated that with the inorganic content increasing,the refractive indices increased and ultraviolet absorption became stronger.At the same time,the nanoparticles sizes increased from 20-30nm to 80-90nm and the hybrid materials kept transparent all the time.Besides,the fill of hybrid materials was able to make the tensile strength of PC/hybrid unchanged,bending strength increased appreciably and impact strength weakened.This kind of material also possessed excellent optic property and preferable transparence.When I50 hybrid contained 3.0wt%hybrid,the refractive ratio of composites would change from 300-800nm within which obvious increase was observed and the transparence could be 75%.This work was financially supported by Technical Innovation Team Project of Shanghai Science and Technology Committee(06DZ05902) and the Cooperative Project Between Shanghai University and Essilor Group of France.