Structural Effects on the Adhesive Properties of Butadiene/Styrene Radial Teleblock Copolymers

The effects of butadiene/styrene ratio, monomer distribution, and molecular weight distribution and branching on the pressure sensitive adhesive properties of butadiene/ styrene radial teleblock copolymers are reported. Styrene content of polymers with varying structures shows a close relation with tack response, and styrene content and structure affect solution viscosity and shear adhesion. When part of the styrene is incorporated into the polybutadiene segment to yield a block progressively enriched in styrene (tapered block), solution viscosity and shear adhesion are reduced. When the butadiene segment is replaced by a block of randomly copolymerized butadiene and styrene, the polymers provide lower solution viscosities and shear adhesion but unchanged tack.

The molecular weight distribution of the radial teleblock polymers can vary from broad, highly branched compositions to narrow molecular weight distributions of almost Iinear polymers. The latter have relatively high solution viscosity and low shear adhesion, whereas the former polymers produce moderate solution viscosity but high shear adhesion. Tack is generally unaffected.     

石墨烯/丁苯橡胶复合材料性能研究

以湿法制备的石墨烯/丁苯橡胶(SBR)母粒作为添加助剂,研究不同用量石墨烯/SBR母粒对SBR性能的影响。结果表明:添加少量湿法石墨烯/SBR母粒可以改善SBR胶料的加工性能;石墨烯的用量和分散性对胶料性能有明显影响,当石墨烯用量较小(0. 125份)时,石墨烯在胶料中的分散性较好,胶料的耐磨性能好,生热和滚动阻力低;石墨烯用量越大,胶料的抗切割性能越好。     

Fracture Behaviour of Styrene/Butadiene Block Copolymers having Different Molecular Architecture

The crack toughness behaviour of styrene/butadiene block copolymers of triblock and star architectures was investigated using instrumented Charpy impact testing. In order to evaluate adequately the toughness behaviour of the investigated materials, different concepts of elastic‐plastic mechanics (J‐integral and crack‐tip opening displacement, CTOD concepts) were used. Although the lamellar block copolymers showed a remarkably enhanced ductility in the tensile test than the neat block copolymer having hexagonal PB cylinders in PS matrix, no pronounced difference in crack toughness was found. This behaviour implies that the tensile strain cannot be regarded as the only parameter defining the toughness value. A brittle/tough transition was observed in a lamellar star block copolymer on blending with a linear thermoplastic elastomeric SBS triblock copolymer.

SEM micrograph showing the details of the stable crack propagation region in a binary block copolymer blend.     

聚酰亚胺/有机蒙脱土/丁苯橡胶复合材料性能的研究

将聚酰亚胺(PI)与有机蒙脱土(OMMT)混合,制备了PI/OMMT粉状材料;将粉状材料与丁苯胶乳(SBR)混合,制备了颗粒状PI/OMMT/SBR复合材料.SEM照片显示,有机蒙脱土可改善聚酰亚胺与丁苯橡胶的相容性.X射线衍射(XRD)结果表明,聚酰亚胺分子链与丁苯橡胶分子链一起插入有机蒙脱土层间,使层间距变大;有机蒙脱土作为交联点存在.动态力学性能测试结果表明,在频率扫描下,加入PI/OMMT后丁苯橡胶的G′最高,但tanδ较低.     

Homogeneous Styrene Butadiene/Acrylonitrile Butadiene Rubber Blends

The graft copolymerization of acrylonitrile (AN) onto butadiene rubber (BR) was carried out in toluene at 80°C, using dibenzoyl-peroxide (BPO) as initiator. The synthesized poly acrylonitrile-grafted-butadiene rubber (AN-g-BR) was characterized by N% elemental analysis and Fourier-transform infrared (FT-IR) spectroscopy. Styrene butadiene rubber/acrylonitrile butadiene rubber (SBR/NBR) blends were prepared with different blend ratios in presence and absence of AN-g-BR, where the homogeneity of such blends were examined with intrinsic viscosity (η) measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The scanning electron micrographs illustrate disappearance of the macro-scale phase separation of SBR/NBR rubber blend as a result of the incorporation of AN-g-BR into that blend. Viscosity measurements confirm homogeneity of that blend. Differential Scanning Calorimetry traces exhibit shifts in glass transition temperatures (T _g's) of SBR and NBR in their blend, indicating some degree of homogeneity. Physico-mechanical properties of the rubber blend vulcanizates with different blend ratios, in presence and absence of AN-g-BR, were investigated before and after accelerated thermal aging. The SBR/NBR (25/75) homogeneous blend possessed the best physico-mechanical properties after thermal aging, together with the best swelling behavior in motor oil. The physico-mechanical properties of SBR/NBR (25/75) filled blend with different types of inorganic fillers during thermal aging were studied.     

