【作者】 陶国良；

【导师】 涂善东；

【作者基本信息】 南京工业大学 ， 化工过程机械， 2006， 博士

【摘要】 材料腐蚀问题遍及国民经济的各个领域,尤其在化工、石油、机械、纺织、冶金、航天航空、国防等工业部门更为突出。腐蚀不仅给社会带来巨大的经济损失,造成灾难性事故和危及人身安全,耗竭宝贵的资源和能源,污染环境,而且阻碍了高科技的正常发展。本文研究的高导热先进复合材料是一种耐苛性腐蚀介质,并具有良好力学性能、优良导热功能的新材料,可望用于苛性腐蚀环境下使用的紧凑换热器的制造。本文研究的主要内容有:聚合物基导热材料制备技术;聚合物基导热材料的热导率测试技术;聚合物基导热材料的逾渗导热模型;高导热先进复合材料的制备技术;高导热先进复合材料板翅式换热器的设计与制备工艺技术。高导热先进复合材料是以聚四氟乙烯(PTFE)材料为基体,通过导热改性和采用碳纤维定向增强复合技术制备的一种新材料,具备以下特点:①优良的耐腐蚀性能,使用介质和环境与聚四氟乙烯材料相仿;②良好的耐热性能,使用温度为-100℃～250℃;③良好的导热性能和换热效果,复合材料的热导率是聚四氟乙烯热导率5倍以上,而且在使用过程中不结垢,能长期保持热交换能力;④优良的综合力学性能和使用寿命,先进复合材料的拉伸强度是聚四氟乙烯材料的3～5倍,而且没有聚四氟乙烯的冷流现象,可以作为结构材料使用;⑤良好的加工性能和成型性能,可以进行焊接、热压等二次成型,为防腐蚀过程装备的设计和制造提供了经济可行的工艺技术。聚合物基导热材料的研究,选用聚丙烯(PP)和聚四氟乙烯(PTFE)为基材,高导热性能的石墨、铝粉和铜粉作为导热填料进行改性。对导热材料的导热和机械性能的试验证明: PP为基材时,导热填料的粒径、含量对材料的导热性能有明显的影响,填料的粒径越小、含量越高,则改性材料的导热性能越好。如石墨的质量含量由15%增加到60%时,石墨/PP改性材料的热导率由0.34 W/(m·K)增加到3.1W/(m·K),是纯聚丙烯树脂热导率的十几倍,但改性材料的拉伸强度和冲击强度只有PP材料的一半左右,综合力学性能下降很多。同样,对于石墨/PTFE改性导热材料,石墨的质量含量为30%时,改性材料的热导率达到1.2W/(m·K),当石墨质量含量为50%时,热导率提高到2.5W/(m·K) ,是纯PTFE树脂热导率的10倍以上,但改性材料的拉伸强度只有PTFE材料的25%左右。更多还原

【Abstract】 The corrosion of materials can be found in almost all fields of the national economy, particularly in the industries such as chemical engineering, petroleum, mechanical engineering, metallurgy, textile, aerospace and national defence, and so on. Corrosion not only causes the enormous economic losses for the society, results in the disaster accidents and endangers personal safety, uses up the precious resources and energy, and pollutes the environment, but also obstructs the healthy development of the high technology. The advanced composite of high- thermal conductivity studied in this dissertation is a new kind of material with excellent corrosion resistance, good mechanical property and high thermal conductivity, which is expected to be used in the manufacturing of compact heat exchangers for caustic environmental applications.The main contents studied in this dissertation include: the preparation of polymer-matrix thermal conductive materials; the measurement of the thermal conductivity of polymer-matrix thermal conductive materials; the percolation thermal conductive model of polymer-matrix thermal conductive materials; the preparation of the high-thermal conductivity of advanced composites; and the design and fabrication of the plate-fin heat exchangers by using the advanced composites.The advanced composite of high-thermal conductivity uses polytetrafluoro- ethylene (PTFE) as matrix, and is prepared by a technology combination of thermal conduction enhancement and directional carbon fiber reinforcement. The developed material possesses the following merits: (1) an excellent corrosion resistance, comparable to that of PTFE; (2) good heat resistance, with the service temperature ranging from -100℃to 250℃; (3) high thermal conductivity and heat transfer efficiency, the thermal conductivity of the composites being about five times higher than that of PTFE, moreover no scaling on the material which helps to maintain high heat conductivity in service; (4) good comprehensive mechanical properties and service life, with a tensile strength of about 3-4 times higher than that of PTFE, and without cold-flow phenomenon that is inherent in PTFE; (5) good processing and molding ability, which allows welding, hot forming etc, and provides an economical and feasible technology for design and manufacturing of the corrosion resistant更多还原