TPU/EVA共混物混炼工艺的研究

采用转矩硫化仪考察填料种类和用量、混炼初始温度、混炼时间和转子转速对热塑性聚氨酯（TPU）/乙烯-乙酸乙烯酯共聚物（EVA）共混物性能的影响。结果表明,与炭黑填充TPU/EVA共混物相比,白炭黑填充胶料的混炼效果和拉伸性能较好,白炭黑最佳用量为30份;TPU/EVA共混物的优化混炼条件为：混炼初始温度160℃,混炼时间10～15min,转子转速45r·min^-1。     

动态硫化TPU/EVM共混物的结构与性能研究

采用熔融共混法制备热塑性聚氨酯(TPU)/乙烯-乙酸乙烯酯橡胶(EVM)动态硫化共混物,并对其结构与性能进行研究.结果表明,TPU/EVM共混体系实施动态硫化的最佳共混比为75/25,硫化剂BIPB用量为0.8份时共混物性能最佳,且不同共混比的TPU/EVM共混物需要的硫化剂最佳用量不同;动态硫化后的EVM以较大尺寸的相畴分散在TPU中;TPU/EVM动态硫化共混物返炼后仍具有较高的重复使用价值.     

TPU/EVM动态硫化共混物的流变性能

采用熔融共混法制备热塑性聚氨酯(TPU)/乙烯-乙酸乙烯酯橡胶(EVM)动态硫化共混物,并研究其流变性能.结果表明,未硫化共混物熔体的表观粘度(ηa)随着温度的升高而减小;动态硫化前后熔体的ηa均随着剪切速率的增大而减小,熔体属于假塑性流体;共混物熔体的ηa随着TPU用量的增大而减小,假塑性变弱.     

TPU/EVAC共混发泡材料制备及性能

以热塑性聚氨酯弹性体(TPU)、乙烯–乙酸乙烯酯共聚物(EVAC)为主要原料,通过挤出共混、模压发泡工艺制备了TPU/EVAC共混发泡材料;探讨了TPU牌号、TPU与EVAC共混比及马来酸酐接枝聚烯烃弹性体(POE-g-MAH)、过氧化二异丙苯(DCP)、偶氮二甲酰胺(AC)用量等对发泡材料性能的影响;利用万能试验机、旋转流变仪和扫描电子显微镜研究了共混材料的拉伸性能、流变性能和微观形貌。实验结果表明,TPU型号为90A,TPU/EVAC质量比为80∶20及POE-g-MAH用量为10份时,共混材料的拉伸性能最好,拉伸强度为23.04 MPa,断裂伸长率为1178%;当DCP用量为2份、AC用量为7份时,发泡材料的综合拉伸性能最优,拉伸强度为1.09 MPa,断裂伸长率为27.8%;旋转流变测试结果表明,添加POE-g-MAH后,共混材料熔体的复数黏度随剪切速率的增大而降低,符合假塑性流体流动规律。添加POE-g-MAH后,共混材料的复数黏度、储能模量及损耗模量均下降,当添加10份POE-g-MAH时,共混材料熔体的复数黏度、储能模量及损耗模量均达到最大值。     

HNBR/EVA共混物力学性能、耐热氧老化和耐油性能的研究

将氢化丁腈橡胶（HNBR）和乙烯-醋酸乙烯酯共聚物（EVA）按不同配比制成共混物,考察不同配比下共混物的物理机械性能、耐热氧老化性能和耐非极性燃料油和石油的性能。结果表明,随EVA用量的增加,共混物的物理机械性能有所提高,加工流动性有所改善;当EVA用量大于30份,且使用温度高于50℃时,共混物机械性能下降较大：随HNBR用量的增加,共混物的耐热氧老化和耐油性能有明显提高。     

FKM/TPU共混物的性能研究

试验研究氟橡胶（FKM）/热塑性聚氨酯（TPU）共混物的耐低温性能和物理性能.结果表明,FKM/TPU共混比为70/30,共混物中FKM和TPU两相的相容性较好,共混物的玻璃化温度比FKM约降低了12 ℃,耐低温性能较好,综合物理性能也较优。     

PC／TPU共混物的流变性能

用毛细管流变仪研究了聚碳酸酯（ＰＣ）及聚碳酸酯／热塑性聚氨酯弹性体（ＰＣ／ＴＰＵ）共混物的流变性能。实验结果表明：ＰＣ熔体粘度对剪切速率（γ）不敏感，而对温度（Ｔ）敏感。温度升高，ＰＣ粘度降低。加入ＴＰＵ大大改善了共混物的流动性能，使共混物的成型加工变得容易进行。当ＴＰＵ含量为４０份时，共混物的熔体粘度出现一极小值。加入不同第三组分对于降低共混物的熔体粘度效果不同，第三组分Ｅ对共混物有增粘作用     

