Adhesion of flame-treated polyolefins to styrene butadiene rubber

Samples of polyethylene and polypropylene have been submitted to repeated short duration (75 ms) flame treatments, at optimum flaming conditions. Surface energies of untreated and flamed specimens were determined by liquid contact angle measurements. It appears that the surface energy of polyethylene increases much more than that of polypropylene after flame treatment. The flamed polymer surfaces were further examined by electron spectroscopy, Fourier Transform IR spectroscopy and secondary ions mass spectrometry. The adhesion properties of modified polymer surfaces were studied by testing in peel the bonded Styrene Butadiene Rubber/polyolefins assemblies. Scanning electron microscopy (SEM) and water contact angle measurements have been used to observe the locus of failure. Good correlations were obtained between surface energy and adhesion strength, the increase in adhesion strength being particularly important for flamed PE/SBR assemblies. In addition, the peeling in a liquid medium allowed the determination of the respective contribution to adhesion of chemical and physical interactions. It is shown that a major part of the adhesion strength increase is of chemical origin, particularly for the bonded flamed PE/SBR assemblies.     

丁苯橡胶充填用环保芳烃油的研制

利用扬子公司范围内的重质物料进行了原料的筛选,提出一种生产环保芳烃油的新型工艺路线,并对环保芳烃油进行了分析及充填橡胶评价。结果表明,与进口典型环保芳烃油相比,生产的环保芳烃油具有密度、黏度、折光偏低的特点,充填橡胶的性能完全达到了指标要求。新型的环保芳烃油完全可替代丁苯橡胶原有非环保高芳填充油。     

Preparation and characterization of exfoliated graphite and its styrene butadiene rubber nanocomposites

Nanocomposites consisting of styrene butadiene rubber (SBR) reinforced with the modified-graphite and natural-graphite with concentrations of 5 wt% were fabricated. Processing techniques such as acid treatment, thermal shock, sonication were employed in the fabrication of modified-graphite.The graphite platelets oxidized using sulfuric and nitric acids were analyzed by the Raman scattering, Fourier transformed infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The FT-IR results indicate the presence of acid groups in the treated samples, and Raman spectroscopy of acid-graphite platelets further corroborate the formation of surface defect due to the introduction of functional groups. However, the structure of XRD peaks did not change irrespective of processing techniques.The SBR-based nanocomposites were characterized using the scanning electron microscopy (SEM), rheometer, Instron tensile machine, thermal and electrical analyser.The results showed that nanocomposites onto acid-graphite platelets enhanced mechanical properties and fatigue properties of nanocomposites compared to those containing natural-graphite due to the increase in the interaction between the polymer and the modified-graphite. And the dynamic properties of nanocomposites had no influence according to the processing techniques. Also, thermal and electrical properties of nanocomposites using acid-graphite platelets were enhanced due to the broadened specific surface by the acid treatment.     

Styrene butadiene rubber/clay nanocomposites for tire tread application

Homogeneous and stable dispersion of layered silicates in their rubber nanocomposite is a matter of interest as it can significantly affect the material properties. Herein we propose a facile and easily industrialised approach for preparing highly dispersed montmorillonite (MMT)/rubber nanocomposites by the latex compounding method. Furthermore, an efficient way of enhancing the interlayer spaces of organically modified MMT (f-MMT) with alkyl-ammonium chains while mixing the styrene butadiene rubber (SBR) is reported. The f-MMT embedded SBR matrix shows a remarkable improvement of the modulus and tensile strength even in the low loading rate, which is ascribed to the well dispersion of the f-MMT enhancing interfacial interaction with the rubber matrix. Furthermore, we manufactured the practical pneumatic tire using f-MMT/SBR nanocomposite with outstanding wear resistance, grip performance and low-rolling resistance for the green tire application, opening up enormous opportunities to prepare high-performance rubber composites for future engineering applications.     

