动态硫化乙华平橡胶/热塑性聚氨酯弹性体共混物

对乙酸乙烯酯质量分数分别为40%和70%的乙烯-乙酸乙烯酯共聚物EVM 400和EVM 700先进行动态硫化制成母炼肢,然后与热塑性聚氨酯弹性体(TPU)进行共混,以过氧化二异丙苯(DCP)作为硫化荆.考察了动态硫化工艺和DCP用量以及返炼对共混物力学性能的影响,并通过相差显微镜对共混物的结构进行了分析.结果表明,EVM 400在动态硫化时,黏度变化对DCP用量改变的敏感性要明显高于EVM 700;随着DCP用量的增大,共混物TPU/EVM 700的力学性能提高,而对TPU/EVM 400共混物的力学性能没有明显改善;EVM动态硫化后,在TPU/EVM 700共混物中,其相畴较TPU/EVM400共混物的更小.更均匀;返炼使TPU/EVM 700共混体系的力学性能下降,但使TPU/EVM 400共混体系的力学性能有所提高.     

热塑性聚氨酯弹性体与ABS共混物的力学性能

通过融熔共混法制备了TPU／ABS共混物。对共混比例为0／100，5／95，7／93，10／90，20／80，30／70和40／60的共混物的力学性能进行研究，发现材料的抗冲性能得到改善，在比例为20／80时冲击强度达到最大，同时其它的力学性能下降。     

热塑性聚氨酯弹性体与塑料的共混体系

本文简述了热塑性聚氨酯弹性体(TPU)与聚氯乙烯(PVC)、聚甲醛(POM)和聚碳酸酯(PC)的共混工艺以及共混物的物理机械性能。结果表明,TPU/PVC、TPU/POM、TPU/PC共混物的性能优异,极具发展潜力。     

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。     

热塑性聚氨酯与聚氯乙烯共混研究进展

综述了热塑性聚氨酯与聚氯乙烯共混改性研究进展，重点介绍了热塑性聚氨酯与聚氯乙烯共混物的相容性、共混方式、热塑性聚氨酯的类型和组分、助剂和第三组分聚合物等对共混物性能的影响及其应用。     

聚氨酯弹性体／橡胶共混改性的研究

本文采用丁苯橡胶和三元乙丙橡胶对热塑性聚氨酯弹性体进行共混改性,经过对共混体系的结晶行为和力学性能分析,得出共混体系的模型假设,为扩大聚氨醋弹性体的应用范围提供了一定的理论依据。     

热塑性聚氨酯弹性体的发展

简单介绍了热塑性聚氨酯弹性体的合成、性能及其在共混、补强、互穿网络等方面的最新发展。     

聚氯乙烯与热塑性聚氨酯的共混改性

将聚氯乙烯（ＰＶＣ）与自制的热塑性聚氨酯（ＴＰＵ）进行共混改性，试验研究了ＰＶＣ分子量、ＰＶＣ／ＴＰＵ共混比及共混方法对共混物性能的影响。结果表明，ＸＳ－３型ＰＶＣ与ＴＰＵ的相容性最好，性能也较为满意。     

氟橡胶接枝马来酸酐增容氟橡胶/热塑性聚氨酯共混物的性能

研究了氟橡胶(FKM)接枝马来酸酐(FKM-g-MAH)增容FKM/热塑性聚氨酯(TPU)共混物的物理机械性能及动态力学性能.结果表明,当FKM-g-MAH质量分数为15%时,FKM/TPU共混物的物理机械性能最佳;添加增容剂FKM-g-MAH后,FKM/TPU共混物中FKM和TPU两相的相容性得到改善,且其阻尼性能优于纯FKM.     

乙酸-乙酸乙烯酯橡胶/聚乳酸共混体系的发泡及阻尼性能

以乙烯-乙酸乙烯酯橡胶(EVM)/聚乳酸(PLA)共混物为基体材料,过氧化二异丙苯(DCP)为硫化剂、偶氮二甲酰胺(AC)为发泡剂,经模压发泡制备橡塑共混发泡材料,用扫描电子显微镜观察材料的泡孔结构及泡孔尺寸分布,采用动态黏弹谱仪对发泡材料的阻尼性能进行研究,考察了AC和DCP用量、发泡时间及白炭黑用量对EVM/PLA发泡材料泡孔结构及阻尼性能的影响。结果表明,随着AC用量的增加,材料的泡孔数目增多但孔径相差不大,阻尼性能也无明显变化,在AC用量为4份时材料的阻尼性能较好;随着DCP用量的增加,材料的泡孔尺寸略有减小,阻尼性能变化不大,DCP用量为5份时材料的阻尼性能较好;随着发泡时间的延长,泡孔尺寸逐渐减小,阻尼性能逐渐提高,发泡时间为5 min时,泡孔孔径与损耗因子均出现突变;填料用量增加,泡孔孔径减小,发泡材料整体损耗因子上升。     

