热预处理乙丙胶对EPDM/MVQ共混胶交联密度及性能的影响

研究了热预处理乙丙胶对EPDM/MVQ共混胶交联密度及性能的影响。由实验得知,随着热预处理乙丙胶母胶时间的变长,乙丙胶母胶的门尼黏度变大,溶胀度减小,共混胶硫化程度变大,工艺正硫化时间减小,EPDM交联密度变大,MVQ交联密度基本不变;老化后,EPDM交联密度继续变大,MVQ交联密度变大,且EPDM交联密度变大程度大于MVQ;扯断伸长率下降,100%定伸应力和硬度变大。     

ZnO用量对CSM硫化胶性能的影响

研究了ZnO用量对秋兰姆类促进剂硫化氯磺化聚乙烯(CSM)胶料的硫化特性、物理综合性能、耐热性能的影响。结果表明,随着ZnO用量的增加,CSM的硫化时间和焦烧时间延长,最大扭矩逐渐增加,说明交联密度逐渐增大;CSM硫化胶的拉伸强度先增大后减小,交联密度、撕裂强度和硬度增大,拉断伸长率明显下降,阻燃性下降,耐油性变好;CSM硫化胶性能保持率降低,耐老化性能变差。差热扫描量热仪分析表明,ZnO用量增加,硫化胶的玻璃化温度向低温方向偏移,结晶区的吸热峰面积减小。热重分析法分析表明,ZnO用量增加,硫化胶高温稳定性变差。     

热氧老化对氯丁橡胶化学结构及性能的影响

对氯丁橡胶（CR）硫化胶进行热氧老化试验,研究100 ℃下老化时间对CR硫化胶化学结构、交联密度、溶胶质量分数和相对分子质量分布、氯质量分数、拉伸性能的影响。结果表明,在热氧老化过程中,CR硫化胶的橡胶分子链发生氧化反应,化学结构发生明显变化。在老化初期,CR硫化胶的交联密度增大,溶胶质量分数和相对分子质量减小,橡胶分子链以交联为主;老化时间超过192 h后,CR硫化胶的交联密度减小,溶胶质量分数、相对分子质量及其分布指数增大,橡胶分子链氧化断裂增多;在老化过程中,交联及脱氯使CR硫化胶结构化越来越严重,导致CR硫化胶的拉伸性能明显降低。     

热氧老化对氯丁橡胶化学结构及性能的影响

对氯丁橡胶(CR)硫化胶进行热氧老化试验,研究100℃下老化时间对CR硫化胶化学结构、交联密度、溶胶质量分数及其相对分子质量分布、氯质量分数、拉伸性能的影响.结果 表明,在热氧老化过程中,CR硫化胶的橡胶分子链发生氧化反应,化学结构发生明显变化.在老化初期,CR硫化胶的交联密度增大,溶胶质量分数和相对分子质量减小,橡胶...     

硫化条件对绿色轮胎胎面配方性能的影响

研究了硫化温度、硫化压力和硫化时间对绿色轮胎硫化胶的化学交联网络、磨耗以及动态性能和物理机械性能的影响。结果表明,随着硫化温度升高,天然橡胶硫化胶的交联密度和物理机械性能有所下降,耐磨性先提高后下降,永久变形、压缩温升和tanδ提高;随着硫化压力升高,硫化胶的撕裂强度下降,交联密度、抗裂口增长性能和相应地物理机械性能有所提高;随着硫化时间的延长,硫化胶的物理机械性能、撕裂强度和硬度下降,耐磨性和交联密度先提高后下降,压缩温升和60℃下的tanδ提高.     