丁苯抗冲树脂偶合规律的研究

以苯乙烯、丁二烯为单体,正丁基锂(n-BuLi)为引发剂,环己烷/正己烷为溶剂,环氧大豆油为偶联剂,通过阴离子聚合和偶合反应,研究了偶联剂的用量、偶合温度、偶合时间、偶联剂的加料次数等对偶合效率的影响,结果表明适宜的偶合温度为70℃～80℃,适宜的偶合时间为10min;并结合偶联剂的分子结构对环氧大豆油的偶合机理进行了探讨.     

丁苯热塑性弹性体对聚丙烯性能的影响

采用熔融共混法制备了聚丙烯(PP)/丁苯热塑性弹性体(SBS)复合材料,研究了SBS对PP力学性能、流动性、耐热性和熔融结晶行为的影响。结果表明:随着SBS用量的增加,PP/SBS复合材料的拉伸强度、弹性模量以及弯曲性能均呈下降趋势,而断裂应变和冲击强度则大幅提高;熔体流动速率和维卡软化温度也有一定程度下降。DSC分析结果表明:随着SBS用量的增加,PP/SBS复合材料的熔融峰温从167.03℃降至164.59℃,而结晶度从35.89%提高至42.58%。     

水性聚氨酯/羧基丁苯橡胶复合材料的制备及性能研究

以聚醚多元醇(N-210,M_n=1 000)和异佛尔酮二异氰酸酯(IPDI)为主要原料制备水性聚氨酯,用羧基丁苯橡胶乳液乳化聚氨酯得到水性聚氨酯/羧基丁苯橡胶复合材料。采用傅里叶变换红外光谱仪、差示扫描量热仪、T-型剥离强度测试、透射电镜分别对复合材料胶膜的结构、热性能、粘接性能和微观形貌进行了测试和表征,探讨了羧基丁苯橡胶的含量对复合材料热性能、粘接性能、微观形貌的影响。当聚氨酯与羧基丁苯橡胶质量比为6∶1时,羧基丁苯橡胶与聚氨酯混合均匀,T-型剥离强度达到最大值24.4 N/cm。     

羧基丁苯胶乳水泥浆的制备及性能研究

羧基丁苯胶乳是一种稳定且含有表面活性剂水溶液的聚合物粒子分散体。作为水泥的添加剂,用于改进水泥砂浆或混凝土的性能,它既要求改性后的水泥材料抗压强度、抗张强度、耐水、耐候性能好,同时又要求胶乳的粘结力强,并与水泥易掺混,在常温下可快速成膜。因此在研究过程中不仅要考虑到胶乳乳液聚合过程,还要考虑到许多影响胶乳性能和最终用途的因素,从而使改性的水泥砂浆可适用于不同的领域。本文综合运用表面活性剂技术、外加剂复配技术以及水泥石物相微观分析测试技术,研究了羧基丁苯胶乳对不同体系的水泥石力学性能的影响。实验结果表明,在羧基丁苯胶乳适当加量下的,使油井水泥浆流变性、强度、稠化时间、和降失水性能都有很大的改善,有助于水泥环在后续施工过程中维持长期有效层间封隔。     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

稀土氧化物／羧基丁苯橡胶复合材料的制备和性能研究

分别用4种稀土氧化物[氧化镧（La2O2）、氧化钐（Sm2O2）、氧化镝（Dy2O2）及氧化铕（Eu2O2）]和羧基丁苯胶乳（XSBR）机械共混,制备了稀土氧化物／XSBR复合材料。硫化曲线表明：4种稀土氧化物均可以不同程度加快XSBR的硫化速度。加入10份稀土氧化物,复合材料的硬度、拉伸强度、撕裂强度和模量均高于来填充XSBR。而拉断伸长率降低。其中La2O2／XSBR的拉伸强度最高,所得复合材料具有一定的荧光性能。     

改性凹凸棒土补强羧基丁苯橡胶性能的研究

采用双-[γ-(三乙氧基硅)丙基]-四硫化物(Si69)对凹凸棒土(AT)进行改性,并通过机械共混制备了羧基丁苯橡胶(CSBR)/AT复合材料,研究了复合材料的硫化性能、力学性能、填料与橡胶基体之间的相互作用及应力软化行为.结果表明,随AT用量增大,CSBR/AT/Si69混炼胶的焦烧时间和正硫化时间均缩短,而硫化速度提高,硫化胶的硬度和拉伸强度增大,与CSBR及CSBR/AT硫化胶相比,CSBR/AT/Si69硫化胶的应力软化行为更明显,说明加入si69提高了AT与CSBR的界面结合力.     

