The Study Of The Surface Modification And Characterization And Interface Property Of Potassium Titanate Whiskers

Among all composites, fiber-reinforced composites are most widely applied. Thefilled fibers have developed from fiberglass to carbon fiber. Crystal whiskers are thestrongest fibers ever known. So many countries' scholars are paying much attention toit in recently 20 years.Potassium titanate whisker is the best in the performance-price rate among allcrystal whiskers and it has been produced in large scale in industry. Because it issteady in chemical property and excellent in mechanical performance, it can be usedas filler and friction material of composites. It's different to fiberglass in size and it ismore exiguous than fiberglass. Comparing with fiberglass, it can be used to makecomplicated, precise, tiny, thin-walled, and glossy composites.Comparing with fiberglass, it is more exiguous and easy to agglomerate, whichaffects the dispersing in polymers. At the same time, the surface of potassium titanatewhiskers is hydrophilic, so interface interaction is very weak and the integratedmechanical performance is not good. The interface interaction is the key factor.Therefore, it's necessary to modify the surface of potassium titanate whiskers. It canmake the potassium titanate whiskers from hydrophilic to hydrophobic. And surfacemodification can decrease the surface energy and polar components, increase thedispersion quality and the degree of interface adhesion.This paper focuses on the study of dispersion quality and the interface interactionin composites. The main idea is to introduce a new layer between the potassiumtitanate whiskers and the polymer, which can change the physical-chemistry propertyand improve the dispersion quality and the degree of interfacial adhesion.The paper discussed the theory of agglomeration and dispersion and the styles ofdispersion. According to the study, the potassium titanate whiskers are uniformlydispersed in water when pH is from 8 to 12. The dispersion quality will increase whenthe surface energy decrease after surface modification. The study also shows that theprogress of the dryness has much effect on the dispersion of potassium titanatewhiskers. This main is due to the liquid bridges exist in whiskers. The study showsthat we can make monodispersed whiskers by spray drying process in large scale inindustry.The paper discussed the influence of two kind of coupling agents to the surfaceproperties. The study shows that the surface energy of potassium titanate whiskers III英文摘要modified by silane coupling agent is lower than by coupling agent of ester titanate.According to the changed surface properties, we can forecast that the compositesreinforced by modified potassium titanate whiskers by silane coupling agent will havea great improve in mechanical performance which was proved it by experiment.This paper first investigated a method of modifying potassium titanate whiskers(K2O·6TiO2) to obtain polymethyl methacrylate (PMMA)/K2O·6TiO2 compositeparticles through emulsion polymerization. The influences of the reaction time, theinitiator concentration, monomer concentration and the reaction temperatures on theefficiency of conversion or percentage of weight gain were investigated in details.Optimal conditions have been found to reach high conversion efficiency. According tothe characterization of FTIR, SEM, EDS and TGA, the surface of potassium titanatewhiskers was modified through covering PMMA on its surface and the compositeparticles have core-shell structure. The characterization of surface energy andinterfacial tension showed that the interface property of modified whiskers haschanged thoroughly and it was similar to that of PMMA, so the whiskers werecovered by PMMA thoroughly. It resulted in the potassium titanate whiskers weremodified from hydrophilic to hydrophobic and the dispersion of whiskers in organicliquids had been improved greatly. According to the characterization of dynamicwetting capacity, the optimal content is about 3.4%.The paper first investig...