碳纤维织物增强热塑性复合材料的制备与研究

发布时间：2018-07-26 18:45

【摘要】：碳纤维织物（CFF）增强热塑性复合材料具有可回收再生、成型时间短、冲击韧性好等性能优势，是一种很有发展前景的材料。聚丙稀（PP）是一种价廉、韧性高、防腐性能和综合性能优良的通用塑料，可以大量用作汽车复合材料基体。聚苯硫醚（PPS）是具有优异的耐高温、耐溶剂性、化学稳定性和高强高模的热塑性特种工程塑料，可以用作航空热塑性复合材料基体。本文通过薄膜叠层模压法制备了碳纤维织物增强聚丙烯（CFF/PP）、碳纤维织物增强聚苯硫醚（CFF/PPS）两种复合材料层压板，并采用扫描电子显微镜（SEM）、偏光显微镜（POM）、静力学性能测试、动态力学分析（DMA）、差示扫描量热仪（DSC）等测试手段对它们的结构、性能及其主要影响因素进行了研究。我们采用在PP基体中添加马来酸酐接枝改性的聚丙烯（MAPP）的方法以改善CF与PP基体间的界面结合力，，探索了不同MAPP/PP(M-PP-x)配比对CFF/PP复合材料层压板力学性能的影响。当MAPP/PP配比为10%时，复合材料的拉伸强度和冲击强度较高；当MAPP/PP配比为15%时，复合材料的弯曲强度和层间剪切强度较高。采用MAPP-PP共混物作为基体对CFF/PP进行界面改性，可以提高CFF/PP复合材料的力学性能，但实际上真正起到改性作用的只是界面层的MAPP，而基体内部过量的MAPP却会牺牲复合材料的强度和模量。我们受到热固性树脂基预浸料优化制备方法的启发，进一步改进了上述工艺。利用MAPP在高温下可溶的特性，提出一种使树脂分布均匀、力学性能稳定的热塑性预浸料及复合材料制备方法：先用MAPP高温溶液对CFF进行表面处理，溶剂挥发后得到预浸料，再进而与PP薄膜经过叠层模压法制备复合材料。采用该工艺方法制备的CFF/PP与前述工艺相比，拉伸强度、弯曲强度、冲击强度和层间剪切强度均显著提高，尤其是拉伸强度提高了2倍左右。本论文还考察了不同界面强度下，织物变形对复合材料力学性能的影响。构筑不同的CF-PP界面结合强度，通过铺层方式改变CFF在复合材料中的规整性，制备出具有相似织物形变但不同界面结合力的复合材料。研究发现，界面结合力越强，织物形变对复合材料力学性能带来的负面影响越大。针对CFF/PPS航空复合材料，本文主要研究了PPS基体的非等温结晶动力学和不同条件下CF诱导PPS的结晶行为。结果表明，降温速率对PPS结晶结构与形态的影响非常明显。当降温速率处于10K/min-70K/min之间，CFF/PPS的起始结晶温度与结晶峰位均随着冷却速率的增加而向低温方向移动，且CFF/PPS复合材料中PPS晶粒尺寸变小、结晶度有所下降，复合材料层压板的强度和韧性提高，弯曲强度提高了23.8%，表征韧性的冲击强度提高了15.1%，但弯曲模量降低了2.1%。如果在CFF/PPS复合材料成型的降温过程中加载压力，CF表面与PPS分子链间的剪切力可以诱导CF附近的PPS基体生成横晶；经过表面涂层改性处理的CF同样可以诱导横晶，且横晶结构更加规整、完善；横晶改变了复合体系中CF-PPS的界面结构，增加了界面结合力，可以有效改善界面的应力传递行为，显著提高了复合材料的力学性能。
[Abstract]:Carbon fiber reinforced thermoplastic composites (CFF) reinforced thermoplastic composites have the advantages of recycling, short forming time, good impact toughness and so on. It is a promising material. Polypropylene (PP) is a kind of low price, high toughness, anticorrosion and comprehensive properties of general plastic material, which can be used as the matrix of automotive composite material, polyphenylene sulfide (PP). S) is a thermoplastic special engineering plastic with excellent high temperature resistance, solvent resistance, chemical stability and high strength and high modulus. It can be used as an aero thermoplastic matrix. In this paper, two kinds of composite laminates of carbon fiber reinforced polypropylene (CFF/PP) and carbon fiber reinforced polyphenylene sulfide (CFF/PPS) were prepared by thin film laminated molding method. The structure, properties and main influencing factors of the plate were studied by scanning electron microscope (SEM), polarizing microscope (POM), static performance test, dynamic mechanical analysis (DMA), differential scanning calorimeter (DSC) and so on.
We use the method of adding maleic anhydride grafted polypropylene (MAPP) in PP matrix to improve the interfacial bonding force between CF and PP matrix, and explore the effect of different MAPP/PP (M-PP-x) ratio on the mechanical properties of the CFF/PP composite laminates. When the ratio of MAPP/PP is 10%, the tensile strength and impact strength of the composites are higher; when MAPP is in MAPP. When the /PP ratio is 15%, the bending strength and interlaminar shear strength of the composites are higher.
The interfacial modification of CFF/PP with MAPP-PP blends can improve the mechanical properties of CFF/PP composites, but in fact, the real modification is only the MAPP of the interface layer, while the excessive MAPP in the matrix will sacrifice the strength and modulus of the composite material. The above process is further improved. Using the soluble properties of MAPP at high temperature, a method of preparing thermoplastic prepreg and composite material is proposed, which makes the resin evenly distributed and the mechanical properties are stable. First, the surface treatment of CFF is carried out with the high temperature solution of MAPP, the prepreg is obtained after the solvent volatilization, and then the laminated PP film is laminated. The tensile strength, the bending strength, the impact strength and the interlaminar shear strength of the CFF/PP prepared by this method are significantly increased, especially the tensile strength by about 2 times.
In this paper, the effects of fabric deformation on the mechanical properties of the composites at different interface strength were also investigated. The binding strength of different CF-PP interfaces was constructed and the regularization of CFF in the composite was changed through the layer method. The composite material with similar fabric deformation but different interfacial bonding force was prepared. The negative influence of fabric deformation on the mechanical properties of composites is greater.
In this paper, the non isothermal crystallization kinetics of the PPS matrix and the crystallization behavior of CF induced by CF under different conditions are mainly studied in this paper. The results show that the effect of cooling rate on the crystalline structure and morphology of PPS is very obvious. When the cooling rate is between 10K/min-70K/min, the initial crystallization temperature and the crystallization peak of CFF/PPS are both. As the cooling rate increases, the grain size of the CFF/PPS composites decreases, the crystallinity decreases, the strength and toughness of the composite laminates are increased, the bending strength is increased by 23.8%, the impact strength of the toughness is increased by 15.1%, but the flexural modulus reduces 2.1%. if the CFF/PPS composite is formed. During the cooling process, the shear force between the CF surface and the PPS molecular chain can induce the PPS matrix to produce transverse crystal near CF, and the transversal crystal can be induced by the CF modified by the surface coating, and the transversal crystal structure is more regular and perfect. The transverse crystal changes the interface structure of the CF-PPS in the composite system and increases the interfacial bonding force. The mechanical behavior of the composites was improved significantly by improving the stress transfer behavior of the interface.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332;TQ327

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