EVA熔体流动速率对PLA/EVA共混物性能的影响

通过熔融共混法制备了聚乳酸（PLA）/乙烯-乙酸乙烯酯共聚物（EVA）共混物,采用SEM、DSC、旋转流变仪等研究了VA质量分数为28%,熔体流动速率（MFR）不同的EVA对PLA/EVA共混物性能的影响。结果表明,EVA熔体流动速率越小,其在PLA基体中分散越均匀,EVA颗粒粒径也越小。共混物的结晶度随EVA熔体流动速率的增大而增大,但PLA的玻璃化转变温度（Tg）基本不受EVA的影响。PLA/EVA共混物的复数黏度和储能模量均随EVA的熔体流动速率的增高而减小。力学性能测试结果表明,当EVA的质量分数为15%时,PLA的断裂伸长率明显升高,冲击强度约是纯PLA的2倍。     

EVA对PP/EVA共混物力学性能的影响

将不同配比的聚丙烯(PP)和乙烯-乙酸乙烯共聚物(EVA)进行共混,测试了共混物的拉伸强度和冲击强度;用差示扫描量热法研究了共混物的结晶性能;用扫描电镜(SEM)二次电子成像系统分析了试样的断口形貌,研究了EVA含量对共混物力学性能的影响。结果表明:EVA的加入提高了EVA/PP共混体系的韧性,同时降低了PP的结晶度。     

TPS/EVA共混物的性能研究

探讨了EVA、甘油的含量和润滑剂对TPS/EVA共混体系的力学性能、熔融流动性以及耐水性的影响。     

Melt-rheological properties of PP/EVA blend

This paper describes a study of melt-rheological properties of the binary blend of isotactic polypropylene (PP) and ethylene–vinyl acetate copolymer (EVA) at varying blending ratios (from 0 to 40 wt % EVA content) and using three samples of EVA containing different vinyl acetate contents (VA %), viz. 9, 12, and 19%. Measurements made on a capillary rheometer at three different temperatures (210, 220, and 230°C) in a shear stress range of 10⁴–10⁶ Pa (shear rate 10¹–10⁴ s^?1) are presented and discussed for the effects of blend composition and shear stress on the flow curves, melt viscosity and melt elasticity. Morphology of the blend studied through scanning electron microscopy revealed distinct differences in size and number density of dispersed EVA droplets, which are discussed in terms of the variation of average size and number density of the dispersed EVA droplets as a function of blend composition and shear stress. Melt-rheological properties and morphology of dispersion are correlated and found quite consistent.     

TPU/CPE共混物性能研究

研究热塑性聚氨酯(TPU)/氯化聚乙烯(CPE)共混比和补强剂品种及用量对TPU/CPE共混物性能的影响.结果表明,当TPU/CPE共混比为70/30和60/40时,TPU与CPE的相容性较好,共混物综合性能优异;补强剂可改善TPU/CPE共混物的加工性能,随着补强剂用量的增大,共混物邵尔A型硬度、拉伸强度和撕裂强度增大,拉断伸长率减小;改性白炭黑对共混物的补强效果优于炭黑N330和N550,其适宜用量为30份左右.     

共混改性的PEO/TPU/PVDF-HFP基聚合物电解质的制备及性能

通过相转化法制备基于聚氧化乙烯(PEO)/热塑性聚氨酯(TPU)/聚偏氟乙烯-六氟丙烯(PVDF-HFP)3种高聚物共混形成的电解质隔膜,将其浸泡在浓度为1 mol/L六氟磷酸锂(LiPF6)的碳酸乙烯酯(EC)-碳酸二甲酯(DMC)-碳酸甲乙酯(EMC)(三者体积比为1:1:1)电解液中形成一种凝胶态聚合物电解质(GPE).采用SEM、EDS、FTIR、XRD、TG、DSC、万能拉力机和交流阻抗法对隔膜进行了表征.结果表明,m(PEO):m(TPU):m(PVDF-HFP)=3:1:4的隔膜具有均匀的多孔形貌,结晶峰面积最低,拉伸强度达到15 MPa左右,离子电导率为7.9×10–3 S/cm,综合性能最佳.将该隔膜装配成CR2032纽扣电池进行电池循环性能测试,结果表明,在0.2 C倍率下电池的充放电比容量分别达到了164和161 mA·h/g,在150次循环后,放电比容量仍能保持在152 mA·h/g左右,库伦效率保持97％以上,表明该GPE是一种优异的电池材料.     

