改性木薯淀粉/橡胶复合材料的制备及性能研究

以木薯淀粉、马来酸酐、苯乙烯为原料,过硫酸钾为引发剂,通过溶液共聚合成了一系列苯乙烯改性淀粉树脂(SMS)。然后将改性淀粉同丁苯橡胶(SBR)、天然橡胶(NR)进行混炼、硫化模压成型,制得苯乙烯改性淀粉/丁苯橡胶/天然橡胶复合材料。采用红外光谱(IR)对苯乙烯改性淀粉接枝共聚物进行了结构表征。通过拉伸性能测试考察了不同苯乙烯含量的木薯淀粉接枝产物对丁苯橡胶/天然橡胶的力学性能的影响。结果表明,淀粉改性后,随着苯乙烯含量的增多,所得复合橡胶的拉伸强度与邵氏硬度均呈现先增加后降低的趋势。当苯乙烯用量为15%时所制得的苯乙烯改性淀粉/丁苯橡胶/天然橡胶复合材料的拉伸强度与邵氏硬度最大且优于未改性淀粉复合材料,其拉伸强度为2.0MPa,邵氏硬度为25.8HD。     

木质素补强乳聚丁苯橡胶研究进展

阐述了木质素补强乳聚丁苯橡胶的原理及方法,原理包括木质素可与橡胶发生接枝反应、木质素可与橡胶形成芳香氢键、木质素与金属离子形成木质素-金属螯合物,补强方法包括混炼工艺、共沉工艺等;综述了木质素补强乳聚丁苯橡胶的国内外研究进展,木质素可以很好地改善橡胶的物理力学性能,如提高胶料的硬度、拉伸强度、拉断伸长率、300%定伸应力、撕裂强度和耐热老化等性能。最后,对木质素在橡胶工业中的应用做了展望。     

橡胶-填料相互作用对丁苯橡胶/白炭黑复合材料性能的影响

本文研究了硅烷偶联剂原位改性白炭黑对溶聚丁苯橡胶(SSBR)性能的影响,结果表明,通过哈克转矩流变仪对含有偶联剂的SSBR/白炭黑混炼胶进行原位热处理后可明显减弱混炼胶的Payne效应,改善白炭黑在橡胶基体中的分散.原位热处理方法能够明显提高硫化胶的300%定伸应力,降低动态压缩温升,同时可使硫化胶在0℃附近具有较高的损耗因子(tanδ),60℃附近具有较低的tanδ.对不同聚合方式得到的丁苯橡胶,即溶聚丁苯橡胶与乳聚丁苯橡胶(ESBR)/白炭黑复合材料的力学性能及动态力学性能进行了研究,结果表明,白炭黑在SSBR2305中分散效果优于在ESBR1502中;采用偶联剂原位改性白炭黑可以使SSBR2305硫化胶获得与ESBR1502硫化胶相当的物理机械性能,更理想的动态力学性能,从而得到力学性能、抗湿滑性、滚动阻力及耐磨性更加均衡的理想轮胎材料.通过对具有不同偶联效率的SSBR/白炭黑体系的微观结构与性能研究发现,随偶联效率的增加,其结合橡胶含量增加,Payne效应减弱;高偶联效率的S-SBR具有较低的动态压缩温升及较好的耐磨性.     

高填充量碳纳米管/丁苯粉末橡胶机械混炼的物理化学机制

将用喷雾干燥法制备的碳纳米管(CNTs)/丁苯粉末橡胶复合材料在开炼机上机械混炼, 考察机械混炼对复合材料常规力学性能的影响, 并对机械混炼对CNTs增强丁苯橡胶复合材料力学性能的影响进行相应的理论研究和机理分析. 结果表明, 与混炼前的复合材料相比, 机械混炼有效地提高了CNTs/丁苯橡胶复合材料的力学性能, 特别是当CNTs加入量较大时, 提高幅度更为显著, 与填充传统补强剂CB复合材料相比, 具有较大的优势. 这是因为机械混炼一方面使CNTs在橡胶基体中获得了更为充分均匀的分散; 另一方面, 混炼过程中产生的自由基以及巨大的剪切力, 使得CNTs与橡胶基体间界面结合如物理吸附、氢键作用、化学结合等得到了进一步增强, 提高了CNTs/丁苯橡胶复合材料的结合橡胶含量, 更好地发挥了CNTs对丁苯橡胶的补强效应, 从而提高了复合材料的拉伸强度和撕裂强度等力学性能. CNTs补强丁苯橡胶复合材料力学性能的机理符合“强键和弱键学说”.     

