DSC法研究乙二醛-尿素树脂的固化性能

为从源头上降低UF树脂及其胶合板材的甲醛释放对环境和人体健康所造成的危害,选用乙二醛(G)取代甲醛(F)与尿素(U)反应,制备乙二醛-尿素(GU)树脂。用差示扫描量热分析(DSC)方法研究了原料物质的量比、反应pH、反应时间、反应温度、pH调节剂对所合成GU树脂固化性能的影响规律;并用不同原料物质的量比的GU树脂制备刨花板并测定了其各项性能。结果表明,GU树脂的较优合成条件为:在弱酸性条件下,乙二醛与尿素物质的量比(G/U)=1.2∶0～1.4∶1.0,反应温度70～80℃,反应时间3h;此条件下合成的GU树脂胶合的刨花板内结合强度IB达到0.44MPa、弹性模量MOE达2298MPa、静曲强度MOR为10.5 MPa,且无甲醛释放。

Study on curing Properties of Glyoxal-Urea Resin by DSC

At present, although a large number of studies on how to reduce the release of the UF resin, the formaldehyde release mechanism of the UF resin can not be fundamentally solved according to the formaldehyde release mechanism of the UF resin, and the formaldehyde release problem of the UF resin can not be fundamentally solved. To reduce the UF resin and its plywood material from the source In this paper, Glyoxal-urea(GU) resin was prepared by the reaction of Glyoxal(G) instead of formaldehyde(F) with urea(U). The effects of molar ratio of raw materials, reaction time of pH, reaction temperature and pH regulator on the curing properties of GU resin were studied by differential scanning DSC(DSC).The particle board was prepared by GU resin with different molar ratio of raw materials and its properties were measured. The results showed that the optimum synthesis conditions of GU resin were as follows: under the condition of weak acidity, the molar ratio of Glyoxal to urea was G/U=1.2∶1.0. Under the conditions of～1.4≤1.0, reaction temperature 70×80 ℃ and reaction time 3 h, the bonding strength IB, elastic modulus MOE, static bending strength MOR and formaldehyde release of GU resin bonded particle board reached 0.44 MPa, 2298 MPA and 10.5 MPa, respectively.