原位聚合无卤阻燃聚酰胺6的结构与性能研究

采用原位聚合添加反应型无卤阻燃剂,是实现聚己内酰胺(PA6)阻燃改性的主要方法。在己内酰胺的水解开环聚合体系中,加入三聚氰胺氰尿酸盐(MCA)的原料单体,原位聚合制备了阻燃PA6(FRPA6),对FRPA6的结构、形貌及性能进行了表征;通过熔融纺丝制备了FRPA6纤维,测试了其力学性能及阻燃性能。结果表明:FRPA6中阻燃剂MCA与PA6基体的相容性良好,MCA自组装反应比较充分,MCA粒子以纳米级均匀分布于PA6基体中;随着MCA含量的增加,FRPA6的熔点、熔融热焓有所降低,结晶温度略有升高,热稳定性下降;当MCA质量分数为7.5%时,FRPA6的阻燃性能达UL94 V-0级,拉伸强度为64.1 MPa,缺口冲击强度为10.4 k J/m2;相比纯PA6纤维,FRPA6纤维具有较好的阻燃性能,极限氧指数达35%以上,但力学性能有所下降。     

PA6/MGF复合材料的力学及摩擦学性能

用硅烷偶联剂KH550和二苯甲烷二异氰酸酯(MDI)分别对磨细玻璃纤维(MGF)进行表面改性(即KMGF,M-MGF),采用熔融法制备PA6/MGF复合材料。实验结果表明:PA6/M-MGF复合材料中M-MGF质量分数为20%时,拉伸强度从65.82 MPa提高到71.78 MPa,缺口冲击强度从11.86 k J/m2提高到23.73 k J/m2,增强增韧作用优于PA6/K-MGF复合材料;摩擦磨损性能研究发现,PA6/M-MGF复合材料的摩擦因数随着M-MGF质量分数的增加而下降;PA6/M-MGF和PA6/K-MGF复合材料的磨损率的变化趋势一致。     

无机填料对PA6/MCA阻燃复合材料性能的影响

研究了不同种类的无机填料(硅灰石、碳酸钙)对尼龙6(PA6)/三聚氰胺氰尿酸盐(MCA)阻燃复合材料性能的影响。阻燃性能测试结果表明,PA6/MCA/硅灰石阻燃复合材料为UL94 V–0级,比PA6/MCA阻燃复合材料(V–2级)有显著提高;然而PA6/MCA/碳酸钙阻燃复合材料的极限氧指数却有所下降。扫描电子显微镜测试分析表明,PA6/MCA/硅灰石阻燃复合材料燃烧后的表面炭层呈连续、致密状;PA6/MCA/碳酸钙阻燃复合材料的表面炭层有很多孔洞,且孔洞直径大。傅立叶变换红外光谱测试结果表明,PA6/MCA/硅灰石阻燃复合材料的表面炭层与Si O2能很好地结合,形成致密的保护层,致使其阻燃性能显著提高。另外,力学性能测试结果表明,硅灰石能够提高PA6/MCA阻燃复合材料的拉伸强度,但降低了缺口冲击强度,而碳酸钙的加入却使得PA6/MCA阻燃复合材料的综合力学性能有所下降。     

水滑石在二乙基次膦酸铝阻燃PA66/GF材料中的应用

采用双螺杆挤出造粒工艺制备二乙基次膦酸铝(AlPi)阻燃玻璃纤维增强尼龙66(PA66/GF)复合材料，研究水滑石替换传统三聚氰胺聚膦酸盐(MPP)对复合材料综合性能的影响。结果表明：水滑石含量增加会导致复合材料拉伸强度及悬臂梁缺口冲击强度降低，水滑石添加质量分数为6%时，复合材料拉伸强度由122 MPa降低至114 MPa,悬臂梁缺口冲击强度由8.3 kJ/m²降低至7.6 kJ/m²,但弯曲强度及弯曲模量有所增加。当水滑石添加质量分数超过6%时，燃烧后碳层强度及致密性明显提升，材料可获得稳定的V-0阻燃等级。锥形量热测试分析进一步证明水滑石的引入可以降低引燃时间(TTI)、平均热释放速率(mHRR)和总热释放量(THR),参与提升碳层强度及致密性，改善复合材料阻燃性能。     