环氧天然橡胶接枝高分散白炭黑增强天然橡胶复合材料的制备及表征

基于白炭黑表面硅羟基与环氧基团的可反应性,利用Haake流变仪的高温高剪切作用,在170℃下,实现了环氧天然橡胶(ENR)对白炭黑的固态原位接枝,制备出一种高分散疏水型白炭黑.探讨了白炭黑和ENR的反应配比对增强性能的影响,确定合适的反应比例为3∶1.FTIR、TGA和TEM的分析结果证实了ENR被接枝到白炭黑表面上.对比研究了接枝前、后白炭黑对增强天然橡胶(NR)复合材料性能的影响,测试结果表明接枝白炭黑在天然橡胶中具有良好的分散性并能明显改善对天然橡胶的增强效果;接枝于白炭黑表面上的环氧天然橡胶分子玻璃化转变向高温偏移,使该复合材料在常温下具备优异力学性能的同时也体现出了高动态滞后的特点.     

相容剂对氯丁橡胶/天然橡胶并用胶性能的影响

本研究利用氯化丁基橡胶和腰果酚作为氯丁橡胶(CR)/天然橡胶(NR)并用胶的相容剂,将其按照一定比例在混炼过程中加入得到CR/NR混炼胶.CR/NR混炼胶在160℃下根据最佳硫化时间硫化得到并用胶.通过橡胶加工分析仪(RPA)研究发现腰果酚的加入,降低了CR/NR混炼胶的储能模量并且降低正硫化时间,提高了CR/NR混炼...     

氯化丁基橡胶/白炭黑复合材料在X射线衍射法中的多晶有序化过程

在固相条件下,氯化丁基橡胶在白炭黑作用下从多晶无序化向单晶有序化转变。采用机械混炼法制备了氯化丁基橡胶/白炭黑复合材料,利用X射线衍射(XRD)和扫描电镜(SEM)表征了复合材料向有序化转变的过程。结果表明:氯化丁基橡胶的有序化转变在机械混炼的过程中就已经发生,在硫化过程中,随着硫化时间的增加,有序化转变的程度有所提高,且随着白炭黑添加量的增多,橡胶分子变得越来越规整,力学性能也得到了改善;混炼胶料硫化过程结束后,橡胶分子链间晶型结构保持在复合材料中。     

炭黑N134在不同橡胶基体中的分散及其混炼工艺调控

以炭黑N134作为填料,对比了异戊橡胶、丁苯橡胶及仿生橡胶3种体系下混炼工艺对硫化胶性能的影响,并针对仿生橡胶体系炭黑分散度低的问题,对混炼工艺进一步优化,从而提高分散度和动静态性能.结果表明,在所研究的密炼时间范围内,随着密炼时间的延长,异戊橡胶体系和丁苯橡胶体系的分散等级由原本的1级左右提升至6级以上.但延长密炼时间并未明显提升仿生橡胶体系的炭黑分散度.针对该问题引入塑炼和包辊工艺,仿生橡胶炭黑分散性明显提高.随炭黑分散等级的增加, 3种橡胶体系的伸张疲劳性能均得到了较大改善.其中仿生橡胶生胶经塑炼后,门尼黏度和重均分子量均明显下降,表明塑炼对于增强胶料的加工性能有明显作用.相同炭黑混炼时间下,随着塑炼时间的延长,硫化胶佩恩效应也增强,这主要是由于炭黑分散程度的提高使得炭黑与橡胶基体的有效接触面积增加,进而在一定程度上增加了界面结合胶的含量.     

衰减全反射红外光谱法测定电工胶带粘合剂

采用衰减全反射傅里叶变换红外光谱法(ATR-FTIR)对31个品牌电工胶带的粘合剂进行分析,通过红外特征吸收峰确定粘合剂的主要成分均为天然橡胶和丁苯橡胶混合物,不同品牌的样品通过红外光谱定性分析无法区分。通过OPUS软件分别选择天然橡胶和丁苯橡胶的红外特征吸收峰进行峰面积积分,计算两种物质特征峰面积的相对比例,采用单因素方差分析确定不同样品天然橡胶和丁苯橡胶特征峰面积的相对比例是否存在统计学差异,然后采用最小显著性差异法进行验后多重比较,分析特征峰面积相对比例存在统计学差异的品牌。31个品牌电工胶带组成的465组样品对中有422组可以区分,区分率达到90.8%。结果表明,通过红外光谱定量分析可实现不同品牌电工胶带粘合剂的区分。     

