充油SEBS改性PP性能研究

用DSC与TG研究了不同的充油比及不同苯乙烯-乙烯/丁烯-苯乙烯(SEBS)摩尔质量时充油SEBS/聚丙烯(PP)共混体系的结晶性能与热稳定性;同时考察共混体系的力学性能和流变性能。结果表明:随着充油比(即油弹比,m油/mSEBS)的增大,熔体质量流动速率(MFR)显著增加,拉伸屈服强度、熔点、结晶度和硬度显著下降。SEBS的摩尔质量影响其对油的吸附能力,摩尔质量越大,吸油能力越好。随着SEBS摩尔质量的增大,材料的熔点、结晶度、拉伸屈服强度增大,硬度变化不明显。     

SEBS分子量和分子结构对其共混物性能的影响

研究了苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物(SEBS)分子量和分子结构对其共混物的力学性能、永久压缩变形和流变性能的影响。结果表明:高分子量的线型SEBS拥有更优的力学性能,更低的高温永久压缩变形;当SEBS的分子量大于临界分子量(7×104~10×104 g/mol之间)时,其室温永久压缩变形不受分子量和分子结构的影响;星型SEBS较线型含有更多的二嵌段苯乙烯-乙烯/丁烯(SEB),其分子量越高,二嵌段SEB含量越高;SEBS的分子量越大,苯乙烯含量越高,共混物的熔体黏度就越大,表观剪切黏度对剪切速率的敏感性越强。     

PC／SAN／SEBS合金的形态结构和动态流变性能

将苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物（SEBS）引入到聚碳酸酯（PC）犀乙烯-丙烯腈共聚物（SAN）合金中，制备了性能优良的PC／SAN／SEBS合金。研究了SEBS含量对合金力学性能的影响，以及合金的动态流变性能。结果表明，SEBS的加入大大提高了PC／SAN合金的冲击强度和断裂伸长率，使合金的冲击强度从不含SEBS的130J／m增加至SEBS含量为7％（质量分数，下同）的971J／m，同时断裂伸长率从23．8％增加至119％；但合金的拉伸强度和弯曲强度以及维卡软化温度却有所降低。同时，SEBS的加入使PC／SAN合金的线性黏弹性范围变窄，并且使合金表现出明显的剪切变稀行为。扫描电镜分析结果表明，SEBS与PC具有更好的相容性，SEBS在PC／SAN／SEI峪合金中大部分分布在PC相中。     

国产SEBS流变性能评价

通过对国产SEBS(氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物)流变性能进行测试．分析不同结构、不同嵌段的S／B质量比值、不同相对分子质量、不同加工温度对SEBS产品流变性能的影响．促进用户对国产SEBS性能的了解。     

GMA接枝SEBS及其对PA 6的改性及增容

用双螺杆反应挤出法将甲基丙烯酸缩水甘油酯(GMA)接枝到氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)上(即SEBS-g-GMA)，研究引发剂过氧化二异丙苯用量、活性单体GMA用量对接枝率的影响；通过双螺杆挤出、共混，制备聚酰胺(PA)6／SEBS-g-GMA、PA 6／SEBS-g-GMA／SEBS合金，研究SEBS-g-GMA对合金体系的相容性影响及增韧作用，探讨了合金体系的形态结构和力学性能。     

SEBS对PP耐辐射性能的影响

以共聚医用聚丙烯(PP)为基材,用氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)对其进行增韧改性,研究了在γ射线辐射下,SEBS对PP耐辐射性能的影响。材料的耐辐射性能通过辐射前后力学性能的变化来评价。研究结果表明:PP基材经过40 kGy辐射后,其断裂伸长率和冲击强度明显降低,分别从651．2％和4．35 kJ／m2下降到 189．8％和3．01 kJ／m2;SEBS的加入可以显著提高PP的耐辐射性能;不同配比的PP／SEBS体系,其耐辐射性能和后期效应不同,PP／SEBS质量配比为90:10时,共混物的耐辐射性能最佳,材料的综合性能可以满足实际应用需求。     

SEBS力学性能的影响因素

分析了嵌段比m(苯乙烯)/m(丁二烯)、相对分子质量、PB段1,2-结构含量、抗氧剂、加氢度等方面对氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)力学性能的影响.结果表明,嵌段比m(苯乙烯)/m(丁二烯)决定着SEBS的力学性能;PB段1,2-结构含量在35％～45％(质量分数),氢化后SEBS的综合力学性能较好;相...     

