橡胶分散在环氧树脂中的新技术

日本粘合剂研究所研究了一种将橡胶分散在环氧树脂中的新技术。这种新技术是把用马来酸酐改性的,氢化的苯乙烯-丁二烯-苯乙烯嵌段共聚物橡胶,苯乙烯-乙烯-丁二烯-苯乙烯(SEBS)分散在环氧树脂中。这种改性树脂的抗撕裂、抗冲击强度是     

马来酸酐接枝SEBS对尼龙6/SEBS共混物聚集态结构的影响

研究了马来酸酐(MAH)接枝的部分氢化苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SEBS)(SEBS-g—MAH)对尼龙6／SEBS的共混物聚集态结构的影响。研究结果表明,SEBS—g—MAH上的MAH侧基和尼龙6的端氨基发生了缩合反应,增加了尼龙6和SEBS的界面相互作用．透射电镜(TEM)的结果表明,当SEBS在尼龙6／SEBS共混物中为分散相时,SEBS-g—MAH使得分散相颗粒尺寸明显减小,两相界面变得模糊．示差扫描量热仪(DSC)的研究结果表明,SEBS-g—MAH的引入对尼龙6／SEBS共混物的熔融峰、结晶峰和结晶度都有明显的影响．因此SEBS-g—MAH与SEBS相比能更有效地与尼龙6相容,在很大程度上改变了尼龙6／SEBS共混体系的聚集态结构。     

PPO/SEBS/SEBS-g-MAH共混物的阻燃性能研究

以苯乙烯-乙烯/丁二烯-苯乙烯嵌段共聚物(SEBS)为弹性体改性剂，SEBS-g-MAH为相容剂，红磷和Mg(OH)₂作为阻燃剂，采用双螺杆挤出技术，制备了阻燃聚苯醚(PPO)/SEBS/SEBS-g-MAH共混物。结果表明：当红磷用量为15份时，Mg(OH)₂仅用80份，PPO/弹性体共混物的极限氧指数(LOI)就能达到28%,燃烧等级达UL94 V-0级，同时燃烧时的热释放速率(HRR)及生烟速率(SPR)均大幅降低。     

热塑性弹性体在医药包装应用的探讨

热塑性弹性体被称作"第三代合成橡胶",广义地讲是指在常温下具有橡胶的弹性,高温下可塑化成型的一类弹性材料,简称TPE(Thermoplastic Elastomer).狭义地讲,TPE是苯乙烯系热塑性弹性体,是一种以SEBS(Styrene-Ethylene-Butylene-Styrene Block Copolymer——氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物)为基材通过共混改性而成的热塑性弹性体.     

国产医用SEBS热氧老化行为及机理

医用苯乙烯-氢化丁二烯-苯乙烯三嵌段共聚物(SEBS)是针对一次性医疗器械或包装材料的专用基础原料。开展国产医用SEBS热氧老化的研究,对促进我国SEBS材料的发展及医用输液与包装材料的更新换代,具有重要的研究价值和现实意义。文中将国产医用级SEBS进行了加速热氧老化实验,通过凝胶渗透色谱、衰减全反射红外光谱(ATR-FTIR)、原子力显微镜(AFM)等手段对热氧老化过程中国产医用SEBS的性能、微相分离结构、机理等进行了研究,并分析了热氧老化对SEBS性能及结构产生影响的原因。研究发现,老化30 d后,SEBS的拉伸强度由未老化前的10.06 MPa下降到4.09 MPa;黄色指数由13.7升高到59.4;数均相对分子质量由未老化前的113100降低至46000,而相对分子质量分布由1.07升高至3.88;ATR-FT-IR研究发现SEBS老化过程中生成了醇、脂肪族酮和脂肪族酯等化合物;AFM的结果表明老化后SEBS的微相分离结构发生了明显的变化。     

