耐磨型尼龙6合金的磨损行为研究

用Ｍ－２００试验机测试了ＰＡ６／ＰＥ合金及ＰＡ６的磨损性能，试验结果表明，ＰＡ６／ＰＥ合金的磨损量显著低于ＰＡ６，而承载能力明显高于ＰＡ６，通过ＳＥＭ对材料的磨损表面形貌和磨屑形貌进行观察发现，ＰＡ６／ＰＥ的磨屑呈片状，ＰＡ６的磨屑呈卷条状。磨屑形貌与材料性质、磨损量大泪密切相关。     

耐磨型尼龙—6合金的摩擦行为研究

用ＭＨＫ－５００和ＳＲＶ型磨损试验机测试了ＰＡ－６／ＰＥ合金的摩擦性能。结果表明，ＰＡ－６／ＰＥ合金的摩擦系数显著低于ＰＡ－６，而且克服了ＰＡ－６摩擦过程中的粘－滑现象，提高了ＰＡ－６的摩擦稳定性。     

阻隔改性组分PA6对HDPE/PA6合金性能的影响

研究了ＨＤＰＥ／ＰＡ６合金阻隔改性组分ＰＡ６的筛选及其含量对该合金阻隔性能和力学性能的影响。结果表明，在增容剂的条件下，具有适当粘度的ＰＡ６能与ＨＤＰＥ共混制得宏观均匀的合金材料；ＰＡ６含量对共混体系的阻隔性能影响显著；当ＰＡ６占３０份以上时，ＨＤＰＥ／ＰＡ６合金阻隔非极性溶剂的性能大幅度提高，同时，ＰＡ６的加入对合金有一定的增强作用。     

工艺条件对HDPE／PA—6共混体系形态结构影响的研究

通过测试ＨＤＰＥ、ＰＡ－６的流变性能和对共混物进行显微镜法（ＰＣＭ）分析,研究了加工温度和剪切速率等工艺条件对ＨＤＰＥ／ＰＡ－６共混形态结构的影响。结果表明：改变加工温度可以调节ＨＤＰＥ／ＰＡ－６共混组成粘度比。ＰＡ－６和ＨＤＰＥ的粘讧比较大时,ＰＡ－６相呈层状分布结构,剪切作用有利于共混体系两相的分散,剪切速率过低易使ＰＡ－６相区尺寸大,分散不均匀。较高的剪切速率使ＰＡ－６相尺寸减小,分散更均匀     

PP-g-MAH/PA6共混物流变性能的研究

探讨了ＰＰｇＭＡＨ／ＰＡ６共混物的流变性能,并同ＰＰ／ＰＡ６共混物作了对比。研究结果表明：ＰＰｇＭＡＨ／ＰＡ６共混物熔体的流变行为符合假塑性流体的流动规律,非牛顿性比ＰＰ／ＰＡ６强,熔体粘度比ＰＰ／ＰＡ６共混物高。     

PA6／POE超韧合金的形态和性能

介绍了尼龙６（ＰＡ６）和乙烯－辛烯共聚物热塑性体（ＰＯＥ）共混制得的ＰＡ６／ＰＯＥ超韧合 形态和性能，并与国外某些超韧ＰＡ６产品性能进行了比较。     

PE—g—MAH对HDPE／PA6共混合金的增容作用

利用ＤＳＣ研究了ＰＥ－ｇ－ＭＡＨ对ＨＤＰＥ／ＰＡ６共混体系的增容作用,并讨论了ＰＥ－ｇ－ＭＡＨ对ＨＤＰＥ／ＰＡ６共混物的混容性能和力学性能的影响。结果表明：ＰＥ－ｇ－ＭＡＨ能有效地增强ＨＤＰＥ／ＰＡ６共混体系两相界面的相互作用,改善ＨＤＰＥ和ＰＡ６的相容性,是效果较好的增容剂。适量的ＰＥ－ｇ－ＭＡＨ的加入可使ＨＤＰＥ／ＰＡ６共混合金的可混性能提高,并有一定的增强作用。     

