阻燃型混杂纤维增强PBS复合材料的界面改性及其性能影响机制研究

To prepare the environmentally friendly functional composite is one of the focuses of biomass material research area. In this study, the ternary flame retardanted composite will be prepared from cassava residue fiber, magnesium sulfate whisker (MHSH) and poly (butylene succinate) (PBS) by melt compounding with the incorporation of expansion flame retardant system. The macromolecular coupling agent will be synthesized from starch/cellulose derivatives and chloride with different chain lengths by means of esterification reaction to improve the interfacial bonding between cassava residue fiber and PBS matrix, and the MHSH will be surface coated by coupling agent to improve the interfacial bonding between MHSH and PBS matrix. The interfacial bonding status will be characterized by means of DMA, SEM and the Peakforce QNM mode of AFM. Then, the correlation between the chemical structure and surface activity of the macromolecular coupling, as well as the composite properties, will be investigated. The correlation between the surface properties of cassava residue fiber and the adaptive of macromolecular coupling agent, as well as the performance of composite, will be illustrated. And then, the interfacial regulation mechanism of macromolecular coupling agent on composite will be revealed. Furthermore, the correlation between cassava residue fiber/MHSH and their interfacial modification and the crystallization behaviors, the rheological behaviors of composite, as well as the mechanical properties, thermal properties and flame retardant properties of composites, will be illustrated. And then, the composite system will be optimized. The study on biomass materials is of great importance to protect the environment, save the fossil resources and develop the application of PBS based composites.

制备功能化的环境友好型复合材料，是近年来生物质材料研究领域的热点之一。拟制备具有阻燃特性的PBS/硫酸镁晶须(MHSH)/木薯渣纤维复合材料。以淀粉/纤维素衍生物的酯化产物作为大分子偶联剂，改善木薯渣纤维与基体的相容性，采用偶联剂表面包覆改善MHSH与基体的相容性，结合膨胀阻燃体系，制备阻燃型复合材料。通过DMA、SEM结合AFM的Peakforce QNM模式对界面结合进行表征，建立大分子偶联剂分子结构与表面活性、复合材料性能之间的相关性，阐明木薯渣纤维表面特性对界面改性及与复合材料性能的相关性，进而揭示大分子偶联剂对复合材料的界面调控机制。阐明木薯渣纤维/MHSH及其界面改性与复合材料结晶行为、流变行为的相关性，与力学性能、热性能及阻燃性能的相关性，进而对复合体系进行优化设计。本研究对于拓展PBS基复合材料的应用范围，提高生物质原料的利用水平，缓解石油危机和保护环境具有重要意义。

本项目以淀粉/纤维素衍生物的酯化产物对木薯渣进行表面改性以改善其与PBS基体的界面结合。以碱式硫酸镁晶须（MHSH）/木薯渣纤维为增效剂，并结合膨胀阻燃（IFR）体系制备了具有阻燃特性的混杂纤维增强复合材料。对复合材料的力学性能、阻燃性能、结晶行为、流变行为及热性能进行了研究，并对所涉及的机理问题进行了深入探讨。取得的主要结论如下：.MHSH协效IFR阻燃改性PBS，可协效阻燃并同步增强。以2%MHSH与23%IFR复配制备的复合材料的拉伸强度、弯曲强度和冲击强度相比只添加25%IFR的复合材料分别提高了33.33%、8.97%和21.80%，UL-94达到V0等级，LOI达到39.8%，pHRR和THR也分别下降50.4%和11.6%。在燃烧时，MHSH形成了热稳定性更高的P-O-Mg-O-P键，并作为三维增强体起到了碳层支撑稳定作用，可有效防止PBS燃烧的熔滴现象，阻碍燃烧热量以及氧气向材料内部的传播。.以质量分数5.0%，取代度为2.13的淀粉和辛酰氯制备的酯化淀粉处理木薯渣(质量分数30%)所制备PBS/木薯渣复合材料界面结合显著提高，拉伸、弯曲和冲击强度分别提高了52.7%、24.0%和34.0%。改性木薯渣在上述阻燃复合体系中的添加，使力学性能进一步提高，相比75P/23I/2M和70P/23I/5C/2M的弯曲强度和冲击强度分别增加了32.16%和38.02%。同时，作为碳源供体的木薯渣使炭层表面O=P-O-C酯键增多，生成了更加致密的碳层，提高了燃烧残碳率。70P/23I/5C/2M的UL-94达到V0等级，LOI达到39.6%。.此外，对热解过程吸热量进行了计算，升温速率为20℃/min下的热解吸热量大小依次为70P/23I/5C/2M>75P/23I/2M>PBS。利用C-R法与Ozawa法对复合体系的燃烧动力学进行了分析，假设的一级动力学模型拟合实验数据较好。.本项目针对可降解脂肪族聚酯材料的同步增强与阻燃改性做了大量研究，为改性生物可降解材料的开发和应用提供了重要的理论依据和技术指导。所制备的改性复合材料具有可降解与阻燃的特性，可应用于多种领域，对于保护环境、保证安全具有一定的实际意义。