SEBS/PP热塑性弹性体阻尼性能研究

以苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)和聚丙烯(PP)为基体材料,采用HAAKE转矩流变仪制备SEBS/PP热塑性弹性体,利用动态热机械分析仪研究PP和填充油用量对SEBS/PP热塑性弹性体力学性能、动态力学性能的影响,进而通过添加萜烯树脂来研究提高热塑性弹性体阻尼性能的方法。结果表明:PP的加入改善了SEBS/PP共混体系的力学性能,但随着PP用量的增加,热塑性弹性体阻尼因子的峰值逐渐下降;SEBS/PP共混体系在添加20 phr PP时,综合性能最佳;随着萜烯树脂用量的增加,阻尼因子的峰值向高温方向移动,且有效温域(阻尼因子tanδ0.3)明显加宽;在添加50 phr萜烯树脂时,热塑性弹性体的tanδ峰值向高温移动20℃左右,且在tanδ0.3的范围内温域拓宽19℃,阻尼性能明显提高;随着填充油用量的增加,SEBS/PP热塑性弹性体的力学性能下降,tanδ峰值变大,阻尼温域变窄,充油比在1:1.1时SEBS/PP热塑性弹性体的综合阻尼效果更好。     

SEBS/PP热塑性弹性体压缩永久变形性能的研究

研究主体材料并用比以及石蜡油、碳酸钙和乙烯丙烯酸树脂用量对氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)/聚丙烯(PP)热塑性弹性体(TPE)性能的影响。结果表明:随着SEBS/PP并用比减小,TPE的邵尔A型硬度和压缩永久变形增大;当石蜡油用量为70份时,TPE的拉伸强度最大,压缩永久变形最小;碳酸钙用量增大,TPE的压缩永久变形减小;添加乙烯丙烯酸树脂,TPE的压缩永久变形先减小后增大,最佳用量为3份。     

不同化学结构的PP对热塑性弹性体复合材料性能的影响

研究了不同化学结构的聚丙烯(PP)对苯乙烯-乙烯/丁烯-苯乙烯共聚物(SEBS)/白油/PP热塑性弹性体复合材料力学性能和流动性能的影响。结果表明,复合材料的力学性能与所添加PP的力学性能保持一致,按照均聚PP、无规共聚PP、共聚PP的化学结构特性,复合材料的拉伸性能、弯曲性能和硬度都依次变小;但是复合材料的流动性能不仅和PP的熔体质量流动速率(MFR)有关系,而且还与PP和SEBS的相互作用有关。在PP的MFR相同的情况下,复合材料的MFR按照均聚PP、无规共聚PP、共聚PP的不同依次降低。     

充油SEBS/PP热塑性弹性体的制备及性能研究

采用HAAKE转矩流变仪制备了充油苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物/聚丙烯(SEBS/PP)热塑性弹性体,利用热重分析(TG)、差示扫描量热法(DSC)等研究了填充油对SEBS/PP加工性能、热稳定性和力学性能的影响,并考察了该充油SEBS/PP中PP的结晶行为。结果表明:填充油的加入可以明显改善SEBS/PP的加工性能。在各种充油SEBS/PP体系中,添加了石蜡油KP6030的SEBS/PP体系具有最优综合力学性能,而且该体系的热分解温度最高、失重率最低、热稳定性能最好。另外在充油SEBS/PP体系中,PP的结晶温度降低、结晶度基本不变、结晶速率加快。     

膨胀石墨改性氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物/聚丙烯弹性体的制备与性能

分别采用膨胀石墨和纳米Fe₃O₄插层膨胀石墨改性氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)/聚丙烯(PP)弹性体材料,探讨了膨胀石墨用量及纳米Fe₃O₄插层复合膨胀石墨对弹性体拉伸性能、回弹性和导电性能的影响规律。结果表明,膨胀石墨的加入可有效提高SEBS/PP弹性体的回弹性和导电性能,当膨胀石墨用量为3.5份(质量)时,弹性体的回弹性最佳,表面电阻率最低,但其拉伸强度有所下降。采用纳米Fe₃O₄插层膨胀石墨改性SEBS/PP弹性体可有效改善其拉伸性能,并可进一步降低表面电阻率和体积电阻率。     

低挤出加工温度耳机线专用热塑性弹性体复合材料的制备及性能研究

系统研究了不同化学结构的聚丙烯(PP)、苯乙烯-乙烯/丁烯-苯乙烯共聚物(SEBS)和碳酸钙对热塑性弹性体复合材料挤出加工温度的影响。实验结果表明,PP的化学结构和PP的添加量是影响复合材料的挤出加工温度的两个最重要因素,低熔点的无规共聚PP和低PP添加量可以有效降低材料的挤出加工温度;SEBS的摩尔质量和碳酸钙的含量对材料的加工温度无劣化作用。     

