Morphological, mechanical and rheological properties of nylon 6/acrylonitrile-butadiene- styrene blends compatibilized with MMA/MA copolymers

The morphological, mechanical and rheological properties of nylon 6/acrylonitrile- butadiene-styrene blends compatibilized with MMA-MA [poly(methyl methacrylate-co- maleic anhydride)] copolymers were studied. A twin screw extruder was used for melt-blended the polymers and the injection moulding process was used to mold the samples. The main focus was on nylon 6/ABS blends compatibilized with one MMA-MA copolymer. This copolymer has PMMA segments that appear to be miscible with the styrene-acrylonitrile (SAN) phase of ABS and the anhydride groups can react with amine end groups of the nylon 6 (Ny6) to form graft copolymers at the interface between Ny6 and ABS rich phases. Tensile and impact and morphological properties were enhanced by the incorporation of this copolymer. Transmission electron microscopy (TEM) observations revealed that the ABS domains are finely dispersed in nylon 6 matrix and led to the lowest ductile-brittle transition temperatures and highest impact properties. It can be concluded that the MMA-MA copolymer is an efficient alternative for the reactive compatibilization and can be used as a compatibilizer for nylon 6/ABS blends.     

Influence of reactive compatibilizers on the rheometrical and mechanical properties of PA6/LDPE and PA6/HDPE blends

In this work, the influence of reactive compatibilizers on the rheometrical and mechanical properties of polyamide 6/low density polyethylene (PA6/LDPE) and polyamide 6/high density polyethylene (PA6/HDPE) blends was investigated. Polyethylene grafted with maleic anhydride (PEgMA), polyethylene grafted with acrylic acid (PEgAA), and ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) were used as compatibilizers. The blends were characterized by torque rheometry, mechanical properties, and morphology. Rheometrical properties results show that PEgMA and PEgAA compatibilizers are more reactive with PA6 than EMA-GMA. Mechanical properties and scanning electron microscopy analysis results show that EMA-GMA compatibilizer is as effective as PEgMA and PEgAA for PA6/LDPE blend. For PA6/HDPE blend, PEgAA and EMA-GMA compatibilizers proved to be as effective as PEgMA. For PA6/HDPE blend compatibilized with PEgAA, an intriguing “web” or “bridge” like structure was observed.     

Morphological,mechanical and thermal properties of nylon 6/ABS blends using glycidyl methacrylate-methyl methacrylate copolymers

Nylon6 is an attractive polymer for engineering applications because it has reactive functionality through amine and carboxyl end groups that are capable of reacting. For this reason, it has been used a lot in polymeric blends. Blends of nylon6/ABS (acrylonitrile-butadiene-styrene) were produced using glycidyl methacrylate-methyl methacrylate (GMA-MMA) copolymers as compatibilizer. The binary blends were immiscible and exhibited poor mechanical properties that stemmed from the unfavorable interactions among their molecular segments. This produced an unstable coarse phase morphology and weak interfaces between the phases in the solid state. The presence of the copolymer in the blends clearly led to a more efficient dispersion of the ABS phase and consequently optimized Izod impact properties. However, the compatibilized blend showed poor toughness at room temperature and failed in a brittle manner at subambient temperatures.     

Effect of a reactive-type flame retardant on rheological and mechanical properties of PC/ABS blends

The effects of a flame retardant (FR; reactive-type: brominated epoxy resin) on the mechanical and rheological characteristics of polycarbonate(PC)/acrylonitrile-butadiene-styrene (ABS) blends were investigated at various conditions. A series of PC/ABS blends with and without the FR were prepared using a twin-screw extruder. The tensile yield strength and flexural strength of the blends increased with PC content, and the blends containing FR showed higher values than that of the blends without FR primarily due to the reactive nature of the FR. Furthermore, gradual increases in heat distortion temperature were observed over the broad range of PC content. The system without FR showed higher impact strength especially at high PC content. The temperature drastically affected the shear viscosity of the ABS matrix, but little changes in shear viscosity were observed for the PC matrix. This temperature dependence provided a characteristic viscosity change with respect to composition ratio in the blends. The relationship between shear viscosity and shear rate was analyzed using the Carreau model. The morphologies of the blends were also examined as a function of PC content.     