PP—g—MAH／PH6共混物流变性能的影响

探讨了ＰＰ－ｇ－ＭＡＨ／ＰＡ６共混物的流变性能,并同ＰＰ／ＰＡ６共混物作了对比。研究结果表明：ＰＰ－ｇ－ＭＡＨ／ＰＰ６共混物熔体的流变行为符合假塑性流体的流动规律,非牛顿性比ＰＰ／ＰＡ６强,熔体粘度比ＰＰ／ＰＡ６共混物高。     

PA6－PEG共聚纤维和PA6－PEG／PA6共混纤维的物理与力学性能

研究了ＰＡ６－ＰＥＧ共聚纤维以及不同组成比的ＰＡ６－ＰＥＧ／ＰＡ６共混纤维的各项性能。得到了平衡吸湿率可达８％左右的改性纤维。纤维的染色性和手感也有显著改善，力学性能可满足纺织加工的要求。     

PA6－PEG共聚纤维和PA6－PEG／PA6共混纤维的物理与力学性能

研究了ＰＡ６－ＰＥＧ共聚纤维以及不同组成比的ＰＡ６－ＰＥＧ／ＰＡ６共混纤维的各项性能。得到了平衡吸湿率可达８％左右的改性纤维。纤维的染色性和手感也有显著改善，力学性能可满足纺织加工的要求。     

Melting behavior and nonisothermal crystallization kinetics of polyamide 6/polyamide 66 molecular composites via in situ polymerization

The melting behavior and nonisothermal crystallization kinetics of pure polyamide 6 (PA 6) and its molecular composites with polyamide 66 (PA 66) were investigated with differential scanning calorimetry. The PA 6/PA 66 composites had one melting peak, whereas the coextruded PA 6/PA 66 blends had two melting peaks. With the addition of PA 66 to PA 6 via in situ anionic polymerization, the melting temperature, crystallization temperature, and crystallinity of PA 6 in the composites decreased. The half‐time of nonisothermal crystallization increased for a PA 6/PA 66 molecular composite containing 12 wt % PA 66, in comparison with that of pure PA 6. The commonly used Ozawa equation was used to fit the nonisothermal crystallization of pure PA 6 and its composites. The Ozawa exponent values in the primary stage were equal to 1.28–3.03 and 1.28–2.97 for PA 6 and its composite with 12 wt % PA 66, respectively, and this revealed that the mechanism of primary crystallization of PA 6 and PA 6/PA 66 was mainly heterogeneous nucleation and growth. All the results indicated that the incorporation of PA 66 into PA 6 at the molecular level retarded the crystallization of PA 6. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2172–2177, 2005     

The Effect of Maleic Anhydride Grafted Styrene-Ethylene-Butylene-Styrene on the Friction and Wear Properties of Polyamide6/Carbon Nanotube Composites

The friction and wear properties of polyamide6 (PA6), polyamide6/carbon nanotube (PA6/CNT) nanocomposites and PA6/maleic anhydride grafted Styrene-ethylene-butylene-styrene (SEBS-g-MA+CNT) nanocomposites was studied by means of a ring-on-block tribometer. The morphologies of the worn surfaces of specimens were observed with a scanning electron microscopy (SEM). All specimen wear increases with increasing load; meanwhile, the friction coefficient decreases. Wear of PA6/CNT is larger than that of PA6. Adding SEBS-g-MA to the PA6/CNT improves the wear resistance. The friction coefficient of PA6/CNT is slightly less than that of PA6 at various loads. The friction coefficient of PA6/(SEBS-g-MA+CNT) is the lowest among PA6, PA6/CNT and PA6/(SEBS-g-MA+CNT).     

