PA6/LDPE/PE-g-MAH共混纳米纤维的制备及结构研究

采用共混海岛纺丝法制备聚酰胺6/低密度聚乙烯/聚乙烯接枝马来酸酐(PA6/LDPE/PE-g-MAH)共混纤维,溶解剥离出LDPE基体相,可制备出PA6纳米纤维;研究了共混物的组成和纺丝条件对共混纤维的相结构、结晶、力学性能及PA6纳米纤维直径的影响。结果表明:随着共混物中PA6分散相含量增加,PA6纳米纤维的直径逐渐增大;PA6质量分数从30%增加至60%时,PA6纳米纤维平均直径由107 nm增至149nm;PA6质量分数为70%时,由于相逆转无法得到PA6纳米纤维;在PA6质量分数为55%条件下,提高拉伸倍数,PA6纳米纤维的直径进一步降低,且结晶度、力学性能增加。     

插层剂对蒙脱土/PA6纳米塑料性能的影响

用4种插层剂合成了有机改性蒙脱土（MMT），将PA6与改性MMT熔融共混制成纳米塑料，用IR、XRD和透射电镜表征了结构，观察到MMT／PA6纳米塑料的无熔滴等阻燃特性。通过改性纳米塑料力学性能的研究表明：质量分数为6％的MMT能提高PA6的LOI值，MMT1831质量分数为3％时弯曲模提高57．1％，MMT1831质量分数为5％时弯曲强度提高42．4％；MMT与常规阻燃剂之间有力学协效作用和阻燃协效作用，能同时提高PA6的力学性能和阻燃性能。     

原位聚合抗磨损PA6/纳米SiO2复合材料制备及其性能研究

为提高聚酰胺6（PA6）的抗磨损性能,采用原位聚合法合成并制备了PA6/纳米SiO2复合材料,研究了该材料的抗磨损性能、耐热性能、力学性能和结晶性能。结果表明,原位聚合PA6/纳米SiO2复合材料具有良好的抗磨损特性,当纳米SiO2含量为1 %(质量分数,下同)时,复合材料抗磨损性能最佳,该材料的热变形温度、拉伸强度、弹性模量和断裂伸长率均明显高于原料PA6;当纳米SiO2含量为3 %时,复合材料热变形温度由原料PA6的64.6 ℃提高到130 ℃。采用原位聚合母料法制备的PA6/纳米SiO2复合材料同样具有理想的抗磨损性能,并可获得更好的力学性能,且可大幅降低材料制备成本。     

LiCl改性聚酰胺6纤维的制备与性能

通过高速共混包覆法和熔融纺丝法制备出聚酰胺6(PA6)-LiCl共混复合纤维,研究了不同含量的LiCl对PA6纤维的结构和性能的影响。差示扫描量热分析、傅里叶变换红外光谱分析、热重分析、纤度及力学性能测试等的结果表明:LiCl中Li+能打开PA6的氢键,并与酰胺基团产生比氢键作用力更强的络合作用,降低了PA6分子链的规整性,从而有利于纤维的热牵伸,在降低纤度的同时提高力学性能。当LiCl质量分数为0.5%时,PA6-LiCl共混纤维的可拉伸倍数最高可至4.8倍,断裂强度为5.3 cN/dtex,断裂伸长率为5.8%,较未加LiCl的样品的断裂强度提高了112%,断裂伸长率降低了74.6%,综合力学性能最佳。     

含银PA6纳米纤维的制备及抗菌性能研究

以次磷酸钠还原硝酸银制得银溶胶,按不同比例加入到质量分数为12%的聚己内酰胺(PA6)/甲酸溶液中,通过静电纺丝制备含银PA6纳米纤维毡,分析了纤维的表面形貌和抗菌性能。结果表明:当纤维中银质量分数为0.1%时,PA6纳米纤维对大肠杆菌的抑菌率达95%以上。扫描电镜和原子力显微镜分析表明,含银PA6纳米纤维比PA6纳米纤维平均直径稍粗,直径分布更集中,纤维直径为80～100 nm,但其表面有明显的褶痕,粗细节较多,不如PA6纳米纤维光滑。     

酚醛树脂改性纳米蒙脱土填充PA6的制备及性能研究

分别利用经十八烷基三甲基氯化铵(OTAC)、酚醛树脂(PF)表面改性的纳米蒙脱土(MMT)填充聚酰胺(PA)6,研究了不同表面改性剂及其用量对PA6的力学性能、热性能和吸水性的影响。结果表明,经OTAC改性的纳米MMT和经PF改性的纳米MMT对PA6的热性能改善效果有限,但有利于提高PA6的刚性和降低吸水性。PF改性纳米MMT对PA6的改性效果优于OTAC改性纳米MMT,当PF改性纳米MMT的质量分数为3%时,材料的拉伸强度、弯曲强度和维卡软化温度分别比纯PA6提高了12.3%、58.8%和2%,吸水率降低0.5%。     

