低密度聚乙烯接枝烯基双酚A醚对HDPE／PC共混体系性能的影响

本文采用烯基双酚Ａ醚接枝低密度聚乙烯（ＬＤＰＥ－ｇ－ＤＢＡＥ）作为高密度聚乙烯／聚碳酸酯（ＨＤＰＥ／ＰＣ）共混体系的增容剂,初步研究了ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系性能的影响。通过对共混物形态观察、耐热性能及力学性能测试,发现ＬＤＰＥ－ｇ－ＤＢＡＥ对ＨＤＰＥ／ＰＣ体系有良好的增容效果;并发现了增容剂的最佳用量质量比大致为１０％,提高增容剂的接枝率更有利于改善共混物的性能。６５／３５ＨＤＰＥ／ＰＣ共混物的ＨＤＴ为９２℃,拉伸强度３０２ＭＰａ,冲击强度２９８ｋＪ／ｍ２,分别比未加增容剂时的８２℃,２７３ＭＰａ和１５５ｋＪ／ｍ２有较大提高。     

增容剂对HDPE／AS合金流变和力学性能的影响

研究了增容剂氯化聚乙烯接枝（丙烯腈／苯乙烯）共聚物对ＨＤＰＥ／ＡＳ共混体系加工流变性能和力学性能的影响。增容剂使共混体系的塑化时间减少,且随着增容剂用量的增加,共混体系的平衡扭矩和拉伸强度增大,而断裂伸长率在ＨＤＰＥ／ＡＳ／ＰＥ－Ｃ－ｇ－ＡＳ＝８０／２０／４时出现极大值;螺杆转速的增加使共混体系的平衡扭矩增大。     

PA－66／（PE／EPDM）－g－MAH共混增韧的研究

本文研究了尼龙－６６（ＰＡ－６６）与聚乙烯（ＬＤＰＥ）共混物的力学性能。结果表明，用马来酸酐接枝聚乙烯和三元乙丙橡胶（ＥＰＤＭ）改善了与基体ＰＡ－６６的相容性。添加弹性体ＥＰＤＭ，使之生成（ＰＥ／ＥＰＤＭ）－ｇ－ＭＡＨ共聚物，可以大幅度度地提高ＰＡ－６６／（ＰＥ／ＥＰＤＭ）－ｇ－ＭＡＨ冲击强度，同时熔体粘度随温度的变化趋于平缓，吸水率有所下降。     

PA—66／（PE／EPDM）—g—MAH共混增韧的研究

本文研究了尼龙－６６（ＰＡ－６６）与聚乙烯（ＬＤＰＥ）共混物的力学性能。结果表明，用马来酸酐接枝聚乙烯和三元乙丙橡胶（ＥＰＤＭ）改善了与基体ＰＡ－６６的相容性。添加弹性体ＥＰＤＭ，使之生成（ＰＥ／ＥＰＤＭ）－ｇ－ＭＡＨ共聚物，可以大幅度地提高ＰＡ－６６／（ＰＥ／ＥＰＤＭ）－ｇ－ＭＡＨ冲击强度，同时熔体粘度随温度的变化趋于平缓，吸水率有所下降。     

PP—gMAH原位反应增容PP／PA—6共混纤维的研究

为探索聚丙烯（ＰＰ）纤维纺后染色的新途径，将少量尼龙－６（ＰＡ－６）与聚丙烯共混，并用马来酸酐枝聚丙烯（ＰＰ－ｇ－ＭＡＨ）对该共混物进行反应性增容，得到了较为满意的结果。本文着重研究了ＰＡ－６用量在２０％以下时，增容剂用量及不同ＰＰ／ＰＡ－６共混比对共混物的亚微形态，流变性能，结晶性能等的影响，并对共混物的染色性能和了初探讨。     

热致性液晶共聚酯／聚丙烯共混物

通过熔融共混制备了不同配比的（ＰＨＢ／ＰＥＴ）／ＰＰ共混物，研究表明，共混物的弯曲弹性模量，弯曲强度及拉伸强度均比ＰＰ有所提高，当液晶含量为１５％，ＰＰ－ｇ－ＭＡＨ为２０％时，（ＰＨＢ／ＰＥＴ）（ＰＰ－ｇ－ＭＡＨ）／ＰＰ三元共混物弯曲弹性模量最大，ＰＰ－ｇ－ＭＡＨ作为两相界面相容剂，改善了两相间的亲合性。ＤＳＣ分析表明，共混物中ＰＰ相的结晶温度有较大幅度的提高，（ＰＨＢ／ＰＥＴ）共聚酯起了ＰＰ结晶     