乙烯-乙烯醇共聚物/尼龙6复合材料的加工流变性能

采用熔融共混法制备了乙烯-乙烯醇共聚物/尼龙6(EVOH/PA6)复合材料,用高级毛细管流变仪和旋转流变仪研究了复合材料的加工流变特性.通过幂律模型对EVOH/PA6复合材料的黏度与剪切速率(?γ)的关系进行了拟合,并用Arrhenius方程描述了复合材料黏度与温度的关系.结果表明,EVOH/PA6复合材料为假塑性流体,复合材料的表观黏度(ηa)和非牛顿常数(n)随着EVOH添加量的增加而增大.在角频率(ω)扫描范围内,EVOH的加入提高了EVOH/PA6复合材料的储能模量(G')、损耗模量(G″)和复数黏度|η*|.用Han曲线、Cole-Cole曲线和扫描电子显微镜(SEM)等方法研究发现,EVOH和PA6之间具有较好的相容性.另外,EVOH/PA6复合材料在EVOH的添加量达到15％(质量分数)时形成了微观相分离结构.     

Effect of testing speed on the crack growth resistance properties of nylon 6/ABS polymer blends

Crack growth resistance values are measured at three loading rates for blends of Nylon 6 and ABS with varying levels of compatibilizer using the generalized locus method [14]. Load against load point deflection curves are obtained at loading rates of 5 mm min^–1 and 500 mm min^–1 using a tensile testing machine. An instrumented drop weight impact testing machine is used to obtain data at a loading rate of 1.2×10⁵ mm min^–1. Dynamic effects can be considered negligible for the three testing speeds used and the effects of these speeds on crack growth resistance values can be observed. The results of these tests help determine the optimum compatibilizer level for high rate loading applications.     

Influence of processing conditions on rheological and mechanical properties of polycarbonate/polypropylene blends

Rheological and mechanical data on polycarbonate/polypropylene blends are reported as a function of the blend preparation. Both kinds of properties depend on the properties of the homopolymers and on the processing conditions. In the molten state the blends are compatible at low content of polypropylene and incompatible at high content. The blends with intermediate compositions can be called semicompatible. Also in the solid state the blends with low content of polypropylene are compatible, while all other blends are incompatible.     

Effect of EVOH on the morphology,mechanical and barrier properties of PA6/POE-g-MAH/EVOH ternary blends

Polyamide 6 (PA6)/maleated poly(ethylene-1-octene) (POE-g-MAH) blends with various ethylene–vinyl alcohol (EVOH) concentrations were prepared via melt-blending. The morphology, mechanical and barrier properties of the blends were investigated in terms of scanning electron microscope (SEM), impact/tensile testing, dynamic mechanical analysis (DMA) and oil absorption rate. The SEM images indicated that the compatibility between PA6 and POE-g-MAH was improved significantly after the incorporation of EVOH. The toughness of blends was correlated with the morphology of the POE-g-MAH and EVOH dispersion phase. It has also demonstrated that the incorporation of EVOH increased evidently the tensile strength, storage modulus and barrier properties, which were contributed to the strong interactions formed through the reaction among PA 6, POE-g-MAH and EVOH.     

Thermal properties of nylon6/ABS polymer blends: Compatibilizer effect

Nylon6/ABS binary blends are incompatible and need to be compatibilized to achieve better performance under impact tests. Poly(methyl methacrylate/maleic anhydride) (MMA-MA) is used in this work to compatibilize in situ nylon6/ABS immiscible blends. The MA functional groups, from MMA-MA copolymers, react with NH₂ groups giving as products nylon molecules grafted to MMA-MA molecules. Those molecular species locate in the nylon6/ABS blend interfacial region increasing the local adhesion. MMA-MA segments are completely miscible with the SAN rich phase from the ABS. The aim of this work is to study the effects of ABS and compatibilizing agent on the melting and crystallization of nylon6/ABS blends. This effect has been investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). Incorporation of this compatibilizer and ABS showed little effect on the melting behavior of the PA6 crystalline phase, in general. DMTA analysis confirmed the system immiscibility and showed evidence of compatibility between the two phases, nylon6 and ABS, produced by MMA-MA copolymer presence. The nylon6/ABS blend morphology, observed by transmission electron microscopy (TEM), changes significantly by the addition of the MMA-MA compatibilizer. A better dispersion of ABS in the nylon6 phase is observed.     

