有机表面改性可膨胀石墨阻燃聚烯烃复合材料的形态结构与性能研究

发布时间：2018-04-20 13:41

本文选题：可膨胀石墨 + 表面改性　；参考：《西南交通大学》2017年硕士论文

【摘要】：聚丙烯(PP)和聚乙烯(PE)作为一种常见而且重要的通用塑料,具有优良的加工性能、力学性能和价格低廉等优点,已经被广泛应用于电子通讯、食品包装、房屋建筑、汽车工业和航空制造工业等。但是其具有容易燃烧的缺点,使其具有引发火灾的潜在危险,在生活应用中时刻威胁着人们的生命和财产安全。为了克服其容易燃烧的行为,对于阻燃方面的研究迫在眉睫。本论文主要研究内容在于:通过向PP和PE中加入有机表面改性可膨胀石墨(EG)阻燃剂,研究了复合材料的燃烧行为、形态结构变化以及对性能的影响。本文中主要采用了 EG为主体阻燃材料,由于它在阻燃过程中会存在比较明显的缺点(加入量较多、劣化材料的力学强度、形成的膨胀石墨疏松且容易脱落、产生烛芯效应等等)。因此本论文主要是针对EG进行表面有机化处理,通过一系列的小分子阻燃剂和硅烷偶联剂对EG进行表面改性,旨在增强EG阻燃效果。主要的研究结果如下:(1)利用磷系阻燃剂A(P-FRA,DOPO)和硅烷偶联剂(KH-560)接枝改性EG制备得到改性的可膨胀石墨(MEG)。将MEG用于阻燃PP,阻燃剂MEG量的增多,阻燃材料的氧指数值也随着增加,当加入量为30%时能够使材料测试到达V-0级别。通过对它的阻燃机理分析,表明MEG可以显著的增加阻燃材料在高温下的残炭量,得到比较连续的膨胀型炭层。由于有机化的表面使得在加入同等填料的情况下,MEG能够减缓其对力学性能的劣化影响。(2)研究了 MEG对高密度聚乙烯/乙烯-醋酸乙烯共聚物(HDPE/EVA)体系的燃烧和阻燃行为的影响。当MEG的添加量为20%就能够使阻燃复合材料达到V-0的级别,同时氧指数为26.5%,在高温下的残炭量到达了 37.7%。采用锥形量热仪表征测试得出MEG能够极大地降低材料的热释放速率和烟密度,改善材料的燃烧行为。由于异相成核的原因,MEG的加入可以使材料的结晶度随之增加。(3)采用氮系阻燃剂(N-FR)和硅烷偶联剂(KH-560)对EG进行表面化处理,制备出了改性的NEG。NEG用于制备阻燃HDPE/EVA材料,复合材料里由于协同阻燃方面的作用,当NEG的添加量为20%时可以让阻燃材料达到V-0级别。由于NEG在高温下能够产生大量不可燃性气体,气相阻燃机理使材料得热释放速率下降,改善了材料的燃烧行为。(4)采取磷系阻燃剂B(P-FRB)和硅烷偶联剂(ITPS)对EG进行表面接枝处理,制备出了表面改性的PEG,其表现出优良的热稳定性能,在高温下的残炭量达到了 86.9%。将PEG阻燃剂用阻燃低密度聚乙烯(LDPE)时,当添加量为12%时就能够使LDPE到达V-0级别,氧指数提高为25.1%。PEG对阻燃材料的熔融和结晶温度影响不大,极大地增加了材料的结晶度,同时使材料维持一定的力学性能。傅里叶红外测试结果表明,EG表面存在的P-FRB和ITPS在高温下能够形成磷酸酯类复合物和在表面形成一层耐高温的保护层,使阻燃材料在高温下呈现出优良的热性能。
[Abstract]:As a common and important common plastics, polypropylene (PP) and polyethylene (PE) have been widely used in electronic communication, food packaging, housing and construction because of their excellent processability, mechanical properties and low price. Automobile industry, aviation manufacturing industry, etc. However, it has the disadvantage of easy combustion, which makes it have the potential danger of causing fire, and it threatens people's life and property safety at all times in the application of life. In order to overcome its flammable behavior, it is urgent to study the flame retardancy. The main contents of this thesis are as follows: the combustion behavior, morphology change and effect on properties of PP and PE composites were studied by adding expandable graphite (EGG) flame retardant to PP and PE. In this paper, EG is mainly used as the main flame-retardant material. Because of its obvious shortcomings in the process of flame-retardant, such as more addition, the mechanical strength of the degraded material, the expanded graphite formed is loose and easy to fall off. Produce candle core effect and so on. Therefore, the surface of EG was modified by a series of small molecular flame retardants and silane coupling agents in order to enhance the flame retardant effect of EG. The main results are as follows: (1) the modified expanded graphite (MEGG) was prepared by grafting modified EG with phosphorous flame retardant Agna P-FRADPOO and silane coupling agent KH-560). When MEG was used in flame retardant PPPs, the content of flame retardant MEG increased, and the oxygen index of flame retardant material also increased with the increase. When the content of MEG was 30%, the material could be tested to V-0 level. Through the analysis of its flame retardant mechanism, it is shown that MEG can significantly increase the carbon residue of the flame retardant material at high temperature and obtain a more continuous intumescent carbon layer. The effect of MEG on the combustion and flame retardation of HDPE / vinylacetate copolymer (HDPE / EVA) system was studied by using the organic surface to slow down the deterioration of mechanical properties under the condition of the same filler. When the content of MEG is 20%, the flame retardant composites can reach V-0 level, and the oxygen index is 26.5, and the carbon residue reaches 37.7% at high temperature. The results of conical calorimeter show that MEG can greatly reduce the heat release rate and smoke density of the material and improve the combustion behavior of the material. Due to the reason of heterogeneous nucleation, the crystallinity of EG was increased with the addition of Meg. (3) the surface treatment of EG was carried out with nitrogen flame retardant (N-FR) and silane coupling agent (KH-560), and the modified NEG.NEG was prepared to prepare flame retardant HDPE/EVA material. Because of the synergistic flame-retardant effect in the composites, the flame-retardant material can reach V-0 grade when the content of NEG is 20. Because NEG can produce a large amount of incombustible gases at high temperature, the flame retardant mechanism of gas phase decreases the thermal release rate of the materials, and improves the combustion behavior of the materials. The surface grafting of EG is carried out by the phosphorous flame retardants BP- FRBB) and silane coupling agent. The surface modified PEG showed excellent thermal stability and the carbon residue reached 86.9% at high temperature. When PEG flame retardant is used as flame retardant low density polyethylene (LDPE), the LDPE can reach V-0 level when the addition amount is 12. The increase of oxygen index to 25.1%.PEG has little effect on the melting and crystallization temperature of the flame retardant material, and greatly increases the crystallinity of the material. At the same time, the material maintains certain mechanical properties. Fourier transform infrared spectroscopy (FTIR) results show that P-FRB and ITPS on the surface of EG can form phosphate complexes at high temperature and form a protective layer of high temperature resistance on the surface, which makes the flame retardant materials exhibit excellent thermal properties at high temperature.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ325.1;TB332

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