无卤阻燃长玻纤增强聚丙烯复合材料的热氧老化性能研究

发布时间：2018-04-25 08:13

本文选题：长玻纤增强聚丙烯 + 无卤阻燃　；参考：《贵州大学》2015年硕士论文

【摘要】：本文较为系统地研究了热氧老化对无卤膨胀阻燃剂(IFR)、红磷阻燃剂(RP)、协效阻燃体系(OMMT/IFR)阻燃长玻纤增强聚丙烯(LGFPP)复合材料。针对膨胀阻燃剂在阻燃过程中以降低其力学性能达到阻燃等缺点,利用协效阻燃体系减少阻燃剂用量,解决复合材料因阻燃剂添加量大导致力学性能降低的问题。在人工加速热氧老化条件下,利用动态力学性能分析阻燃材料的动力学,对热氧老化对长玻纤增强聚丙烯复合材料无卤阻燃体系的影响进行一个较为系统的研究。热氧老化对IFR/LGFPP阻燃体系的热稳定性无太大影响,但却显著降低了阻燃体系的起始分解温度;随着热氧老化时间的延长,RP/LGFPP阻燃体系的Tmax呈现升高趋势,T5%却呈现出先上升后下降的趋势;OMMT/IFR/LGFPP阻燃体系的热稳定性随着热氧老化处理时间的延长呈现先增大后减小的变化,这与复合材料阻燃性能、燃烧性能的变化规律相对应。随着热氧老化时间的延长,三种无卤阻燃体系的LOI呈现先增大后减小的变化规律,IFR/LGFPP阻燃体系和RP/LGFPP阻燃体系的阻燃等级基本保持为FV-0级不变,OMMT/IFR/LGFPP阻燃体系的阻燃级别逐渐下降。IFR/LGFPP、OMMT/IFR/LGFPP阻燃体系经过热氧老化处理后,与未老化试样相比,老化试样的第一个PHRR较高;且随着热氧老化时间的延长,第一个PHRR值逐渐增加,MHRR和THR值呈现不断增大的趋势。而RP/LGFPP随着热氧老化时间的延长,试样的TTI逐渐增加,PHRR值逐渐降低,MHRR和THR呈现不断下降的趋势。通过对锥形量热仪燃烧测试残余物的宏观形貌图分析可知,未老化试样燃烧后形成黑色致密而均匀的残留物。形成的碳层能阻隔燃烧热向未燃部分的反馈以及分解产物向火焰区的扩散燃烧,起到隔热、隔质作用,能够有效地降低材料的热释放速率,延缓材料的燃烧。随着热氧老化时间的延长,试样燃烧后形成的炭层颜色逐渐变浅,不致密并出现了较多裂纹,阻燃剂有从基体内部向表面迁移的现象。随着热氧老化时间的推移,阻燃体系基体的结晶度减小,力学性能显著下降。说明分子量降低,发生了显著的热氧化降解。红外光谱表明,随着热氧老化时间的延长,试样表面会产生更多的生色基团使材料发生黄变,说明PP基体分子链发生了老化断裂。PP基体分子链断裂,以及长玻纤与PP基体间发生界面脱黏是导致阻燃体系宏观力学性能下降的主要原因。
[Abstract]:In this paper, the flame retarded long glass fiber reinforced Polypropylene (LGFPP) composites by thermo-oxygen aging for halogen-free intumescent flame retardants (IFRN), red phosphorus flame retardants (RPX) and synergistic flame retardant systems (OMMT / IFR) have been studied. In order to reduce the mechanical properties of intumescent flame retardants in the process of flame retardation, the synergistic flame retardant system is used to reduce the amount of flame retardants and to solve the problem that the mechanical properties of composites are reduced due to the large amount of flame retardants. The kinetics of flame retardant materials was analyzed by dynamic mechanical properties under the condition of artificial accelerated thermal oxygen aging. The effect of thermal oxygen aging on halogen-free flame retardant system of long glass fiber reinforced polypropylene composites was studied systematically. Thermal oxygen aging had little effect on the thermal stability of IFR/LGFPP flame retardant system, but significantly decreased the initial decomposition temperature of flame retardant system. With the prolongation of the aging time, the Tmax of RP- / LGFPP flame retardant system increased at first and then decreased with the increase of T5%. The thermal stability of OMT / IFR / LGFPP flame retardant system increased first and then decreased with the prolongation of thermal oxygen aging time. This corresponds to the change of the flame retardant and combustion properties of the composites. With the increase of thermal oxygen aging time, The LOI of the three halogen free flame-retardant systems increased first and then decreased. The flame-retardant grade of IFR / LGFPP and RP/LGFPP flame-retardant system remained basically unchanged as FV-0 grade. The flame-retardant grade of IFR / LGFPFP / OMFT / R / LGFPP flame-retardant system decreased gradually after thermal oxygen aging. The first PHRR of the aged sample is higher than that of the unaged sample, and the first PHRR value increases gradually with the increase of the thermal oxygen aging time. However, with the increase of thermal oxygen aging time, the TTI values of the samples gradually increased and the TTI values decreased gradually. The TTI and THR values of the samples decreased gradually with the increase of the thermal oxygen aging time. Based on the analysis of the macroscopic morphology of the residue from the combustion test with a cone calorimeter, it can be seen that after burning the unaged sample, the black dense and uniform residue is formed. The resulting carbon layer can block the feedback from the combustion heat to the unburned part and the decomposition product to the flame zone, which can effectively reduce the heat release rate of the material and delay the combustion of the material. With the increase of thermal oxygen aging time, the color of the carbon layer becomes lighter after burning, and there are many cracks in the carbon layer, and the flame retardant moves from the inside of the matrix to the surface. The crystallinity and mechanical properties of the flame retardant matrix decreased with the aging time. The results showed that the molecular weight decreased and the thermal oxidation degradation occurred significantly. The IR spectra show that with the increase of the aging time, more chromophore groups appear on the surface of the sample, which indicates that the PP matrix molecular chain has the aging fracture and the PP matrix molecular chain breaks. The interfacial debonding between long glass fiber and PP matrix is the main reason for the decrease of macroscopic mechanical properties of flame retardant system.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ327.1;TB33

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