聚磷酸三聚氰胺/季戊四醇/水滑石阻燃体系改性EVA热塑性弹性体的研究

采用聚磷酸三聚氰胺/季戊四醇（MPP/PER）膨胀阻燃体系与水滑石（LDH）并用阻燃改性乙烯—醋酸乙烯酯（EVA）热塑性弹性体。结果表明,当EVA/MPP/PER/LDH质量比为60/20/10/10时,复合材料阻燃级别达到UL94V-0,极限氧指数（LOI）为30.6%。TGA分析结果表明,阻燃体系MPP/PER和LDH协同效应提高了EVA热分解残留率。炭层扫描电镜（SEM）分析表明,MPP/PER与LDH协同作用有利于形成连续致密的炭层,提高了EVA/MPP/PER/LDH复合材料的阻燃性能。     

不同协效剂对膨胀阻燃长玻纤增强聚丙烯体系的影响

将有机蒙脱土(OMMT)与水滑石(LDH)分别作为协效剂,与膨胀型阻燃剂(IFR)协同阻燃长玻纤增强聚丙烯(LGFPP)复合材料。利用氧指数(OI)、垂直燃烧测试(UL 94)、热失重分析(TGA)、扫描电子显微镜(SEM)和力学性能测试等手段研究了不同协效剂对LGFPP/IFR性能的影响。结果表明:OMMT与LDH均能在一定程度上提高其阻燃性能,当LDH含量为1%、OMMT含量为2%时,复合材料的阻燃性能最佳。而LGFPP/IFR/OMMT体系的阻燃性能更好,能够生成更加致密和稳定的炭层,并且表现出更好的热稳定性与力学性能。     

阻燃LGFPP的阻燃性能研究

将有机蒙脱土(OMMT)和水滑石(LDH)分别与膨胀阻燃剂(IFR)构成阻燃体系,对长玻纤增强聚丙烯(LGFPP)复合材料进行阻燃改性,通过极限氧指数(LOI)和锥形量热仪(CONE)测试,对比研究了两种体系阻燃LGFPP的阻燃性能及阻燃机理。结果表明:当OMMT质量分数为2%时,复合材料的LOI达到最大值24.2%,且垂直燃烧达到了UL-94 V-0级;当LDH质量分数为1%时,LOI达到最大值23.3%,而垂直燃烧等级仍为V-1级。以炭层阻隔的IFR/OMMT体系比以稀释阻燃的IFR/LDH体系更加有效地改善LGFPP的阻燃性能。     

不同成炭剂对阻燃复合材料的性能影响研究

用21%(质量分数,下同)聚磷酸铵(APP)、4%三聚氰胺(MEL)、5%成炭剂和高密度聚乙烯(HDPE)制备膨胀型阻燃复合材料。研究了不同成炭剂对阻燃复合材料力学性能、燃烧性能、热稳定性能及成炭炭层影响。研究发现乙二醇成炭剂不仅提高阻燃剂的阻燃效率并且提高了复合材料的冲击性能。     

PS/APP/EG/CaCO_3复合材料阻燃炭层形成机理研究

采用聚磷酸铵(APP)、膨胀石墨(EG)、碳酸钙(CaCO3)对聚苯乙烯(PS)进行阻燃改性,得到一种膨胀体积较大、结构稳定、阻隔性较好的PS/APP/EG/CaCO3复合材料阻燃炭层。通过极限氧指数(LOI)测量、UL 94等级判别等方式测定了该复合材料的阻燃性能;利用X射线衍射(XRD)、扫描电镜(SEM)及傅里叶变换红外光谱分析(FTIR)等表征方法,对其化学结构、表面微观形貌等进行分析,探索PS/APP/EG/CaCO3复合材料阻燃炭层的形成机理。结果表明:阻燃炭层的形成是由于CaCO3与APP在高温下形成黏状钙盐,黏结EG形成的膨胀物质所致,钙盐在保证其膨胀倍率的基础上加强了炭层结构的稳定性,使该复合材料的阻燃性能得以提升。     

双组分膨胀型防火涂料的阻燃性能研究

研制了一种高固体分双组分膨胀型环氧防火涂料,考察了树脂种类、钛白粉含量、阻燃填料、膨胀体系含量对防火涂料阻燃性能的影响,研究结果表明:(1)双组分环氧防火涂料选用环氧树脂E51与环氧树脂E20搭配使用,辅加氨基树脂起到助发泡的作用,有助于提高膨胀层的膨胀倍率,从而提高耐火极限。(2)添加适宜量的钛白粉可以提高膨胀炭层的强度,起到隔热阻燃的作用。(3)氢氧化铝与三氧化二锑复配,可显著减少发烟量,提高膨胀炭层强度,增强阻燃性能。(4)选用膨胀石墨和三元膨胀体系搭配,形成石墨结构炭和类石墨结构炭两种结构的膨胀炭层协同配合,增强阻燃效果。     