PA6静电纺纳米纤维

讨论了PA6静电纺丝工艺,利用扫描电镜(SEM)观察纤维的形态结构,研究了影响PA6静电纺丝 的因素及其对所形成纤维的形态、直径的影响。结果表明,在甲酸溶液中,PA6质量分数为8％、电压值为15 kV、喷丝头到收集板的垂直距离为20 cm是PA6静电纺丝的最佳工艺条件,可得到直径小于100 nm的PA6 纳米纤维。     

纤维级复合阻燃PA 6的制备及其热稳定性研究

以三聚氰胺氰尿酸盐(MCA)与硫化锌(ZnS)或类石墨相氮化碳(g-C_3N_4)或9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物衍生物(ZDOPO)复配体系为阻燃剂,与聚己内酰胺(PA 6)切片共混、造粒、干燥、纺丝,制备阻燃PA 6纤维;通过常规升温热失重分析以及模拟纺丝过程恒温热失重分析,研究阻燃剂种类及含量对PA 6共混体系热稳定性的影响。结果表明:在阻燃剂总质量分数为6.0%条件下,添加MCA/ZDOPO复配体系对PA 6共混体系的热稳定性影响最小,制备的阻燃PA 6纤维具有良好的力学性能和阻燃性能;添加MCA质量分数3.0%、ZDOPO质量分数3.0%,PA 6/MCA/ZDOPO共混体系热失重5%时的热分解温度为393.8℃,热失重10%时的热分解温度为412.6℃,与纯PA 6的热学性能非常接近,制备的阻燃PA 6纤维的断裂强度为1.9 cN/dtex,断裂伸长率为75.8%,极限氧指数可达29.0%。     

Fe2O3/PA6复合材料的制备及性能研究

将通过液压-热晶法合成的纳米Fe2O3粒子加入到聚合反应体系中进行原位聚合,制得纳米Fe2O3/PA6复合材料。通过扫描电镜研究了纳米Fe2O3在PA6基体中的分散情况,将复合材料挤压成直径为1mm的细线,测试了其力学性能和热学性能。结果表明,纳米Fe2O3在基体中分散均匀,当纳米Fe2O3质量分数为16.7%时,复合材料的最大失重速率温度比纯PA6提高了16.0℃,热稳定性得到提高,拉伸强度和拉伸模量比纯PA6分别提高了27.78%和109%。     

聚酰胺6/纳米二氧化硅复合材料的制备和界面研究

采用原位聚合法制备了聚酰胺6/纳米二氧化硅（PA6/nano-SiO2）复合材料,用力学性能测试、 扫描电镜和差示扫描量热法对纳米SiO2粒子和PA6基体之间的界面黏结性进行了表征和研究。结果表明：利用经验公式和力学性能数据计算得知PA6/改性SiO2纳米复合材料的界面参数B值都比PA6/未改性SiO2纳米复合材料的大;SEM观察表明在PA6中加入纳米SiO2,材料的微观结构发生了变化,改性SiO2与PA6基体之间形成了较好的界面结合;分散于PA6基体中的纳米SiO2粒子起到了异相成核作用,改性后的SiO2和PA6基体之间形成柔性界面层有利于PA6基体的结晶。     

Thermal insulation behaviour of Ethylene propylene diene monomer rubber/kevlar fiber based hybrid composites containing Nanosilica for solid rocket motor insulation

The current research discusses the properties of an elastomeric heat-shielding material, based on nano-silica (NS) filled ethylene propylene diene monomer (EPDM) rubber/Kevlar fiber (KF) hybrid composites. The developed elastomeric insulating material consists of an aromatic polyamide fiber (KF) and silica nanoparticles. An in-depth analysis of mechanical properties, density, coefficient of thermal expansion, thermal conductivity, thermogravimetric analysis, and heat release rate of the insulating materials -was performed. TEM micrograph represents an excellent distribution of nanoparticles in the EPDM matrix. The improvement in the mechanical and the flame retardancy of the NS filled EPDM/KF hybrid composite insulations is based on the fiber/matrix adhesion. Maleic anhydride grafting confers polarity to the nonpolar rubber matrix. The char residues of the insulations inspected by scanning electron microscopy and energy dispersive spectroscopy are depicting a rigid and rough surface by the optimal composites, which can aid in better insulation. The optimal formulation of the hybrid composites exhibited a 220% enhancement in char residue with improved thermal stability and mechanical properties.     

