| Bubble is a common phenomenon in daily life, theexcessive foamcan bring adverse effects of different degree, so the defoamer was used as essential additivesin the industrial production. According to the different of defoaming active substances, the defoamertypes can be divided into four main kinds: animal oil, mineral oil, polyether and organic silicon. The polyether modified silicone defoamer was most widely used. Based on above, different long chain alkyl ester and polyether modified silicone oil was designed. It was used as the monomer of antifoaming activity owner and made emulsion. The defoaming performance was researched. The main results were as follows:(1) the preparation of long chain alkyl ester: tetradecyl methacrylate(TMA) was obtained under the catalysis of p-toluene sulfonic acid, hydroquinone as inhibitor from esterification reaction of using methyl acrylic acid and tetradecyl alcohol as raw materials. Through orthogonal experiment and range analysis the optimized reaction conditions were obtained: reaction temperature is 130℃, reaction time is 6 h, the mass fraction of catalyst(relative to the total quality of reactant) is 1.5%, the mole ratio of n(acid):n(alcohol)= 1.1:1, the esterification rate is 94.88%. The lauryl methacrylate(LMA) and hexadecyl methacrylate(CMA) are prepared through the same process, the esterification rate are 94.26% and 93.67% respectively. The degree of esterification of LMA/TMA/CMA is high, the product are brownish red, and the viscosity are smaller. The long chain alkyl methacrylate has already been characterized by infrared spectrum and nuclear magnetic hydrogen spectrum, and it also was affirmed by functional analysis and the experiment itself.(2) The preparation of the long chain alkyl methacrylate(LMA, TMA, CMA), polyether(FB) modified silicone oil(PHMS): The long chain alkyl ester, polyether modified silicone oil(P1/P2/P3)was obtained through silicon hydrogen addition reaction by using LMA, TMA, CMA and FB as raw materials, H2 Pt Cl6·6H2O as catalyst. Reaction temperature, reaction time, catalyst dosage, n(Si-H):n(C=C)(silicon double bond and hydrogen mole ratio) on the influence of Si-H conversion on the modified silicone oil were discussed and analysed. And through the orthogonal experiments and range analysis the optimized P1 reaction conditions were gained:reaction temperature is 90℃, reaction time is 6 h, 6 H reaction temperature 90 ℃, reaction time, the dosage of catalyst is 30μg·g-1, n(Si-H):n(C=C)= 1:1.20. Under the reaction conditions the conversion rate of Si-H could reached 93.45%. The best preparation conditions of P2: reaction temperature is 95℃, reaction time is 6 h, the dosage of catalyst is 30μg·g-1, n(Si-H):n(C=C)= 1:1.20. Under the condition of the reaction, the conversion rate of Si-H could reached 92.75%. The best preparation conditions of P3: reaction temperature is 95 ℃, reaction time is 6 h, the dosage of catalyst is 30μg·g-1, n(Si-H):n(C=C)=1:1.20. the conversion rate of Si-H could reached 91.39%. The long chain alkyl methacrylate and polyether has been introduced into the main chain of the silicone oi, This results were explained By IR, 1H NMR analysis of modified products and product properties, reaction phenomena, it’s in accord with the expected design. The tension test results of the modified silicone oil surface shows that P1, P2 and P3 minimum surface tension are 22.236 m N/m, 21.881 m N/m and 22.033 m N/m.(3) Silicon defoamer emulsion was prepared by compound of paste, P1/P2/P3 and emulsifier. P1 optimized formulation: the mass fraction of the silicon paste( m(dimethyl silicone oil):m(hydrophobic silica) = 95:5) is 10%, the P1 mass fraction is 6%, the mass fraction of HLB = 9.5 ternary compound emulsifier is 4%(including m(Span 60):m(Tween 60):m(OP-10) = 3:2:1).The optimized formula of P2 and P3 defoamer emulsion: m(dimethyl silicone oil):m(hydrophobic silica)= 95:5, the mass fraction of silicon paste is 10%, the mass fraction of P2/P3 is 6%, the mass fraction of HLB= 10 ternary composite emulsifier(S60:T60:OP-10= 4:3:2) is 4%. In this condition, the P1/P2/P3 latex has good foam suppression performance, good appearance, stable character,good storage.After elimination suppression performance evaluation,foam suppression performance is P2>P3>P1. |
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