竹笋壳/脲醛树脂改性淀粉胶黏剂复合材料的降解特性

【目的】研究不同环境中竹笋壳/脲醛树脂(UF)改性淀粉胶黏剂复合材料的质量损失率、结构及微观形态变化等降解特性。【方法】采用自然暴露法、土壤掩埋法、水性培养液法和纤维素酶法对复合材料进行了降解处理,测定了复合材料在降解过程中的质量损失率,并通过X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)和扫描电子显微镜(SEM)分析了复合材料降解后的相对结晶度、化学结构和微观形貌。【结果】复合材料经过自然暴露、土壤掩埋、水性培养、纤维素酶缓冲溶液浸泡等4种环境降解后,其终质量损失率依次为2.1%、21.7%、25.7%和29.9%,相对结晶度由空白对照组的43.9%依次增大到46.4%、49.7%、53.2%和55.4%,并且特征吸收峰发生了不同程度的降低; SEM分析显示,经过4种环境降解后,复合材料表面变得粗糙,竹笋壳出现了不同程度的破坏,其中以纤维素酶缓冲溶液降解后的变化最为显著。【结论】竹笋壳/脲醛树脂(UF)改性淀粉胶黏剂复合材料在土壤、水性培养液和纤维素酶环境中具有良好的生物降解特性。
【Objective】Evaluate the degradability of bamboo shoot shell/urea formaldehyde(UF)-modified starch adhesive composites under different conditions.【Method】The composites were degraded by outdoor exposure, soil burying, aqueous medium, and cellulose tests.The mass loss rate was determined during the degradation process.There lative crystallinity, chemical structure and microstructure of the composites after degradation were analyzed by X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), and scanning electron microscope(SEM)respectively. 【Result】The final mass loss rates of the composites after the 4 degradation conditions were 2.1%, 21.7%, 25.7% and 29.9%. XRD analysis showed that the relative crystallinities of the composites after degradation under the 4 conditions increased to 46.4%, 49.7%, 53.2% and 55.4%, respectively, as compared with that(43.9%)of the control group. FTIR analysis indicated that the characteristic absorption peak values of the composites decreased on different degree after degradation under the 4 conditions. SEM analysis showed that the composite surface became rough and that bamboo shoot shell surface under went degrees of damage; in particular,the bamboo shoot shell showed the most obvious change after degradation under the cellulose condition.【Conclusion】Bamboo shoot shell/UF-modified starch adhesive composites showed good biodegradability under the soil, aqueous medium and cellulose conditions