PP/丙烯基弹性体/SEBS医用热塑性弹性体的性能

以聚丙烯(PP)、丙烯基弹性体和苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)为主要原材料,采用熔融共混改性方法制备PP/丙烯基弹性体和PP/丙烯基弹性体/SEBS两种热塑性弹性体。采用转矩流变仪、拉伸试验机、硬度计和雾度计分别对共混体系的流变性能、拉伸性能、硬度和透光率进行分析与表征。结果表明,随着PP/丙烯基弹性体配比的增加,二元共混体系的平衡扭矩降低、硬度(邵A)提高、透光率变好、断裂伸长率增加,当其配比为1∶1时,共混体系的拉伸强度达到最大值(34.2 MPa);当PP与丙烯基弹性体配比为1:1不变时,随着SEBS含量增加,三元共混体系的平衡扭矩增大、硬度(邵A)减小、透光率变差、断裂伸长率提高;当PP、丙烯基弹性体和SEBS配比为47.5∶47.5∶5时,共混体系的透光率可达87%,硬度(邵A)为87,拉伸强度为35.2 MPa,断裂伸长率为750%,100%定伸强度为11.8 MPa,可满足医疗输液器械的要求。     

无卤阻燃PP/SEBS复合材料的研究

采用高速混合机将聚丙烯(PP)、SEBS(苯乙烯-乙烯/丁烯-苯乙烯三嵌段聚合物),白油,含磷阻燃剂MPP(0,0-二甲基-0-[(4-甲巯基-3-甲基)-苯基]硫代磷苯酯)及协同剂等按照比例预混,经双螺杆挤出机挤出,制备无卤阻燃PP/SEBS热塑性弹性体材料。并采用聚氯乙烯(PVC)电线押出机制备单芯电线。燃烧测试结果发现:阻燃PP/SEBS材料的热释放速率(HRR)及热释放速率峰值(PHRR),总热释放量(THR)均明显降低,UL 94最高可以达V-0级,极限氧指数(LOI)达30%,材料的阻燃性显著提高。白炭黑(Si02)具有明显的阻燃协同作用。同时,对PP/SEBS阻燃材料及其制造的电线进行了测试,结果表明:制备的PP/SEBS阻燃电线阻燃性能达到VW-1级,强度≥10.0 MPa,热老化后的强度和断裂伸长率的保持率≥88%,其各项物性指标符合UL62/1581的要求,综合性能优异,是替代含卤PVC电线材料的良好选择。     

SEBS对SBR/PP热塑性弹性体增容作用的研究

以氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）作为丁苯橡胶（SBR）/聚丙烯（PP）热塑性硫化胶（TPV）的增容剂,研究增容剂对共混体系的力学性能、共混物硫化交联网络结构、熔融温度以及断面形貌的影响。结果表明,SEBS添加量为6份时,体系的综合力学性能最佳;SEBS的加入提高了有效共硫化程度。增加了体系的化学交联密度;随着SEBS用量的增加,TPV的熔融温度逐渐下降;扫描电镜图片显示SEBS能有效提高界面结合力,提高PP与SBR的相容性。     

用于包覆丙烯腈-丁二烯-苯乙烯共聚物的苯乙烯嵌段共聚物热塑性弹性体的制备与性能

以苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)为基体,白油为增塑剂,热塑性聚氨酯(TPU)为极性改性剂,SEBS接枝马来酸酐(SEBS-g-MAH)为相容剂,利用双螺杆挤出机共混挤出制备了用于包覆丙烯腈-丁二烯-苯乙烯共聚物(ABS)的包覆料,考察了填料种类和TPU、白油及SEBS-g-MAH的用量对包覆料物理机械性能、黏结性能及微观相态的影响。结果表明,随着TPU用量的增加,SEBS包覆料的邵尔A硬度、拉伸强度和扯断伸长率均提高,且对ABS的剥离强度增大,综合考虑,TPU最佳用量为50份;在碳酸钙、滑石、云母和高岭土4种填料中,碳酸钙填充的SEBS包覆料对ABS的剥离强度最佳,滑石的效果最差;随着白油用量的增加,SEBS包覆料对ABS的剥离强度减小;加入SEBS-g-MAH后,SEBS包覆料的相界面不明显,趋向于形成连续相结构;随着SEBS-g-MAH用量的增加,包覆料对ABS的剥离强度先增大后减小,当SEBS-g-MAH用量为5份时,剥离强度达到最大值(2.5 k N/m)。     