超高相对分子质量PA6冻胶的流变行为研究

以氯化钙为络合剂,将聚酰胺6(PA6)粉末与氯化钙溶解在甲酸/氯仿混合溶剂中制得冻胶样品,研究了PA6/氯化钙/甲酸冻胶体系的流变性能,以及温度、PA6的相对黏度、CaCl2与PA6的摩尔比和PA6的质量分数对冻胶的ηa-γ觶流变曲线、非牛顿指数和结构黏度指数的影响。结果表明:冻胶溶液属于宾汉流体,具有明显的非牛顿性;体系的表观黏度随着温度的升高而降低,随PA6的质量分数的升高、络合剂CaCl2与PA6的摩尔比的增大或PA6的相对黏度增大而增大;溶液的结构黏度指数随温度的升高而减少,随溶液PA6的相对黏度的升高或PA6的质量分数的升高而增大。     

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。     

尼龙6/丙烯酸酯橡胶热塑性弹性体非等温结晶动力学

采用动态硫化法制备尼龙6/丙烯酸酯橡胶热塑性弹性体(PA6/ACM TPE),通过差示扫描量热仪研究了PA6和PA6/ACM TPE在5种不同冷却速率下的结晶过程,并分别用Jezirony法、Ozawa法以及Mo法分析了PA6和PA6/ACM TPE的非等温结晶动力学。结果显示,冷却速率越大,PA6和PA6/ACM TPE结晶峰的峰形变宽,半高宽变大,初始结晶温度和结晶峰温度降低,半结晶时间缩短;Jezirony法和Mo法均可分析PA6和PA6/ACM TPE的非等温结晶行为,而Ozawa法不适用;Jezirony法分析得出PA6和PA6/ACM TPE的Avrami指数(n)在2.0~3.0之间,且PA6/ACM TPE的修正后的结晶速率常数(Zc)比PA6的大,说明随着降温速率的增加,结晶速率提升,结晶时间缩短;Mo法研究表明PA6/ACM TPE的结晶动力学参数[F(T)]比PA6的小,PA6/ACM TPE的结晶速率高于PA6的结晶速率,说明添加ACM相加速了PA6的结晶过程。     

Improvement of polyamide/thermoplastic polyurethane blends with polyamide 6-polyurethane copolymer prepared via suspension polymerization as compatibilizer

The polyamide 6-polyurethane copolymer (PA6-b-PU-b-PA6) was synthesized through anionic suspension polymerization and then mixed with polyamide 6/thermoplastic polyurethane (PA6/TPU) and polyamide 6, 6/thermoplastic polyurethane (PA66/TPU) blends using as the compatibilizer. The results show that the PA6-b-PU-b-PA6 copolymers powders several can be obtained through suspension polymerization using dimethicone as disperse medium. The average diameter of PA6-b-PU-b-PA6 copolymer powders decreased with the increasing of PU content. With the addition of PA6-b-PU-b-PA6, the TPU phase dispersed more uniformly in PA6 or PA66 matrix, and the size of TPU dispersed phase decreased obviously. The PA6-b-PU-b-PA6 copolymer with higher PU content shows better compatibilizing effect. Addition of PA6-b-PU-b-PA6 can improve both strength and toughness of the PA/TPU blends. When the amount of PA6-PU25% copolymer was 5 phr, the tensile strength and notched impact strength of PA6/TPU/PA6-PU25% blends increased 29 and 159.4%, respectively, compared to the PA6/TPU blend without compatibilizer.     

From hybrid fibers to microfibers: The characteristics of polyamide 6/polypropylene blend via one-step twin-screw melt extrusion