基于乙烯-乙酸乙烯共聚物/丁腈橡胶热塑性硫化橡胶超亲水材料的制备与性能

采用动态硫化法制备了基于乙烯–乙酸乙烯酯共聚物/丁腈橡胶的热塑性硫化橡胶（EVA/NBR TPV）,以不同型号金相砂纸为模板,通过模压法在其表面构建具有微纳米结构的表面,研究了橡塑质量比对EVA/NBR TPV粗糙表面超亲水行为的影响及EVA/NBR TPV超亲水表面的微观结构和超亲水性能,并初步探讨了EVA/NBR TPV表面的亲水机制。结果表明,当EVA/NBR TPV的橡塑质量比为20/80时,采用模板法且以耐水砂纸为模板制得的EVA/NBR TPV表面亲水性较好。其中,当橡塑质量比为20/80时,以NO 1000砂纸为模板,模压温度为165 ℃,经过预热10 min、热压3 min、冷压5 min后制得的EVA/NER TPV薄膜表面的亲水性最佳。     

高抗冲聚苯乙烯/乙烯-乙酸乙烯共聚物/丁苯橡胶热塑性硫化胶的黏弹行为

采用动态硫化法制备了高抗冲聚苯乙烯/乙烯-乙酸乙烯共聚物(EVA)/丁苯橡胶热塑性硫化胶(TPV),考察了EVA用量对TPV的动态硫化操作性、微观相态、力学性能、熔体表观黏度、动态黏弹行为及应力弛豫的影响。结果表明,在基质树脂相中加入EVA,可改善TPV动态硫化的操作性及制品的外观质量,且TPV的形变回复能力得到增强,但对TPV力学性能和表观黏度的影响不明显。随着TPV中EVA用量的增加,在频率扫描模式下,TPV的储能模量和损耗模量下降,损耗因子出现一定程度的波动;在温度扫描模式下,储能模量、损耗模量及损耗因子均下降。随着EVA用量的增加,TPV应力弛豫测试的残留应力降低。     

乙烯基硅树脂改性EVA胶膜的制备

以混合氯硅烷及硅氧烷为单体,采用水解共缩聚的方法制备了乙烯基硅树脂,并研究了合成该树脂的影响因素;以乙烯基硅树脂为改性剂,以高乙酸乙烯含量的乙烯-乙酸乙烯共聚物(EVA)为基体,通过熔融混炼法添加各种助剂,得到改性的EVA胶膜,探讨了乙烯基硅树脂对EVA胶膜性能的影响。结果表明:乙烯基硅树脂改性的EVA胶膜热稳定性和老化性能得到了提高;含有苯基的乙烯基硅树脂改性EVA胶膜时,所得胶膜的热氧老化性能好,透光率高,且黄色指数增大速率较慢。因此,含苯基乙烯基硅树脂是EVA胶膜的理想改进剂。     

撕裂模式下乙烯-乙酸乙烯酯共聚物/氯丁橡胶热塑性硫化胶的Mullins效应及其可逆回复

采用动态硫化法制备了乙烯-乙酸乙烯酯共聚物（EVA）/氯丁橡胶（CR）热塑性硫化胶（TPV）,对其微观形貌、撕裂强度、撕裂模式下的Mullins效应、热处理后的可逆回复行为及其机制进行了研究。结果表明,EVA/CR TPV橡塑质量比为30/70时其撕裂模式下的应变和撕裂强度较高,橡胶相与树脂相呈“海-岛”结构;撕裂模式下EVA/CR TPV的单轴循环测试中表现出明显的Mullins效应,增大应变时,其最大撕裂强度、瞬时残余应变、内耗值和阻尼因子均增加,但应力软化因子趋于下降;随着热处理温度的上升,Mullins效应的可逆回复效果获得改善,且温度为70℃时其可逆回复行为最好。     