SEBS增韧PVDF的研究

采用不同结构热塑性弹性体苯乙烯-乙烯-丁烯-苯乙烯(SEBS)作为增韧剂添加到聚偏氟乙烯(PVDF)中以提高韧性;并探索两种相容剂聚丙烯接枝马来酸酐(PP-g-MAH)和苯乙烯-(乙烯-丁烯)-苯乙烯嵌段共聚物接枝马来酸酐(SEBS-g-MAH)对PVDF/SEBS共混体系物理机械性能的影响。结果表明,线型结构的SEBS有利于提高PVDF的拉伸韧性,相容剂SEBS-g-MAH有助于进一步提高拉伸韧性,其用量在1%时共混体系的断裂伸长率达到最大值。     

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。     

充油SEBS的结构、力学性能和紫外辐照稳定性

自制了一种中间基的苯乙烯-乙烯/丁烯-苯乙烯三嵌段共聚物(SEBS)弹性体用填充油,并从分子结构及微相结构上分析了线型和星型SEBS充油体系的力学性能、紫外辐照稳定性与其结构的关系。通过小角X射线散射(SAXS)、透射电子显微镜(TEM)表征了SEBS充油体系的微观结构,揭示了SEBS分子结构是影响充油体系微观结构的主要因素,且软硬段电子密度差以及PS相间距越大,SEBS的微相分离程度越高。结合Instron万能材料试验机的测试结果,发现SEBS微相分离程度高有利于充油体系力学性能的提高。通过傅里叶红外光谱(FTIR)研究了经紫外辐照后SEBS体系的化学结构变化,结果显示,经紫外辐照后的体系均在1700~1740 cm-1、1800 cm-1附近出现吸收峰,且吸收峰强度越大,力学性能下降得越快,表明氧化降解是造成SEBS体系力学性能下降的主要因素。     

Effect of polypropylene on the rheology of co‐continuous PS/SEBS blends

Polypropylene (PP) was added to a co‐continuous blend of polystyrene (PS) and styrene‐ethylene/butylene‐styrene (SEBS) to investigate the effect of PP on the morphology and rheological behavior of PS/SEBS blends. For this purpose, a reference blend of 50 wt% PS and 50 wt% SEBS was chosen and an isotactic PP was added to it by increments of 10 wt% up to a maximum of 50 wt% of the total weight. Environmental SEM (ESEM) studies on the PS/SEBS/PP blends showed that PP could be added up to 10 wt% without changing the morphology of the co‐continuous PS/SEBS blend, whereas at 20 wt% PP formed a separate discrete phase. The discrete PP phase finally formed a fully developed matrix structure from 40 wt% onwards. Dynamic rheological measurements showed that at low frequencies the storage modulus was largely unaffected by addition of PP in small concentrations (up to 10 wt%), showing a significant effect of the PP/SEBS interface at low deformation rates. Melt strength tests on the PS/SEBS/PP blends showed the existence of a proportional correlation with their corresponding storage moduli, measured at frequencies from 10–100 rad/s. POLYM. ENG. SCI., 45:1432–1444, 2005. © 2005 Society of Plastics Engineers     

Effect of Organo-Modified Montmorillonite on the Morphology and Properties of SEBS/TPU Nanocomposites