尼龙6/橡胶/天然粘土纳米复合材料的制备及其力学性能

采用一种新型的超细全硫化粉末橡胶/蒙脱土复合粉末(UFPRM),可以制备出剥离型的尼龙6/橡胶/天然粘土(尼龙6/UFPRM)纳米复合材料,所用的橡胶是一种具有特殊结构的超细全硫化粉末橡胶(UFPR).微观分析表明,橡胶粒子在尼龙6基体中分散良好,同时天然粘土在橡胶粒子之间的基体中剥离.在一定份数下,复合粉末可以同时提高尼龙6的韧性、刚性及耐热性;随着复合粉末含量的增加,材料的冲击强度进一步增加.而且,复合粉末对高分子量尼龙6的增强、增韧效果好于低分子量尼龙6.进一步研究发现,在适当的剪切速率下,尼龙6/橡胶/天然粘土纳米复合材料可以获得较好的综合力学性能.     

γ射线辐照对PA6/PTFE合金吸水与力学性能的影响

为了探讨辐照对尼龙6(PA6)基共混材料吸水性能和力学性能的影响,制备了PA6和聚四氟乙烯(PTFE)共混合金并在室温下进行不同剂量的60Coγ射线辐照.通过吸水率测试、准静态拉伸和弯曲实验以及缺口冲击测试,研究了辐照对PA6/PTFE共混体系吸水性能以及吸收水和辐照剂量对共混合金动静态力学性能的影响.结果表明,辐照过程引发交联反应,共混合金的拉伸强度、拉伸模量和弯曲模量均随辐照剂量的增大而增大,而缺口冲击强度和吸水率则随之减小.吸收水对共混合金缺口冲击强度的影响与合金组分有关.PTFE含量较低时,吸收水抑制PTFE对合金冲击强度的减弱作用;当PTFE的质量分数大于7%时,吸收水反而加剧PTFE对材料冲击强度的减弱效应.此外,PA6/PTFE合金的吸水率随PTFE含量的增加而降低,而弯曲模量则先增后减.     

Effect of the processing method on the mechanical properties and morphology of compatibilized PA6/LDPE blends

In this work, the effect of the processing method on the mechanical properties and morphology of compatibilized PA6/LDPE blends was investigated. The blends were prepared by two processing methods: Injection and Extrusion followed by Injection. The compatibilizers used were polyethylene grafted with acrylic acid (PEgAA) and polyethylene grafted with maleic anhydride (PEgMA). The results showed that in both processing methods the impact strength and elongation at break of the compatibilized blends were greater than those of the uncompatibilized ones. For the blends prepared by injection, the impact strength of PA6/PEgMA/LDPE blend was greater than that of PA6/PEgAA/LDPE blend. For the blends prepared by extrusion followed by injection, the impact strength of the PA6/PEgAA/LDPE blend was greater than that of PA6/PEgMA/LDPE blend. SEM analysis showed that the morphology of the PA6/PEgAA/LDPE blend prepared by extrusion followed by injection was more stable than that of the same blend prepared only by injection.     

Morphological and mechanical properties of extruded polypropylene/nylon-6 blends

Blends of polypropylene and nylon-6 extruded into ribbons at varying draw ratios generated laminar morphologies under our conditions. For the binary system, the size and distribution of the dispersed phase is coarse. The addition of an ionomer to the nylon prior to blending compatibilized the phases and produced much finer domains. The tensile properties of the virgin matrix material respond to the draw ratio in a parabolic manner attaining a maximum at intermediate values. Blending with nylon-6 attenuates the effect without improving the tensiles markedly. The compatibilized system however demonstrates greatly improved mechanical properties.     

三元乙丙橡胶接枝马来酸酐共聚物对PA6/PP共混物结构和性能的影响

通过Molau实验、扫描电子显微镜(SEM)观察和力学、热学性能测试,研究了三元乙丙橡胶接枝马来酸酐共聚物(EPDM-g-MAH)增容剂在PA6/PP共混物中的作用.重点讨论了PA6/PP配比、EPDM-g-MAH用量对共混物结构、冲击强度、热变形温度和吸水率的影响.实验结果表明:EPDM-g-MAH是一种反应型增容剂.适量的EPDM-～MAH加入可很好地改善PA6和PP两相的相容性,减小PP分散相的粒径,提高PA6、PP两相界面的相互作用.当PA6/PP/EPDM-g-MAH质量比为80/20/(10～15)时,共混物综合性能最好.和纯PA6相比,共混物冲击强度提高3倍以上,热变形温度提高7℃以上,吸水率减少2/3.     