SEBS/PP热塑性弹性体压缩永久变形性能研究李善良

通过双螺杆挤出机制备了SEBS/PP热塑性弹性体,研究了各种因素对热塑性弹性体压缩永久变形性能的影响。实验结果表明：PP含量越高,材料的压缩永久变形越大;提高SEBS或碳酸钙含量,能有效降低材料的压缩永久变形; 石蜡油能改善材料的性能,当油含量为20%时,材料的性能达到最佳;乙烯丙烯酸树脂能改善材料与碳酸钙界面结合力,降低材料的压缩永久变形。     

Distribution of oil in olefinic thermoplastic elastomer blends

The distribution of processing oil in two olefinic thermoplastic elastomer (OTPE) blends was determined using dielectric spectroscopy. The OPTE blends are blends of dynamically vulcanised EPDM with polypropylene (PP), TPVs, and blends of PP with SEBS. Both blend types contain paraffinic oil, which is present in both the PP and in the elastomer phase. The determination of the actual oil concentration by measuring the reduction in the glass transition temperatures (T_g) is inaccurate using DSC or DMA, because the glass transition dynamics of the two phases overlap. The blends were made sensible for dielectric spectroscopy by the addition of a probe molecule. The oil distribution was determined by modelling of the dielectric loss of the OPTE blends in the T_g regime from the ones of the binary mixtures. The mean value for the oil distribution coefficient was found to be 0.6 for PP/SEBS blends and 0.63 for TPVs.     

PA／PP／SEBS三元合金的结构与性能

本文作者采用氢化ＳＢＳ（ＳＥＢＳ）三嵌段热塑性弹性体增韧ＰＡ／ＰＰ共混体系，应用挤出反应技术在双螺杆挤出机内就地产生相容剂，可改善体系的相容性，从而获得了超高韧性的尼龙合金，还采用ＳＥＭ和ＴＥＭ技术研究了此类体系的形态结构特征，这些形态结构为进一步研究结构与性能关系提供了丰富的资料。     

纳米CaCO3在SEBS／PP中的应用研究

以苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）和聚丙烯（PP）为基体树脂,以纳米碳酸钙和普通重质碳酸钙为填充材料,在一定的工艺条件下用开炼机混炼。通过对SEBS／PP力学性能的测试及扫描电镜的比较,研究了纳米碳酸钙和普通重质碳酸钙对SEBS／PP共混料性能的影响及在基体中的分散情况。实验结果表明,纳米碳酸钙对共混物起到补强作用且其在共混物体系内呈纳米分散,随着纳米碳酸钙用量的增加,材料性能呈上升趋势,至12份时达到最大值。     

Influence of Elastomer Modification on Impact Strength of PP/Elastomer/CaCO3 Composite

Polypropylene (PP)/elastomer/fine filler particle ternary composite was prepared using polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) or carboxylated SEBS (C-SEBS) as elastomer and calcium carbonate (CaCO₃) having mean size about 160 nm as filler. First, SEBS (or C-SEBS) and CaCO₃ particles were mixed to form master batch. Second, the prepared master batch and PP matrix were kneaded. In the PP/SEBS/CaCO₃ ternary composite, CaCO₃ particles and SEBS particles were dispersed in the PP matrix separately. In the PP/C-SEBS/CaCO₃ ternary composite, CaCO₃ particles were encapsulated in C-SEBS and formed a core–shell structure at lower CaCO₃ concentration; however, some CaCO₃ particles were dispersed in PP matrix at higher CaCO₃ concentration. In the PP/SEBS/CaCO₃ composite, the impact strength increased with the amount of incorporated CaCO₃ particles. Whereas, in the PP/C-SEBS/CaCO₃ composite, the impact strength increased with the amount of CaCO₃ particles dispersed in PP matrix. The master-batch method was found to be useful for improving the dispersibility of CaCO₃ particles than the commonly used single-batch method.     

Influence of Filler Size on Impact Properties of PP/Elastomer/Filler Ternary Composites

Influence of filler size on impact properties for polypropylene (PP)/elastomer/filler ternary composites was investigated. Calcium carbonate (CaCO₃) particles with a diameter in the range from 120 to 1200 nm were used as a filler and polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) was used as an elastomer. In the PP/SEBS/CaCO₃ ternary composite, CaCO₃ particles and SEBS particles were dispersed in the PP matrix separately. In the case that SEBS elastomer volume fraction was below 0.12, the impact strength improved gradually with a decrease of CaCO₃ mean diameter from 1200 to 160 nm. In the case that SEBS volume fraction was above 0.17, the impact strength improved significantly by the incorporation of CaCO₃ particles with a mean diameter in the range from 120 to 900 nm. However, the impact strength hardly improved by the incorporation of CaCO₃ particles with a mean diameter of 1200 nm.     