In this study, novel polystyrene-b-poly(ethylene-butylene)-b-polystyrene (SEBS)/thermoplastic polyurethane (TPU)/organo-modified montmorillonites (OMMT) nanocomposites were prepared by melt mixing. Three different organo-modified montmorillonites, DK2, DK3, and DK4 (listed in descending order of hydrophilicity) were selected. The compatibilizing and reinforcing effects of OMMT on the structure, morphology, thermal stability, mechanical and rheological properties of the SEBS/TPU blends were studied. It was found that the hydrophilic DK2 nanoparticles were largely located in the continuous TPU phase and partially dispersed at the phase interphase, whereas DK3 and DK4 nanoparticles were preferentially located at the phase interface with an intercalated/exfoliated and intercalated structure, respectively. Scanning electron microscopy (SEM) results showed that SEBS/TPU/OMMT nanocomposites exhibited a more densely organized and interconnected structure compared with SEBS/TPU blends. Better thermal property was achieved after adding DK3, with the tensile properties of the SEBS/TPU increased considerably. Rheological analysis revealed that hydrophilic DK2 nanoparticles were more effective in improving rheology properties and showed a more pronounced nonlinear effect. The prepared SEBS/TPU/OMMT nanocomposites displayed desired thermal, mechanical and rheological properties, which are important for many applications. POLYM. ENG. SCI., 60:850–859, 2020. © 2020 Society of Plastics Engineers     

A study on functionalizing SEBS through ozone treatment and the mechanical properties of its blend with polyamide 6

Two types of styrene‐b‐(ethylene‐co‐1‐butene)‐b‐styrene triblock copolymer (SEBS) were functionalized through ozone treatment. The structure and properties of ozonized SEBS and the mechanical properties of their blend with Polyamide 6 (PA6) were studied by FTIR spectroscopy, gel permeation chromatography, gel content measurement, contact angle measurement, SEM, and mechanical properties measurement. The experimental results show that through ozone treatment, some oxygen‐containing groups (mainly carbonyl groups) are introduced onto the molecular chains of SEBS. The polarity of SEBS is thus improved. Compared with star‐shaped SEBS602, SEBS503 of linear shape is more susceptible to ozone oxidation. The polarity of ozonized SEBS503 is higher than that of ozonized SEBS602. The improvement of mechanical properties of PA6/ozonized SEBS blend is attributed to the improvement of the dispersion of ozonized SEBS in PA6 matrix and the interfacial adhesion between PA6 and ozonized SEBS. Compared with that of PA6/ozonized SEBS602 blend, the size of dispersed phase in PA6/ozonized SEBS503 blend is smaller, and the interfacial adhesion is stronger. The notched Izod impact strength of PA6/ozonized SEBS503 (90 min) (90/10) blend is 49.6 kJ/m², is higher than that of PA6/ozonized SEBS602 (90 min) (90/10) blend, which is only 21.3 kJ/m². The impact strength of PA6/ozonized SEBS503 (90 min) (80/20) blend is 68.7 kJ/m², is still higher than that of PA6/ozonized SEBS602 (90 min) (80/20) blend, which is 60.2 kJ/m². © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Melt rheology and properties of compatibilized recycled poly(ethylene terephthalate)/(styrene‐ethylene‐ethylene‐propylene‐styrene) block copolymer blends

Blends of recycled poly(ethylene terephthalate) (R‐PET) and (styrene‐ethylene‐ethylene‐propylene‐styrene) block copolymer (SEEPS) compatibilized with (maleic anhydride)‐grafted‐styrene‐ethylene‐butylene‐styrene (SEBS‐g‐MAH) were prepared by melt blending. The compatibilizing effects of SEBS‐g‐MAH were investigated systematically by study of the morphology, linear viscoelastic behavior, and thermal and mechanical properties of the blends. The results show that there is good agreement between the results obtained by rheological measurement and morphological analysis. The rheological test shows that the melt elasticity and melt strength of the blends increase with the addition of SEBS‐g‐MAH. The Cole‐Cole plots and van Gurp‐Palmen plots confirm the compatibilizing effect of SEBS‐g‐MAH. However, the Palierne model fails to predict the linear viscoelastic properties of the blends. The morphology observation shows that all blends exhibit a droplet‐matrix morphology. In addition, the SEEPS particle size in the (R‐PET)/SEEPS blends is significantly decreased and dispersed uniformly by the addition of SEBS‐g‐MAH. Differential scanning calorimeter analysis shows that the crystallization behavior of R‐PET is restricted by the incorporation of SEEPS, whereas the addition of SEBS‐g‐MAH improves the crystallization behavior of R‐PET compared with that of uncompatibilized (R‐PET)/SEEPS blends. The Charpy impact strength of the blends shows the highest value at SEBS‐g‐MAH content of 10%, which is about 210% higher than that of pure R‐PET. J. VINYL ADDIT. TECHNOL., 22:342–349, 2016. © 2014 Society of Plastics Engineers     