PP－g－MAH原位反应增容PP／PA－6共混纤维的研究

为探索聚丙烯（ＰＰ）纤维纺后染色的新途径，将少量尼龙－６（ＰＡ－６）与聚丙烯共混，并用马来酸酐枝聚丙烯（ＰＰ－ｇ－ＭＡＨ）对该共混物进行反应性增容，得到了较为满意的结果。本文着重研究了ＰＡ－６用量在２０％以下时，增容剂用量及不同ＰＰ／ＰＡ－６共混比对共混物的亚微形态，流变性能，结晶性能等的影响，并对共混物的染色性能作了初步探讨     

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。     

MAH—g—PP对PP／EVAL共混体系的增容作用

系统研究了不同组成及配比的马来酸酐接枝聚丙烯（ＭＡＨ－ｇ－ＰＰ）及其用量对聚丙烯（ＰＰ）与乙烯－乙烯醇共聚物（ＥＶＡＬ）的共混体系（ＰＰ／ＥＶＡＬ）力学性能借用Ｂｒａｂｅｎｄｅｒ塑化仪测试了ＰＰ／ＥＶＡＬ／ＭＡＨ－ｇ－ＰＰ共混体系的加工性能。结果表明,ＭＡＨ－ｇ－Ｐ接枝物对ＰＰ／ＥＶＡＬ共混体系有较好的增容作用,适量加入,可使ＰＰ／ＥＶＡＬ共混体系的力学性能明显提高,而加工性能基本不变。     

PC／PET／PE—g—MAM三元共混体系流动性的研究

以ＰＥ－ｇ－ＭＡＨ和ＰＥ－ｇ－ＭＡＮａ、ＰＥ－ｇ－ＭＡＺｎ马来酸盐离聚物为相容剂性组成ＰＣ－ＰＥＴ／ＰＥ－ｇ－ＭＡＭ三元共混体系。用毛细管流变仪研究了不同ＰＥ－ｇ－ＭＡＭ的接枝率及用量对共混物流动性的影响。     

Deformation and morphology development of poly(ethylene terephthalate)/polyethylene and polycarbonate/polyethylene blends with high interfacial contact during elongation

Immiscible blends of poly(ethylene terephthalate) (PET)/polyethylene (PE) and polycarbonate (PC)/PE were examined to study the influence of the high interfacial contact (pseudo‐adhesion) on the mechanical properties and the morphology developed during elongation. The high interfacial contact resulted from the contraction difference of the two polymers during cooling from the processing temperature to room temperature. As a result of the pseudo‐adhesion, the tensile strength and modulus of the PET/PE and PC/PE blends increased steadily with the increase of PET and PC concentration. In PC/PE blends, numerous PC microfibers were formed in‐situ, while in PET/PE blends, slippage took place between the PET particles and the matrix. Moreover, the macroscopic morphology development of both blends upon elongation was quite different. For PET/PE blend, necking was initiated at one point close to the non‐gate end of the specimen, and then propagated uniformly from this point. For the PC/PE blend, necking‐initating sites and propagation were irregular, and consequently the whole tested zone was deformed. The recoil of partially elongated specimens indicated that the recoverability of the PC/PE blend is higher than that of the PET/PE blend. Polym. Eng. Sci. 44:1561–1570, 2004. © 2004 Society of Plastics Engineers.     

Evaluating PE/PLA interfacial tension using ternary immiscible polymer blends

Blending with ethylene-based flexible polymers such as polyethylene (PE) is one of the strategies to toughen poly(lactic acid) (PLA), an inherently brittle biodegradable plastic enjoying growing demands worldwide. Interfacial tension plays a crucial role in blend formulation. Yet several literature reports on the PE/PLA interfacial tension contradict each other, giving ~5 mN/m and ~11 mN/m. In this work, we demonstrate that the PE/PLA interfacial tension is at least 9 mN/m. We use a cocontinuous PE/polystyrene (PS)/PLA ternary blend. Scanning electron microscopy (SEM) revealed complete wetting morphology with PS phase separating PE and PLA phases in the ternary blend. In addition, the complete wetting behavior was maintained at a PS volume fraction as low as 3%. This morphology together with the Harkins equation, indicate that the PE/PLA interfacial tension is higher than 10.5 ± 1.4 mN/m at 180°C.     

