【作者】 宿磊；

【导师】 徐建中；

【作者基本信息】 河北大学 ， 应用化学， 2010， 硕士

【摘要】 木塑复合材料是利用木屑和废旧热塑性塑料为主要原料,经高温混炼、再经成型加工而制得的一种新型复合材料,是当代工业基础材料废物利用的最佳科研成果在工业生产上的应用,其应用领域非常广阔,主要产品是回廊板、楼梯、护栏以及少量民用消费品。木材与各种基质的高聚体复合后得到的复杂体系与普通材料一样容易燃烧,且放热量大、发烟量大,从而大大限制了木塑复合材料的应用。故研究木塑复合材料的降解机理及影响因素不仅有利于该材料的长期稳定使用,而且也利于今后对材料的循环再利用以及对可降解材料的设计与运用,这不仅具有理论意义,更具实际价值。利用热分析技术研究复合材料的热分解特性与材料的燃耗密切相关,在阻燃研究中常用来判断材料的热稳定性,推测阻燃机理,使复合材料得到更广泛的应用。本文首先以PVC为基质合成木塑复合材料,利用TG,DTA,DTG等方法分析PVC及其复合材料、阻燃复合材料在不同气氛、不同升温速率下的热分解特性,并通过单一升温速率法、分布活化能模型等热分析动力学研究方法,计算材料的活化能,通过活化能变化规律研究其降解机理及加入的阻燃体系对降解机理的影响,对材料的热解动力学进行了探讨,研究其阻燃机理。结果发现复合材料中由于PVC热解产生的氯自由基使木粉中的纤维素和半纤维素氯化,Ea比木粉与PVC的总活化能要少。阻燃剂ZnSnO3的加入使得复合材料两个阶段的活化能降低很大。第二部分,以LDPE为基质合成木塑复合材料,并选择绿色环保的无机阻燃体系添加到复合材料中制备阻燃复合材料,在研究其TG曲线的基础上,对比质子流强度随温度变化曲线,根据其热解产物推导热解过程,通过不同的动力学模型计算活化能随失重率变化规律,研究复合材料的热解机理及阻燃剂对复合材料热解过程的影响。结果发现,木粉在热解过程中木纤维的炭化在LDPE的热解过程中有成炭剂的作用。加入金属氢氧化合物类阻燃剂后,由于阻燃剂的热解反应及成炭作用使复合材料热解活化能降低。第三部分,以EVA为基质合成木塑复合材料,并添加对高聚体阻燃效果明显的膨胀阻燃体系制备阻燃复合材料,通过热重质谱曲线分析热解产物,推导热解过程,通过动力学方法分析活化能的变化规律,研究复合材料的热解机理及阻燃体系对复合材料热解过程的影响。结果发现,在复合材料热解过程中,EVA中的醋酸乙烯酯可与木粉表面羟基形成分子间氢键,且木粉的成炭作用使其活化能较EVA过程减少。而阻燃复合材料中由于膨胀型阻燃剂中气源的稀释和碳源的成炭使复合材料总体活化能减少。更多还原

【Abstract】 Wood-plastic composite material is a new composite material ,which is composited from polymer matrix and Pretreatment of plant fiber or powder as filler, It is mainly use waste wood and thermoplastics as the main raw material, high-temperature mixing, and then obtained by the molding process and is the basis of modern industrial materials recycling the best scientific research applications in the industrial production,As a new wood-plastic composite materials and extensive use of green materials, its applications are broad, the main product is the gallery board, stairs, fence and a small amount of civilian consumer goods.Timber with a variety of high-polymer matrix composite of the complex system are as easy and common materials, combustion, and heat capacity, heavy smoke, which greatly limits the application of wood-plastic composite materials.Therefore, the degradation of wood-plastic composite materials, mechanisms and affecting factors not only conducive to long-term stability of the materials used, but also conducive to the future use of recycled materials and biodegradable materials on the design and use. This is not only of theoretical significance, more practical value.Thermal analysis technique application of composite materials and has an important role in recovery。Studying the thermal decomposition characteristics of composite materials is closely related to research in the fuel consumption of materials , Flame retardant commonly used in the study to determine the thermal stability, suggesting that fire-retardant mechanism of the composite materials more widely used.First, wood and plastic composites were prepared with PVC as matrix, and the thermal decomposition properties of PVC and its flame-retardant composites at different atmosphere and heating rate were analyzed by TG DTA and DTG. The activation energy of the composites were calculated by Freeman method and Distributed activation energy model (DAEM) and other kinetic study method. The mechanism of degradation about flame retardant system and composites were studied by the variation law of activation energy. Also, the kinetics of pyrolysis and the mechanism of degradation of composites were discussed. Second,wood and plastic composites were prepared with LDPE as matrix,and inorganic green flame retardant system were choosed to add into the composite meterials. In the study based on the TG curve, derived pyrolysis process according to its thermal decomposition products through the comparison of proton flow strength varies with temperature.Calculate activation energy variation with loss weight through diferent dynamic model,study the thermal decomposition mechanism of composite materials and the affects of flame retardants on pyrolysis process of composite materials.The result shows ,the wood fiber’s carbonization has the role of carbon dose during the thermal decomposition of LDPE.Because of the flame retardants’thermal decomposition and carbonization,the activation energy of composite materials reduced after the metal hydroxide flame retardants were added.Third, wood and plastic composites were prepared with EVA as matrix, and intumescent flame retardant system were choosed to add into the composite meterials In the study based on the TG curve, derived pyrolysis process according to its thermal decomposition products through the comparison of proton flow strength varies with temperature.Calculate activation energy variation with loss weight through diferent dynamic model,study the thermal decomposition mechanism of composite materials and the affects of flame retardants on pyrolysis process of composite materials.The result shows ,intermolecular hydrogen bonds can be formed by vinylacetate in EVA and wood surface hydroxyl groups,and the overall activation energy of the composite materials reduced, because of the dilution gas source and carbon source as carbon composite of the intumescent flame retardant in the flame retardant composite materials更多还原