| On the basis of BPF epoxy, which has obviously advantage on viscosity, novel organo-silane modifiers were designed and synthesized for improving toughness, thermal resistance and furthermore decreasing viscosity. And their modification results were studied. A kind of novel modifier with low viscosity was obtained and its synthesis technique was determined. It can increase the toughness and strength of the cured epoxy resin, while the thermal resistance remaining. The modification mechanism of the novel silane was studied. Considering the requirements of vacuum assisted molding technique, for the resin having low viscosity and being cured at relatively low temperature, modification of BPF epoxy by copolymerization and blending was studied also, and formular of the cured system was optimized. Rheological behavior of the matrix during the curing process was studied. A rheological model based on Dual-Arrhenius Equation was used to simulate rheological behavior of the matrix. The processing window of the resin and the optimum processing condition can be well determined by the established model. The main results of this paper are as follows:1. Calculation results of the solubility parameter and the force function between molecules of the designed epoxy-group terminated two functional aliphatic polysiloxane, dihydroxyldiphenoxydimethyl silane and 3,3 , ,3 ,, --trihydroxyltriphenoxymethyl silane triglycidyl ether showed that the solubility parameter of all these novel modifiers are higher than that of poly(dimethyl siloxane) and thus can improve their compatibility with the epoxy. These three modifiers are different in polarity, dispersion force, hydrogen bond and solubility parameter. The solubility parameter of 3,3,,3,,-trihydroxyltriphenoxymethylmethyl silane triglycidyl ether is the most similar to that of epoxy resin.2. Semi-empirica-M1 and Molecular Dynamics in HyperChem 7.0 were used to optimize synthesis reaction of 3,3,-dihydroxyldiphenoxydimethyl silane. It was shown that synthesis of 3,3,-dihydroxyldiphenoxydimethyl silane by dimethydiethoxyalkoxy silane and dihydroxybenzene was of advantage according to thermodynamic calculation results.3. The preferred synthesis condition of 3,3,,3,,- trihydroxyltriphenoxy methyl silane was as follows: The mixture of 1,4-dihydroxybenzene and methytriethoxyalkoxy silane reacted at 100℃for 9h, and then 120℃for 6h followed by 140℃2h under N2 condition, during which by-producer alcohol was moved from the reaction system continuously. In order to increase producing ratio of the target molecule, product of the substitution reaction can be directly used in the followed epoxide procedure, during which the excessive reactant can be changed into epoxy resin also. The mole ratio of ECH to the substitution product was nearly 10:1. Externalization temperature was 90℃, reacting for 5~6h. Closed loop reaction temperature was 60℃, the total amount of alkali added 2% greater than the theoretical one. Alkali was added evenly in nine times in 1.5h . Then the excessive ECH was distilled and the second closed loop reaction was undertaken in tulent solvent at 80℃for 1h. Epoxy value of the distilled product synthesized was 0.594~0.650mol/100g,the viscosity of which being 900~1050 mPa·s at 25℃.4. Epoxy-group terminated two functional aliphatic polysilane and dihydroxyldiphenoxydimethyl silane modifier can improve the mechanical properties of the epoxy resin, but Tg temperature decreased somewhat. 3,3,,3,,-trihydroxyltriphenoxy methyl silane triglycidyl ether can improve the tensile strength and flexural strength of the cured epoxy resin by 10.4% and 53.6% ,respectively. The thermal expansion coefficient below Tg reduced about 18.8%, the internal stress index decreased about 22.8% and the crack resistance index increased about 52.2%. Meanwhile, Tg temperature of the cured epoxy hardly decreased.5. The mechanism of novel organo-silane 3,3,,3,,-trihydroxyltriphenoxy methyl silane triglycidyl ether modified epoxy resin was different from that of normal polysilaxene modified epoxy. It has influence on the crosslinking reaction speed and character of the curing process, increasing the motion ability of polymer chain, which resulting an important influence on the structure and properties of the cured epoxy resin.6. The viscosity of BPF epoxy greatly decreased when modified by novel organo-silane, copolymerization or blending with novel diluent CHD. Mechanical properties and thermal resistance of the cured epoxy modified either by copolymerization with resorcinol or by novel organo-silane were improved. The viscosity of BPF epoxy changed from 3550mPa·s to 1300mPa·s when 10% weight content of CHD was added ,the mechanical properties of the cured epoxy decreasing by 10%. When the content of CHD increased up to 30%, there is only slightly additional decreasing in mechanical properties, but the viscosity of the modifiied epoxy resin decreased greatly.7. TEA cured BPF epoxy had a long pot temper life. When cured by 20% TEA at 60℃for 8h, the tensile strength and flexural strength of the cured epoxy were 78.5MPa and 106.0MPa respectively.The Tg temperature was 106.0℃. TEA cured epoxy resin could resolve the inconsistency between low-temperature-curing and prolonging the pot life, and the inconsistency between low-temperature-curing and high thermal endurance of the cured epoxy.8. A rheological model based on Dual-Arrhenius Equation was used to simulate rheological behavior of TEA cured BPF epoxy resin in curing temperature range of 40~90℃. It was shown that in the studied temperature range the simulated rheological behavior was well accordant with the experimental results in a certain time range.9. TEA cured BPF epoxy resin has long time low viscosity window under the processing schedule of rejecting at 40℃and curing at 80℃. The rheological behavior under this condition, which was determined by the reaction characteristic, can meet the requirements of Vacubm Assisted Resin Transfer Molding.
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