Thermoplastic Elastomer Composites of Palm Ash-Filled Ethylene Vinyl Acetate/Natural Rubber Blends: Effects of Palm Ash Loading and Size

Thermoplastic elastomer composites of ethylene vinyl acetate (EVA)/natural rubber (NR) blends filled with palm ash were prepared by melt-mixing using a Haake Rheomix Polydrive R600/610 at 120°C with rotor speed of 50 rpm for 10 minutes. Increase in palm ash loading in composites resulted in increase the value of stabilization toque, Young's modulus and swelling resistance of the composites, but decreased the tensile strength and elongation at break. Scanning electron microscope micrographs revealed that higher filler loading resulted in agglomeration of palm ash in the composites. When smaller particle size of palm ash was used, further improvement in tensile strength, elongation at break, swelling resistance and stabilization torque value were observed.     

改性剂对废胶粉/高密度聚乙烯热塑性弹性体性能的影响

研究废胶粉(WRP)改性剂对共混型WRP/高密度聚乙烯(HDPE)热塑性弹性体性能的影响。结果表明:采用间苯二酚/六亚甲基四胺(质量比1/0.7)、偶联剂Si69和偶联剂KH-550改性WRP,且质量分数分别为6%,9%和6%时,热塑性弹性体综合性能较好;3种改性剂中间苯二酚/六亚甲基四胺的改性效果最佳。     

Investigation into Paraffin Wax and Ethylene Vinyl Acetate Blends for Use as a Carrier Vehicle in Ceramic Injection Molding

An experimental study into paraffin wax and ethylene vinyl acetate-28 blends has been undertaken to investigate the potential for their use as carrier vehicles for ceramic injection molding applications. Carrier systems are critical for the fabrication of this type of molded component, making their properties at all stages of the process of great importance. Paraffin wax and ethylene vinyl acetate-28, in most circumstances, combine to form stable homogeneous blends, which experience relatively small changes in the melting and solidification phase transition behavior. However, these blends exhibit notable viscosity shifts and flexural strength performance changes with increasing ethylene vinyl acetate-28 content. The melt flow behavior of the blends at shear rates of 100 s^?1 varies from 0.01 Pa.s for paraffin wax to 10 Pa.s for the composition by weight of 50% paraffin wax and 50% ethylene vinyl acetate-28, which suggests the upper viscosity limit for successful carrier systems. All paraffin wax/ethylene vinyl acetate-28 blends experience shear thinning behavior with increasing shear rate, which can be modeled with reasonable accuracy using the Cross and Carreau models. Increasing the ethylene vinyl acetate-28 content in a blend causes the initiation of shear thinning at progressively lower shear rates and also forms a blend with an increasing elastic character at typical injection temperature. Yield stress is not developed for blends containing less than 50 wt% ethylene vinyl acetate-28. The addition of ethylene vinyl acetate-28 significantly alters the mechanical properties of the blends, modifying the brittle nature of paraffin wax to develop increasing flexible and plastic properties. Although with less than 25 wt% ethylene vinyl acetate-28 in a blend fracture failure still results, greater ethylene vinyl acetate-28 content represses the failure mechanisms, developing the increasing degrees of plastic deformation.     

热塑性聚氨酯与聚氯乙烯共混改性研究

采用机械共混法制备了热塑性聚氨酯(TPU)与聚氯乙烯(PVC)共混物。探讨了共混比对TPU／PVC共混物性能的影响，优化出TPU／PVC共混比30／70(质量比)，在此基础上研究了增塑剂、热稳定剂、填料对TPU／PVC共混物力学性能、流变性能和耐油、耐溶剂性能的影响。研究结果表明，TPU／PVC共混物的力学性能在共混时有协同作用，耐油、耐溶剂性均较好，从成本和实用两方面出发，选择TPU／PVC=30／70共混比更有实用性。随增塑剂DOP的增加，共混物的力学性能呈下降趋势。在所选热稳定剂中，以硬脂酸钙制得共混物的力学性能最好；在所选填料中，白炭黑的补强效果最好。扫描电镜观察共混物的微观结构显示，TPU／PVC共混比为30／70有较好的相容性，这与力学性能结果相一致。TGA分析显示，TPU的加入提高了共混物的热稳定性。红外光谱分析表明，TPU和PVC共混只是一个简单的物理共混过程。     

Effect of Compatibilizer Concentration on Rheological Behavior,Morphologies, and Mechanical Properties of PVDF/TPU Blends