The role of organically modified layered silicate in the breakup and coalescence of droplets in PBT/PE blends

In this study, we investigated the effect of organically modified nanoclay (organoclay) on the morphology of immiscible polymer blends (PBT/PE) with various compositions of PBT ranging from 1 to 90 wt%. When a small amount of organoclay between 1 and 3 phr is added to the blend, the thin clay tactoids of the thickness of the order of 10 nm are located at the interface between PBT and PE phase. As its content is increased, the additional organoclay positions in a specific component depending on its affinity with the component. The addition of a small amount of organoclay results in the effective size reduction for PBT/PE blend. The organoclay located at the interface forms the interfacial phase with a non-homogeneous distribution of clay along the interface and changes the interfacial tension, which result in the coalescence suppression of the droplets. Rigid organoclay with a high aspect ratio allows the blend morphology with long-term thermal stability by suppressing the Brownian motion. This ability of the organoclay to suppress the coalescence of the droplets effectively reduces the droplet size. On the other hand, additional organoclay results in the rheological properties of particular component being increased, which means the change in the viscosity ratio. The change in the viscosity ratio, together with the coalescence suppression effect, affects the determination of the droplet size, depending on the location of the organoclay. Therefore, the organoclay suppresses the coalescence of the droplets at the interface, while simultaneously influencing the breakup of the droplets due to the change of viscosity ratio.     

The effect of temperature on the interfacial tension of polycarbonate/polyethylene blends

Controlling interfacial tension during the processing of blends is critical to developing morphologies that will yield consistent and acceptable mechanical properties. Determination of the interfacial tension is important in developing a predictive understanding of the effects of processing conditions on the morphology and the physical properties of multicomponent systems. The focus of the research reported herein was to investigate the temperature dependence of the interfacial tension for blends composed of polycarbonate (PC) and polyethylene (PE). The effects of temperature were characterized by direct measurements of the interfacial tension using the imbedded fiber retraction (IFR) method. The interfacial tensions of PC/PE were measured at 210, 220, 230, and 240°C. The temperature dependence of the interfacial tension was found to be ?0.018 ± 0.006 dyn/cm-°C. In general, the interfacial tension, evaluated for low-viscosity simple fluids, is commonly a weak function of temperature (on the order of 0.01 dyn/cm-°C). The results found in this study are in accord with those findings.     

Evaluation and characterization of vector fluids and peroxides in a process of in situ compatibilization of polyethylene and polystyrene

An organic functional silane was found to be the most efficient among several vector fluids in reactive blend compatibilization of the polyethylene (PE) / polystyrene (PS) / peroxide / vector fluid system. This paper involves further analysis of this reactive blending system. Surface tension data was used to calculate spreading coefficients which were compared to the amount of PE-PS copolymer formed during blending. A good correlation between a computed spreading coefficient and the degree of grafting of PS onto PE was found. The results suggest that the pattern of distribution of the vector fluid in PE / PS blends is the key factor leading to effective results. Furthermore, different peroxides were evaluated in PE / PS blends, in order to determine the dependence of PE / PS interfacial grafting reaction on the structure of the peroxide.     

Interfacial adhesion reaction of polyethylene and starch blends using maleated polyethylene reactive compatibilizer

The interfacial reaction of the polyethylene (PE)/starch blend system containing the reactive compatibilizer maleated polyethylene (m‐PE) was directly characterized by Fourier transform infrared (FTIR) spectroscopy. A significant amount of anhydride groups on m‐PE existed as hydrolyzed forms, resulting in a large amount of carboxyl groups. Using a vacuum‐heating‐cell designed in the laboratory, the carboxyl groups were successfully transformed into the dehydrolyzed state (i.e., anhydride group). This result enabled the direct spectroscopic observation of chemical reaction occurring at the interface. For the PE/starch blend system containing m‐PE, the chemical reaction at the interface was verified by the evolution of ester and carboxyl groups in the FTIR spectra. The effect of the reactive compatibilizer on the interfacial morphology was also examined by scanning electron micrography (SEM). Enhanced interfacial adhesion was clearly observed for the blend system containing reactive compatibilizer. Tensile strengths of blend systems containing m‐PE also increased noticeably compared with the corresponding system without compatibilizer. A similar observation was made for the breaking elongation data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 767–776, 2002     

Blends of thermoplastic polyurethane and maleic-anhydride grafted polyethylene. I: Morphology and mechanical properties

Thermoplastic polyurethane elastomers (TPU) and polyethylene (PE) form immiscible blends with an extremely low compatibility. In order to improve the dispersion, stability, and properties of these blends, polyethylene was grafted with maleic anhydride (PE-g-MA). Subsequently, it was blended with a commercial polyester - type TPU in a twin-screw extruder. With PE-g-MA as blend component, the particle size was dramatically reduced in comparison with PE. Coalescence was significantly reduced and the increase in particle size with composition was less pronounced than in blends with PE. In addition, the phase adhesion and the mechanical properties were improved by using PE-g-MA as minor component. Grafting of the MA onto the PE leads to a decrease of the molecular weight, the melt viscosity, and the mechanical properties of the pure PE. Hence, the reactive blend system exhibits a lower viscosity ratio. Comparison of these results with those from uncompatibilized blends with different viscosity ratios revealed that the reduction in viscosity ratio has a big influence on the blend morphology and because of that on the mechanical properties. In addition, there is a further effect on morphology and properties caused by the reduction in interfacial tension, which results from the compatibilizer formed at the interface.     

