摘要
针对聚己内酰胺6(PA6)高温氧化诱导分子链断裂产生的持续燃烧和熔体滴落等问题,利用均三嗪环阻燃剂(CFA)的膨胀成炭性质,采用熔融共混方式得到阻燃抗熔滴PA6复合树脂,分析了CFA阻燃剂的成炭性能,研究了添加不同质量分数CFA阻燃剂的PA6复合树脂的阻燃性能与燃烧后残炭的结构及形貌。结果表明:当CFA质量分数为8%时,阻燃抗熔滴PA6复合树脂的垂直燃烧等级达到V-0级,点燃后仅燃烧1 s即熄灭,熔滴滴落1滴;阻燃抗熔滴PA6复合树脂极限氧指数从纯PA6的24.5%提升到33.4%,总烟释放量下降13.3%;受阻燃剂高温残炭量高的影响,随着CFA质量分数的增加,在空气氛围中,残炭量从纯PA6的1.87%提高到4.84%;CFA诱导PA6阻燃机制为气相中的不燃性气体的稀释效应以及凝聚相中炭层的阻隔效应;CFA阻燃剂的加入并未导致PA6拉伸断裂强度下降,反而使其有所提升,CFA质量分数为8%时,PA6复合树脂的拉伸断裂强度提升28.8%。
Objective Polycaprolactam 6(PA6)is a polymer material widely used in daily life,but it is flammable.High-temperature oxidation during combustion process would cause its molecular chain to break,resulting in problems such as continuous combustion and melt dripping.At present,charring technology has become an important means to solve these problems.The homotriazine ring flame retardant has excellent charring performance by virtue of its conjugated stable structure,which has greatest potential to solve the problem of PA6 flame retardant.Method Triazine flame retardant forms a carbon layer on the polymer surface to resist the further combustion of flame,hence improving the flame retardancy of PA6.Triazine ring structure also has certain structural compatibility with PA6 molecular chain,which would not affect the processing and mechanical properties of PA6.Therefore,homotriazine ring flame retardant(CFA)was added to PA6 by melt blending to improve the flame retardancy of PA6.The charring performance of the PA6 composite resin was studied through the thermal experiment.By examining the limiting oxygen index,vertical combustion and cone calorimetry experiment,the influence on the flame retardant and charring property on PA6 resin was studied,which was used for explaining the mechanism of the CFA flame retardant.Results In this research,a series of composite resin were prepared by melt blending CFA flame retardant and PA6.After adding 8%CFA flame retardant to PA6 resin,the vertical combustion rating reached V-0 level,the limiting oxygen index increased from 24.5%to 33.4%(Tab.1 and Fig.2),and the total smoke release decreased by 13.3%(Fig.3),suggesting the effectiveness of CFA in many aspects.The charring rate of CFA flame retardant itself in the air atmosphere reached 8.3%,and the charring rate of PA6 composite resin after adding 10%CFA was more than twice that of pure PA6,from 1.87%to 4.84%(Fig.4),because of better isolation to oxygen and heat.By analyzing the four decomposition processes of CFA flame retardants in a nitrogen gasatmosphere,it was found that the charring performance of CFA was mainly by virtue of the tertiary nitrogen structure contained,and a stable carbon layer were be formed during the high-temperature process,thereby improving the high-temperature formation of the composites(Fig.5).In order to understand the effectiveness of the flame retardant carbon structure,the structure of residual carbon and the composition of decomposition gas were analyzed.Compared with the carbon layer formed by the series of PA6 samples,it was revealed that the addition of CFA made the carbon layer rougher.When the mass fraction of CFA reaches more than 8%,the carbon layer began to become smooth again,facilitating effective protection to the internal PA6,thereby improving heat insulation and dripping resistance of PA6 composite resin(Fig.6).The gas phase flame retardant mechanism was also found playing a role in improving the flame retardancy of PA6 resin(Fig.8).Based on the above analysis,it was believed that good flame retardancy of PA6 composite resin is mainly because of the dilution effect of non-combustible gases in the gas phase and the barrier effect of the carbon layer in the condensed phase in the combustion process.The addition of CFA flame retardant did not lead to a decrease in the tensile break strength of PA6,but rather improved it.When the mass fraction of CFA was 8%,the tensile break strength of PA6 composite resin increased by 28.8%.Conclusion After studying the performance of flame retardant PA6,It was found that CFA greatly increased the limiting oxygen index and vertical combustion of flame retardant PA6,and decreased smoke emission.CFA flame retardant can also improve the smoke suppression effect of PA6 to a certain extent,and enhance the tensile strength of PA6,greatly expanding the application range of PA6.The experimental results also verified the good compatibility between CFA and PA6 molecular chains.The research on PA6 flame retardant mechanism needs be further studied to improve the flame retardancy of PA6.
作者
张文琪
李莉莉
胡泽旭
魏丽菲
相恒学
朱美芳
ZHANG Wenqi;LI Lili;HU Zexu;WEI Lifei;XIANG Hengxue;ZHU Meifang(State Key Laboratory for Modification of Chemical Fibers and Polymer Material,Donghua University,Shanghai 201620,China;College of Materials Science and Engineering,Donghua University,Shanghai 201620,China;Shanghai Defulun New Material Technology Co.,Ltd.,Shanghai 201502,China)
出处
《纺织学报》
EI
CAS
CSCD
北大核心
2023年第11期1-8,共8页
Journal of Textile Research
基金
国家自然科学基金项目(52003042,52073047)
上海市优秀技术带头人计划项目(20XD1433700)
上海市“一带一路”国际合作项目(20520740800)
教育部“创新团队发展计划”滚动支持项目(IRT16R13)。
关键词
聚己内酰胺6
阻燃改性
抗熔滴
均三嗪环
成炭性能
熔融共混
polycaprolactam 6
flame retardant modification
dripping resistant
homotriazine ring
charring performance
melt blending
