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。     

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。     

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。     

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。     

~1H-NMR法测定苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物的加氢度和微观结构

采用核磁共振氢谱(1H-NMR)法测定苯乙烯-乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)的加氢度和微观结构。结果表明,采用镍系催化剂对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)进行加氢反应制备SEBS时,在苯乙烯链段未参与加氢反应的前提下,通过对SBS和SEBS的谱峰进行归属,建立了用1H-NMR测定SEBS总加氢度的方法,且无需已知苯乙烯的摩尔分数,适用范围较宽;用该法还可直接得到SEBS中各微观结构含量和丁二烯1,2-结构和1,4-结构的加氢度。     

充油SEBS力学性能的研究

研究了不同牌号的橡胶填充油对苯乙烯-乙烯／丁烯-苯乙烯共聚物（SEBS）力学性能的影响及以聚丙烯（PP）为改性剂对充油SEBS进行改性的效果。结果表明：随着填充油用量的增加，拉伸强度下降，弹性回复增加，断裂伸长率也增大。PP是充油SEBS体系的一种很好的相容剂，在体系中加入PP后，随着PP用量的增大，材料的拉伸强度的增大；断裂伸长率迅速下降；回弹性和熔体质量流动速率也迅速下降。     

不同的充油工艺对充油SEBS改性PP的影响

采用不同的充油工艺制备白油/聚丙烯(PP)/苯乙烯-(乙烯/丁烯)-苯乙烯(SEBS)共混样品,利用TG、偏振显微镜、SEM和熔体流动速率仪研究体系的失重情况和体系各成分分散情况,同时利用烘箱考察充油SEBS的热稳定性。结果表明:采用喷嘴喷洒方式充入白油,适当地提高混合机的转速和充油温度,以及增加SEBS充油后的放置时间,共混体系的热稳定性有所提高,体系各成分分布更均匀,体系的熔体质量流动速率(MFR)分布更窄。     

SEBS的臭氧处理及增韧PA6的研究

研究了臭氧处理对氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)分子结构及其极性的影响,并对臭氧处理SEBS增韧PA6进行了研究。结果表明,通过臭氧处理可在SEBS分子链上引入羰基含氧基团,臭氧处理的SEBS相对分子质量下降,相对分子质量分布变宽,表面能提高,极性增大。与PA6／SEBS体系相比,PA6／臭氧处理SEBS体系的相容性得到明显改善,其冲击强度和断裂伸长率大幅度提高。     

LDPE/SEBS复合材料化学交联及相关性能的研究

采用二段混炼的方法,制备低密度聚乙烯/苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(LDPE/SEBS)复合材料。探究SEBS的不同含量对LDPE/SEBS力学性能的影响。通过双叔丁基过氧异丙基苯(BIBP)化学交联LDPE/SEBS,制备LDPE/SEBS/BIBP复合材料,探究LDPE/SEBS/BIBP的力学性能、微观形貌、凝胶含量、热学性能和流变性能。结果表明:SEBS用量为50份时,LDPE/SEBS具有较好的力学性能。当BIBP用量为0.9份,LDPE/SEBS/BIBP的力学性能最佳,拉伸强度为26.22 MPa,断裂伸长率为732.23%。随着BIBP用量的增加,LDPE/SEBS/BIBP的界面相容性、凝胶含量和黏度上升,熔融温度、结晶度和损耗模量下降,储能模量曲线的斜率先下降后趋于稳定。     

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。     

Influence of compositional variables on the morphological and dynamic mechanical behavior of fatty acid based self-crosslinking poly (urethane urea) anionomers

