纳米氧化铜基防腐型酚醛树脂类原位聚合法合成机理及应用基础研究

The development of nano Copper Oxide (CuO) based phenol formaldehyde (PF) resin is aimed to provide a new approach to protect wood based composites against bio attack. Synthesis of PF resin with alkaline catalyst will be performed simultaneously with the preparation of nano CuO by precipitation method in the same reaction environment. Then macro molecular weight and micro molecular weight PF resins containing nano CuO were prepared, which will be applied to manufacture structural strand board and solid wood treatment, respectively. Soluble copper salt with low cost was selected as the raw material in this project, which was cooperated with alkaline precipitant and catalyst. In order to improve the loading level of nano CuO in PF resin and stability of synthesized PF resin, the chemical computation result was set as theoretical foundation, then the synthesis craft, dispersant and dispersion conditions, ultrasonic frequency and duration, as well as complexation technology were adjusted to achieve the final goal. Thus, the best synthesis parameters would be obtained for both macro molecular weight and micro molecular weight PF resins, and the morphological analysis, curing kinetics and molecular structure analysis of cured PF resins were conducted. The effect of wood preservation was confirmed by evaluating the physical and mechanical properties of structural strand board and treated solid wood, as well as the relation between bio resistance and leaching ability of CuO and valency changing of Cu2+ ion. This project protected wood based composites against bio attack by the way of modifying PF resin synthesis process, which provide a scientific foundation to improve bio resistance of wood based composites and reduce the cost of nano technical modification of PF resin.

纳米氧化铜（CuO）基防腐型酚醛（PF）树脂的研发旨在开辟解决人造板耐腐性问题的新途径。本项目将PF碱性催化法合成与纳米CuO化学沉淀法制备在同一反应环境中同时进行，制得大/小分子体系含纳米CuO的PF树脂，分别应用于结构刨花板生产和实木防腐处理。以可溶性铜盐为原料，选用碱性沉淀剂和催化剂，以化学计算的理论结果为指导，通过改进结合工艺、分散体系、超声及络合技术，优化界面相容性及相容持久性，最大程度提高PF树脂对纳米CuO的承载能力，获得纳米CuO基PF树脂最佳合成工艺；并进行PF树脂固化产物形态学、固化动力学、固化前后分子结构变化等固化机理研究。通过检测结构刨花板和处理实木的物理力学性能、CuO流失性及Cu2+离子化合价变化与板材生物耐久性的关系，评价其防腐性。本研究从合成防腐型PF树脂胶粘剂的角度赋予人造板充分耐腐性，为有效解决人造板防腐问题及PF树脂低成本化纳米改性研究提供科学依据。

通过纳米氧化铜（CuO）改性酚醛（PF）树脂胶黏剂，再以其制备工程木质复合材料，是为此类木质人造板赋予生物耐久性的新途径；而直接使用纳米CuO颗粒改性PF树脂，存在应用成本高、分散工艺复杂等卡脖子问题。本项目从廉价铜盐出发，将PF碱性催化法合成与纳米CuO化学沉淀法制备在同一反应环境中同时进行，一步法制得含纳米CuO的PF树脂胶黏剂，并将其应用于结构刨花板生产；主要完成了纳米CuO基PF树脂最佳合成工艺探寻、衍生纳米CuO形貌学、改性PF树脂固化动力学、固化前后分子结构变化等固化机理研究、以及所制备定向结构刨花板（OSB）物理力学性能和生物耐久性检测及分析。本研究在业界首次实现了一步法制备含纳米CuO颗粒的PF树脂胶黏剂，铜盐水溶液滴加速度随铜盐种类和浓度不同宜控制在0.5-4.0 ml/min，发现铜盐种类和铜盐浓度是决定衍生纳米CuO形貌变化的最关键因素，共获得5种不同结构的纳米CuO颗粒，其粒径为10nm至400nm且分散良好；改性PF树脂主要官能团化学位移向低场区移动，苯氧基上的氧与铜离子发生配位络合反应；固化动力学分析表明，改性PF树脂的固化顶峰温度前移、表观活化能降低，加成和缩合反应速率被加快；活化能随转化率的变化趋势结果映证了纳米CuO的引入使PF树脂反应更加充分，其中加成反应速率要高于缩聚反应速率；改性PF树脂胶黏剂制备的OSB弹性模量和静曲强度有所提高，当以氯化铜为铜源，其改性胶黏剂制备的OSB垂直方向静曲强度增幅达44%-74%，特别当氯化铜浓度为50%时，其2小时吸水厚度膨胀率降幅达到42%；OSB的实验室抗白蚁及室外抗白蚁性能均显著提高，由AWPA抗白蚁等级的4级提高至7-8级。本研究进一步丰富了改性PF树脂合成理论，从“结构-功能”角度，为纳米材料改性PF树脂和性能优化、以及所制备工程木质复合材料生物耐久性功能开发提供科学依据。