【作者】 韩曙光；

【导师】 余晓容；

【作者基本信息】 郑州大学 ， 材料加工工程， 2010， 硕士

【摘要】 聚对苯二甲酸乙二醇酯(PET)是一种有很多优良物理性能的热塑性塑料。但其的缺点如结晶速率慢、模量低、热变形温度低限制了在工程塑料方面的应用。与纯PET相比,添加少量蒙脱土(MMT)于PET基体中制得的插层或剥离型的PET/MMT纳米复合材料在结晶速率、耐热性、力学性能、气体阻隔性能和阻燃性能等方面都得到显著的提高,因此PET/MMT纳米复合材料的研究备受关注。本文制备了三种有机MMT (OMMT),研究了插层剂与制备工艺对MMT的改性效果的影响,采用熔融插层法制备得到了剥离型和插层絮凝型PET/MMT纳米复合材料,并研究了改性MMT的种类和含量与复合材料结构和性能之间的关系。主要工作如下：1、使用传统的插层剂十六烷基三甲基溴化铵(CTAB).与PET相容性很好的聚乙二醇(PEG)及二者的混合物来有机化MMT得到OMMT;红外光谱结果表明插层剂都进入到蒙脱土层间,广角X射线结果表明蒙脱土层间距从1.5nm增大到了2.22nm,TG结果表明CTAB和PEG混合插层热稳定性最好。2、研究了CTAB有机化MMT的优化工艺,发现影响MMT的层间距最大因素为CTAB摩尔量与MMT的离子交换容量的比例,搅拌速率和温度在研究范围内影响很小。3、熔融共混了MMT、有机MMT与PET制得一系列PET/MMT纳米复合材料。广角X射线结果表明有机MMT改性的PET得到了插层絮凝型纳米结构。而MMT直接改性的PET-MMT体系得到了剥离型纳米结构。4、研究了PET/MMT的流动性能,结果发现剥离型的PET-MMT体系的流动性能最差。MMT含量越高,PET-MMT体系中剥离的蒙脱土纳米结构对PET的流动阻碍越大,CTAB的增塑作用使PET-CTAB-MMT体系的流动性能逐渐变好,但流动性能都比纯PET差。对PET-CTAB-PEG-MMT的流动性能实验发现,仅MMT含量为8%时,其流动性能好于纯PET,这和PEG与PET的相容性好有关。5、TG结果表明,所研究的复合材料中只有CTAB-PEG-MMT含量为4%的PET/MMT热稳定性好于纯PET,本文认为这与PEG和PET强烈的氢键作用有关。6、通过DSC和POM来研究PET/MMT的结晶性能。结果表明PET/MMT的结晶速率都高于纯PET, MMT纳米片层结构在PET结晶时充当了成核剂的作用,使得PET在MMT纳米片层结构上面异相成核。PET-MMT的剥离结构使其结晶速率最快。MMT含量越高,PET-CTAB-PEG-MMT的结晶速率变快,而其他两种PET/MMT结晶速率基本不变,这和PEG与PET相容性好有关。更多还原

【Abstract】 Poly(ethylene terephthalate)(PET) is a thermoplastic with many excellent physical. However, the disadvantages such as low rate of crystallization, low thermal distortion temperature and low modulus have limited its application as an engineering plastic. PET/MMT nanocomposites with intercalated/exfoliated nano-structure can be prepared by adding a small amount montmorillonite (MMT) to PET matrix. Compared with the pristine PET, PET/MMT nanocomposites have remarkable improvements in crystallization rate, mechanical property, thermal stability, gas barrier property and flame retardancy. Therefore, more and more attentions are focus on this field.Three organo-modified MMT(OMMT) were prepared, and the impact of the intercalation agents and preparation processing on OMMT was studied. PET/MMT nanocomposites with intercalated and exfoliated nano-structure are prepared by melt intercalation. And the impact of the types and contents of modified MMT on the structure and properties of composite materials was studied. The main work is as follow:1、OMMT were organo-modified by intercalation agents of hexadecyltrimethyl ammonium bromide (CTAB), polyethylene glycol(PEG)and both of them; FT-IR showed OMMT included the intercalation agent; Wide-angle X-ray diffraction showed the interlayer spacing of MMT increased from 1.5nm to 2.22nm; TG showed CTAB-PEG-MMT had the best thermal stability all of OMMT.2、Study on the optimization process of CTAB-MMT showed that the biggest affect factor of the layer spacing of MMT was the ratio between the molar mass of CTAB and the exchange capacity ratio(CEC) of MMT, but stirring rate and temperature range in my study had little effect on it.3、A series of PET/MMT nanocomposites were prepared by melt intercalation. Wide-angle X-ray diffraction showed PET/OMMT obtained intercalated’and agglomerate nano-structure, PET-MMT compounding MMT and PET obtained exfoliated nano-structure. 4、Study on flow property of PET/MMT showed flow property of PET-MMT was worst all of PET/MMT, because of its exfoliated nano-structure.As the content of MMT increased, the exfoliated nano-structure of PET-MMT gradually blocked flow of PET, and the plasticization of CTAB in PET-CTAB-MMT system gradually made the flow property better, but the flow property of PET-MMT and PET-CTAB-MMT was poor than pristine PET.Only PET/MMT containing 8%of CTAB-PEG-MMT had a good flow property than pristine PET, because of the good compatibility between PEG and PET.5、TGA showed that all of composite materials, only PET/MMT contenting 4% CTAB-PEG-MMT had better thermal stability than pure PET, because of a strong hydrogen bonding between PEG and PET.6、PET/MMT of crystallinity property was studied by DSC and POM. The result showed PET/MMT nanocomposites had a higher level of crystallization rate than pristine PET,because MMT behaved as a nucleating agent and nucleated the PET crystallization process. PET-MMT had a highest level of crystallization property because of its exfoliated nano-structure. As the content of MMT increased, the crystallinity rate of PET-CTAB-PEG-MMT became quick, while that of the others became slow. This related to the compatibility between PEG and PET.更多还原