三聚氰胺氰尿酸盐阻燃PA6复合材料性能研究

以三聚氰胺氰尿酸盐(MCA)为阻燃剂,制备了聚酰胺6(PA6)阻燃复合材料,采用氧指数、垂直燃烧和热失重(TG)重点研究分析了MCA对PA6复合材料的阻燃性能的影响,同时,考察了MCA对PA6复合体系力学性能和吸水性能的影响。结果表明,当MCA用量为10份时,PA6复合材料的氧指数达到28%,符合难燃材料的要求;TG分析表明,MCA的加入,使复合体系最大分解速率温度升高44℃,提高了PA6的热稳定性,但MCA的促炭能力不强;MCA的加入,复合材料拉伸强度随MCA的加入先增加后降低,而冲击强度逐渐降低;MCA的加入也降低了复合材料的吸水率。     

高灼热丝阻燃增强回收PA6的制备

利用双螺杆挤出机制备了玻纤阻燃增强回收聚酰胺6(PA6)系列复合材料,探讨了红磷母粒(P)、氢氧化镁[Mg(OH)2]、三聚氰胺尿酸盐(MCA)、硼酸锌(ZnBO3)、增韧剂乙烯辛烯共聚物接枝马来酸酐(POE-g-MAH)对阻燃增强回收PA6力学性能及灼热丝温度的影响,采用力学测试方法、灼热丝试验仪研究了回收PA6复合材料的力学性能和灼热丝温度。结果表明:在阻燃增强回收PA6体系中,用P、MCA复配效果最好,当质量比为2/1的P/MCA和POE-g-MAH加入量(质量分数)分别为2%和5%时,材料的拉伸强度为123.6 MPa,缺口冲击强度为10 kJ/m2,1.6 mm阻燃等级为V-0,灼热丝温度达到810℃,满足电子电气对材料高灼热丝温度的要求。     

MCA与MH阻燃PA-6复合材料性能研究

分别以三聚氰胺氰尿酸盐(MCA)和氢氧化镁(MH)为阻燃剂制备了聚酰胺6(PA-6)阻燃复合材料,研究和对比了MCA和MH对复合材料的阻燃性能、力学性能影响.结果表明,当MCA和MH用量同为20份时,PA-6/MCA复合材料的极限氧指数(LOI)达到30.5%,而PA-6/MH复合材料的LOI仅为23.5%,说明MCA的阻燃效率比MH高.同时,PA-6/MCA复合材料的拉伸强度为66.8 MPa,是PA-6/MH复合材料的1.14倍.熔体流动速率PA6/MCA复合材料熔体流动速率达74 g/10min,是PA-6/MH复合材料的4.9倍.     

CaCl_2对PA6/OMMT/POE-g-MAH复合材料结构与性能的影响

通过挤出机熔融共混法制备了PA6/POE-g-MAH/OMMT/CaCl_2复合材料,研究了CaCl_2含量对PA6/POE-gMAH/OMMT/CaCl_2复合材料结晶行为及其力学性能的影响。结果表明:随着CaCl_2含量的增加,PA6/POE-g-MAH/OMMT/CaCl_2复合材料的弯曲强度呈现出逐渐增大的趋势。当CaCl_2为9%时,复合材料的弯曲强度达到最大值76.6 MPa。另外,随CaCl_2含量的增加,复合材料拉伸强度和冲击强度都呈现出先增大后减小的趋势。当CaCl_2为5%时,复合材料的拉伸强度(70.8 MPa)和冲击强度(11.8 k J/m2)分别达到最大值,与纯PA6相比拉伸强度(65.5 MPa)和冲击强度(5.5 k J/m2)分别提高了8%和114%。结晶性能研究表明:随着CaCl_2含量的增加,复合材料的成核温度、增长温度及熔融温度向低温方向移动。     

无卤阻燃PA6复合材料的阻燃性能及热分解动力学研究

从不同阻燃剂之间具有的协同效应入手,通过双螺杆挤出机制备样品,讨论了氢氧化镁(MH)、微粉化红磷(HP)、有机蒙脱土(OMMT)之间不同含量的协效阻燃作用。研究结果表明:钛酸酯偶联剂用量为氢氧化镁质量的2%时,能使MH的活化能力达到最佳,减少了MH在尼龙6(PA6)中的团聚,分散性得到提高;MH:HP为6:4时,具有最佳协同阻燃效果;添加1%的OMMT时,复合材料的UL 94在保持V-0级别的同时,其拉伸性能也提高到73.6 MPa,阻燃剂用量由15%降至14%。PA6/MH/HP/OMMT复合材料的热分解活化能达到157.8 kJ/mol,表明该复合材料体系的热稳定性最高。     