Fatty acid based self-crosslinking polyurethane urea (PUU) anionomers can find potential applications in coatings field due to enhanced chemical resistance properties. To optimize their performance in coatings, the molecular features that influence the microphase morphology and dynamic mechanical (DM) behavior of polymer films must be understood and exploited. In this work, comprehensive materials characterization of model PUU anionomers films with oxidative-crosslinking microstructure is addressed. For this, linoleic fatty acid based precursor (LPE) was included in polymer backbone which provides reactive sites for autooxidative polymerization. Three series of compositions were prepared with urea content of 8.4%, 13.2% and 18.1% where within each series LPE content has been increasing in same proportion. Different experimental techniques like FTIR, DSC, DMA and mechanical testing were utilized to study the effect of compositional variables on the extent of phase segregation, domain structure and mechanical properties of fully cured polymer samples. The extent soft segment (SS) oxidative crosslinking had marked effect on the microphase morphology and DM properties of materials of lowest urea content. Significant phase mixing was observed with evolvement of single heterogenous phase in the sample with highest LPE content. Samples with 13.2% urea shows less sensitivity toward increased SS crosslinking in their microphase morphology change. Their mechanical and DM properties were observed to be dominated by interlocked hard domains. With higher urea content, such kind of hard segment cohesion results due to greater strength of bidenate H-bonding among urea linkages. While samples with highest % urea, were clearly found to be well microphase separated compared to other two series with highest HS interconnectivity and have marginal effect of extent of SS crosslinking on microphase separation. This study gives an insight about effect of extent of complex oxidative crosslinking on the microphase separation and DM behavior of segmented PUU anionomers based films with different urea content which is useful in designing such materials in coating system with specific surface structure and function.     

Synthesis and properties of polyester-based TPUs prepared by solution polymerisation

Abstract

The polyester based thermoplastic polyurethane elastomers (TPUs) were prepared by one-step solution polymerisation to obtain a product with completely linear molecular structure and with excellent solubility. The synthesis technique was determined by investigation of the influence of solvent and catalyst on the viscosity of the reaction system and the mechanical properties of the resulting product. The effects of the molecular structure on the mechanical, damping and crystallisation properties of TPUs were studied in terms of the type of diisocyanate, mass fraction of hard segment, type and molecular weight of soft segment, and type of chain extender. The structure and morphology of TPUs were characterised by FTIR, GPC and AFM analysis. There was microphase separation in the molecules of TPU, in which the hard-segment phase was dispersed in the soft-segment phase.     

Preparation of Branch Polyethyleneimine (BPEI) Crosslinked Anion Exchange Membrane Based on Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)

Anion exchange membranes with chemical stability, high conductivity, and high mechanical properties play an important role in alkaline fuel cells. Here, a series of CPX anion exchange membranes based on poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) and branch polyethyleneimine (BPEI) are achieved by casting, in which BPEI acts as both a crosslinking agent and an OH⁻ conducting functional group. The introduction of BPEI facilitates the formation of good hydrophilic/hydrophobic microphase separation structure, thus improving the ion transport channel of CPX membrane. The physicochemical and electrochemical properties of the CPX membrane are significantly improved when the mass ratio of SEBS to BPEI is within an appropriate range. The OH⁻ conductivity of the CP2 membrane (the mass ratio of SEBS to BPEI is 2) can reach 66.63 mS cm⁻¹ at 80 °C, and more than 80% initial OH⁻ conductivity is maintained in 1.0 m NaOH solution for 20 d at 60 °C. The strategy of using a polymer with excellent alkali resistance and oxidation resistance as the main body and introducing a conductive group that can construct microphase separation can simultaneously improve the conductivity and membrane stability. This viable strategy is a promising construction method for anion exchange membranes that can be applied to fuel cells.     

Morphology and mechanical properties of styrene–ethylene/butylene–styrene triblock copolymer/high‐density polyethylene composites

The morphology and mechanical properties of a styrene–ethylene/butylene–styrene triblock copolymer (SEBS) incorporated with high‐density polyethylene (HDPE) particles were investigated. The impact strength and tensile strength of the SEBS matrix obviously increased after the incorporation of the HDPE particles. The microstructure of the SEBS/HDPE blends was observed with scanning electron microscopy and polar optical microscopy, which illustrated that the SEBS/HDPE blends were phase‐separation systems. Dynamic mechanical thermal analysis was also employed to characterize the interaction between SEBS and HDPE. The relationship between the morphology and mechanical properties of the SEBS/HDPE blends was discussed, and the toughening mechanism of rigid organic particles was employed to explain the improvement in the mechanical properties of the SEBS/HDPE blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚醚氨酯结构与微相分离的研究