聚酰胺6/黏土/聚乙二醇共混调温纤维的制备与性能

通过熔融纺丝法制备了系列聚酰胺6/黏土/聚乙二醇(PTFs)共混调温纤维,并采用傅里叶红外光谱仪、差示扫描量热仪、热红外成像仪、热失重分析仪和复丝强力仪测试了纤维的结构、热性能、调温性能和力学性能。研究显示,PTFs调温纤维的结晶温度为33℃,结晶焓值达到8.46 J/g,且在100次升降温热循环后调温纤维仍保持良好的热性能。通过模拟冷热环境交替下纤维的温度—时间响应行为发现,在热环境(90℃)和冷环境(10℃)下,调温纤维体现出明显的温度滞后响应,与纯PA6纤维相比温差达到3℃。黏土/聚乙二醇在纤维中的最大质量分数为15%,在牵伸4倍时,纤维的拉伸断裂强度达到3.15 cN/dtex。     

Effect of Polyamide 66 on the Mechanical and Thermal Properties of Post-Industrial Waste Polyamide 6

Post-industrial waste (PIW) polyamide 6 is successfully used in lieu of commercial virgin polyamide 6, in several automotive applications. The presence of polyamide 66 in the final formulation may affect the mechanical and thermal properties of the PIW polyamide 6 materials. Using unreinforced polyamide 6 from PIW and commercial sources, it was found that the addition of polyamide 66 (below 10 wt.%) lowered the crystallization rate and crystallinity level of all polyamide 6 materials. The thermal and mechanical properties of glass fiber (GF) reinforced PIW polyamide 6 compounds with and without polyamide 66 were also studied. Differential scanning calorimetry (DSC) showed that reinforced materials without polyamide 66 had a higher level of crystallinity. Furthermore, dynamic mechanical analysis (DMA) showed that reinforced compounds without polyamide 66 also had a faster storage modulus buildup immediately after injection molding. Reinforced PIW polyamide 6 compounds without polyamide 66 also exhibited higher tensile and higher vibration weld strengths as well as a thicker heat affected zone (HAZ) than those with polyamide 66, leading to the conclusion that polyamide 66 had a detrimental effect on crystallinity level and consequently on the mechanical properties of GF-reinforced PIW polyamide 6 materials.     

Mechanical and Morphological Properties of Mica and Short Glass Fiber Reinforced Polyamide 6 Composites

In this study, the influence of short glass fiber and lamellar particle mica fillers on the mechanical properties of polyamide 6 was investigated. Reinforcement materials of 10 to 30% by weight were added to polyamide 6 polymers. Tests were carried out and the results showed that the strength and flexural modulus of the polyamide 6 composite increased with the increase in added short glass fiber and mica. However, tensile and flexural strength showed insensitivity to the increase in mica reinforcement content. Moreover, the impact strength and elongation at break values decreased with the increase in mica reinforcement ratio.     

GF增强PA6复合材料的力学与摩擦性能研究

采用熔融共混法制备玻璃纤维(GF)增强尼龙(PA)6复合材料,研究了GF含量对PA6/GF复合材料力学性能和摩擦性能的影响,并利用扫描电子显微镜对复合材料的磨损机理进行分析.结果表明,GF显著影响复合材料的力学性能和摩擦性能,GF质量分数为15%时增强效果较好,PA6/GF复合材料的缺口冲击强度比纯PA6提高5倍,摩擦因数降低43%,磨损量减少33%.GF含量较低时,PA6/GF复合材料的磨损以磨粒磨损和粘着磨损为主,含量较高时则主要表现为磨粒磨损和疲劳磨损.     

Preparation and Characterization of Thermoplastic Elastomer Based on Amino-terminated Polyamide-6 and Diisocyanate-terminated Polytetramethylene Glycol

Polyamide thermoplastic elastomers are successfully synthesized by adding polycondensation of amino-terminated polyamide-6 (with a molecular weight of 1000 and 2000 g/mol) and diisocyanate-terminated polytetramethylene glycol (with molecular weight of 1500 and2500 g/mol) with dimethylacetamide as solvent at 140°C. The structures of oligomers and polyamide thermoplastic elastomers are characterized by Fourier transform infrared. The thermogravimetry analysis result shows that the product displays good thermostability. Differential scanning calorimetry curves of polyamide thermoplastic elastomers exhibit two melting temperatures indicating phase separation of polyamide thermoplastic elastomers. Besides, the polyamide thermoplastic elastomers display excellent mechanical properties of high tensile strength (33–61 MPa) and high elongation at break (384–1220%).     

