【作者】 李立；

【导师】 施利毅；

【作者基本信息】 上海大学 ， 材料学， 2008， 博士

【摘要】 聚合物的高性能与多功能化是近年来高分子材料理论与应用领域研究热点,纳米粒子在聚合物中的填充改性对于开发新型复合材料具有十分重要的意义。本文从熔盐辅助煅烧技术制备小粒径高分散纳米粒子出发,采用偶联剂和聚合物接枝改性的方法对纳米粒子进行表面处理,并与聚碳酸酯（PC）熔融共混制备PC纳米复合材料。考察PC纳米复合材料的力学、耐热、抗紫外老化等性能。并通过溶胶-凝胶法制备了透明杂化体纳米材料,初步探索了该材料与PC树脂共混后的力学和光学等性能。（1）小粒径高分散纳米ZrO₂改性填料的制备与表征分别采用反相微乳液法和反相化学沉淀法结合熔盐辅助煅烧前驱物制备小粒径高分散的纳米ZrO₂。研究不同反应条件、煅烧温度和煅烧方式对纳米ZrO₂晶型和分散性的影响规律。反相微乳液法中,根据电导率的变化配制稳定的TritonX-100/Span85/环己烷/正己醇微乳液体系,为纳米颗粒制备提供微反应器。反相化学沉淀法中,在沉淀过程中加入表面活性剂,通过正丁醇共沸蒸馏干燥前驱物可以防止产物团聚。两种方法得到的前驱物辅以一定比例LiNO₃熔盐煅烧后,产物的分散性均得到明显的提高。优化制备工艺合成小粒径高分散的立方晶相球形纳米ZrO₂,最后讨论了熔盐煅烧对产物分散性的影响机理。（2）纳米ZrO₂粉体表面改性及其PC纳米复合材料的制备与表征以硅烷偶联剂3-甲基丙烯酰氧基丙基三甲氧基硅烷（KH570）接枝改性,聚对苯二甲酸乙二醇酯（PET）接枝聚合改性两种方法对纳米ZrO₂的表面进行有机改性。采用FT-IR,TGA,TEM,XPS接触角等分析了改性前后纳米粒子表面情况,两种改性方法均为化学改性。通过熔融共混法,将未改性ZrO₂、以KH570和PET接枝改性的纳米ZrO₂与PC复合,制得了PC/ZrO₂纳米复合材料,并考查了其力学、动态力学、耐热等性能。结果表明,粉体的加入能提高动态力学性能的储存模量、损耗模量。同时复合材料的耐热性也得到提高。在对力学性能考察时发现,粉体加入能不同程度的提高弯曲强度和模量,但当加入未改性ZrO₂时,复合材料的缺口冲击性能,拉伸性能都变差,而加入ZrO₂-KH570和ZrO₂-g-PET会使复合材料的缺口冲击强度、拉伸性能均随着添加量增加呈现先升高后降低的趋势。由缺口冲击断面的SEM可看出,改性后纳米粉体均匀地分散在PC基体中,具有较好的界面相容性,能够起到增强增韧的作用,填充ZrO₂-g-PET的效果好于ZrO₂-KH570,加入ZrO₂-g-PET的冲击强度最大值要比加入ZrO₂-KH570高出10%以上。同时通过引入TPT公式对三种粒子与PC的界面关系进行了半定量的分析,反映界面性能的B值ZrO₂-g-PET＞ZrO₂-KH570＞未改性ZrO₂,界面性能ZrO₂-g-PET最好。（3）纳米TiO₂粉体表面改性及其PC纳米复合材料的制备与表征通过熔融共混法,将未改性TiO₂、以KH570和PET接枝改性的纳米TiO₂与PC复合,制得了PC/TiO₂纳米复合材料,并考查了其力学、动态力学、耐热及抗紫外老化等性能。结果表明,所得PC/TiO₂纳米复合材料的力学、动态力学及耐热等性能均有不同幅度改变,改性后的粉体能在一定添加量内能有效提高综合性能,但过大的添加量会产生团聚导致力学性能下降。同时,添加了TiO₂的纳米复合材料显示出良好的抗紫外老化性能,紫外光照射240h后,材料的力学性能的保持率明显高于未加入改性TiO₂粉体的纯PC。（4） P（MMA-co-MSMA）/TiO₂/ZrO₂杂化体的制备及在PC中应用初探通过溶胶-凝胶法制备了均相透明的P（MMA-co-MSMA）/TiO₂/ZrO₂新型杂化体（hybrid）材料,并将其与PC树脂共混,得到了PC/hybrid复合材料。研究结果表明,随着无机组分的增加,杂化体的折射率提高,紫外吸收增强。同时,当纳米粒子粒径由20-30nm增大到80-90nm时,杂化体始终保持透明。另外,杂化体的添加,使得PC/hybrid复合材料拉伸强度保持不变,弯曲强度略有上升,而冲击强度下降。复合材料显示出优异的光学性能,具有较好的透明性。当150杂化体含量为3.0 wt%时,复合材料的折射率在300-800nm内均有较大幅度的提高,同时透光率可达75%。更多还原

【Abstract】 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.更多还原