有机蒙脱土/天然橡胶纳米复合材料的阻燃性能研究

采用机械混炼插层法制备有机蒙脱土/天然橡胶(TMT/NR)纳米复合材料.使用X-射线衍射(XRD)和红外表征了有机蒙脱土的结构特性,并用锥形量热仪测试了纳米复合材料的燃烧性能.结果表明,有机蒙脱土/NR纳米复合材料的热释放速率(HRR)、生烟速率(SPR)等较纯天然橡胶、未改性蒙脱土/NR复合材料均所有降低,表现出较好的阻燃性能.通过对纳米复合材料的燃烧性能和燃烧残余物分析,探讨了该体系的阻燃机理.     

改性合成橡胶在轮胎工业中的应用

介绍了几种合成橡胶的改性在轮胎工业中的应用现状。为了提高轮胎的综合行驶性能 ,近年来国外开发出了性能良好的溶聚丁苯、Nd系顺丁、乙烯基顺丁、3,4-异戊胶、卤化丁基胶、苯乙烯 -异戊二烯 -丁二烯橡胶、星型支化丁基胶及溴化三元乙丙胶等一系列改性合成橡胶新品种     

Comparative study of natural rubber and acrylonitrile rubber reinforced with aligned short aramid fiber

The aims of this paper are three-fold. The first is to determine the reinforcement of high performance short aramid fiber in two representative rubber matrices, namely natural rubber and acrylonitrile rubber. The second is to ascertain the effect of rubber polarity on the reinforcement. The third is to establish a pattern of reinforcement for use with less studied fibers. The rubbers were reinforced either with only aramid fiber or with a hybrid of aramid fiber and carbon black. The fiber contents were varied at 0, 2, 5 and 10 parts (by weight) per hundred rubber (phr) while those of carbon black were 0, 10, 20 and 30 phr. Conventional sulfur vulcanization was used. It was found that aramid fiber can reinforce both rubbers in the low strain region effectively, although to a significantly different degree. The hybrid carbon black provides additional reinforcement at low to medium strains and allows high strain stress upturn to occur in both rubber matrices. The findings enable the preparation of rubber composites having a wide, controllable range of mechanical behavior for specific high-performance engineering applications. Significantly, they also serve as a benchmark for developing reinforced systems from alternative fibers, particularly those from natural sources.     

Blending of Natural Rubber/Recycled Ethylene-Propylene-diene Rubber: Promoting the Interfacial Adhesion Between Phases by Natural Rubber Latex

This article deals with blends based on natural rubber (NR) and recycled ethylene-propylene-diene rubber (R-EPDM). Natural rubber latex (NRL) was introduced into the blends to enhance interfacial adhesion between NR and R-EPDM. A new route of compounding was also suggested. The blends were prepared by mixing R-EPDM and other additives in NRL before blending with natural rubber on a two-roll mill. By applying this method, the homogeneity of the blends and cross-linking distribution are significantly improved. The blends exhibited superior state of cure, swelling resistance, mechanical properties and dynamic mechanical properties. The degree of entanglement between NR and R-EPDM also increased after NRL modification.     

Preparation of high damping elastomer with broad temperature and frequency ranges based on ternary rubber blends

Based on the blends of chlorinated butyl rubber (CIIR), nitrile butadiene rubber (NBR) and chloroprene rubber (CR), a kind of high damping elastomer with broad temperature and frequency ranges is prepared. CIIR/NBR binary blend is prepared to take advantage of the immiscibility and the large difference in cross‐link density of the different phases caused by the curatives and accelerators migration. The dynamic mechanical analysis reveals that the binary blend was immiscible and its loss factor (tanδ) versus temperature curves show two separated and expanded loss peaks when compared with those of pure cured CIIR and NBR. In order to improve its damping properties at room temperature, the third component CR with the polarity between CIIR and NBR was blended into the binary blend. The resulted CIIR/NBR/CR ternary blend has gained effective damping properties (tanδ > 0.3) in the temperature range of ?86.4 to 74.6°C and the frequency range of 10^?2 to more than 10⁹ Hz. Other effects on the damping properties of the ternary rubber were also studied. Copyright © 2013 John Wiley & Sons, Ltd.     

A critical review on analytical methods and characterization of butyl and bromobutyl rubber

The molecular structure characterization of butyl and bromobutyl rubber (BIIR) requires the definition of three main parameters: (I) the unsaturation degree of the rubbers, (II) the total bromine content of the BIIRs, and (III) the functional bromine content of the BIIRs. The analytical methods for the determination of the previously mentioned parameters have been described and critically examined in this review.     

