| Acrylate copolymer latex were Synthesized by seeding emulsion polymerization. The ratio of soft monomers/hard monomers of acrylate copolymer is 1: 2. emulsifier V and OP-10 as multi- emulsifier and when the quality ratio is 1: 1 the latex has best integrated performance, conversion of acrylate monomers reach 90%. Discussed the effect of synthesized process to the performance of latex. The monomers have high conversion when the content of initiator is 0.2% and speed of the reaction is well situated. The best temperature of the reaction is 85℃.On the basis of synthesizing acrylate copolymer latex, siloxane was used to synthesize the Siloxane-modified acrylate copolymer latex. The modified latex was transparent or translucent and bright bluish. The particle size distribution of the latex was relatively narrow and the diameter of modified emulsion particles was controlled at about 90nm. With good mechanical performance, outstanding withstanding to chemical, good freeze-thaw stability and excellent water-resistance, the Siloxane-modified acrylate copolymer latex had a broad foreground to apply in many fields such as inner decoration, protecting coating in industry and finishing coatings of leather and fabric. In the meanwhile, the possible reactions of siloxane was discussed and the methods of how to control the reactions were bring forward. FTIR was used to token that siloxane participated the co-polyreaction reaction. DSC was used to token that the Tg of the latex had a low depress and it is about 33.7℃. TEM was used to token that the distribution of the particle size of the latex was well-proportioned.The principium of the acrylate copolymer co-polymerization reaction was studied through quanta chemic calculation. The result of quanta chemic calculation shows that the standard enthalpy of the dimmer of MMA and BA is -82. 12580 kJ/mol, the standard Gibbs energy is -6. 93987 kJ/mol, the decrease of entropy is -42. 621 Cal/Mol-K. Because of△H＜0,△S＜0,△G△0, so, if without any exterior force, we can not get the dimmer of MMA and BA. With APS as initiator, the carbon atom on double-bond in molecule of acrylate copolymer was excitated and outside electron arose transition and reach a position with high energy. The result of molecule orbit approved that the double-bond in molecule of acrylate copolymer changed and was on the place of excitated position. The IRC calculation to acrylate copolymer shows that in the process of the reactions to form of the chain and to increase of chain the reactant must get energy to get over activation energy and reach to transition state which has high energy position. The transition state is unstable and it will release energy and get resultant with lower energy. The reaction to form of the chain has a low activation energy. The activation energy of transition state to reactant is about 36.96kJ/mol. The released energy of transition state to resultant is about 36.96kJ/mol, the reaction is easy to realize. The reaction to increase of the chain also has a low activation energy. The activation energy of transition state to reactant is about 35.43kJ/mol kJ/mol. The released energy of transition state to resultant is about 47.35kJ/mol. the whole process of the two reactions to form of the chain and to increase of chain are the same, released energy.
|
PDF Full Text Request