氢氧化镧对聚丙烯膨胀阻燃体系性能影响

采用燃烧性能测试、热重分析、扫描电镜和力学性能测试等手段,分别研究了氢氧化镧对聚丙烯/磷酸密胺盐/季戊四醇(PP/MP/PER)复合材料阻燃性能和力学性能的影响。结果表明,添加氢氧化镧的PP/MP/PER复合材料的垂直燃烧指数均达到V0级别,当氢氧化镧添加量为0.5 %（质量分数,下同）时,复合材料的极限氧指数可达33.0 %,说明氢氧化镧能在一定程度上提高了PP的阻燃性能,是一种有效的阻燃协效剂。这可能是因为膨胀阻燃PP体系在燃烧过程中,氢氧化镧可与膨胀型阻燃剂反应形成网状结构、提高体系黏度,促进体系形成致密的炭层,提高体系的残炭量。研究还表明,在膨胀阻燃PP体系引入适量的氢氧化镧可在一定程度上提高体系的力学性能。     

多壁碳纳米管对聚丙烯膨胀阻燃体系阻燃性能的影响

将多壁碳纳米管(MWNTs)添加到三聚氰胺甲醛树脂包覆的聚磷酸氨(APPM)和季戊四醇(PER)膨胀型阻燃聚丙烯(PP)体系中,采用氧指数(OI)、热分析(TGA)、扫描电镜(SEM)和锥形量热仪(CONE)对材料进行测试,考察MWNTs对PP膨胀阻燃体系阻燃性能的影响,探讨其作用机理.结果表明:MWNTs在适量的添加量下可以提高体系的氧指教.TG结采表明:MWNTs的加入可以提高膨胀炭层在高温时的热稳定性,增加高温时残余物的量;膨胀炭层的SEM照片表明:MWNTs可以改善膨胀炭层的形貌,提高炭层的隔热隔质性能.0.5％的MWNTs复配用于膨胀阻燃体系中,可以在阻燃剂添加25％下,样品氧指数达到32.5％,样品(3.2 mm)通过UL94 V-0级.加入5％的MWNTs同时可以将PP复合材料的电导率从1×10-27 S/cm提高到4.4×10-4S/cm.     

铁酸镍在膨胀阻燃聚乳酸复合材料中的作用

利用水热法制备了铁酸镍(NiFe_2O_4)纳米粒子,基于生物可降解材料聚乳酸(PLA)的易燃性,将NiFe_2O_4纳米粒子作为协效剂与膨胀型阻燃剂(IFR)复配,应用于PLA的阻燃改性。结果表明,所有的PLA复合材料均达到UL-94 V-0级别,LOI显著提高至39%以上;NiFe_2O_4纳米粒子有助于PLA膨胀阻燃体系形成更为膨胀和相对致密的炭层,明显提高炭渣中有序化炭的含量,有效提高PLA膨胀阻燃体系的初始降解温度,并显著提高其成炭量。因此,NiFe_2O_4纳米粒子在PLA膨胀阻燃体系中具有良好的协效作用,能够显著提高PLA膨胀阻燃体系的热稳定性和阻燃性能。     

水滑石/膨胀型阻燃剂复合体系改性LDPE/EVA共混物研究

以氯磷酸二苯酯、乙二胺等为原料,合成了膨胀型阻燃剂N,N′-双(二苯氧基磷酰基)-2,2′-乙二胺(PEA),水滑石(LDH)与PEA复配阻燃改性低密度聚乙烯(LDPE)/乙烯-醋酸乙烯共聚物(EVA)共混物。结果表明,当LDPE/EVA/LDH/PEA的质量比为80/20/20/10时,所得复合材料的阻燃等级可达到UL94 V-1级别,极限氧指数(LOI)达28.3%;LDH与PEA复配使用提高了LDPE/EVA共混物热分解残留率;LDH和PEA协同作用强化了炭层,提高了复合材料的阻燃性能。     

EAA对HDPE/Al-Mg-LDH复合材料性能的影响

利用熔融共混法制备高密度聚乙烯(HDPE)/水滑石(LDH)复合材料,研究乙烯-丙烯酸共聚物(EAA)对复合材料的增容作用、力学性能以及结晶行为的影响.结果表明:EAA可以促进HDPE基体的结晶速率,提高复合材料结晶度;EAA对复合材料有很好的增容作用,能明显增强LDH与HDPE之间的界面粘合,促进LDH在基体中的有效分散;力学测试表明:加了EAA的复合材料比没有加EAA的复合材料力学性能有明显提高,且能使强度和韧性同时提高.     