不同弹性体对聚丙烯的协同增韧

以弹性体乙烯-α-辛烯共聚物(POE)、苯乙烯-乙烯/丁烯-苯乙烯共聚物(SEBS)和SEBS/POE作为增韧剂,对不同弹性体协同增韧聚丙烯进行了研究,考察了共混体系的力学性能、结晶行为、结晶形貌、动态力学分析以及低温脆断面形貌。结果表明,弹性体SEBS、POE均对PP具有增韧作用,当SEBS、POE用量分别为20%、25%时完成了"脆韧转变",其中SEBS增韧效果较佳;SEBS、POE作为弹性体加入,使PP的结晶度降低;当SEBS/POE复配增韧PP,且m(PP)/m(SEBS)/m(POE)=70/20/10时,具有协同增韧效应,冲击强度最高;此外,POE在PP/SEBS复配增韧中相当于相容剂,起到了"桥梁"作用。     

LDPE/SEBS共混型形状记忆聚合物的结构与性能

以苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)热塑性弹性体和低密度聚乙烯(LDPE)为主要原料,采用硫化工艺制备了LDPE/SEBS共混型形状记忆聚合物(SMP)。通过DSC、SEM、WXRD分析,测试了试样记忆性能和凝胶度,研究了固定相LDPE/可逆相SEBS配比与共混型SMP结构和性能的关系。结果表明,LDPE/SEBS配比是影响SMP互穿网络相尺寸和形状、SMP结晶度、玻璃化温度、以及SMP形状回复率、形状固定率等记忆特性的重要因素。     

高韧性聚乙烯合金的制备与性能

采用氢化苯乙烯-丁二烯-苯乙烯共聚物(SEBS)、二元乙丙橡胶(EPR)、三元乙丙橡胶(EPDM)及乙烯-辛烯共聚物(POE),分别与高密度聚乙烯(HDPE)以不同比例在双螺杆挤出机中熔融共混,制备高韧性聚乙烯合金。冲击测试表明,在四种共混物中,HDPE/POE具有较佳的力学性能;Vu-Khanh方程表明,Gi与冲击性能有很好的对应关系;扫描电镜表明,弹性体在HDPE中有很好的分散,橡胶粒径较小,分散均匀;形变区观察显示,纯HDPE为脆性断裂,而HDPE/弹性体断裂表面发生塑性形变,发生剪切屈服,呈明显的韧性断裂。     

热塑性弹性体SBS的开发及应用

一、世界的供需情况苯乙烯-丁二烯-苯乙烯(SBS)的嵌段共聚物,又称热塑丁苯橡胶或丁苯嵌段共聚物,是一种新型的热塑性弹性体。它是采用阴离子催化剂先将苯乙烯(S)聚合,再加入丁二烯(B)聚合,最后加苯乙烯(S)聚合而成的。这     

SEBS改性再生鞋用橡胶微发泡材料

采用充油的SEBS、乙烯-醋酸乙烯共聚物(EVA)、偶氮二甲酰胺(AC)、过氧化二异丙苯(DCP)、纳米白炭黑对再生橡胶(RR)进行改性,使之能够适用于鞋用改性微发泡材料。实验结果表明,充油的氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)能显著改善再生橡胶的加工流动性;EVA可使发泡材料的力学性能得到改善,而硅烷偶联剂处理的白炭黑的加入,使材料的撕裂强度及硬度上升,但白炭黑用量超过10%后,会导致材料的发泡倍率过小。改变发泡剂内AC和交联剂DCP的用量,可对再生橡胶微发泡材料的密度进行调整。最终,得到了密度为0.8g/cm3～1.0g/cm3的微发泡材料,此材料可用于皮鞋、运动鞋等鞋类产品的大底,具有普通橡胶硫化底的优异性能。     