不同硫化时间对NBR/EPDM共混胶性能的影响研究

研究了NBR/EPDM共混胶在不同硫化时间下性能的变化规律,并且进行了平衡溶胀法测交联密度的实验,测量共混胶中两相各自的交联密度,与宏观物理机械性能相结合,讨论共混胶的性能变化规律,结果发现:随着硫化时间的延长,共混胶的硫化程度变大,扯断伸长率下降,定伸应力升高,且共混胶总交联密度变大,共混胶中NBR相交联密度略微上升,EPDM相交联密度大幅升高。     

天然橡胶硫化胶的热氧老化性研究

用热分析法(TGA、DSC)和裂解气相色谱-质谱分析(PGC-MS)研究了天然橡胶硫化胶的耐老化性能及其机理。结果表明,天然橡胶硫化胶的热氧老化初期力学性能和交联密度增加,热失重起始温度上升,随着老化过程的进行,降解效应占优势,硬度和交联密度下降,热氧稳定性变差。其热解机理可能是主链中键的断裂,产物主要是异戊二烯单体和1,4-二甲基-4-乙烯基环己烯。     

硫化剂对天然杜仲胶记忆材料的性能影响

依据杜仲胶橡塑二重性,以体系内硫化剂调整其硫化胶的结晶度,实现不同硫磺用量下的杜仲胶记忆材料制备,并进行相应的力学、动态力学、热性能的表征。结果表明,当硫黄用量增加到一份时,硫化胶交联密度没有明显变化,硫黄用量超出1份以后,交联密度显著增加。定伸应力和拉伸强度随硫黄用量的增加时呈先减小而后增大趋势,拉断伸长率表现相反;同时,热致回复温度范围降低,而且在硫黄用量为1份时最小。     

原位合成甲基丙烯酸锂增强丁腈橡胶的性能和结构

讨论了在过氧化二异丙苯(DCP)的作用下,氢氧化锂和甲基丙烯酸在混炼过程中原位生成的甲基丙烯酸锂(LiMA)增强丁腈橡胶(NBR)的性能和结构。结果表明,原位生成LiMA对NBR有较明显的增强作用,随着LiMA生成量的增加,NBR硫化胶的邵尔A硬度、100%定伸应力和撕裂强度逐渐增加,拉伸强度和扯断伸长率呈现先上升后下降的趋势;在DCP的作用下,LiMA可显著提高NBR的硫化速率及硫化程度,硫化速率与LiMA生成量呈线性增加关系;随着LiMA生成量的增加,NBR硫化胶的总相对交联密度、离子键相对交联密度增加,而共价键相对交联密度有所下降,说明LiMA改变了NBR的结构。     

黑液/高岭土复合物在丁腈橡胶和丁苯橡胶中的应用研究

通过絮凝沉降法制备了一种复合补强剂——黑液/高岭土复合物(CLK),将其分别与丁腈橡胶(NBR)和丁苯橡胶(SBR)共混制备了NBR/CLK与SBR/CLK复合材料。考察了CLK的添加量对橡胶复合材料硫化特性、交联密度、力学性能、热氧老化性能以及热降解性能的影响。结果表明:随着CLK含量的增加,在NBR/CLK复合材料体系中,焦烧时间、正硫化时间和硫化速度指数先增加而后逐渐降低;交联密度和力学性能则逐渐增大;老化性能及热性能没有显著改善。在SBR/CLK复合材料中,焦烧时间、硫化速度指数先增加而后逐渐降低,正硫化时间先减少而后逐渐增加;交联密度和力学性能则逐渐增大;老化性能没有显著改善,但热性能得到了提高。     

Crumb tire rubber and polyethylene mutually stabilized in asphalt by screw extrusion

In order to put recycled rubber and plastics into practical use for asphalt's modification, the polyethylene (PE)/crumb tire rubber (CTR) blends were blended to prevent them from phase separation in asphalt during hot storage. The effect of screw extrusion on storage stability, morphology, and thermal properties of modified asphalt were investigated. The results showed that the storage stability of PE/CTR modified asphalt was significantly improved after screw extrusion in the presence of a compatibilizer. The extruded PE and CTR were more finely and uniformly dispersed in the asphalt. The rheological properties of modified asphalts were improved at both higher and lower temperature's range. The density discrepancy between asphalt and the extruded PE/CTR particles was neutralized by the combination between PE and CTR. The interactions among PE, CTR and asphalt were improved by the compatibilizer. Both the reduction of density difference and the enhanced interactions are critical to obtain a stable modified asphalt system. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41189.     