废弃PCB非金属材料增强PA6/GF复合材料的制备及性能

采用环氧树脂a胶对自制的废弃印刷电路板(PCB)非金属材料(N-wPCB)超细粉体进行表面处理,然后通过双螺杆熔融共混制备了尼龙(PA)6/玻璃纤维(GF)复合材料。研究了在不同的搅拌时间下表面处理剂用量对N-wPCB改性PA6性能的影响,在此基础上探讨了在不同N-wPCB含量下GF含量对PA6/GF复合材料性能的影响。结果表明,当表面处理剂用量为N-wPCB质量的2%且表面处理时的搅拌时间为60 min,N-wPCB与PA6质量比为1∶10,GF含量为PA6质量的20%时,PA6/GF复合材料综合性能最佳,其拉伸强度为116 MPa,弯曲强度为205 MPa,缺口冲击强度为18 kJ/m²,熔体流动速率(MFR)为10.6 g/10 min。通过加入十溴二苯乙烷进一步制备了阻燃PA6/GF复合材料,加入10份表面改性N-wPCB后,阻燃复合材料的拉伸强度由103 MPa提高到了112 MPa,弯曲强度由181 MPa提高到了186 MPa,缺口冲击强度由10 kJ/m²提高到了12 kJ/m²,阻燃等级由V–1变成V–...     

Enhancement of flame retardancy and mechanical properties of polyamide 6 by incorporating melamine cyanurate combined with attapulgite

In this study, the nanocomposites are prepared which used polyamide 6 (PA6) composite as matrix, melamine cyanurate (MCA) as fire retardant and attapulgite (AT) as synergistic agent. The mathematical model between MCA content, AT content, and limited oxygen index (LOI) is established by multiple linear regression fitting. The polymer materials are characterized using Fourier transform infrared spectroscopy, X-ray diffraction, Thermogravimetric Analysis, and scanning electron microscopy. Through response surface methodology, the important variables (polymerization time, the content of MCA, and the content of AT) affecting the mechanical strength of composites are modeled. Results demonstrate that when the t is 0.6 h, the AT content is 6.2%, and the MCA content is 11.5%, the mechanical properties of the PA6/MCA/AT composite are up to 44.81 MPa, and the sample passes the UL-94 V-0 flammability rating, and the LOI reaches 27.9%. Therefore, polymers with highly effective flame retardancy and optimal mechanical properties are prepared. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47298.     

聚酰胺表面改性三聚氰胺氰尿酸盐及其阻燃聚酰胺6研究

以聚酰胺树脂的无机酸溶液为介质进行三聚氰胺-氰尿酸分子自组装合成三聚氰胺氰尿酸盐(MCA),并同时实现聚酰胺树脂对阻燃剂的表面包覆改性,集MCA的合成及表面改性于一体。该阻燃剂与目标阻燃树脂聚酰胺6 的相容性良好,阻燃剂粒子与聚酰胺6(PA6)树脂基体之间相界面基本消失。聚酰胺6中添加7％该阻燃剂即达到 UL94-1．6mm V0级别,成功解决了传统MCA阻燃PA6燃烧熔滴易引燃脱脂棉的问题,其极限氧指数高达34％,阻燃效率远高于传统MCA。材料力学性能良好,具有较好的市场应用前景。     

尼龙基MCA母粒的制备及其在阻燃尼龙的应用

针对三聚氰胺氰尿酸盐(MCA)粉体对尼龙(PA)进行阻燃改性时,MCA分散性差,材料阻燃性能不稳定的问题,运用特殊的包覆工艺成功制得了PA基MCA母粒。将制得的MCA母粒及MCA粉体分别与PA6或PA66共混挤出,制得阻燃PA材料。对比分析了MCA母粒及MCA粉体阻燃PA6或PA66的垂直燃烧性能和力学性能。结果表明,与MCA粉体相比,MCA母粒可在MCA含量较低的情况下使厚度为0.8 mm及1.6 mm的阻燃PA6或PA66试样的垂直燃烧等级达到V–0级。MCA母粒及粉体对阻燃PA6的弯曲强度和PA66的拉伸强度影响很小,MCA母粒阻燃PA6的拉伸强度较粉体阻燃的高,而阻燃PA66的弯曲强度低;MCA母粒使阻燃PA的缺口冲击强度降低,而MCA粉体对PA的缺口冲击强度影响较小,当MCA含量较低时,MCA母粒阻燃PA的缺口冲击强度明显高于MCA粉体阻燃的PA。制备的MCA阻燃母粒对PA的阻燃效果不受黑色母料的影响,且具有较好的阻燃稳定性。     