异苯橡胶和环化异苯橡胶结构表征

异苯橡胶和环化异苯橡胶结构表征孙晓日，李大珍，余尚先（山东昌潍师范专科学校化学系山东潍坊２６１０１３）（北京师范大学化学系北京１００８７５）关键词异苯橡胶，环化异苯橡胶，结构异戊二烯与苯乙烯无规共聚或嵌段共聚得到异苯橡胶已有不少研究和报导￣［１，２］...     

TBIR应用于航空胎侧胶的热氧老化性能

研究了反式-1,4-丁二烯-异戊二烯共聚橡胶(TBIR)应用于航空轮胎胎侧胶[天然橡胶(NR)/顺丁橡胶(BR)/TBIR]的耐热氧老化性能. 结果表明, 与NR/BR硫化胶相比, 10~20份质量的TBIR取代BR后, NR/BR/TBIR硫化胶的交联密度明显提高, 压缩温升降低2.2~3.4 ℃, 耐屈挠疲劳性能提高约100%, 填料分散性改善, 填料团聚体体尺寸减小, 拉伸性能基本不变. 随热氧老化时间延长, 硫化胶的交联密度先增加后降低, 并用TBIR的硫化胶交联密度在老化48 h后趋于平缓. 与NR/BR相比, 老化后的NR/BR/TBIR硫化胶生热最低, 耐屈挠疲劳性最高.     

Preparation of hydrogenated nitrile rubber using palladium acetate catalyst: Its characterization and kinetics

Hydrogenated nitrile rubber was prepared by using palladium acetate as the homogeneous catalyst system. The effect of different reaction parameters on the level of hydrogenation was studied. The extent of hydrogenation increased with increase in reaction time, temperature, pressure, and catalyst concentration. A maximum conversion of 96% could be achieved. The degree of hydrogenation was estimated from IR and NMR spectroscopy. The selectivity of the catalyst in reducing ? C?C? in presence of ? C?N was supported by IR and ¹³C-NMR spectra. ESCA studies further confirmed this observation. Properties of hydrogenated nitrile rubber were investigated by various techniques such as gel permeation chromatography (GPC), glass transition temperature (T_g), stress-strain behavior and rheological measurements. GPC studies showed no significant change in molecular weights of the products after the reaction. T_g value decreased with an increase in the level of hydrogenation. The ultimate stress improved significantly with the increase in the extent of hydrogenation. The die swell decreased with hydrogenation at a particular shear rate. The kinetics of the NBR hydrogenation were investigated. With the increase of the hydrogen pressure and catalyst concentration, the rate of the reaction increased. The reaction was apparently first order with respect to olefinic substrate at higher hydrogen pressure. The apparent activation energy, enthalpy, and entropy of the reaction were calculated as 29.9 kJ/mol, 27.42 kJ/mol, and –0.20 kJ mol^?1 K^?1, respectively.     

Hysteresis loss as a measure of metal–rubber adhesion

As in the case of reinforcing filler-induced increase in hysteresis in rubbers, placement of aluminum (A1) foil to the surface of a rubber blend of epichlorohydrin rubber and carboxylated nitrile base induces increased hysteresis of the rubber due to adhesion between Al and the rubber blend. Changes in hysteresis loss due to Al foil can be correlated with the peel strength of Al-rubber-Al joints. © 1995 John Wiley & Sons, Inc.     

Unique rheological behavior of rubber based nanocomposites

Montmorillonite clay (N) based nanocomposites were prepared using three different grades of acrylonitrile butadiene rubber (NBR) (19%, 34%, and 50% acrylonitrile contents), styrene butadiene rubber (SBR), and polybutadiene rubber (BR). Rheological study was carried out on these nanocomposites at three different temperatures (110 °C, 120 °C, and 130 °C) over a range of shear rates for comparison. The results showed that the shear viscosity decreased with increasing shear rate and incorporation of the unmodified (N) and the modified (OC) fillers up to a certain loading, when the results were compared with the gum rubber. This effect became more prominent with increasing polarity of the rubber. The die swell, on the other hand, decreased with loading of N and OC. With increasing filler volume fraction, the die swell further decreased. Decrease of viscosity with concomitant decrease of die swell is unique in such systems. Consecutive runs of the same sample over different shear rates increased the viscosity. The results were explained with the help of X‐Ray Diffraction (XRD) data and Transmission Electron Microscopy (TEM).© 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1854–1864, 2005