不同活化橡胶改性沥青性能研究及对比

试验分别采用微波活化、抽出油活化和次氯酸钠活化三种方式对橡胶粉进行活化改性,并用活化胶粉制备橡胶沥青.测定其粘度、软化点之差和车辙因子,对比分析不同活化橡胶沥青的粘度、相容性以及流变性能的差异,评价三种胶粉活化方式的优劣性,并进行活化胶粉对沥青改性的显著性分析.分析结果表明:胶粉掺量对橡胶沥青的粘度、热存储稳定性和流变性能均有显著影响;活化胶粉可显著降低橡胶沥青的粘度,提高其热存储稳定性;采用不同方式制得的活化胶粉对橡胶沥青性能的影响各有不同,相比而言,微波活化胶粉降粘效果较差,抽出油活化橡胶沥青存储稳定性最好,但会使橡胶沥青流变性能减弱,且随掺量增加而减小,次氯酸钠活化胶粉对橡胶沥青流变性能的改善最为显著.     

Effect of γ-radiation on the dynamic mechanical properties of silicone rubbers

Dimethyl-, trifluoropropyl-, and high phenyl content polysiloxanes were irradiated in a ⁶⁰Co source to doses of 100 Mrad. The hardness of the specimens increased with dose. Crosslink density changes did not directly reflect the hardness changes. The crosslink density of the dimethyl polymer increased significantly and that of the trifluoropropyl polymer increased only slightly. There was a slight decrease in the crosslink density of the aromatic material. The storage moduli reflected the changes in crosslink density. Loss moduli of the dimethyl- and trifluoropropylpolysiloxanes initially decreased and then increased on continuing irradiation. Dynamic moduli of the high aromatic content polymer were essentially unchanged by the radiation. All the dynamic data were correlated by the WLF time–temperature relationship.     

Role of geopolymer as a cure activator in sulfur vulcanization of epoxidized natural rubber

Geopolymer (GP) was synthesized and used as activators in sulfur vulcanization of epoxidized natural rubber (ENR). Influences of GP on cure characteristics, crosslink density, mechanical, thermal, and morphological properties were investigated and compared to the conventional rubber formulation with ZnO activator. The ZnO is a hazardous chemical for the environment and has proclaimed that its application in rubber technology should be reduced and controlled. It was found that the GP-activated ENR compounds showed significantly higher vulcanization rate than cases with the conventional ZnO compound. This was indicated by the GP activated compounds having shorter scorch time, cure times, and lower activation energy but higher cure rate index (CRI). Also, the GP activated ENR compounded with stearic acid exhibited the highest conversion. This matches well the highest torque difference and crosslink density, observed by temperature scanning stress relaxation (TSSR) and swelling measurements. Furthermore, the GP-activated vulcanizate had better thermal stability than the ZnO-activated ENR material. In addition, the GP-activated ENR vulcanizate with stearic acid exhibited high 100% moduli, tensile strength, and hardness. This proves that GP has a high potential for use as activators in sulfur vulcanization of rubber compounds, as an alternative to the conventional ZnO. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48624.     