乙烯-乙酸乙烯酯共聚物Levapren 800硫化胶溶度参数的测定及应用

采用溶胀实验及计算机HSPiP软件对牌号为Levapren 800的乙烯-乙酸乙烯酯硫化胶的溶度参数进行了研究。结果表明,单一溶剂与混合溶剂都可用于Levapren 800硫化胶溶度参数的测定,用溶胀法测得其一维溶度参数(δt)为18.90~19.25(J/cm3)1/2。通过HSPiP软件测得Levapren 800硫化胶的δt为19.97(J/cm3)1/2;三维溶度参数的色散力、极性力和氢键力溶度参数分别为18.20,5.50,6.10(J/cm3)1/2。利用三维溶度参数可以预测Levapren 800硫化胶在标准实验油中的溶胀行为;相对能量差对预测聚合物在溶剂中的溶胀性能方面具有一定的应用价值。     

Thermal and physicomechanical properties of ethylene-vinyl acetate copolymer and layered double hydroxide composites

A series of ethylene-vinyl acetate (EVA) copolymer films have been prepared with different compositions viz. 2, 4, 6, and 8 wt % layered double hydroxide (LDH) nanoparticles by solution intercalation method. These solution-casted EVA/LDH nanocomposite films were dried and characterized by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. EVA/LDH films were further tested for tensile strength, density, moisture content, solubility resistance, flammability, and electrical properties. The DSC and FTIR analysis indicate strong interactions between the LDH layers and vinyl acetate groups in EVA. Further, EVA nanocomposite films show enhanced tensile strength, limiting oxygen index (LOI), and flammability rating for the addition of LDH without sacrificing the electrical properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Rheological and mechanical properties of thermoplastic polyurethane elastomer derived from CO2 copolymer diol

CO₂ copolymer diol‐based thermal polyurethane elastomers (PPC‐TPU) were prepared by the reaction of CO₂ copolymer diol and methylene diphenyl diisocyanate and chain extender (ethylene glycol/1,4‐butanediol/1,6‐hexanediol) (EG/BDO/HG). The rheological and mechanical properties of PPC‐TPU were analyzed. The effects of shear rate, shear temperature, hard segment content, and variety of chain extender on the properties of PPC‐TPU were studied. The results showed that the apparent viscosity (η) of PPC‐TPU decreased with the increasing shear rate (τ), and the non‐Newtonian index (n) was less than 1. PPC‐TPU exhibited a typical character of pseudoplastic non‐Newtonian rheological behavior. The degradation during the processing was obviously inhibited by adding plasticizer and antioxidant. It was also discovered that the apparent viscosity varied with the content of hard segment and chain extender. Under the same temperature (185 °C) and shear rate (50 s^?1), the apparent viscosity increased considerably with the raise of hard segment content, and the apparent viscosity and tensile strength of PPC‐TPU with EG as chain extender was the maximum. It can be seen that with the apparent shear rate increasing, the variation tendency of apparent shear stress levels off, and the nonlinear relationship of τ–γ curve tended to be obvious. PPC‐TPU exhibited a typical character of pseudoplastic non‐Newtonian rheological behavior. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45974.     

Free volume properties of thermoplastic polyurethane/polymethylmethacrylate blends: Evidence of interchain interaction

A polymer blend based on thermoplastic elastomeric polyurethane and polymethylmethacrylate (TPU/PMMA) has been studied by positron annihilation lifetime spectroscopy (PALS) and thermomechanical analysis. Thermomechanical analysis allowed the determination of two glass transitions for the blends in the overall range of compositions. The first one (T_g¹) showed a constant value of ?45°C for all blends, the same value of the pure TPU. The second glass transition (T_g²), which is associated with a PMMA rich phase, presented variations with composition. T_g² showed minimum values for the blends in the 20–40 wt % TPU range, which indicates increase of interaction in this composition region. PALS systematic investigation allowed the determination of relative mean free volume fractions, f_v/C, and binary interchain interaction parameters, β. These parameters exhibited a noticeable negative deviation from additivity in all range of composition and minima for the 20 wt % TPU blend. PALS results were interpreted as associated to a strong attractive interchain interaction between TPU and PMMA in the PMMA rich phase which contracts the free volume fraction of the blends. Moreover, the miscibility achieved in the PMMA rich phase would allow a good adhesion between this phase and the TPU phase, which was corroborated by scanning electron microscopy images. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007