辐照法制备无卤阻燃HDPE/EPDM/硅橡胶共混物

以氢氧化镁和红磷为阻燃剂,硅橡胶、三元乙丙橡胶(EPDM)为共混材料,高密度聚乙烯(HDPE)为基体制备了阻燃共混物,并对其进行电子束辐照,考察了阻燃共混物的力学性能、阻燃性能和微观形貌。结果表明:EPDM的加入明显改善了阻燃共混物的力学性能;硅橡胶的加入使得无机阻燃剂粒子在聚合物基体中的分散性提高,阻燃共混物的氧指(数OI)提高;辐照交联后,阻燃共混物的拉伸强度增强,OI明显提高,燃烧后的炭层更加致密。     

A study of γ‐radiation‐crosslinked HDPE/EPDM composites as flame retardants

The dynamic flammability of flame‐retardant composites that consist of high‐density polyethylene (HDPE) and ethylene–propylene–diene rubber (EPDM) and other additives, and can be used as wire‐ and cable‐insulation materials, was studied before and after irradiation. The data for the heat‐release rate (HRR), the time to ignition, the specific extinction area and the concentrations of CO and CO₂ from the burning process of cone colorimeter tests were assessed. By blending HDPE with EPDM, the HRR of HDPE was reduced and the residue char of the composite increased. The HRR of HDPE/EPDM was further reduced and the residue char of HDPE/EPDM was further increased after irradiation. The oxygen index, mechanical properties, and thermal stability of the composites, and the morphology of the char formed in the cone calorimeter test, were also investigated. Copyright © 2004 Society of Chemical Industry     

Comparative mechanical,fire‐retarding,and morphological properties of high‐density polyethylene/(wood flour) composites with different flame retardants

Aluminum hydroxide, magnesium hydroxide, and 1,2‐bis(pentabromophenyl) ethane were incorporated into high‐density polyethylene (HDPE) and wood flour composites, and their mechanical properties, morphology, and fire‐retardancy performance were characterized. The addition of flame retardants slightly reduced the modulus of elasticity and modulus of rupture of composites. Morphology characterization showed reduced interfacial adhesion among wood flour, HDPE, and flame retardants in the composites compared with control composites (HDPE and wood flour composites without the addition of flame retardants). The flame retardancy of composites was improved with the addition of the flame retardants, magnesium hydroxide and 1,2‐bis(pentabromophenyl) ethane, especially 1,2‐bis(pentabromophenyl) ethane, with a significant decrease in the heat release rate and total heat release. Char residue composition and morphology, analyzed by attenuated total reflectance, Fourier‐transform infrared spectroscopy, and scanning electron microscopy, showed that the char layer was formed on the composite surface with the addition of flame retardants, which promoted the fire performance of composites. The composites with 10 wt% 1,2‐bis(pentabromophenyl) ethane had good fire performance with a continuous and compact char layer on the composite surface. J. VINYL ADDIT. TECHNOL., 24:3–12, 2018. © 2015 Society of Plastics Engineers     

表面改性对HDPE/Nano-CaCO_3复合材料性能的影响

采用熔融共混法制备了高密度聚乙烯(HDPE)/纳米碳酸钙(nano-CaCO3)复合材料,研究了nano-CaCO3表面改性前后对复合材料力学性能的影响,利用扫描电镜(SEM)分析了nano-CaCO3表面改性前后在HDPE基体中的分散性。结果表明:加入量较小时,nano-CaCO3表面改性与否对复合材料的力学性能及其在HDPE基体中的分散性基本没有影响;加入量较大时,表面改性nano-CaCO3使复合材料具有更好的力学性能,并且其在HDPE基体中的分散性也更好。     

PA6含量对HDPE/PA6/MRP合金性能影响的研究

固定微胶囊化红磷（MRP）用量为11份,研究了不同尼龙6（PA6）含量对高密度聚乙烯（HDPE）／PA6／MRP合金阻燃性能、力学性能的影响,并用热重分析技术探讨了不同PA6含量时合金材料的残炭率、热降解起始温度。结果表明,当PA6含量为50份时,合金的阻燃性能、冲击强度及拉伸强度产生转变拐点,此时材料的冲击强度及残炭率最差。     