The rheological behavior, morphologies, and tensile properties of reactively compatibilized PVDF/TPU blends are reported. Using PVDF‐g‐AAc as the compatibilizer, PVDF/TPU 90/10 and 10/90 blends are prepared. The carboxylic acid groups of PVDF‐g‐AAc react with the urethane linkages of TPU during melt blending to generate in situ PVDF‐g‐AAc‐g‐TPU which leads to compatibilization of PVDF/TPU blends. The introduction of PVDF‐g‐AAc into the PVDF/TPU blends causes an increase in viscosity. The rheological behavior of the compatibilized PVDF/TPU 90/10 and 10/90 blends are well described by the generalized Zener model. The addition of the compatibilizer PVDF‐g‐AAc reduces the dispersed‐phase domain size and narrows the size distribution. ?Author: The summary has been shortened to comply with the maximum of 700 characters. Pls check/confirm changes!?

     

The Use of Ethylene/Propylene Copolymers as Compatibilizers for Recycled Polyolefin Blends

Compatibilizing effects of ethylene/propylene (EPR) diblock copolymers on the morphology and mechanical properties of immiscible blends produced from recycled low‐density polyethylene (PE‐LD) and high‐density polyethylene (PE‐HD) with 20 wt.‐% of recycled poly(propylene) (PP) were investigated. Two different EPR block copolymers which differ in ethylene monomer unit content were applied to act as interfacial agents. The morphology of the studied blends was observed by scanning‐ (SEM) and transmission electron microscopy (TEM). It was found that both EPR copolymers were efficient in reducing the size of the dispersed phase and improving adhesion between PE and PP phases. Addition of 10 wt.‐% of EPR caused the formation of the interfacial layer surrounding dispersed PP particles with the occurrence of PE‐LD lamellae interpenetration into the layer. Tensile properties (elongation at yield, yield stress, elongation at break, Young's modulus) and notched impact strength were measured as a function of blend composition and chemical structure of EPR. It was found that the EPR with a higher content of ethylene monomer units was a more efficient compatibilizer, especially for the modification of PE‐LD/PP 80/20 blend. Notched impact strength and ductility were greatly improved due to the morphological changes and increased interfacial adhesion as a result of the EPR localization between the phases. No significant improvements of mechanical properties for recycled PE‐HD/PP 80/20 blend were observed by the addition of selected block copolymers.     

橡胶型乙烯-醋酸乙烯酯共聚物与热塑性聚氨酯弹性体共混物耐油性能研究

将2种乙烯-醋酸乙烯酯共聚物（EVM400，EVM700）和2种热塑性聚氨酯弹性体（聚酯型TPU385E和聚醚型TPU8685）按不同并用比进行交叉共混，考察了共混体系的耐油性能。结果表明，3#标准油较1#标准油对EVM／TPU共混胶性能影响大，且VA含量低的EVM400共混胶比VA含量高的EVM700共混胶受3#标准油的影响大；EVM700／TPU385E共混胶具有最好的耐油性；EVM／TPU共混胶并用比为50／50时．浸油前后性能变化最大，即耐油性最差。     

乙烯-醋酸乙烯酯共聚物对茂金属聚乙烯的改性研究

以添加不同比例的茂金属聚乙烯 (mLLDPE) /乙烯 醋酸乙烯酯 (EVA)共混物为研究对象 ,考察了EVA含量对mLLDPE/EVA共混物的力学性能、热性能、流变性能、动态力学性能和形态结构的影响。研究结果表明 ,EVA添加到mLLDPE中 ,增加了mLLDPE的剪切敏感度、降低了mLLDPE的熔融粘度、改善了mLLDPE的流动性和加工性 ;在一定的添加比例范围内mLLDPE和EVA具有很好的相容性 ,可以在改善mLLDPE加工性能、引入极性基团的同时又保持与纯mLLDPE相近的力学性能 ,但会导致共混物材料的刚性下降 ,柔性增加。热分析数据说明 ,mLLDPE/EVA共混体系中 ,在EVA含量较小时共混物存在大量共晶 ,与mLLDPE有很好的相容性 ,无论是熔融曲线还是降温曲线都只出现一个峰。当EVA含量增大时 ,mLLDPE/EVA共混物出现相分离 ,曲线出现双峰 ,但两峰值呈现靠近趋势 ,预示mLLDPE/EVA共混物中仍存在少量共结晶     

Super‐Tough and Highly‐Ductile Poly(l‐lactic acid)/Thermoplastic Polyurethane/Epoxide‐Containing Ethylene Copolymer Blends Prepared by Reactive Blending