Effect of viscosity in ternary polymer blends displaying partial wetting phenomena

Partial wetting in a ternary polymer blend is the thermodynamic state where all three phases meet at a three-phase line of contact. Pickering emulsions, where solid particles situate at the interface of two other phases is a classic example of this state. This paper studies the presence of partial wetting in PE/PP/PS and in PE/PP/PC ternary polymer blends and examines, in particular, the influence of polyethylene viscosity on PS droplet formation at the PE/PP interface. Quantitative analysis of PS droplet growth and coverage at the PE/PP interface during static annealing were obtained by image analysis. A new approach was established to estimate the co-continuous PE/PP coarsening rate and was found to be in agreement with previous studies. In this work it is shown that the polyethylene viscosity can be of significant importance in ternary partial wetting when the interfacial driving force for partial wetting is weak and viscosity directly affects the quantity and size of PS droplets at the interface during annealing. The equilibrium between droplet stability at the interface, as predicted by spreading theory, and the interfacial mobility generated by coarsening determines the PS droplet size and surface coverage at the PE/PP interface.A ternary PE/PP/PC system, which displays a strong partial wetting driving force, was also investigated. The morphology of the blend system studied demonstrated a clear dominance of partial wetting over complete wetting.     

Double Yielding in Injection‐Molded Polycarbonate/Polyethylene Blends: Composition Dependence

Summary: A fiber‐dependent double yielding phenomenon was recently observed in a structurally different blend, PC/HDPE, in which the first yield point is yielding of HDPE, and the second is caused by the yielding of injection‐induced PC fibers. The present study described the composition dependence of the double yielding in PC/HDPE blends with PC contents ranging from 0 to 45 wt.‐%. Morphology observation indicated that the injection‐molded PC/HDPE blends displayed a typical skin‐core structure with more or less injection‐induced elongated PC particles in the sub‐skin layers, and spherical PC particles in the core layers. Stress‐strain curves indicated that the blends with PC contents from 10 to 20 wt.‐% exhibit double yielding behavior and the cold drawing zone after the second yield point shortens with increasing PC content. The blends with too low‐ or too high‐PC contents exhibited only one yield point. Scanning electronic microscope micrographs of the blend with 15 wt.‐% PC showed that when the strain was beyond the first yield point the PC fibers notably yielded and even were broken, which served as an evidence that the yielding of PC phase was responsible for the second yielding. The origin of the composition dependence of the double yielding was discussed in detail through the interfacial stress transfer.

Representative stress‐strain curves for PE10, PE15, PE17.5, and PE20.     

Morphology development of PC/PE blends during compounding in a twin-screw extruder

The morphological development of a polycarbonate/polyethylene (PC/PE) blend in a twin-screw extruder was studied using a scanning electron microscope (SEM). The effects of extrusion temperature, viscosity ratio (the ratio of the viscosity of the dispersed phase to that of the matrix), and the screw configuration on the morphology of the PC/PE blend during the extrusion were discussed in detail. It was found that the morphology of the dispersed particles and the interfacial adhesion between the dispersed phase and matrix were both influenced by the extrusion temperature. The dispersed phase had a spheroidal shape and a small size during the high temperature processing, and an irregular shape and a large size when it was processed at low temperature. The PC phase with a lower viscosity was easier to disperse and also to coalesce. Therefore, the deformation of the low-viscosity dispersed phase during the processing was more intense than that of the high-viscosity dispersed phase. By comparing the effects of the different screw configurations on the morphology development of the PC/PE blend, it was found that the melting and breaking up of the dispersed phase were mainly affected in the initial blending stages by the number of the kneading blocks. While a kneading block with a 90 degree staggering angle was used, the size of the dispersed particles decreased and the long fibers were shortened, the large particles were drawn by the additional kneading zone. Finally, all of these structures were completely changed to the short fibers. POLYM. ENG. SCI., 47:14–25, 2007. © 2006 Society of Plastics Engineers