丁腈橡胶增容丁苯橡胶/聚氯乙烯共混体系

采用一系列结合丙烯腈质量分数不同的丁腈橡胶(NBR)作为丁苯橡胶(SBR)／聚氯乙烯(PVC)不相容共混物的增容剂,研究了SBR／PVC／NBR硫化胶的力学性能,并用扫描电子显微镜、傅里叶变换红外光谱仪和动态黏弹仪研究了该硫化胶的形态结构与相容性。结果表明,结合丙烯腈质量分数为20％～26％的NBR是SBR／PVC的优良增容剂,可提高共混物的力学性能,使SBR相和PVC相达到微细均匀化分散,并在两相之间形成了界面层,使得增容效果达到最佳。     

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。     

Cure characteristics and mechanical properties of short nylon fiber reinforced acrylonitrile butadiene rubber/reclaimed rubber blends

Cure characteristics and mechanical properties of short nylon fiber reinforced acrylonitrile butadiene rubber-reclaimed rubber composites were studied. Minimum torque, (maximum-minimum) torque and cure rate increased with fiber concentration. Scorch time and cure time decreased by the addition of fibers. Properties like tensile strength, tear strength, elongation at break, abrasion loss and heat build up were studied in both orientations of fibers. Tensile and tear properties were enhanced by the addition of fibers and were higher in the longitudinal direction. Heat build up increased with fiber concentration and were higher in the longitudinal direction. Abrasion resistance was improved in presence of short fibers and was higher in the longitudinal direction. Resilience increased on the introduction of fibers. Compression set was higher for blends.     

CM和HDPE对再生橡胶物理机械性能的影响

研究CM和HDPE对再生橡胶物理机械性能的影响。结果表明,再生橡胶的门尼粘度随着CM用量的增加而降低,随着HDPE用量的增加而增加。再生橡胶的拉伸强度和拉断伸长率随着CM和HDPE用量的增加逐渐增加;扫描电镜研究表明,添加CM的再生橡胶硫化胶的拉伸断面相对平整,断层更均匀。综合比较当CM用量为8phr时,再生橡胶的综合性能最佳。     

Stabilization and control of phase morphology of PA/SAN blends via incorporation of exfoliated clay

The effect of nanoclay on phase morphology development of polyamide/styrene-acrylonitrile (PA/SAN) blends has been investigated. PA/SAN blends of various compositions, with and without the presence of exfoliated nanoclay in the PA phase, were prepared and the morphology of these blends was examined. Efforts have also included the study of morphology stability of these blends and the nanoclay effect on morphology stability of PA/SAN. The results suggest that at compositions where PA remains as the matrix domain, the nanoclay can be effective on reducing dispersed domain size to less than half the original size and furthermore improving the morphology stability of PA/SAN blends upon annealing by preventing coalescence of SAN domain. Implication of the present finding for effective preparation of stable incompatible blends is discussed.     

Structure–property relationship of electron‐beam‐modified EPDM rubber

Electron‐beam‐initiated grafting of trimethylolpropane triacrylate (TMPTA) onto the bulk ethylene propylene diene monomer (EPDM) was carried out with varying concentrations of TMPTA at a constant irradiation dose of 100 kGy and over a wide range of irradiation doses (0–500 kGy) at a fixed concentration (10%) of TMPTA. The rubber was also modified in the bulk by tripropylene glycol diacrylate (TPGDA, 10%) and tetramethylol methane tetraacrylate (TMMT, 10%) at an irradiation dose of 100 kGy. The modified rubbers were characterized by IR spectroscopy, crosslinking density measurements, and mechanical, dynamic mechanical, and electrical properties. The IR studies indicated increased peak absorbances at 1730, 1260, and 1019 cm⁻¹ due to increased 〉CO and C O C concentrations up to certain levels of TMPTA and irradiation dose. These are accompanied by an increase in the crosslinking density. The tensile strength of the samples increases gradually with increasing both the concentration of the monomer and radiation dose up to a certain level. The values of the modulus also increase at the expense of the elongation at break. An increase in the number of double bonds from two in the case of the diacrylate to four in the case of the tetraacrylate also brings about an increase in the tensile strength and moduli values. The elongation at break, however, decreases. The DMTA measurements indicate changes in the glass transition temperature, T_g, and tan δ_max on modification. The T_g shifts to a higher temperature with a simultaneous lowering of the tan δ_max values as the TMPTA level is increased. A similar trend is observed when the irradiation dose is increased and the nature of the monomer changes from di‐ to tetraacrylate. The dielectric loss tangent registers an increase on modification by irradiation of TMPTA while the permittivity is decreased. All the results could be explained on the basis of the structural modification and crosslinking density. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 323–337, 2000     

Identification of rubber polymers in rubber blends

Abstract

Solid phase extraction (SPE) was used to separate pyrolysates of rubber blends. Then each rubber polymer in rubber blends was identified, based on interpreting infrared spectrum of separated pyrolysates. By using this method, nature–ethylene–propylene, ethylene–propylene–silicone, butyl–styrene–butadiene and ethylene–propylene–butadiene–acrylonitrile rubber blends were analysed. The analytical results show that each characteristic pyrolysate of polymer in rubber blend pyrolysate can be separated by SPE. The method for identification of rubber polymers in rubber blends by infrared coupled with SPE is flexible, rapid and low cost, compared with the method by pyrolysis gas chromatography coupled with infrared spectroscopy or mass spectroscopy.     