The effect of SEBS on interfacial tension and rheological properties of LDPE/PS blend

The effects of SEBS as a compatibilizer on the interfacial tension and rheological properties of LDPE/PS blend have been studied. Interfacial tension was measured by the breaking thread method. The measured interfacial tension of the LDPE/PS blend was 8.26 dyn/cm. It decreased rapidly with SEBS contents to 1 wt % and then leveled off to a saturation value, 3.6 dyn/cm. Dynamic oscillatory shear, elongational viscosity, and recovery after elongation were measured as the rheological properties. Storage modulus at low frequencies decreased with SEBS contents to 1 wt %. More addition of SEBS, however, increased the storage modulus at low frequencies. Similar behaviors could be observed in elongation viscosity and recovery after elongation. Hardening of elongational viscosity and recovery after elongation were reduced with 1 wt % SEBS, and they enhanced again with more SEBS contents. This means that there is a critical concentration of SEBS that acts as a compatibilizer and reduces the interfacial tension. More SEBS than the critical concentration saturates the interface and increases the elasticity of the LDPE/PS blend, while maintaining the interfacial tension between LDPE and PS constant. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 905–911, 2005     

The Effect of Vulcanized Thermoplastics and SEBS on the Impact Strength of PPT

Poly(trimethylene terephthalate) (PTT) is a semi crystalline engineering polymer. It has high physical and mechanical properties like tensile, flexural, stiffness, processabilty and chemical resistance. However, low impact strength limits its versatility. Impact modification of PTT using SEBS and PP-g-EPDM was successfully carried out. The blends of poly(trimethylene terephthalate) (PTT)/styrene-ethylene/butylene-styrene (SEBS) and poly(trimethylene terephthalate) (PTT)/ethylene propylene diene monomer (EPDM) with different composition have been studied. The investigation in the effect of SEBS and PP-g-EPDM on mechanical, thermal, rheological and morphological properties with PTT was done. The tensile strength and flexural strength showed some decrease with increase in concentration of SEBS and PP-g-EPDM in PTT. The impact strength of PTT, however, was found to increase significantly with increasing SEBS and PP-g-EPDM content. The examination of etched surfaces of PTT/SEBS and PTT/PP-g-EPDM using scanning electron microscopy indicated significant improvements in interfacial adhesion. It was found that the addition of SEBS and PP-g-EPDM at higher content reduces the droplet size of the dispersed phase. This is an indication of interfacial saturation of PTT/SEBS and PTT/PP-g-EPDM. Rheological characterization has showed a shear viscosity increased due to the addition of SEBS and PP-g-EPDM in PTT. It means these rheological properties also support for the improvement of impact strength. Thermal properties using differential scanning calorimetric (DSC) results did not show any significant changes.     

The effect of process parameters on the properties of elastic melt blown nonwovens: Air pressure and DCD

An elastic masterbatch and elastic melt blown nonwovens are prepared based successively on styrene-ethylene/butylene-styrene (SEBS) and polypropylene (PP) blend. The phase separation morphology, rheological properties and crystal structure of the elastic masterbatch are investigated. The results show that a compatible and stable structure is obtained in molten SEBS and PP blend with excellent mobility in the temperature range of 210–230°C. The crystallization of PP slows down resulting in a finer structure due to the restriction of the SEBS network structure with rarely change of crystalline structure. The relationship between process parameters and properties of the elastic nonwoven is also studied in detail. Air pressure and die to collector distance (DCD) have discernible effects on fiber diameter and bonding between fibers, further influencing the performances of nonwovens including porosity, tensile strength and elastic recovery. Elastic recovery is shown to be significantly more affected by DCD than by air pressure.