Rheological behaviors of glass bead‐ and wollastonite‐filled polypropylene composites modified with thermoplastic elastomers

Steady‐ and oscillatory‐shear rheological behaviors of polypropylene/glass bead (PP/GB) and PP/wollastonite (PP/W) melts modified with thermoplastic elastomers, poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) copolymer (SEBS) and the corresponding block copolymer grafted with maleic anhydride (SEBS‐g‐MA), were examined by means of a parallel‐plate rheometer. With adding the elastomers (SEBS and SEBS‐g‐MA) and fillers (spherical GB and acicular W) to PP, viscosity especially at low shear rates and shear‐thinning flow behavior at high shear rates were pronounced as evidenced quantitatively by Carreau–Yasuda (CY) parameters, but Cox–Merz analogy became weakened. Besides, melt‐elasticity in terminal region and relaxation time (t_c) in crossing point increased, indicating an enhancement in quasi‐solid behavior of molten PP. Comparing with the elastomers, rheological behaviors of molten PP were more influenced with adding the rigid fillers, especially with W due to distinct acicular shape of W particles. SEBS‐g‐MA elastomer more affected rheological behaviors of the ternary composites than SEBS elastomer, implying that SEBS elastomer and the filler particles behaved individually (i.e., development of separate microstructure) in (PP/GB)/SEBS and (PP/W)/SEBS ternary composites, but core‐shell microstructure developed with strong interfacial adhesion by adding SEBS‐g‐MA elastomer, and the filler particles encapsulated with the thick SEBS‐g‐MA elastomer interlayer (i.e., core‐shell particles) acted like neither big elastomer particles nor like individual rigid particles in melt‐state. Moreover, effects of SEBS‐g‐MA elastomer reached a maximum on rheological behaviors of (PP/W)/SEBS‐g‐MA ternary composite, indicating a synergy between core‐shell microstructure and acicular W particles. Correlations between oscillatory‐shear flow properties and microstructures of the blends and composites were evaluated using Cole–Cole (CC), Han–Chuang (HC), and van Gurp–Palmen (vGP) plots. COMPOS., 2012. © 2012 Society of Plastics     

Highly transparent thermoplastic elastomer from isotactic polypropylene and styrene/ethylene‐butylene/styrene triblock copolymer: Structure‐property correlations

Polypropylene (PP) is one of the most useful general purpose plastics. However, the poor transparency and brittleness of PP restricts its applications in the field of medical and personal care where silicone and polyvinyl chloride (PVC) are presently used. This work concentrates on developing highly transparent elastomeric PP blends and also thermoplastic elastomer by blending isotactic polypropylene (I‐PP) with styrene/ethylene‐butylene/styrene (SEBS) triblock copolymer. PP/SEBS blend derived from high melt flow index (MFI) PP and high MFI SEBS exhibit remarkable transparency (haze value as low as 6%) along with good percentage of elongation and processability. The reduction in difference of refractive index (RI) between PP and SEBS has been observed by blending SEBS with PP. The wide angle X‐ray diffraction studies show that there is significant reduction in the percentage crystallinity of PP by the addition of SEBS block copolymer. Temperature‐dependent polarized light microscopy studies reveal the reduction in spherulites size by the addition of SEBS block copolymer. Transmission electron micrographs show that the SEBS polymer forms a fine lamellar structure throughout the PP matrix with phase inversion at higher SEBS concentration. Development of phase morphology, crystalline morphology, and crystallinity in different blends has been analyzed and microstructure‐haze correlations have been developed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

SBS and SEBS block copolymers as impact modifiers for polypropylene compounds

Blends of polypropylene (PP) and thermoplastic elastomers (TPE), namely SBS (styrene‐butadiene‐styrene) and SEBS (styrene‐ethylene/1‐butene‐styrene) block copolymers, were prepared to evaluate the effectiveness of the TPE type as an impact modifier for PP and influence of the concentration of elastomer on the polymer properties. Polypropylene homopolymer (PP‐H) and ethylene–propylene random copolymer (PP‐R) were evaluated as the PP matrix. Results showed that TPEs had a nucleating effect that caused the PP crystallization temperature to increase, with SBS being more effective than SEBS. Microstructure characterization tests showed that in most cases PP/SEBS blends showed the smallest rubber droplets regardless of the matrix used. It was seen that SEBS is a more effective toughening agent for PP than SBS. At 0°C the Izod impact strength of the PP‐H/SEBS 30% b/w blend was twofold higher than the SBS strength, with the PP‐R/SEBS 30% b/w blend showing no break. A similar behavior on tensile properties and flexural modulus were observed in both PP/TPE blends. Yield stress and tensile strength decreased and elongation at break increased by expanding the dispersed elastomeric phase in the PP matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 254–263, 2005