有机硅丙烯酸酯改性水性聚氨酯的合成与性能

Synthesis and Properties of Silicone Acrylate Modified Waterborne Polyurethane

摘要:

以异佛尔酮二异氰酸酯(IPDI)、γ-氨丙基三乙氧基硅烷(KH550)、甲基丙烯酸甲酯(MMA)、γ-（甲基丙烯酰氧基）丙基三甲氧基硅烷(KH570)等为原料，合成了水性聚氨酯预聚体(WPU)、聚丙烯酸酯(PA)、有机硅改性的水性聚氨酯预聚体(SiWPU)和有机硅改性的聚丙烯酸酯(SiPA)，然后以WPU、SiWPU、PA、SiPA为原料，采用互穿网络聚合法合成了有机硅丙烯酸酯双重改性水性聚氨酯(SiWPUA)等改性WPU，通过测定吸水率和水接触角考察了PA、SiPA、SiWPU含量对胶膜耐水性能的影响并分析了反应机理。结果表明：SiWPU-40%-SiPA-37.5%〔40%为SiWPU的含量（以WPU和SiWPU总质量为基准，下同）；37.5%为SiPA在体系中的质量分数〕胶膜吸水率从改性前样品WPU的37.4%降低至改性后的6.8%，接触角从56.8°增至86.4°，铅笔硬度从改性前的HB提升至H。热重分析显示，Tmax（样品热分解速率最大时的温度）从改性前的340.2℃提升至412.4℃；TEM表明，改性后的乳胶粒形成了核壳结构，XRD和断面的SEM显示PA和有机硅改性均增加了聚合物的交联度。

Abstract:

Waterborne polyurethane prepolymer (WPU), polyacrylate (PA), silicone modified waterborne polyurethane prepolymer (SiWPU) and polyacrylate (SiPA) were synthesized using isophorone diisocyanate (IPDI), γ-aminopropyltriethoxysilane (KH550), methyl methacrylate (MMA) and γ-(methacryloyloxy)propyltrimethoxysilane (KH570) as main raw materials. Then, silicone acrylate double modified waterborne polyurethane (SiWPUA) emulsions were synthesized by interpenetrating network polymerization using WPU, SiWPU and SiPA as raw materials. The effects of PA addition amount, SiPA addition amount and SiWPU addition amount on the water resistance of the emulsion films were investigated by measuring water absorption rate and water contact angle and the mechanism was analyzed. The results showed that the water absorption rate of SiWPU-40%-SiPA-37.5% (40% is the content of SiWPU based on the total mass of WPU and SiWPU, the same below, and 37.5% is the mass fraction of SiPA in the system) film was reduced from 37.4% before modification to 6.8%, the contact angle was increased from 56.8° to 86.4°, and pencil hardness was increased from HB to H. Thermogravimetric analysis demonstrated that the Tmax (the temperature at which the decomposition reaction occurs) of SiWPU-40%-SiPA-37.5% was 412.4℃, higher than that of WPU (340.2℃). TEM results revealed that the modified latex particles had a core-shell structure. SEM of film section and XRD results showed that both PA and silicone modification increased the crosslinking degree of the polymer.