稻草中密度纤维板用改性脲醛树脂的研究

对比三聚氰胺、二甲基硅油、硅树脂和偶联剂KH-550四种改性剂改性的脲醛(UF)树脂性能的差别及其对稻草中密度纤维板性能的影响,并进行经济评价,最终确定适用于稻草纤维板的改性UF树脂的工艺条件,同时借助于红外光谱(FT-IR)和差热扫描分析(DSC)研究最佳改性UF树脂的结构和固化特性.结果表明,三聚氰胺改性脲醛(MUF)树脂不论是对树脂性能、板性能改善还是从成本分析方面均为稻草纤维板最佳的胶黏剂,FT-IR显示出与未加三聚氰胺相比,加入三聚氰胺后树脂的羟甲基含量降低了10 %,DSC分析则表明其峰值温度有较大幅度的提高,但放出的热量较少.加入三聚氰胺改性的UF树脂其表面张力变小.

Study on Modified Urea-formaldehyde Resin for Rice-straw Medium Density Fiberboard

In order to prepare modified urea-formaldehyde (UF) resin suitable for manufacturing rice-straw medium density fiberboard (MDF), the differences among properties of modified UF resins were investigated,including the influences on the properties of rice-straw MDF bonded with UF resin modified with melamine, KH-550, dimethyl silicon oil and silicone resin respectively. The results showed that UF resin modified with melamine (MUF) was effective to bond rice-straw fiber boards, which could improve the properties of board and had an reasonable cost. Analyses by FT-IR, UF and MUF resins showed similar curve shapes. MUF resin was water-proof with more amino groups and fewer methylol. DSC results showed that MUF resin demanded higher curing temperature compared to UF resin. The surface tension of MUF resin was 6.3 % less than that of UF resin, hence wetting ability of MUF to straw fiber was improved, which enhanced the diffuse and penetration of the resin into straw fibers and resulted in higher bond strength of the board.