硼酸锌对氮磷协效阻燃玻纤增强尼龙66性能的影响

为提高三聚氰胺聚磷酸盐(MPP)和二乙基次膦酸盐(OP)协效阻燃玻纤(GF)增强尼龙66(PA66)的综合性能,引入少量的无机阻燃剂硼酸锌(ZB)作为协效剂,系统研究了不同添加量的ZB对阻燃材料的阻燃性能、热稳定性、力学性能和白度的影响。结果表明,当MPP和OP的总添加量为15%,复配0.5%的ZB时,阻燃GF增强PA66的垂直燃烧阻燃等级达到UL94 V–0级,且热释放总量由MPP/OP体系的15.4 k J/g降为13.7 k J/g;ZB的引入促进了连续、致密炭层的形成,增强了凝聚相阻燃;ZB增强了阻燃材料的热稳定性,ZB复配量为1.0%的阻燃材料的初始降解温度提高到了301℃,有效避免了加工过程中的降解;当ZB添加量为1.0%时,阻燃材料的拉伸强度和缺口冲击强度分别为100.9 MPa和4.22 k J/m~2,均优于未添加阻燃剂的纯GF增强PA66;同时,样品的白度得到了明显提升,有利于阻燃GF增强PA66的工业化应用。     

改性MCA的固相合成及其在PA6中的应用

本实验选用一种新的方法合成改性三聚氰胺氰尿酸盐(MCA),将三聚氰胺(MA)、氰尿酸(CA)和极少量水混合成膏状物并使其在室温下反应一定时间,再加入少量MCA和二氧化硅(Si O2)溶胶使其继续反应以制备改性MCA(mMCA)阻燃剂。将制备的mMCA与尼龙6(PA6)熔融共混制备阻燃PA6复合材料。用FTIR、XRD和TG对所制mMCA进行了表征,对阻燃PA6复合材料的阻燃性能和力学性能进行了测试。结果表明:所制mMCA的FTIR、XRD特征峰与MCA的特征峰一致;m MCA的最大热失重温度有了较大的提升达到465.2℃。在PA6复合材料中,当阻燃剂含量为13%时,阻燃PA6复合材料的极限氧指数(LOI)达到33%,阻燃性能为UL-94 V0级,锥形量热测试的PHRR降低了26.3%。随着阻燃剂含量的增加,复合材料的力学性能有所提高。与传统大量水体系制备mMCA方法相比,此法具有工艺简单、不需加热、耗水量极低,没有污水排放等优点。     

BPS/有机氮磷复合阻燃增强增韧PA66材料的性能

以溴化聚苯乙烯(BPS)和自制的有机氮磷阻燃剂(NPR)为尼龙(PA)66的阻燃剂,以短切玻璃纤维为增强剂,加入增韧剂三元乙丙橡胶,制备了阻燃增强增韧PA66材料,研究了阻燃剂的加入及复配对材料力学性能、极限氧指数(LOI)、垂直燃烧性能、最大烟密度、热稳定性等性能的影响。结果表明,相对于BPS,NPR对材料力学性能的不利影响更大,单独使用BPS时材料的阻燃效果较差,而单独使用NPR可明显提升材料的阻燃性能,当NPR质量分数为15%时,材料的LOI为34%,垂直燃烧等级达到V–0级,拉伸强度、弯曲强度和缺口冲击强度分别为161,224 MPa和12 kJ/m~2。在阻燃剂总质量分数为15%的条件下,与单独使用NPR相比,BPS与NPR的复配进一步降低了材料的拉伸与弯曲强度,但在保持阻燃性能的同时降低了材料成本。NPR的加入导致材料最大烟密度有所增大,热降解提前,而BPS与NPR的复配进一步增大了材料的最大烟密度,使热降解有所延后。     

Effect of halloysite nanotubes on thermal and flame retardant properties of polyamide 6/melamine cyanurate composites

In this study, polyamide 6 (PA6) with various contents of halloysite nanotubes (HNTs) and melamine cyanurate (MCA) were prepared by a twin‐screw extruder. The flame retardant and physical properties of PA6 composites were examined. X‐ray diffraction (XRD) patterns of PA6/HNTs and PA6/MCA/HNTs composites showed that HNTs as a nanoscale material dispersed in PA6 whether with MCA or not. Thermo gravimetric analyzer (TGA) results showed the presence of HNTs can improve thermal stability of PA6 and PA6/MCA composites. The incorporation of HNTs seemed to result the increase of crystallinity of PA6 and PA6/MCA composites from the differential scanning calorimetry (DSC) results. The combined of HNTs and MCA that leads to further improvements limiting oxygen index (LOI) value of PA6 to 31.7% exerted a positive effect on flame retardancy of PA6. What's more, some mechanical enhancements of PA6 with adding of HNTs were achieved and HNTs also made the tensile properties of PA6/MCA composites improved. POLYM. COMPOS., 36:892–896, 2015. © 2014 Society of Plastics Engineers     