界面相互作用对尼龙6/SEBS共混体系流变行为的影响

利用高压毛细管流变仪研究了SEBS-g-MAH对PA6／SEBS共混体系的流变行为影响，结果表明，PA6／SEBS共混体系的粘度随SEBS增加先降低后升高；PA6／SEBS—g—MAH共温体系的粘度随SEBS-g—MAH含量增多有较大幅度的增加；将SEBS和SEBS—g—MAH混合使用时，共温材料的流变行为表现为二者的协同作用结果，其中SEBS—g—MAH对共混材料流变性能的影响更大．红外分析的结果表明，共混后SEBS—g—MAH与尼龙6发生了反应，生成群离羧酸，并且随SEBS—g—MAH含量的增加，游离羧酸的量也逐渐增加，即共混后增加了体系中分子键长度，流动时分子键间更易发生缠结，使粘度增加，这与高压毛细管流变实验的结果是对应的。     

PA6/SEBS/PP-g-MAH的共混改性

用双螺杆挤出机对PA6用SEBS和SEBS／PP-g-MAH进行共混改性,PA6／SEBS／PP-g-MAH比PA6／SEBS的力学性能如拉伸强度、弯曲强度和冲击强度都有不同程度的提高;PA6／SEBS／PP-g-MAH比PA6／SEBS、PA6的吸水率有较大幅度降低;用扫描电镜(SEM)研究了PA6／SEBS／PP-g-MAH争PA6／SEBS样品的冲击断面,PA6／SEBS／PP-g-MAH中SEBS分散相粒子半径远比PA6／SEBS中SEBS分散相粒子半径小争均匀,这表明PA6／SEBS／PP-g-MAH改性后的PA6与SEBS的相容性有很大的改善。     

Effect of eggshell and silk fibroin on styrene–ethylene/butylene–styrene as bio-filler

SEBS (poly(styrene-b-ethylene/butylene-b-styrene)) biodegradable composites reinforced with various eggshell contents and silk fibroin are prepared by melt processing technique followed by different characterization techniques. Compare with SEBS/eggshell composites, the SEBS/eggshell/silk composites exhibit the reduction in particle size and increase interface interaction within the matrix. Thermal stability also increases in quantity.     

Physical and mechanical properties of SEBS/polypropylene nanocomposites reinforced by nano CaCO3

In present study, styrene‐b‐(ethylene‐co‐butylenes)‐b‐styrene triblock copolymer (SEBS) and polypropylene (PP) are prepared. This mixing is followed by adding 3, 5 and 10 wt% of nano CaCO₃. The morphology and thermal behavior of PP/SEBS/nano‐CaCO₃ compounds are characterized by different methods. Scanning electron microscopy micrographs of cryo‐fractured PP/SEBS/nano‐CaCO₃ nanocomposites show that with increasing nano‐CaCO₃ loading, the aggregation becomes worse. However, followed by adding 5 wt% nano‐CaCO₃ into PP/SEBS nanocomposites, nano‐CaCO₃ is homogeneously dispersed in PP matrix. The photomicrograph of transmission electron microscopy confirms that SEBS/PP/nano‐CaCO₃ nanocomposites are formed, as low aggregations of calcium carbonate were well‐dispersed in polymer matrix. With a rise in nano‐filler content, the tensile and impact strength of PP/SEBS/CaCO₃ nanocomposite are fixed while the elastic modulus of PP/SEBS nanocomposites increases followed by adding nano‐CaCO₃ to polymer blend, which could be due to the acceptable nano‐CaCO₃ dispersion quality.     

AAS/PA-6合金的相容性

用反应挤出法制备了一系列的尼龙６／苯乙烯丙烯酸丁酯丙烯腈共聚物（ＰＡ６／ＡＡＳ）合金的相容剂,采用透射电子显微镜（ＴＥＭ）观察了所得合金的微观形态,结合合金的力学性能,对所选用及所制备相容剂进行了筛选。结果表明,以ＳＥＢＳ与ＭＡＨ的接枝物作为相容剂（ＳＥＢＳ是苯乙烯,丁二烯的三嵌段共聚物）,或以ＳＥＢＳ的ＭＡＨ接枝物与ＳＭＡ（苯乙烯马来酸酐聚合物）作为复合相容剂,既可得到以粘度较高的ＡＡＳ为连续相且冲击强度很高的ＡＡＳ／ＰＡ６合金,也可以得到以ＰＡ６为连续相高冲击强度的ＰＡ６／ＡＡＳ合金。     

