超声波与纳米TiO_2改性脲醛树脂的研究

Urea-formaldehyde resin modified by nano-TiO_2 under ultrasonic treatment

为了降低脲醛树脂的游离甲醛含量及其胶接制品的甲醛释放量,采用超声波技术,在脲醛树脂合成的过程中加入纳米TiO2对脲醛树脂进行改性。通过改变超声频率和纳米TiO2的添加量考察了其对脲醛树脂的黏度、固化时间、游离甲醛含量及胶合板的甲醛释放量和胶合强度的影响。结果表明:超声频率和纳米TiO2添加量对脲醛树脂甲醛释放量和胶合强度影响显著。当超声频率为28 kHz、纳米TiO2的添加量为0.05%时,树脂的游离甲醛含量降低了77.8%,胶合板的胶合强度提高了155%,甲醛释放量降低了68.3%。13C-核磁共振分析显示,在超声波的作用下,纳米TiO2改性脲醛树脂中有Uron-CH2-Uron结构存在。

In order to decrease free formaldehyde of urea-formaldehyde （UF） resin and therefore to lower the formaldehyde emission level of its products, UF resin was modified by adding nano-TiO2 and applying ultrasonic dispersing technology. Effects of ultrasonic frequency and addition amount of nano-TiO2 on viscosity, curing rate, free formaldehyde content of UF resin, formaldehyde emission level and bond strength of plywood with this kind of resin were evaluated. The results showed that viscosity and curing rate were affected by ultrasonic frequency and addition amount of nano-TiO2 indistinctively ; when ultrasonic frequency was 28 kHz and the addition amount of nano-TiO2 was 0.05 % of UF resin solid content, compared with normal UF resin, free formaldehyde content of modified UF decreased by 77.8 %, bond strength of plywood enhanced about 155% and formaldehyde emission level of plywood with this kind of resin decreased by 68.3%. 13C-NMR analysis indicated that Uron-CH2-Uron structure was found in modified UF resins.