Preparation and properties of environmental friendly nonhalogen flame retardant melamine cyanurate/nylon 66 composites

Melamine cyanurate (MCA) was utilized as an environmental friendly additive to prepare the nonhalogen flame retardant MCA/Nylon 66 composites by melt blending technique. Because of the strong hydrogen bond interactions and fine interfacial compatibility between MCA and Nylon 66, the resultant even dispersion of MCA filler in polymer matrix leads to the better toughness and strength of MCA/Nylon 66 composites than those of neat Nylon 66. Both Nylon 66 and MCA/Nylon 66 composites exhibit similar α‐crystalline structure, but the presence of MCA influences the distribution of α1 and α2 crystalline phases in Nylon 66 by inducing its hydrogen‐bonded sheet separation. Moreover, the blending of MCA and Nylon 66 increases the crystallization temperature and exothermicity but decreases the thermal stability of Nylon 66 and accelerates the degradation of MCA. The MCA/Nylon 66 composites show better flame retardancy at intermediate MCA contents of 10 and 15 wt %. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Influence of nano silica hybrid expandable graphite on flammability,thermal stability,and mechanical property of polypropylene/polyamide 6 blends

Silica (SiO₂) nanohybrid expandable graphite (nEG) particles fabricated through one-step method are used as an efficient flame retardant for polypropylene (PP)/polyamide 6 (PA6) blends. The effect of nEG on the flammability, thermal stability, crystallization behaviors, and mechanical properties of PP/PA6 composites is investigated by using limit oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared, scanning electron microscopy, and mechanical tests. Compared with pure expandable graphite (EG), nEG improves the flame retardancy of composites. The results of LOI show that LOI of PP/PA6/nEG10 and PP/PA6/nEG15 composites are 26.0% and 27.2%, respectively. But the LOI values of PP/PA6/EG10 and PP/PA6/EG15 composites are 25.7% and 26.9%, respectively. The UL-94 test results show that PP/PA6/nEG10 composites reach V-1 level when the nEG content is only 10%. However, the PP/PA6 composites with 10% EG does not pass the UL-94 test. In addition, PP/PA6 composites with 15% nEG can reach V-0 level. The CCT results further show that nEG has a higher flame-retardant efficiency than pure EG for PP/PA6 blends. The thermal stability of PP/PA6/nEG composites is better than that of PP/PA6/EG composites. The mechanical property tests indicate that nEG is more conducive to maintain the tensile and impact strengths of PP/PA6 blends than EG due to the enhanced compatibility and interfacial adhesion.     

The effect of morphology on the flame‐retardant behaviors of melamine cyanurate in PA6 composites

Three types of melamine cyanurate (MCA) with micrometer‐size sphere‐like, micrometer‐scale rod‐like, and nanometer‐scale flake‐like morphologies were synthesized by changing the chemical circumstances of the reactions. The microcosmic morphologies of MCA were characterized via scanning electron microscopy and X‐ray diffraction. After the MCAs with different morphologies were incorporated into polyamide 6 (PA6), the flame‐retardant properties of the MCA/PA6 composites were investigated using the limited oxygen index (LOI), UL94, and cone calorimeter tests. The MCA/PA6 composites with nanometer‐scale flake‐like MCA obtained an LOI value of 29.5% and a UL94 V‐0 rating, which were higher than those with micrometer‐size sphere‐like and rod‐like MCAs. However, the different morphologies did not affect the heat release rate, total smoke release, average carbon monoxide yield, and average carbon dioxide yield based on the cone calorimeter. The flame‐retardant mechanism of MCAs with different morphologies was investigated via thermal gravimetric analysis (TGA) and TGA‐Fourier transform infrared spectra. The results show that the different morphologies of MCA resulted in different dispersed evenness of MCA. Further, the nanometer‐scale flake‐like morphology of MCA brought more interactions of hydrogen bond between MCA and PA6, which resulted in the delay of MCA decomposition and the enhancement of MCA flame‐retardant effect. The nanometer‐scale flake‐like MCA had a better performance compared with the other samples because of the delaying and even release of flame‐retardant effect by the decomposition of evenly dispersed MCA. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40558.