补强体系对NR硫化胶疲劳破坏特性的影响

用断裂力学方法研究炭黑N330、炭黑N330/白炭黑和白炭黑补强NR硫化胶的疲劳破坏特性.结果表明,与炭黑N330和炭黑N330/白炭黑补强的NR硫化胶相比,白炭黑补强的NR硫化胶疲劳寿命较长,内部潜在缺陷较少,抗裂纹扩展性能较好;随着疲劳时间的延长,NR硫化胶拉断时的应变能密度减小;疲劳寿命方程能够快速、准确地预测NR硫化胶的疲劳寿命.     

炭黑/白炭黑补强硫化胶的疲劳过程及使用寿命预测

应用断裂力学的方法，解析和预测了采用高耐磨炭黑与白炭黑并用补强体系的天然橡胶。在疲劳过程中形变能密度的变化，疲劳破坏寿命和断裂特征，建立了数学模型，预测了胶料动态疲劳破坏寿命。研究结果表明，在天然橡胶中采用高耐磨炭黑与白炭黑并用补强体系，随白炭黑用量的增加。胶料疲劳破坏寿命延长，胶料内部潜在缺陷减小，裂纹扩展速度减慢，形变能密度下降缓慢，建立的数学模型能较好地预测含高耐磨炭黑与白炭黑补强体系的胶料疲劳破坏寿命。     

白炭黑对炭黑／丁苯橡胶复合材料耐疲劳性能的影响

研究白炭黑对炭黑/丁苯橡胶(SBR)复合材料耐疲劳性能的影响。结果表明:与炭黑/SBR复合材料相比,白炭黑/炭黑/SBR胶料的t10延长,交联密度下降,硫化胶的100%和300%定伸应力减小,拉断伸长率增大;在相同应变下,SBR复合材料的疲劳寿命延长,疲劳裂纹增长速率对撕裂能的敏感程度差别不大;白炭黑粒径越小,比表面积越大,结构度越低,对SBR复合材料的耐疲劳性能越有利。     

炭黑/白炭黑补强硫化胶的疲劳破坏特性

应用断裂力学的方法解析和预测了天然橡胶采用高耐磨炭黑与白炭黑并用补强体系在疲劳过程中形变能密度的变化，疲劳破坏寿命、断裂特征和能量释放率。结果表明：在天然橡胶中采用高耐磨炭黑与白炭黑并用补强体系，随白炭黑用量的增加，胶料疲劳破坏寿命延长，胶料内部潜在缺陷减小，裂纹扩展速度减慢，形变能密度下降缓慢，胶料的能量释放率增加。     

不同炭黑种类对丁腈橡胶性能的影响

研究炭黑种类对丁腈橡胶物理机械性能、动态力学性能、耐热性能的影响。研究结果表明:炭黑粒径越高,混炼胶口型膨胀率越大,炭黑N550在混炼胶中的分散性较好;炭黑粒径越小,胶料的流动性降低,拉伸强度和硬度越大,补强效果越好,同时压缩生热量越大,压缩永久变形越大;填充N330和N774硫化胶耐热老化性较差。     

炭黑和硫化程度对天然橡胶硫化胶疲劳性能的影响

研究了4种不同粒径的炭黑和不同硫化程度对天然橡胶(NR)硫化胶在25℃和100℃下耐疲劳性能的影响。结果表明,NR硫化胶的疲劳性能与炭黑粒径、硫化程度和疲劳温度有关,不同炭黑填充的NR硫化胶在100℃下的疲劳寿命均高于25℃下的疲劳寿命,100℃下疲劳破坏后胶料的交联密度增高,而25℃下疲劳破坏后则降低;100℃下以工艺正硫化时间(t_(90))制备的胶料疲劳寿命高,填充大粒径炭黑有利于延缓胶料的初始破坏,25℃下以理论正硫化时间(t_(100))制备的胶料疲劳寿命高,填充小粒径炭黑有利于延缓胶料的初始破坏。     