Ethylene‐methyl acrylate‐glycidyl methacrylate copolymer (E‐MA‐GMA) is employed to improve the impact toughness of poly(l ‐lactic acid) (PLLA)/thermoplastic polyurethane (TPU) blends by reactive melt‐blending. The reaction and miscibility between the components are confirmed by Fourier transform infrared spectroscopy, dynamic mechanical analysis, and differential scanning calorimetry. A super‐tough PLLA/TPU/E‐MA‐GMA multiphase blend (75/10/15) exhibits a significantly improved impact strength of 77.77 kJ m^?2, which is more than 17 times higher than that of PLLA/TPU (90/10) blend. A co‐continuous‐like TPU phase structure involving E‐MA‐GMA phase at the etched cryo‐fractured surface and the high‐orientated matrix deformation at the impact‐fractured surface are observed by scanning electron microscopy. The high‐orientated matrix deformation induced by the co‐continuous TPU phase structure is responsible for the super toughness of PLLA/TPU/E‐MA‐GMA blends.     

Influence of Compatibilizer on Morphology and Dynamic Rheological Behavior of Polyethylene-Octene Elastomer/Starch Blends

The morphology and rheology of polyethylene-octene elastomer (POE)/crosslinked starch (CS) immiscible blends with various amounts of compatibilizer were experimentally examined. A graft copolymer, POE-g-MAH, acting as the compatibilizer, was used to modify the interface of the blend. The particle radius in the POE/CS 80/20 system decreased with increasing compatibilizer up to 5 wt%, beyond which the particle size slightly increased. This indicates that the interface reaches saturation when the compatibilizer content is 5 wt%, leading to reduced effectiveness of the compatibilizer. From the SEM micrographs, the compatibilized blends were found to have better interfacial adhesion between the POE and starch phase than the uncompatibilized blends. Rheological examination shows a sharp reduction of the viscoelastic modulus and complex viscosity in blends containing 10 wt% compatibilizer. When the content of compatibilizer is less than 5 wt%, the viscoelastic modulus and complex viscosity of the blends increase with increasing the content of compatibilizer.     

Blends of epoxy–amine resins with poly(phenylene oxide) as processing aids and toughening agents: I. Uncured systems

The effect of two different bisphenol‐A‐based diepoxides—nearly pure DGEBA340 and a DGEBA381 oligomer—and an aromatic diamine curative (MCDEA) on the solubility and processability of poly(phenylene oxide) (PPO) was studied. The solubility parameters of the diepoxies and the curative calculated from Fedors's method suggest miscibility of PPO with the components, and this was observed at the processing temperature; however, some of the blends were not transparent at room temperature, indicating phase immiscibility and/or partial PPO crystallization. The steady shear and dynamic viscosities of the systems agreed well with the Cox–Merz relationship and the logarithmic viscosities decreased approximately linearly with increasing amounts of DGEBA381, DGEBA340 or MCDEA, thus causing a processability enhancement of the PPO. The dynamic rheology of intermediate PPO:DGEBA compositions at 200 °C showed gel‐like behaviour. Dynamic mechanical analysis of blends with varying PPO:DGEBA ratios showed that the main glass transition temperature (T_g) of the blends decreased continuously with increasing epoxy content, with a slightly higher plasticizing efficiency being exhibited by DGEBA340 compared to DGEBA381. However, blends with 50 and 60 wt% PPO had almost identical T_g due to the phase separation of the former blends. The blends of MCDEA and PPO were miscible over the concentration range investigated and T_g of the blends decreased with increasing MCDEA concentration. © 2013 Society of Chemical Industry     

Preparation of EPDM/SAN Dry Blends by Reactive Processing

Reactive blending of the rubber EPDM (a terpolymer consisting of ethylene, propylene and a diene) and the thermoplastic material SAN (a copolymer of styrene and acrylonitrile) is reinvestigated with special attention to EPDM/SAN blends with a 50/50 blend ratio. A resin cure system based on a low molecular weight phenol formaldehyde condensate, which primarily consists of dimethylolphenol and stannous dichloride, is used for compatibilization of EPDM and SAN, as well as for crosslinking of the EPDM phase. The amounts of phenolic resin and SnCl₂ · 2H₂O as well as the EPDM grade and the EPDM/SAN blend ratio are varied. The blends are characterized by stress‐strain measurements, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Unreacted EPDM, unreacted SAN and gel plus graft copolymer are quantitatively determined by fractionation of the blends with a binary solvent mixture which exhibits phase separation at room temperature. Blends prepared from EPDM grades that are amorphous and have a high molar mass exhibit high levels of gel and rather poor mechanical properties. With these blends, gel formation is favored over the formation of EPDM/SAN graft copolymers. Even with low levels of the resin cure system, the formation of gel cannot be avoided. It is therefore not possible to prepare graft copolymers without some gelling. Blends prepared from an EPDM grade with high crystallinity and a low Mooney viscosity exhibit substantially better mechanical properties than blends based on amorphous and higher viscosity EPDM grades. TEM and SEM micrographs reveal good dispersion of the two polymers, as well as good interfacial adhesion between the EPDM and the SAN phase. This electron microscopic evidence, in combination with low gel contents, supports the view that the tendency towards graft copolymer formation and gelling strongly depends on the EPDM grade used. Variation of the EPDM/SAN blend ratio between 5–90 wt.‐% results in blends which cover the product range from toughened thermoplastics to thermoplastic elastomers.