基于储存稳定性的橡胶改性沥青制备工艺

为了制备储存稳定性良好的橡胶改性沥青,基于高温混炼工艺,使用聚苯乙烯-聚丁二烯-聚苯乙烯嵌段聚合物(SBS)、芳烃油、辛烯聚合物橡胶反应剂(TOR)、稳定剂与橡胶粉对基质沥青进行复合改性。提出了橡胶改性沥青的制备方法,分析了改性剂对沥青常规性能和流变特性的影响,并通过荧光试验观察改性剂在沥青中的分散效果。研究结果表明:添加质量分数为25%的40目(380 μm)胶粉可以明显提高沥青的高温性能;180 ℃下剪切60~90 min后溶胀发育60 min可以得到稳定性良好的橡胶改性沥青;加入相容剂和稳定剂可以提高胶粉的溶胀与分散程度,改性剂之间对沥青性能的影响存在协同作用;复合改性沥青具有良好的弹性恢复能力和高温抗变形性能;橡胶粉、SBS在沥青中的溶胀程度和分散均匀性是影响沥青常规性能和储存稳定性的直接因素。     

Study of the crosslink density,dynamo-mechanical behaviour and microstructure of hot and cold SBR vulcanizates

Vulcanizates of hot and cold styrene-butadiene rubber (SBR) were prepared with five different cure systems based on sulphur, 2-mercaptobenzothiazole disulphide (MBTS) and tetramethylthiuram disulphide (TMTD). The degree of crosslinking was investigated by swelling in benzene and stress-strain analysis. Thiol-amine chemical probes were employed to determine the type of crosslinks in the sulphur vulcanizates, and their dynamic-mechanical properties and thermal stability were studied in both the raw (non-crosslinked) and crosslinked state. The butadiene microstructure and the total unsaturation were determined by Raman spectroscopy. The influence of the crosslink density and the type of crosslink formed on the measured properties is discussed.     

Effects of fillers on mechanical properties of a water‐swellable rubber

The mechanical properties of the water‐swellable rubber prepared by blending polychloroprene with precipitated silica, crosslinked sodium polyacrylate, polyethylene oxide, and vulcanizing agents—such as stress at break, strain at break, modulus, energy at break, and hardness—were studied before and after swelling with water. The results showed that the addition of the reinforcing filler (precipitated silica) increased the mechanical properties, while adding crosslinked sodium polyacrylate decreased the mechanical properties, although it could improve water‐absorbent properties of the water‐swellable rubber. If some polyethylene oxide was included in the rubber formulation, the water‐absorbent properties and the mechanical properties of the rubber both increased; but, with the increase of more polyethylene oxide, the mechanical properties decreased. Wide‐angle X‐ray diffracting analysis was conducted to study the crystalline behavior of the rubber, which showed that the crystallinity of the vulcanized polychloroprene increased first and then decreased with an increase in the amount of polyethylene oxide. The crosslink density of the rubber was calculated by the Flory–Rehner equation. The mechanical strength of the rubber significantly decreased after swelling with water, compared with that before swelling with water. The morphology of blends was shown by scanning electron microscopy graphs. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 577–584, 1999     

天然橡胶/再生胶共混胶的交联密度与力学性能

对不同天然橡胶(NR)/再生胶(RR)共混比、不同硫磺及轻质碳酸钙含量的NR/RR共混胶的交联密度和力学性能进行分析测试,并对RR的橡胶烃含量、炭黑含量和无机杂质含量进行热失重测试分析。结果表明,随着RR含量和硫磺含量的增加,硫化胶交联密度上升,轻质碳酸钙含量变化对于硫化胶交联密度没有产生规律性的影响。NR/RR共混比为70/30,硫磺用量为2.5份时NR/RR共混胶综合性能最佳。     

Characteristics of natural rubber hybrid composites based on marble sludge/carbon black and marble sludge/rice husk derived silica

This paper discusses an extensive overview of characterization of marble sludge (MS) with carbon black (CB) and rice husk derived silica (RHS) in hybrid natural rubber (NR) composite. Cure characteristics, mechanical and swelling properties of MS/CB and MS/RHS hybrid NR composite were investigated. As CB and RHS content increases in weight ratio of MS/CB and MS/RHS a decrease in scorch and cure time and increase in the torque, tensile, tear, modulus, hardness, crosslink density were observed, while elongation at break and swelling coefficient decreased. The aging behavior of corresponding hybrid composite materials was also evaluated at two different temperatures.