纳米SiO_2改性聚氨酯胶粘剂的制备及性能研究

Study on preparation and properties of polyurethane adhesive modified by nano-SiO_2

采用预聚体一步法制备了单组分湿固化nano-SiO2(纳米SiO2)改性PU(聚氨酯)胶粘剂,并利用红外光谱(FT-IR)法、热失重分析(TGA)法、差示扫描量热(DSC)法和扫描电镜(SEM)等对nano-SiO2改性PU胶粘剂的性能进行了分析和探讨。结果表明:纳米粒子的存在使PU的氢键结构发生了变化;随着nano-SiO2含量的不断增加,改性PU胶粘剂的初始粘接强度和最终粘接强度均呈先升后降态势,并且在w(nano-SiO2)=1.2%(相对于PU预聚体质量而言)时相对最大,而且分别比纯PU胶粘剂增加了117%和108%;同时,与纯PU胶粘剂相比,用1.2%nano-SiO2制备的PU胶粘剂,其熔融温度和分解温度分别提高了2.67℃和2.92℃;当w(nano-SiO2)≤1.2%时,nano-SiO2在PU胶粘剂基体中的分散性相对较好。

An one-component moisture-curing PU （polyurethane） adhesive modified by nano-SiO2 was prepared by prepolymer one-step method,and the properties of PU adhesive modified by nano-SiO2 were analysed and discussed by infrared spectrum （FT-IR）, thermo-gravimetric analysis （TGA）, differential scanning calorimetry （DSC） and scanning electron microscopy（SEM） methods. The results showed that the presence of nano-particles shall change PU＇s hydrogen bond structure. The initial bonding strengths and ultimate bonding strengths of modified PU adhesive had all trend of rise-fall with increasing nano-SiO2 contents,and had relatively maximal value when mass fraction of nano-SiO2 was 1.2% in PU prepolymer,which maximal initial bonding strength and uhimate bonding strength of modified PU adhesive were 117% and 108% respectively more than those of pure PU adhesive. At one time,the melting temperature and decomposing temperature of PU adhesive made by 1.2% nano-Si02 were 2.67 ℃ and 2.92 ℃respectively more than those of pure PU adhesive. The dispersibility of nano-SiO： in PU adhesive matrix was relatively better when mass fraction of nano-SiO2 was not more than 1.2%.