Multimaterial textiles are frequently employed to attain a certain function or aesthetic effect. The multimaterial assemblies face recycling limitations due to challenges to sort and separate the component materials. A one-step melt extrusion approach to process two mixed common textile polymers, polyamide 6 (PA6), and polypropylene (PP), into PA6:PP hybrid fibers is reported in this study. PA6:PP hybrid fibers were produced in four different configurations; PA6-50 (50 wt% PA6), PA6-60 (60 wt% PA6), PA6-65 (65 wt% PA6), and PA6-80 (80 wt% PA6). The PP component was sacrificially removed from the hybrid fibers and the resultant PA6 fiber structure was analyzed. The SEM images show the development of PA6 microfibers in PA6-50 and PA6-60 hybrid fibers with mean diameters of 0.76 μm and 1.13 μm upon fiber drawing, respectively. In PA6-65 hybrid fibers, the PA6 microfibers were found along with areas where PA6 was encapsulating the PP. Thermal and mechanical properties of the untreated and treated hybrid fibers were also investigated. PA6-60 hybrid fibers were processed into single jersey knitted fabrics and treated to obtain PA6 microfibers fabrics. The bursting strength and wicking properties of the fabric, before and after treatment, were comparatively studied. POLYM. ENG. SCI., 60:690–699, 2020. © 2020 Society of Plastics Engineers     

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     

Enhancement of Mechanical Properties of PA6 Blending with Talcum for Fused Deposition Modeling

The objective of this work is to fabricate polyamide 6 (PA6) composite filament with enhanced mechanical properties and low cost for fused deposition modeling (FDM). The composite filaments are obtained by compounding PA6 and talcum fillers and then single screw extruding. Virgin PA6 and commercial e‐PA6 are set as controls. First, the rheological behaviors and thermal properties of PA6/talc, PA6, and e‐PA6 pellet materials are investigated, including viscosity, melting temperature, crystallinity, and decomposition temperature, which are important parameters for fabricating filament feedstocks. The results show that 10 wt% addition of talcum content accelerates the increase of the viscosity among the processing temperature. Accordingly, virgin PA6 and PA6/talc5 with good flowability are produced and subsequently evaluated by tensile and flexural tests. It is notable that the introduction of talcum increases the diameter constant and shape stability of PA6‐based filament. Also, it is found that both PA6 and Pa6/talc5 filaments exhibit superior tensile properties to the commercial e‐PA6 counterparts. Especially, PA6/talc5 filaments achieve the maximum tensile yield strength of 67.1 MPa and modulus of 3.10 GPa. Finally, auxetic lattice parts are successfully printed via FDM using lab‐made PA6, PA6/talc5, and commercial e‐PA6 filaments, and PA6/talc5 exhibits remarkable loading and energy absorption capability.     

Influence of morphology on PTC effect for poly (ethylene-co-butyl acrylate)/nylon6 blends with multiwall carbon nanotubes dispersed at interface and in matrix

Multiwall carbon nanotubes (MWCNTs) filled poly (ethylene-co-butyl acrylate)/nylon6 (EBA/PA6) blends were prepared by melt-mixing method. MWCNTs were localized in PA6 phase and the percolation threshold was 6 wt%. A weak PTC (positive temperature coefficient) effect was observed. The method that EBA-g-MAH was first reacted with MWCNTs, and then blended with EBA/PA6 was employed to prepare EBA/PA6/EBA-g-MAH/MWCNTs composites. TEM results showed that MWCNTs were localized both at the interface and in PA6 phase, resulting in the sharp decrease of the percolation threshold. Influence of morphology on the PTC effect of EBA/PA6/EBA-g-MAH/MWCNTs composites was studied. In composites with dispersed PA6 phase, the conductive pathways were fabricated by the contact of dispersed PA6 phase and MWCNTs in PA6 phase. The melt of polyethylene segment crystals in EBA and PA6 phase interrupted the contact of dispersed phases and conductive network formed by MWCNTs in PA6 phase, resulting in the double PTC effect. For composites with dispersed EBA phase, although the conductive pathways were similar with the composites with dispersed PA6 phase, the single PTC effect was observed. And the PTC effect was attributed to the melt of PA6 phase. The conductive pathways of composites with co-continuous morphology were fabricated by MWCNTs at the interface and in continuous PA6 phase. Two strong and a weak PTC effect were observed. PTC effects appeared at the melting temperature of PA6 crystals, polyethylene segment crystals and viscous flow temperature of butyl acrylate units in EBA.