Structure, thermal properties and mechanical properties of sPS-based nanocomposites with and without styrenic elastomer inclusions

Syndiotactic polystyrene (sPS)-based nanocomposites with and without toughener inclusions were successfully prepared. One organo-montmorillonite (20A) and two styrenic elastomers (SBS and SEBS) served as the reinforcing filler and as tougheners, respectively. XRD and TEM results confirmed the achievement of intercalated and partially exfoliated sPS/20A nanocomposites. The presence of SBS or SEBS slightly depressed the dispersibility of 20A. DSC results indicated that 20A inhibited the crystallization of sPS. The presence of SBS or SEBS further retarded the crystallization of sPS; this effect was more apparent with SEBS. The presences of 20A and SBS/SEBS facilitated the formation of α-form sPS crystals. The thermal stability enhancement of sPS/20A nanocomposites was confirmed, and was further improved with the inclusion of SBS or SEBS. The stiffness of sPS increased with the sole addition of 20A. The addition of SBS or SEBS greatly increased the impact strength of the composites, especially with the addition of SEBS. The achievement of toughened sPS-based nanocomposites was confirmed.     

SEBS增容等规聚丙烯/间规聚苯乙烯共混体系的结构与性能

用3种组成相近而分子量不同的苯乙烯-乙烯/丁烯-苯乙烯共聚物(SEBS)作为增容剂,对等规聚丙烯/间规聚苯乙烯(iPP/sPS)共混物进行增容。研究了共聚物的分子量对iPP/sPS共混物的形态结构及力学性能的影响。结果表明,中、低分子量的SEBS具有较好的增容作用,能有效提高共混物的拉伸强度;而高分子量的SEBS则能显著改善共混物的韧性。用SEM观察了增容剂在共混物中的分布情况,揭示了共混物的力学性能不仅取决于增容剂的界面活性,而且还与增容剂在共混物中的分布密切相关。     

PA6/SEBS(SEBS-g-MAH)/CaCl2共混体系的性能

对PA6／SEBS(SEBS—g—MAH)／CaCl2共混体系进行了一系列结构和性能的研究。SEM研究结果表明,加入SEBS后材料的断裂方式由脆性断裂变为韧性断裂,随CaCl2含量的提高断裂方式由韧性断裂向脆性断裂转变．DMTA测试结果为CaCl2和SEBS在共混体系中对尼龙6的玻璃化转变都产生作用．力学测试发现,当CaCl2含量为3％时,SEBS／SEBS-g-MAH的含量为5％～10％,共混物的断裂伸长率能达到300％以上,大大高于纯尼龙6以及相同SEBS配比的PA6／SEBS共混物的断裂伸长率．增强和增韧,二者在某种程度上是竞争反应,因此可以通过调整二者的含量和加入的顺序实现尼龙6力学性能(增强或增韧)的可控．     

Improvement in the mechanical strength of asymmetric polyolefin model interfaces

The influence of two types of a styrene–ethylene/butylene–styrene (SEBS) triblock copolymer, one as received and the other functionalized with maleic anhydride, on model interfaces of high-density polyethylene (HDPE) and isotactic polypropylene (iPP) was investigated. Using a special preparation technique, it was possible to prevent gross interdiffusion at the interface and to attribute the problem to an adhesion-dominated phenomenon. The weak mechanical strength of the unmodified interfaces, iPP/iPP and HDPE/HDPE, was greatly improved by the triblock copolymer as was shown by the results of a T-peel test. The morphologies of the peeled surfaces of the modified and unmodified interfaces were analysed with light microscopy. The morphology of both model interface systems show differences, thus revealing different processes at the interfaces and thus different interactions of SEBS with iPP and HDPE and a different influence of the functionalization. The best results were achieved using the functionalized SEBS; the influence of functionalization was greater in the HDPE system. The results are in good agreement with a model proposed by the present authors elsewhere for the concentration-dependent role of SEBS in binary iPP/SEBS and ternary iPP/PE/SEBS blends.