Thermal stability and abrasion resistance of polyacrylate/nano-silica hybrid coatings

Polyacrylate (PAE)/nano-silica (SiO₂) hybrids were prepared by an in situ sol–gel process of tetraethyl orthosilicate in the presence of PAE toluene solution. The hybrid coatings were fabricated using a PAE/SiO₂ suspension by the traditional casting. Their intermolecular interaction and morphology, as well as thermal, mechanical, and optical properties, were investigated using Fourier transform infrared spectroscopy, field-emission scanning electron microscope, differential scanning calorimetry and TG/DTA thermogravimetric analysis, coating impact testing, and UV–Vis spectroscopy, respectively. At the same time, their abrasive properties were carried out by abrasion resistance and nanoindentation tests. The results indicate that silica nanoparticles, with diameter about 30 nm, can disperse homogeneously in the PAE matrix, where hydrogen bonds between the PAE and nano-silica are formed. Therefore, homogeneous dispersion of nano-silica particles provides high transparency for the PAE/SiO₂ hybrid coating as the size of nano-silica phase is much smaller than the wavelength (390–770 nm) of visible light. PAE/nano-silica hybrid coatings have increased T _g and thermal stability including the onset decomposition temperature, 10 % weight loss temperature, and char at 700 °C. Additionally, the incorporation of nano-silica particles improves the glossiness of the PAE/nano-silica hybrid coatings and enhances their abrasion resistance and surface hardness. The nano-silica content has obvious effect on the thermal, mechanical, optical, and anti-abrasion properties of PAE/SiO₂ hybrid coatings. With the consideration of all the properties of hybrid coatings, the PAE/SiO₂ hybrid containing 10 phr of nano-silica has the optimal composition. These PAE/nano-silica hybrid coatings have potential applications in high-performance hologram image recording.     

Microstructure and fracture behavior of (co)injection‐molded polyamide 6 composites with short glass/carbon fiber hybrid reinforcement

The mechanical and fracture properties of injection molded short glass fiber)/short carbon fiber reinforced polyamide 6 (PA 6) hybrid composites were studied. The short fiber composites of PA 6 glass fiber, carbon fiber, and the hybrid blend were injection molded using a conventional machine whereas the two types of sandwich skin–core hybrids were coinjection molded. The fiber volume fraction for all formulations was fixed at 0.07. The overall composite density, volume, and weight fraction for each formulation was calculated after composite pyrolysis in a furnace at 600°C under nitrogen atmosphere. The tensile, flexural, and single‐edge notch‐bending tests were performed on all formulations. Microstructural characterizations involved the determination of thermal properties, skin–core thickness, and fiber length distributions. The carbon fiber/PA 6 (CF/PA 6) formulation exhibits the highest values for most tests. The sandwich skin‐core hybrid composites exhibit values lower than the CF/PA 6 and hybrid composite blends for the mechanical and fracture tests. The behaviors of all composite formulations are explained in terms of mechanical and fracture properties and its proportion to the composite strength, fiber orientation, interfacial bonding between fibers and matrix, nucleating ability of carbon fibers, and the effects of the skin and core structures. Failure mechanisms of both the matrix and the composites, assessed by fractographic studies in a scanning electron microscope, are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 957–967, 2005     

玻纤增强聚酰胺6/蒙脱土复合材料的制备及其力学性能研究

通过螺杆挤出法制备了玻璃纤维增强聚酰胺6/蒙脱土复合材料,利用电子万能试验机对复合材料的力学性能进行了测量,并对实验结果进行了分析。结果表明,随着玻璃纤维含量的增加,聚酰胺6/蒙脱土/玻璃纤维复合材料的拉伸强度和冲击强度相应地增大,且长度为12mm的玻璃纤维增强的复合材料比6mm玻璃纤维增强的复合材料高;当玻璃纤维含量为10%(质量分数,下同)时,12mm玻璃纤维增强的复合材料的拉伸强度和冲击强度分别比聚酰胺6/蒙脱土复合材料提高了17.4%和84.1%。     

NR-g-(MAH-co-St)对纳米SiO2改性NR/PP共混型热塑性弹性体的影响

研究了马来酸酐／苯乙烯(MAH／St)多单体熔融接枝NR[NR-g-(MAH-CO-St)]对纳米SiO2改性天然橡胶／聚丙烯动态硫化共混型热塑性弹性体(NR／PPTPV)力学性能的影响；采用SEM分析了TPV的断面形貌。结果表明：纳米SiO2的质量分数为0.03时，NR-g-(MAH-CO-St)通过改善纳米SiO2分散的均匀性和细化交联NR分散相，使NR与PP两相的相容性得到明显改善，两相界面结合强度明显提高，NR／PP／纳米SiO2 TPV的力学性能提高。