炭黑对SSBR-T2000R屈挠疲劳的影响

通过改变炭黑的种类及用量,考察了炭黑粒径、结构度、用量对SSBR-T2000R屈挠性能及断面形貌的影响,并与乳聚丁苯橡胶ESBR-1502作了对比。结果表明,炭黑粒径对SSBR-T2000R屈挠性能有一定影响,粒径太小,炭黑对橡胶分子的吸附力大,使得承受应力的橡胶链段不能很快地通过分子运动产生应力松弛;粒径太大,对SSBR-T2000R硫化胶的补强作用差,强度低,屈挠疲劳性能降低。结构度对SSBR-T2000R屈挠性能的影响比ESRB-1502大。结构度高,SSBR-T2000R屈挠断面较不平整。SSBR-T2000R硫化胶的屈挠疲劳寿命随着炭黑用量的增多先增大后减小,炭黑用量在15份左右时硫化胶的耐屈挠性能最好;炭黑对SSBR-T2000R的补强效果高于对ESBR-1502的,从而使SSBR-T2000R的耐屈挠性能提高较快。     

炭黑填充硫化胶的网络结构同力学性能间相关性——(Ⅱ)炭黑的补强作用和它的表征

本文从炭黑填充和未填充硫化胶的弹性形变自由能和应力一应变关系式出发,利用两者形变自由能和形变应力的差值法,提出了三种炭黑补强作用的表征方法:多余形变自由能、多余形变应力和模量法,后者能定量地区分物理补强,化学补强和短链补强作用.最后以不同炭黑品种和用量填充硫化的天然胶,合成异戊胶和丁苯胶等的大量应力一应变实验数据验证了炭黑填充硫化胶大形变弹性分子理论、补强作用理论和三种补强作用的表征方法,结果表明在给定品种和用量范围内理论同实验均能较好地符合.并讨论了抗张强度同炭黑品种的依赖性.     

N99O炭黑在轮胎帘布胶中的应用探讨

研究N99O新型炭黑在轮胎内层帘布挂胶中的应用。补强体系应用N3O0炭黑/N990新型炭黑代替N330炭黑/半补强炭黑，并对并用比例及软化剂、促进剂用量作适当调整，可使硫化胶的胶线粘合性能及抗压缩疲劳生热性能提高，内层帘布挂胶的总体性能水平不下降，配方成本降低。     

微观结构对丁腈橡胶硫化胶物理性能的影响

研究橡胶基体及填料微观结构对丁腈橡胶(NBR)硫化胶物理性能的影响。结果表明:随着丙烯腈质量分数的增大,炭黑补强NBR硫化胶的拉伸强度先增大后减小,拉断伸长率减小,邵尔A型硬度和撕裂强度增大;随着生胶门尼粘度的增大,炭黑补强NBR硫化胶的邵尔A型硬度基本不变,定伸应力增大,拉伸强度和拉断伸长率减小;随着炭黑粒径的减小,硫化胶的定伸应力呈增大趋势,拉伸强度和撕裂强度增大,高定伸下炭黑粒径对应力的贡献较大;随着炭黑结构度的提高,硫化胶定伸应力增大,拉伸强度和撕裂强度减小。     

Effects of hot‐air aging and dynamic fatigue on the structure and dynamic viscoelastic properties of unfilled natural rubber vulcanizates

