Research Of The Control Of Dynamic Voltage Restorerof Distribution Network

Silicone due to Si-O active groups, may be combined with other organic resin to form a new type of resin with excellent performance, and then to recieve wider applications between industries. In my laboratory, siloxane-modified polyesters resins were synthesized with silanol (saturated hydroxy silane) which hydroxyl value was between 7 and 8 as the new modifier.In my experiments, the effects of the synthesis conditions, silicon content on the synthesis process and the properties of modified polyester was mainly discussed. In this paper, effects of reaction temperature, reaction time, catalyst amount, molar ratio of alcohol to acid etc. on the synthesis of silanol-modified polyester resin were researched to determine the synthesis conditions. Siloxane-modified polyesters resins had been influenced by the changes of synthesis process conditions and synthesis process greatly, mainly depended on the degree of Si-O-C bond linked in resins chemically which formed by polymerization reaction of silicon alcohol.In the first experiments, modified saturated polyester resins were synthesized by silanol, 1,2-propylene glycol and adipic acid as mainly raw materials, butyl titanate as catalyst. The optimum synthetic conditions were confirmed as follows:reaction temperature for 200℃, reaction time for 5 h, the dosages of butyl titanate were 0.2%, the molar ratio of 1,2-propylene glycol and adipic acid was 1.3:1, the conversion reached 94.8%. Silicon active groups would be self-polymerization under a certain condition, the tendencies of self-polymerization could be increased with the growth of temperature and silicon content, thus finally affected basic properties of the product. Research showed that the surface activity of polyester-modified was effectively changed while the silicon alcohol content for 3%, surface tension dropped from 47.6 mN/m to 27.1 mN/m.In another experiments, modified unsaturated polyester resins were synthesized by silanol,1,2-propylene glycol, adipic acid and MA as mainly raw materials, butyl titanate as catalyst. The optimum synthetic conditions were confirmed as follows:reaction temperature for 220℃, reaction time for 6 h, the dosages of butyl titanate were 0.2%, the molar ratio of 1,2-propylene glycol and adipic acid was 1.3:1, molar ratio of MA/adipic acid was 1.8:l,the conversion reached 92.4%. Research showed that the surface properties of unsaturated polyester-modified was effectively reduced while the silicon alcohol content for 3.5%, surface tension dropped from 47.6 mN/m to 27.1 mN/m. After curing, properties of modified polyester as follows:anti-impact intensity reached 3.5 kJ/m2, tensile strength was 57 MPa, 5% weight loss by the temperature for 318℃. IR analysis results showed that silanol via Si-O-Si bond andC-C bond forming Si-O-C bond, and connected to the internal structure of polyester resin. Research found that properties of paint film made from siloxane-modified saturated polyesters resins had been improved on different levels:adhesion to 1 level; anti-impact intensity increased to 4.5 MPa, pencil hardness increased to 2 H level; no ever been yellow under the medium-wave ultraviolet irradiation for 72 h, and maintain glossiness basically unchanged.In addition, this laboratory also studies the effect of 1,3,5-Tris(2-hydroxyethyl)cyanuric acid (THEIC) on the properties of modified reins, and found that the THEIC could effectively improved transmittance of modified resin, the transmittance could be raised to above 92%.