聚甲基丙烯酰亚胺泡沫塑料的制备、结构及性能研究

发布时间：2019-06-02 00:49

【摘要】：随着航天航空等特殊领域的快速发展，要求芯层材料具有更高的强度、刚度和耐热性。而通用泡沫塑料（如PE、PP等）耐热强度差，高温形变使得夹层结构的尺寸稳定性遭到破坏，不能满足上述领域的使用要求。聚甲基丙烯酰亚胺（PMI）泡沫塑料作为新型高性能泡沫塑料之一，它所具有的强度和耐热性是现有泡沫塑料中最高的。目前国内在上述领域使用的PMI泡沫塑料主要是从德国进口，价格昂贵。为了打破长期依赖进口的局面，降低成本，研发具有自主知识产权的PMI泡沫塑料刻不容缓。本文采用自由基预聚体法制备了PMI泡沫塑料。研究了配方中各组分对PMI泡沫塑料质量的影响，确定了各组分的用量范围和制备PMI泡沫塑料的基本配方。通过傅里叶转变红外光谱分析（FTIR）、差示扫描量热法（DSC）和热重分析（TG）对PMI泡沫塑料分子结构热转变进行了研究；利用扫描电镜（SEM）和光学显微镜对PMI泡沫塑料泡孔的微观结构进行了观察；对PMI泡沫塑料的机械性能和热性能进行了测试；讨论了发泡工艺和密度对PMI泡沫塑料分子结构和性能的影响。结果表明：通过丙烯腈（AN）58~50份、甲基丙烯酸（MAA）42~50份、偶氮二异丁腈（ABIN）0.25~0.45份、丙烯酰胺（AM）2份、甲酰胺2~8份、碳酰胺0.5份组成的配方能够制备出质量轻、性能较高的PMI泡沫塑料。在许可范围内，调节发泡剂用量和发泡温度可制得密度不同的轻质PMI泡沫塑料，且随发泡剂用量和发泡温度的提高密度减小。BMI可用作制备高密度PMI泡沫塑料的密度控制剂，密度随BMI用量的增加而大幅度提高。少量交联剂的加入可使PMI泡沫产生一定的交联结构，可有效提高PMI泡沫塑料的一些物理机械性能。碳酰胺具有良好的成核作用，能有效减小泡沫泡孔孔径，使泡孔分布更均匀，可作为制备PMI泡沫塑料的成核剂。高温发泡和热处理过程中，PMI泡沫塑料的分子结构发生了重大转变，形成了一系列的环状结构和交联结构。PMI泡沫塑料的闭孔率高达100%，各向同性，，具有优异的机械性能、耐热性能和成型加工性能，是夹层结构选用的理想芯层材料。
[Abstract]:With the rapid development of aerospace and other special fields, core materials are required to have higher strength, stiffness and heat resistance. However, the thermal strength of general foam (such as PE,PP, etc.) is poor, and the dimensional stability of sandwich structure is destroyed by high temperature deformation, which can not meet the requirements of the above fields. Polymethacrylic imide (PMI) foam, as one of the new high performance foams, has the highest strength and heat resistance among the existing foams. At present, the domestic use of PMI foam in the above fields is mainly imported from Germany, the price is expensive. In order to break the long-term dependence on imports and reduce costs, it is urgent to develop PMI foam with independent intellectual property rights. In this paper, PMI foam was prepared by free radical prepolymer method. The effect of each component on the quality of PMI foam was studied, and the dosage range of each component and the basic formula of preparing PMI foam were determined. The molecular structure and thermal transformation of PMI foam were studied by Fourier transform infrared spectroscopy (FTIR),) differential scanning Calorimeter (DSC) and thermogravimetric analysis (TG). The microstructure of PMI foam was observed by scanning electron microscope (SEM) and optical microscope, and the mechanical and thermal properties of PMI foam were tested. The effects of foaming process and density on the molecular structure and properties of PMI foam were discussed. The results showed that there were 50 parts of (AN), 42 parts of (MAA), 0.25 parts of (ABIN), 2 parts of acrylamide (AM) and 8 parts of formamide. PMI foam with light weight and high performance can be prepared by 0.5 phr carbamide formula. Within the allowable range, lightweight PMI foams with different densities can be prepared by adjusting the amount of foaming agent and foaming temperature, and the density decreases with the increase of foaming agent dosage and foaming temperature. BMI can be used as a density control agent for the preparation of high density PMI foam. The density increased greatly with the increase of BMI dosage. The addition of a small amount of crosslinker can make PMI foam produce certain cross-linking structure, and can effectively improve some physical and mechanical properties of PMI foam. Carbamide has a good nucleation effect, can effectively reduce the pore size of foam pores, make the distribution of foam pores more uniform, and can be used as a nucleating agent for the preparation of PMI foam. During the process of high temperature foaming and heat treatment, the molecular structure of PMI foam has undergone a great change, forming a series of ring structure and cross-linking structure. The closed porosity of PMI foam is as high as 100%, isotropism, and has excellent mechanical properties. Heat resistance and molding performance are ideal core materials for sandwich structure.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TQ328.0

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