PET/EVA共混纤维的制备及其性能研究

将PET/EVA共混物切片在微型柱塞式纺丝机上进行熔融纺丝、拉伸等试验,对其纤维的结构和性能进行了分析。结果表明,随着EVA含量的增加,共混切片的纺丝性能下降;初生共混纤维的密度、机械性能、可拉伸性能下降;共混纤维的取向度、结晶度降低。     

Studies on polymer blends with moderate specific interactions 1. Mechanical properties of SAN/TPU and SAN/EVA/TPU

Polymer pairs with moderate specific interactions may lead to phases with low interfacial energy, which is desirable for rubber-toughening plastics. SAN and some polyurethane elastomers (TPU) belong to this kind of system. Without adding compatibilizer, SAN/TPU blends possess excellent mechanical properties. However, SAN and EVA form mechanically incompatible blends. The properties of the SAN/EVA blends can be substantially improved by incorporating TPU. Scanning electron microscopy (SEM) observations prove that TPU acts as a compatibilizer preferentially locating at the interface.     

Compatibilization and properties of ethylene vinyl acetate copolymer (EVA) and thermoplastic polyurethane (TPU) blend based foam

Ethylene vinyl acetate copolymer/thermoplastic polyurethane (EVA/TPU) blending foams are rarely reported so far because of their poor compatibility, and addition of a compatibilizer to the blend system was our major interest, which can improve interfacial adhesion between the two phases. In this paper, TPU-grafted EVA (EVA-g-TPU), as a compatibilizer, was simply prepared using maleic anhydride-grafted EVA (EVA-g-MAH) and 4,4′ diamino diphenyl methane in the mixing process of TPU and EVA matrix. Fourier transform infrared spectroscopy and differential scanning calorimetry were used to investigate the structures of EVA-g-TPU and the interfacial reaction in the mixing process, and the effect of EVA-g-TPU on compatibilization between the two phases of EVA/TPU blends was investigated using scanning electron microscopy. Finally, EVA/EVA-g-TPU/TPU foams based on the good compatibility of the resin blends were prepared, and the physical properties directly related to the compatibility were investigated as a function of the theoretical quantity (molar mass) of EVA-g-TPU (n _EVA-g-TPU) in the foams. Moreover, the tensile strength, elongation at break, tear strength and compression set were improved by 19.0, 9.3, 43.6 and 7.5 %, respectively. Overall, EVA/EVA-g-TPU/TPU foams with excellent mechanical properties were obtained without sacrificing other important physical properties (lower density etc.) through popular and friendly means in this research.     

Electron beam cross-linking of EVA/TPU blends

Abstract

Ethylene vinyl acetate (EVA) copolymer and thermoplastic polyurethane (TPU) with different blending ratios were melt mixed in an internal mixer. The blends were then exposed to electron beam (EB) irradiation with different doses of 50, 100, 150, 200 and 250 kGy. FTIR spectroscopy and dynamic mechanical thermal analysis (DMTA) were used to investigate the effect of cross-linking and blending ratio on chemical structure as well as solid state viscoelastic properties of the blends. FTIR spectroscopy showed interchain cross-linking during melt blending and also radiation cross-linking during solid state irradiation. Observation of one damping peak for blends at almost all blending ratios was an indication of miscibility of these blends. The results indicated formation of interchain cross-linking stabilised with exposure to EB irradiation. Mechanical properties of the blends were investigated via stress–strain curves. Modulus showed a monotonic increasing trend with the radiation dose, but tensile strength and elongation at break were initially increased and then decreased with increasing radiation dose. This was attributed to two competing parallel factors of strain induced crystallisation and degree of cross-linking.     

Effect of maleated EVA on compatibility and toughness of PETG/EVA blend

Maleic anhydride (MAH) grafted onto ethylene vinyl acetate copolymer (EVA), mEVA (modified EVA) was blended with poly(ethylene glycol‐co‐cyclohexane‐1,4‐dimethanol terephthalate) (PETG) with various mEVA and EVA (unmodified) content in the internal mixer. The effect of reactive compatibilizer to decrease the dispersed particle diameter was observed. The brittle–ductile transition was found at about d_n: 0.37 µm and d_v: 0.55 µm of particle diameter, a critical particle diameter, regardless of EVA content, and the blend was also toughened at above the critical particle diameter regardless of dispersed EVA content and compatibility. The toughening mechanism and the effect of the particle diameter on the impact strength of the blend were investigated by morphological observation, and it was found that the toughening of the PETG/EVA blend system resulted from the shear deformation, induced by cavitation of dispersed EVA particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013