Preparation And Application Of Hyperbranched Silicone Oil

So far the studied matrix materials are mainly high polymerization degree straight-chainpolysiloxane （such as methyl silicone rubber, methyl vinyl silicone rubber and methyl phenylvinyl silicone rubber） and silicone oil （such as dimethyl silicone oil and low-phenyl siliconoil）, which are used for the buffer clay. The viscosity and cushioning properties of buffer clay,which takes high polymerization degree straight-chain polysiloxane and silicone oil as thematrix materials, usually decrease with the rise of the system’s temperature. Especially above100°C, the performances decline dramatically, which has a significant impact on thecushioning properties of buffer. Through the study of the relationship between clay’s andsilicone oil’s structure, we can find that the viscosity-temperature coefficient of linear siliconeoil is large. The key point which leads to the decline of clay viscosity is the low viscositycaused by high temperature.Hyperbranched silicone oil as an important branch of organosilicone dendrimer, due totheir unique physical and chemical properties, they have a widely potential applicable value invarious fields. The viscosity of hyperbranched silicone oil will change greatly according tothe different length of the branch chains. If the molecular chain’s length among branchingpoints is longer than the critical chain’s, the entanglement between molecules will beincreased. At high temperature, molecular chains of the hyperbranched silicone oil is not easyto be formed orientation under shear, shear-thinning and the phenomenon of viscosity declineis difficult to be formed. It can keep the viscosity of system. Thereby viscosity decline of thebuffer clay can be resolved. The relationship between hyperbranched silicone oil and apparentviscosity is studied through the design of silicone oil with different branch-chain’s length,which has a great significance for revealing the motion law of complex structure silicone oil’severy structure unit, the relationship between structures and properties, silicone oil and filler,etc.However, due to Si-O-Si main chain’s worse selectivity and harder controllable structurethan Si-C main chain’s, as well as the damage on hyperbranched structure easily caused bySi-O-S chain’s equilibrium reaction, so far there are only some reports about the synthesis ofthe hyperbranched macromolecules which takes Si-O-Si structure as main chain. This thesis takes hydrosilylation method and two-step method to prepare Hyperbranched silicone oil Aand Hyperbranched silicone oil B. The specific program is as following:Take low polyhydrosiloxane and vinyl terminated methylphenyl silicone oil as main rawmaterials, Chloroplatinic acid solution in isopropanol as catalyst. Hyperbranched silicone oilA was prepared through hydrosilylation. The experiment showed that the optimum conditionsto synthetize hyperbranched silicone oil A is as follow, N₂is passed into, the reactiontemperature80⁹0℃, Chloroplatinic acid dosage60μg/g, the mol ratio of Si-H bondSi-CH=CH₂（Si-Vi）bond is2to1.Intermediate branched product was prepared using low H-silicone andVinyltriethoxysilane （A151）as original reactants through hydrosilylation reaction under pt/IPA’s catalysis. The alkyl oxidation reaction was made by intermediate branched product andhydroxy silicone oil under sodium methylate’s catalysis, then hyperbranched silicone oil Bwas prepared.Finally,1H-NMR was used to characterize the structure of intermediate branched productand hyperbranched silicone oil A and B. Huck torque rheometer rotational viscometer andthermal gravimetric analysis （TG） were used to characterize hyperbranched silicone oil B’sperformance. The dynamic performance, rheological properties and thermal properties ofHyperbranched silicone oil A and B and straight chain phenyl silicone were compared.The three buffer clays were prepared through surface-treated fillers （wollastonite powder,carbon soot, molybdenum disulfide and fume colloidal silica） wre added into hyperbranchedsilicon oil A, B and straight chain phenyl silicone oils by Huck torque rheometer. Variation ofequilibrium torque was determined under different temperature and rotational frequency.Rheological law of the three buffer clays was compared under different temperature. Analysisof TG of the three buffer clays was made, and the variation of TG of three buffer clays wascompared.