TEM of compatibilized EPDM/SAN blend.     

Effect of Barium Titanate on the Thermal,Morphology, Surface,and Mechanical Properties of the Thermoplastic Polyurethane/Barium Titanate Composites

The aim of this study was to improve thermal stability, mechanical, and surface properties of thermoplastic polyurethane (TPU) with the addition of BaTiO₃. The TPU/BaTiO₃ composites having various ratios of TPU and BaTiO₃ were prepared. The chemical structure of the prepared composites was investigated by FTIR. Thermal stability of the samples were evaluated by thermogravimetric analysis and differential scanning calorimetry. Mechanical properties of the samples were characterized with stress–strain test. Hydrophobicity of the samples was determined by the contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy.     

Synthesis and characterization of polyethylene/oxidized polyethylene miscible blends and role of OPE as a viscosity control

Polymer blending allows for new materials to be designed with unique properties. Here, blends of linear low density polyethylene (PE) and oxidized polyethylene (OPE) have been prepared. PE/OPE blends are characterized for their molten state properties by thermal analysis and rheology; the solid state properties are studied by scattering, diffraction, and tensile testing. Melt miscibility was confirmed by a negative Flory‐Huggins interaction parameter (χ ～ ?2.3) from Hoffman‐Weeks plots. Additionally, a continuous decrease in melting temperature (from 123 to 119 °C) and thermal stability of blends (25% weight loss from 454 to 416 °C) was observed with increasing OPE loading from 0 to 50 wt %. Time‐temperature master curves revealed the shifting of the glassy region to higher frequencies and formation of relaxed polymer chains in the glassy region. A plasticization effect was observed with zero shear viscosity of the blends decreasing with increasing OPE loading. Finally, a decrease in lamellar thickness of PE (from 180 to 140 Å) with increasing OPE resulted in increasing the blends' brittleness. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43521.     

Modelling of the Nonlinear Behavior of Compatibilized Polyethylene/Polyamide Blends in Shear and Extensional Flows

We have studied the effect of the amount Φ_c of a reactive compatibilizer on the rheological properties of a polyethylene/polyamide blend, under steady shear and transient extensional flows. Here, we propose to describe the viscosity η(γ) and the first normal stress coefficient γ₁(γ) using a Carreau‐type power‐law model, which is a three‐parameter model. A single model is sufficient to express the behavior of γ₁(γ) On the other hand, the complete η(γ) curve is described by the superposition of two Carreau models, in relation to the presence of two relaxation mechanisms. Moreover, the extentional viscosity η_E(?), estimated using the end pressure drop observed in capillary flow experiments, is expressed by a two‐parameter power‐law model.     

相容剂对弹性体TPU/POE共混体系流变性的影响

我们通过动态频率、应变流变仪研究了添加POE-g-MAH、POE-g-NH2相容剂的TPU/POE共混物三元共混体系在200℃下的动态流变学行为。随POE-g-MAH、POE-g-NH2添加量的增加,共混体系的动态模量G'也显著增加,而且曲线随着频率增大而逐渐靠近。这是因为POE分子链上的酸酐及氨基基团与TPU分子上的氨基甲酸酯发生反应,TPU与POE之间形成的界面区和界面粘结力增加,从而使相态结构的稳定性提高。POE-g-MAH、POE-g-NH2的加入,导致二元共混斜率完全偏离线性关系,极大地提高了POE与TPU的相容能力。     

Improvement of the Photostability of Low-Density Polyethylene and Ethylene Vinyl Acetate Blends with Nanoclay: Toward Durable Nanocomposites for Potential Application in Greenhouse Cover Films