Development, structure and strength properties of PP/PMMA/FA blends

A new type of flyash filled PP/PMMA blend has been developed. Structural and thermal properties of flyash (FA) filled polypropylene (PP)/polymethyl methacrylate (PMMA) blend system have been determined and analysed. Filled polymer blends were developed on a single screw extruder. Strength and thermal properties of FA filled and unfilled PP/PMMA blends were determined. Addition of flyash imparted dimensional and thermal stability, which has been observed in scanning electron micrographs and in TGA plot. Increase of flyash concentration increased the initial degradation temperature of PP/PMMA blend. The increase of thermal stability has been explained based on increased mechanical interlocking of PP/PMMA chains inside the hollow structure of flyash.     

Morphological, rheological and mechanical characterization of polypropylene nanocomposite blends

In the present work, the effectiveness of styrene/ethylene-butylene/styrene rubbers grafted with maleic anhydride (MA) and a metallocene polyethylene (mPE) as toughening materials in binary and ternary blends with polypropylene and its nanocomposite as continuous phases was evaluated in terms of transmission electron microscopy (TEM), scanning electron microscopy (SEM), oscillatory shear flow and dynamic mechanical thermal analysis (DMA). The flexural modulus and heat distortion temperature values were determined as well. A metallocene polyethylene and a polyamide-6 were used as dispersed phases in these binary and ternary blends produced via melt blending in a corotating twin-screw extruder. Results showed that the compatibilized blends prepared without clay are tougher than those prepared with the nanocomposite of PP as the matrix phase and no significant changes in shear viscosity, melt elasticity, flexural or storage moduli and heat distortion temperature values were observed between them. However, the binary blend with a nanocomposite of PP as matrix and metallocene polyethylene phase exhibited better toughness, lower shear viscosity, flexural modulus, and heat distortion temperature values than that prepared with polyamide-6 as dispersed phase. These results are related to the degree of clay dispersion in the PP and to the type of morphology developed in the different blends.     

PP-g-MAH对PP/SiO2纳米复合材料力学性能的影响

为了进一步提高聚丙烯的力学性能,以马来酸酐接枝聚丙烯(PP-g-MAH)为聚丙烯/二氧化硅(PP/SiO2)纳米复合材料的界面相容剂,研究了PP-g-MAH添加量对PP/SiO2的力学性能、微观形态以及结晶行为的影响,并研究了其增容机理.研究表明:PP-g-MAH的加入使纳米PP/SiO2纳米复合材料的力学性能得以全面提高,使纳米二氧化硅与聚丙烯的界面粘结得到改善,并且,由于PP-g-MAH导致复合材料的界面强度提高和界面层厚度增加,使KH-570与PP-g-MAH并用的PP/PP-g-MAH/纳米SiO2复合材料比单用KH-570的PP/SiO2纳米复合材料的改性效果更加明显;PP-g-MAH对PP的结晶过程具有较明显的成核作用,使改性PP的结晶温度提高.     

Effect of crystallinity on the mechanical properties of starch/synthetic polymer blends

Crystallization behaviour of starch and maleated blends was studied at 50°C over a period of 20 weeks using wide angle X-ray diffraction (WAXS). The variation of mechanical properties (tensile and flexural) and stress relaxation behaviour of the blends stored at 50°C and −10°C were studied over the same period. The starch content in the blends was 70% by weight. The synthetic polyolefins used in the blends were two grades of ethylene-co-vinyl acetates (EVA) containing 28% and 18% VA, two grades linear low-density polyethylene (melt index of 40 and 20) and high density polyethylene. An increase in the tensile properties of all the blends was observed in the first 5 weeks for samples kept at both temperature conditions. Blend samples kept at 50°C had higher tensile strengths than the ones at −10°C. Flexural strength remained constant over the duration of time. Freshly moulded specimens relaxed faster than the samples aged at either temperature. X-ray diffraction patterns showed that the starch was completely melted and had lost its crystallinity. Also, starch blends with EVA did not show any crystalline structure. The crystallinity in the starch blends with polyethylene was mainly due to the crystallinity of the synthetic polymer. The X-ray patterns of pure synthetic polymers were not found to be different from their functionalized counterparts. Crystal intensity was found to decrease for all the polyethylene blends. The effect of crystallinity on the mechanical properties is discussed. This revised version was published online in November 2006 with corrections to the Cover Date.