CURE CHARACTERISTICS AND MECHANICAL PROPERTIES OF NATURAL RUBBER/RECLAIMED RUBBER BLENDS

Cure characteristics and mechanical properties of natural rubber/reclaimed rubber blends were studied. The minimum torque values of the blends were lower than that of the gum compound. The (maximum–minimum torque) and scorch time decreased with increasing reclaim content. The cure rate of the blends were lower than that of the virgin compounds. The tear strength was improved by the addition of reclaimed rubber. Tensile strength, elongation at break, and resilience decreased with increasing reclaim loading. The heat buildup was higher for the blends.     

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.     

丁苯橡胶市场分析及预测

本文综述了丁苯橡胶国内外发展概况、国内产需平衡、进出口、“八五”发展情况.对1993年丁苯橡胶市场进行了预测并提出了改进建议.     

Vulcanization kinetics of nano-silica filled styrene butadiene rubber

It was shown that the physical filler-polymer and filler–filler interactions, apart from the filler surface chemistry, has a substantial role in controlling the vulcanization kinetics of styrene butadiene rubber filled with nano-silica in a sulfur vulcanization system. Kinetic studies by the oscillating disc rheometer, differential scanning calorimeter, and swelling tests revealed that the vulcanization rate goes through a maximum as loading of silica increases, but conversion in crosslinking continuously decreases as the amount of silica increases. The effect of silica loadings on the vulcanization reactions was linked to the immobilization of rubber chains around particles as well as in a polymer-mediated filler network, which were differentiated by the nonlinear viscoelastic behavior of rubber vulcanizates. By surface modification of nano-silica, the accelerating/decelerating effects of nano-silica on the vulcanization reactions were altered corresponding to the non-linear viscoelastic behavior of the vulcanizates. Therefore, a mechanism was proposed which correlates vulcanization kinetics of rubber to the dynamics of chains influenced by the reinforcing fillers.     

丁二烯及其自聚物的危险性与风险防控

简要介绍了丁二烯的物化性质,系统总结了丁二烯及其自聚物可能产生的各种危险性,简要分析了丁二烯自聚物的产生条件,列举了丁二烯造成危害的典型案例,并详细总结了丁二烯自聚物危险性的防范措施.     

Cure modeling and mechanical properties of counter rotating twin screw extruder devulcanized ground rubber tire—natural rubber blends

Ground rubber tire (GRT) powder was devulcanised using a counter-rotating twin-screw extruder and the product was mixed with virgin natural rubber (NR) in various proportions. The data obtained from a cure rheometer was used to fit in a four-parameter logistic model to correlate the variation of torque with time. The mechanical properties were evaluated which suggested that tensile strength and elongation at break increased with increase in virgin natural rubber when added to the extrusion processed GRT.     

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.     

Effect of maleimide curing on mechanical properties of ground tyre rubber/waste polypropylene blends

Abstract

Blends of ground tyre rubber and waste polypropylene with a maleimide curing system (50∶50 blends of ground tyre rubber/waste polypropylene) were prepared in a Haake Rheocord Polylab System, at 180°C and 90 rev min^–1 for 5 min. The curing agent and the activator used were N,N′-meta-phenylene dimaleimide (HVA-2) and di(tert-butylperoxyisopropyl) benzene (DTBPIB) respectively. The HVA-2 level varied from 0 to 5 parts per hundred parts (pphp), while the DTBPIB level varied from 0 to 1 pphp. Melt viscosity, tensile strength and elongation at break showed an increase with HVA-2 content, while the impact energy showed an optimum at 3 pphp level. The addition of the DTBPIB increased melt viscosity further and produced a homogeneous phase morphology of the blends. Impact energy improved with the DTBPIB level, while elongation at break and tensile strength showed an optimum at 0·6 pphp. Swelling behaviour and gel/sol from the boiled xylene extractions were studied, and the results obtained were correlated with the impact and tensile properties.