以聚四氢呋喃二醇(PTMEG)为软段，以4，4’-二苯基甲烷二异氰酸酯(MDI)和间苯二胺为硬段，合成了一系列聚醚氨酯嵌段共聚物。利用傅立叶红外光谱(FTIR)、差热分析(DSC)和小角X光散射(SAXS)对聚醚氨酯嵌段共聚物的微相分离进行了研究，发现在聚醚氨酯嵌段共聚物中存在两相结构，其微相分离程度随硬段含量的增加而降低。     

固化剂用量对苯甲基化木材制得的聚氨酯树脂微相分离的影响

以二价酸酯与乙酸丁酯混合溶剂为液化试剂,将苯甲基化木材溶液化,得到的木材溶液与三羟甲基丙烷与甲苯二异氰酸酯的预聚物反应制备聚氨酯树脂。利用FTIR、SEM、DTA、TG及DSC等测试手段,研究了固化剂用量对聚氨酯树脂的微观结构和热性能的影响。结果表明,由于木材结构的特殊性和复杂性,使木材溶液得到的聚氨酯树脂较传统的聚氨酯热稳定性提高,表现在其软段、硬段的初始分解温度比传统的聚氨酯分别提高了 4℃和 99℃;随着w(固化剂)由 23. 8%增大到 69 .9%,树脂的玻璃化转变温度提高,微相分离程度增大,并出现相转变;且相转变完成后,即w(固化剂) =69. 9%时,涂膜各项性能指标发生明显的改善,其铅笔硬度可达 4H,附着力≥1级。     

Thermoplastic polyurethanes from renewable resources: effect of soft segment chemical structure and molecular weight on morphology and final properties

The effect of soft segment molecular weight and chemical structure on the morphology and final properties of segmented thermoplastic polyurethanes containing various hard segment contents has been investigated from the viewpoint of the degree of microphase separation. Vegetable oil‐based polyesters and corn sugar‐based chain extender have been used as renewable resources. The synthesis has been carried out in bulk without catalyst using a two‐step polymerization process. Physicochemical, thermal and mechanical properties, and also morphology, have been studied using Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, atomic force microscopy, X‐ray diffraction and mechanical testing. Chemical structure and molecular weight of polyols strongly affect the properties of the synthesized segmented thermoplastic polyurethanes. An increase in soft segment molecular weight leads to an increase of the degree of soft segment crystallinity and microphase separation, thus giving enhanced mechanical properties and higher thermal stability. Copyright © 2012 Society of Chemical Industry     

Thermoplastic polyurethane elastomers based on polycarbonate diols with different soft segment molecular weight and chemical structure: Mechanical and thermal properties

A series of thermoplastic polyurethane elastomers based on polycarbonate diol, 4,4′‐diphenylmethane diisocyanate and 1,4‐butanediol was synthesized in bulk by two‐step polymerization varying polycarbonate diol soft segment molecular weight and chemical structure, and also hard segment content, and their effects on the thermal and mechanical properties were investigated. Dynamic mechanical analysis termogravimetric analysis, differential scanning calorimetry, Fourier transform infrared‐attenuated total reflection spectroscopy and mechanical tests were employed to characterize the polyurethanes. Thermal and mechanical properties are discussed from the viewpoint of microphase domain separation of hard and soft segments. On one hand, an increase in soft segment length, and on the other hand an increase in the hard segment content, i.e., hard segment molecular weight, was accompanied by an increase in the microphase separation degree, hard domain order and crystallinity, and stiffness. In phase separated systems more developed reinforcing hard domain structure is observed. These hard segment structures, in addition to the elastic nature of soft segment, provide enough physical crosslink sites to have elastomeric behavior. POLYM. ENG. SCI., 2008. © 2007 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     

炭黑对聚氨酯泡沫塑料微相分离和力学性能的影响

利用红外光谱仪（IR）、动态热机械分析仪（DMA）和力学性能测试法研究了炭黑对聚氨酸泡沫塑料的微相分离和力学性能的影响，并与基体泡沫做了对照。结果表明：炭黑能加速聚氨酯泡沫的微相分离，明显地降低泡沫的力学性能；如果采用先用TDI浸渍炭黑，能很大程度上降低炭黑对泡沫力学性能的不良影响。