接枝改性对HDPE基微波竹炭复合材料性能的影响

采用高密度聚乙烯(HDPE)作为基体树脂,微波改性竹炭作为填料,通过熔融接枝法制备了HDPE基微波竹炭复合材料,分析了顺丁烯二酸酐(MAH)、过氧化二异丙苯(DCP)的含量及比例,对复合材料静态、动态力学性能和热稳定性能的影响。静态力学性能结果表明,随着MAH、DCP含量的增加,HDPE基微波竹炭复合材料的力学性能呈先增大后降低的趋势;当MAH含量一定,MAH∶DCP比例为2∶0.1时,HDPE基微波竹炭复合材料的力学性能较优。动态热机械分析仪(DMA)与热重分析仪(TGA)分析表明,MAH熔融接枝改性提高了HDPE与微波竹炭两相之间的界面作用力,有利于改善HDPE与微波竹炭的界面性能,与SEM分析结果一致;并且,还能提高复合材料在高温下的热稳定性。     

Effect of the particle size of expandable graphite on the thermal stability,flammability, and mechanical properties of high‐density polyethylene/ethylene vinyl‐acetate/expandable graphite composites

In this article, high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites filled with two different particle sizes (45 and 150 µm) of expandable graphite (EG) were prepared by using a twin‐screw extruder. The thermal stability, flammability, and mechanical properties of HDPE/EVA/EG composites were investigated by thermogravimetric analysis (TGA), cone calorimeter test (CCT), tensile test, and scanning electron microscopy (SEM). The results from TGA and CCT indicated that EG significantly enhanced the thermal stability and fire resistance of HDPE/EVA blend. The thermal stability and flame retardancy of HDPE/EVA/EG composites were improved with decreasing particle size of EG. Although the onset of weight loss of the flame‐retardant composites occurred at a lower temperature than that of HDPE/EVA blend, the flame‐retardant composites produced a large amount of char residue at a high temperature. The consolidated char layer formed a barrier, which could reduce heat, low‐molecular transfer, and air incursion, and thus enhanced the flame retardancy. The data from the tensile test showed that the addition of EG deteriorated the mechanical properties; however, the tensile stress and strain of HDPE/EVA/EG composites increased with decreasing the particle size of EG owing to the strong interface adhesion between polymer matrix and inorganic particles. POLYM. ENG. SCI., 54:1162–1169, 2014. © 2013 Society of Plastics Engineers     

Functionalization of high density polyethylene in melt state through ultrasonic initiation and its effect on mechanical properties of glass fiber reinforced composites

Summary Functionalization reaction of high density polyethylene (HDPE) with γ-methacryloxy-propyltrimethoxysilane (MAS) or with MAS and MAH performed in melt state through ultrasonic initiation by a laboratory-scale ultrasonic extruding reactor was studied in this paper. The effect of ultrasonic intensity on the percentage of grafting and melt flow rate of the functionalized products was investigated. The results show that by imposing ultrasonic vibration during melt-extruding process, the scission of HDPE chain bonds can be caused to form macroradicals, the functionalization reaction of HDPE with MAS or with MAS and MAH can be realized. The percentage of grafting and the melt flow rate of the functionalized products depend upon the ultrasonic intensity and reaction temperature. The fuctionalization reaction of HDPE with MAS can be promoted by adding a second grafting monomer MAH. The ultrasonic-induced products have a higher reactivity with the coupling agents coated on the surface of glass fibers, the mechanical properties of the composite improved by the ultrasonic induced product are higher than that of by peroxide initiated product and the mechanical properties of HDPE/GF composite modified by HDPE-g-MAH-MAS are higher than that of by HDPE-g-MAH. The SEM experimental results indicate that an oriented crystal layer exists between the interface of glass fiber and the HDPE matrix, the interfacial bonding strength is the determining factor of the formation of the oriented crystal layer.     

Studies on recyclable composites: nylon fibre reinforced high density polyethylene composites

Abstract

A commercial grade of high density polyethylene (HDPE) matrix reinforced with nylon fibre up to 30 wt-% of HDPE was studied as a potential candidate for recyclable composites. These composite materials show improvement in mechanical properties such as tensile strength and flexural strength. Modification using styrene maleic anhydride – grafted HDPE significantly improved the mechanical and thermal properties. The HDPE/nylon composites/blends obtained by recycling of the composites also show good mechanical properties.