三聚氰胺/纳米TiO_2联合改性脲醛树脂胶粘剂研究

Study on the adhesive of urea-formaldehyde resins modified with melamine/TiO_2 nanoparticles

以甲醛、尿素为原料,纳米TiO_2和三聚氰胺为改性剂,采用"碱-酸-碱"的合成工艺合成脲醛树脂,并对三聚氰胺/纳米TiO_2联合改性脲醛树脂工艺进行优化。研究结果表明:当纳米TiO_2用量不变,脲醛树脂的黏度、固含量、胶合强度随三聚氰胺加入量增加而增大,而固化时间和游离甲醛含量则呈现出相反的变化趋势;添加w(三聚氰胺)=1.5%(相对于尿素添加质量而言)改性后的脲醛树脂游离甲醛含量为0.41%,耐水胶合强度为1.25 MPa,对不同配比的甲醛/尿素(F/U)脲醛树脂,三聚氰胺/纳米TiO_2联合改性性能相似;改性后的脲醛树脂及纳米TiO_2能够均匀分布于木材表面,以保证较好的胶合强度和联合改性效果。

Urea-formaldehyde resins were synthesized by an alkali-acid-alkali synthetic method using formaldehyde, urea, melamine, and TiO2 nanoparticles. The process for the melamine and TiO2 nanoparticles modified UF resin synthesis was further improved.The research results showed that with a fixed amount of TiO2 nanoparticles, the viscosity, solid content, and bonding strength of the UF resin were increased with the increase of melamine content, while the curing time and free formaldehyde content were decreased. When adding with 1.5% mass fraction of melamine, the free formaldehyde content of the UF resin was 0.41%, the wet bonding strength was 1.25 MPa.However, melamine and TiO： nanoparticles had little effect on the properties of UF resins with the change of formaldehyde to urea （F/U） proportion ratio. The modified UF resin and the TiO2 nanoparticles could distribute uniformly on the wood surface to ensure a better adhesion strength and good synergistic effects.