The effect of three different organomodified nanoclays (Cloisite 20A, Cloisite 30B, and Nanomer I28E) as well as the effect of a compatibilizer (PEgMA) was studied, with the purpose of developing greenhouse cover films based on polyethylene/ethylene vinyl acetate blends. Three organomodified clays were analyzed. The influence of organomodifier clay on film optical, morphology, mechanical, and photo-oxidative degradation properties as well as the effect of incorporation of maleic anhydride-grafted polyethylene as a compatibilizer was studied. The combined effect of these nanoclays with two different UV-oxidative protection systems for polyethylene/ethylene vinyl acetate-nanostructured films was evaluated. Two types of UV stabilizer combination systems were studied; one with a combination of heat and light stabilizers of mixture of antioxidants (phenolic and metal deactivator, Irgatec NC66) with hindered amines, Tinuvin 494AR (designated as system-A) and other with a combination of metal deactivator antioxidant, Irganox MD1024 with hindered amines Tinuvin NOR 371 and benzophenones, Chimasorb 81 (designated as system-B). A strong influence is observed in the use of compatibilizing agent, type, and content of nanoclay in the degree of dispersion as well as in the photo-oxidation behavior. The structure obtained is very dependent on the modified clay used; mostly, intercalated–exfoliated clay structure is produced. The induction period for the photodegradation reaction to start is shorter in the samples with the nanoclay than in the pure polymer. There was a difference in the effectiveness of two stabilizing systems used. It was found a better performance for the stabilizer system-A, regardless of the type of clay used. These greenhouse cover films should allow the pass-through of visible light into the greenhouse during day but restrict the pass-through of the infrared radiation out of the greenhouse during night.     

Influence of various crosslinking systems on the mechanical properties of gas phase EPDM/PP thermoplastic vulcanizates

Dynamically cured thermoplastic elastomers or thermoplastic vulcanizates (TPVs) are widely used nowadays for their unique characteristics. In this paper, gas phase ethylene–propylene–diene terpolymer (GEPDM)/Polypropylene (PP) TPVs with various crosslinking systems have been extensively studied to optimize the curative level in each crosslinking system with special reference to their mechanical properties. Optimized systems were compared for heat aging, recyclability, crosslink density, morphology studies, and dynamic mechanical analysis. Crosslinking by peroxide in the presence of triallyl cyanurate as a coagent gives best overall performance with reference to excellent heat aging behavior, tension set, and compatibility between GEPDM and PP. Conventional EPDM/PP system was also compared with GEPDM/PP system. GEPDM/PP system was found to exhibit better behavior in all respects. Significant correlations were obtained between delta torque values obtained from Moving Die Rheometer and modulus or cross link density of TPVs irrespective of the nature of crosslinking agent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5463–5471, 2006     

Dynamically vulcanized PP/EPDM blends: Influence of curing agents on the morphology evolution

Thermoplastic vulcanizates (TPE‐Vs) are a special class of thermoplastic elastomers (TPEs), where the rubber phase is dynamically crosslinked in the presence of a thermoplastic matrix. The goal of this work is to compare the behavior of two curing agents systems, conventional peroxide named Peroximon and bismaleimide/dicumyl peroxide, in TPE‐Vs based on PP/EPDM 35/65 w/w. It was also investigated the TPE‐Vs morphological evolution and samples was collected at different times during the mixture and dynamic crosslinking. The materials were characterized by some techniques, which allowed investigating mechanical, morphological, hardness, and swelling properties. Considering the used curing agents contents, the TPE‐Vs obtained by using Peroximon presented lower tensile strength, lower swelling degree, and remarkable lower deformation than those obtained with BMI/DCP system. The hardness properties were not significantly affected by the content of the curing agent, showing only a slight decrease when the Peroximon content was increased. The study of the evolution of morphology showed the rubber phase undergoes crosslinking after adding the curing agent. It could be observed by the increase of the torque and by the appearance of domains in the micrographs. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚乳酸/乙烯-醋酸乙烯酯共聚物/碳酸钙复合材料的性能研究

采用熔融共混法制备了聚乳酸/乙烯-醋酸乙烯酯共聚物/碳酸钙（PLA/EVA/CaCO3）复合材料,利用差示扫描量热仪、X射线衍射仪、偏光显微镜、扫描电子显微镜、力学性能测试和热变形温度测试等手段,研究了EVA和CaCO3对复合材料的结晶性能、断面形貌、力学性能和耐热性能的影响。结果表明,EVA 具有增韧作用,但降低了复合材料的强度和耐热性;而CaCO3可以提高复合材料的强度、韧性、结晶性能和耐热性能;CaCO3与EVA的加入对PLA有协同增韧作用,且不改变PLA的晶型;当PLA/EVA=90/10,加入10 %（质量分数,下同）的CaCO3时,复合材料有最佳的综合性能。