Silicon Modified High Performance Phenolic/Epoxy Resin:Preparation And Properties

In this dissertation, on the basis of the comprehensively review of the research progress on high performance phenolic resin, we intend to solve two key issues in phenolic resin applications by silicone modification:1. Improve the electrical and processing properties of phenolic resins; and 2. Substitute glass fiber with sisal fiber to reinforce phenolic molding compound, and overcome the defects brought by sisal fibers, such as low flame retardancy and poor mechanical strength by silicone modification. For the first issue, we prepare silicone modifier by hydrosilylation of silicone and bio-resourced eugenol, and further prepare silicon modified phenolic resin by in-situ polymerization. The silicone modifier improves phenolic resin’s processing properties (low viscosity, good fluidity). Besides, it also enhance phenolic molding compounds’volume electrical resistance from 1014 Ω·m to 1016 Ω·m . Thence the silicon modified phenolic molding compound is suitable for microelectric insulation. As to the second issue, silicone modifier altogether with layered double hydroxide can overcome the negative effects of sisal fiber improving their flame retardancy and mechanical properties. The LDH contained silicon modified sisal fiber reinforced phenolic composites’total heat release rate (according to Cone Calorimeter Test results) can be reduced to 20 MJ/m2 (compared with 27 MJ/m2 of unmodified samples). All these researches build up foundation for developing cost-effective and environemtal friendly high-performance thermoset composites.Researches on epoxy resin mainly focus on improving thermal stability, flame retardancy, and mechanical strength. According to published literatures, novel types of epoxy curing agents, functional nano fillers and bio-based epoxy are three directions for epoxy. Thence, we did our job according to these aspects.Siloxane contained amine curing agents have stable molecular structure, low curing temprature and low curing activation energy. Thus they have high industrial application value. However, there is few reports on this area. We take byproducts of silicone industry as raw materials to produce novel silicone contained aliphatic amine, and further study their isothermal/nonisothermal curing behavior with epoxy resins. All the data provide theroetical base for their industrial applicatoin.Layered Double Hydroxides (LDHs) have been proved to be effective in improving flame retardancy of PE, PP and PUR. However, their effectiveness in epoxy need further research. Besides, according to previous research, LDH lead to negative effect on polymer’s mechanical property. Thus, we synthesize novel silicone intercalater to modify LDH, try to improve property of epoxy. The limited oxygen index (LOI) of LDH modified epoxy achieves 27.5. Interestingly, the epoxy’s impact strength is enhanced as well, from 7.5 kJ/m2 (pure epoxy) to 10 kJ/m2.Previous research on bio-based epoxy are focused on synthesis process, rather than properties (especially flame retardancy). We incorporate silicone into bio-based epoxy, and find that the flame retardancy is largely improved. The limited oxygen index (LOI) of phenyl contained silicone modified bio-based epoxy achieves to 31. Our work provide a method for improvement in bio-based epoxy properties.