不同牌号丁苯橡胶的耐低温性能研究

研究3种牌号丁苯橡胶(SKMS-10,SL-4525-0,SBR1502)的硫化特性、物理性能和耐低温性能。结果表明:SKMS-10具有优异的耐低温性能,生胶的玻璃化转变温度(T_g)为-73.3℃,硫化胶的T_g为-59.8℃,适于在极寒条件下使用;SL-4525-0胶料的F_max-FL较大,硫化胶的拉伸强度为19.3 MPa,撕裂强度为53 kN·m^-1,T_g为-48.6℃,具有优异的综合性能;SBR1502硫化胶的拉伸强度高达24.9 MPa,撕裂强度为49 kN·m^-1,但T_g为-38.4℃,耐低温性能较差,适用于载荷较大且耐低温性能要求不高的橡胶减振制品。     

有机化蒙脱土对丁苯橡胶动态力学性能的影响

利用壳聚糖季铵盐的离子活性,对具有离子交换能力和吸附特性的二维层状蒙脱土进行有机化改性,采用转矩流变仪混合器和双辊开炼机的两段共混技术,制备了丁苯橡胶/蒙脱土纳米复合材料,通过红外光谱和橡胶加工分析仪,对蒙脱土的结构和纳米复合材料的动态力学性能进行了分析.在改性蒙脱土的红外谱图上,3617cm-1、2900 cm-1～...     

类苯乙烯对PVC性能的影响研究

采用双辊混炼机将类苯乙烯与聚氯乙烯(PVC)熔融共混,制备类苯乙烯/PVC共混物,考察了不同含量类苯乙烯对PVC的透明性、低温性能、微观形态结构、力学性能、塑化温度及动态黏弹性等的影响。研究表明,类苯乙烯/PVC共混物具有良好的透明性,类苯乙烯可使PVC的低温冲击强度提高1.6倍,脆性温度降低12℃,使PVC的塑化温度、储能模量和损耗模量降低。     

茂金属乙烯/苯乙烯共聚物的开发

综述了近１０年来国内外在茂金属催化剂合成乙烯／本乙烯共聚物方面的研究状况,着重介绍了用限定几何形催化剂开发的ＥＳ共聚物的结构及物理机械性能。     

Mechanical and Processing Properties of Polystyrene-(Styrene Butadiene) Blends

Abstract

Blends of Polystyrene-(Styrene Butadiene) rubber copolymers were prepared in a twin screw extruder and then injected. The samples were characterized by various techniques and their properties compared to those of a sample with 0% rubber content. The results show that the morphology of the segregated phases in the blends as well as the chemical architecture of the rubber phase have a definite influence on the mechanical and rheological properties of these materials.     

新型苯乙烯/丁二烯共聚物的交联研究

研究了新型苯乙烯/丁二烯共聚物的交联控制方法,考察了交联剂的种类、用量、温度、时间对材料性能的影响。结果表明:采用过氧化二异丙苯(DCP)作交联剂,其质量分数在0.4%～0.5%之间,硫化温度165℃、硫化时间150s的条件下,材料的综合性能优异。     

极性和非极性单体对丙烯酸酯共聚物粘结性能的影响

本文研究了几种极性和非极性单体丙烯酸羟乙酯（ＨＥＡ，含－ＯＨ）、丙烯腈（ＡＮ，含－ＣＮ）、丙烯酰胺（ＡＭ，含－ＣＯＮＨ２），苯乙烯（Ｓｔ，含－Ａｒ）、丙烯酸（ＡＡ，含－ＣＯＯＨ）等对丙烯酸酯共聚物粘结性能的影响。文中分别考察了含有一种和两种上述单体参与共聚的丙烯酸酯共聚物的粘结性能变化。结果表明，含有ＡＮ，ＡＡ，ＡＭ单体的共聚物，其内聚强度和剥离强度均较大     

Effect of Silane Coupling Agent on the Mechanical Properties of Clay Filled Styrene Butadiene Rubber

Abstract

The effect of treatment of coupling agent [Bis (3-triethoxy-silyl-propyl) tetrasulphide] on mechanical properties of composites made from styrene butadiene rubber and clay is reported in this paper. The coupling agent in the form of solution (1.0%) was used for treatment of the filler. The treatment resulted in enhancement of mechanical properties of composites when compared with composites containing untreated clay. The properties under consideration were tensile strength, modulus at 100% and 400%, Young's modulus, hardness, etc. Good reinforcement was observed due to treatment of 1% coupling agent. Tensile strength was improved by 11%, modulus at 400% was found to improve by 237%, elongation at break was improved by 250%, while Young's modulus also was improved by 298% for treated clay composites, respectively, at 0.41 volume fraction when compared with untreated clay composites.