Study On The Synthesis Of High Temperature Resistant Phenolic Resol Resins And Its Modification

Phenolic resol resins(PF) possess many excellent properties and are widely utilized in many fields as a high performance thermosetting resin for many industrial applications. However, most thermosetting materials have many disadvantages, such as the great brittleness in the cured state and low heat-resistance.So it is difficult to fit for the requirements of the developing engineering technology and restricts its application in some special occasion. Therefore it is very important to enhance its heat resistance or composites'heat resistance.In this paper, molybdenum-phenolic resol resins were sythetised at first, and then, various analysis techniques were used in studying the physicochemical characterization of modified molybdenum-phenolic resol resin. Some advanced composites, such as molybdenum-phenolic resol resins modified with LNBR or SiO2. The composition, structure, curing reaction, mechanics performance and other properties related to performance of modified resin matrix were studied.(1)The conditions, mainly molar ratios between phenol,formaldehyde and molybdenum acid, temperature and reaction time, under which reactions of phenol formaldehyde and molybdenum acid were carried out, were studied. The modified has its best performance when molar rates=1:1.2:0.06,T=90℃,time=40min.The process of curing was studied by means of IR, DSC. Using DSC technique, the curing kinetics of the system was performed based on Kissinger model under dynamic curing conditions. Ideal curing temperature was simulated. Thermal mechanics performance, dynamic mechanics performance and phase structure were studied by DSC,DMA and SEM.(2)The novel composites matrix were prepared by the molybdenum-phenolic resol resins and liquid NBR. The modified has its best performance when the amount of LNBR was 6phr.The process of curing was studied by means of IR. Thermal mechanics performance, dynamic mechanics performance and phase structure were studied by DSC,DMA and SEM.(3) Nano-SiO2which after Surface modification with coupling agents were added to the system, and FTIR spectrums approved that the molecule of KH-550 effectively gratfed to the surfaces of nano-SiO2.The dosages of fillings and coupling agent were examined via their mechanical properties. The additions of nano-SiO2 played an important role in heat-resistance and mechanical properties. Dynamic mechanical analysis (DMA) and thermo-gravimetric analysis(TGA)charactered the heat-resistance of the modified resins. Nano-SiO2 made glass transition temperature(Tg) and heat decomposition temperature separately improve.The mechanical properties of nano-SiO2 is improved also.