The effects of hot‐air aging and dynamic tensile fatigue on the network structure and dynamic viscoelastic properties of unfilled natural rubber (NR) vulcanizates were investigated with magnetic resonance crosslink density spectrometry, Fourier transform infrared spectroscopy/attenuated total reflection (FTIR–ATR), and dynamic mechanical analysis. The results showed that there was a carbonyl weak absorption peak at 1723 cm^?1 in the FTIR–ATR spectra of unfilled NR vulcanizates after hot‐air aging; The crosslink density decreased continuously as the aging time increased. The dynamic modulus of an aged specimen declined considerably, and the value of tan δ after 72 h of aging greatly increased. There was a large difference in the FTIR–ATR spectra of unfilled NR vulcanizates before and after tensile fatigue. The peaks at 1597, 1415, and 1015 cm^?1 increased concurrently with the tensile fatigue time. Initial analysis suggested that structures such as conjugated dienes appeared in the network structure. The modulus declined sharply, whereas the value of tan δ increased noticeably, after tensile fatigue. The effects of hot‐air aging and tensile fatigue on the crosslink density and FTIR–ATR spectra of unfilled NR vulcanizates were different, but both affected the viscoelastic properties dramatically. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Abrasion resistance of pre-stressed and stressed rubber vulcanizates

The abrasion resistance of carbon black-reinforced SBR-1500 vulcanizates has been shown to be drastically reduced by the application of tensile strain during the abrasion process. Pre-stressing of similar vulcanizates, however, has no effect upon the abrasion resistance.     

低滞后炭黑DZ13对胎面胶物理性能及疲劳破坏行为的影响

采用以天然橡胶(NR)、NR/顺丁橡胶(BR)和NR/BR/溶聚丁苯橡胶(SSBR)为基体的轮胎胎面胶配方,研究低滞后炭黑DZ13对3种硫化胶物理性能和疲劳破坏行为的影响。结果表明:低滞后炭黑DZ13部分替代炭黑N234后,NR,NR/BR和NR/BR/SSBR硫化胶的物理性能变化规律相似,即定伸应力略有增大、拉断伸长率和撕裂强度减小;耐磨性能、耐压缩疲劳性能和耐割口增长性能的变化依赖于基体橡胶;其中NR/BR硫化胶的屈挠疲劳次数提高,但疲劳破坏界面的微观形貌更加粗糙。     

纳米Al2O3/炭黑并用增强天然橡胶

研究了不同并用比纳米Al2O3/炭黑填料对天然橡胶硫化胶性能的影响。分析了填料－橡胶的相互作用。结果表明，当Al2O3／炭黑质量比为1／1时，天然橡胶硫化胶的拉伸强度和撕裂强度最高，当Al2O3／炭黑质量比为3／1时，天然橡胶硫化胶的耐磨性和耐疲劳性能最佳，填料与橡胶朴素作用中的氢键是影响天然橡胶硫化胶疲劳性能的重要因素，共价键是影响其拉伸强度的重要因素。     

反式聚辛烯橡胶改性天然橡胶/顺丁橡胶共混胶的性能

研究了反式聚辛烯橡胶(TOR)改性天然橡胶(NR)/顺丁橡胶(BR)(二者质量比80/20)共混胶的性能.结果表明,采用5～15份(质量,下同)TOR改性NR/BR混炼胶的门尼黏度逐渐降低、Payne效应基本不变,共混胶的焦烧时间和工艺正硫化时间延长、硫化速率减慢.相比NR/BR硫化胶,NR/BR/TOR硫化胶的拉伸强...     

Physico-Mechanical,Aging Properties,and Permeability of Ketones Through Vulcanizates Prepared by Different Mixing Schemes

This article reports on the physico-mechanical properties, chemical resistance, aging properties, sorption, diffusion, and permeability of ketones (cyclohexanone and acetone) through vulcanizates from blends of natural rubber (NR) and epoxidized low molecular weight natural rubber (ELMWNR) compounded by three different mixing schemes. The compounding ingredients were mixed with the two mentioned rubbers using three different mixing schemes by adopting a semi-efficient sulphur vulcanization compounding formulation. In Scheme 1, the natural rubber and ELMWNR were first mixed before adding the compounding ingredients. In Scheme 2, the compounding ingredients were first mixed with the NR before adding the ELWMNR and in Scheme 3, the compounding ingredients were first mixed with the ELMWNR before adding the NR. The physico-mechanical results of the vulcanizates showed that changes in the mixing schemes significantly influence the tensile properties of the vulcanizates. The tensile strength of the vulcanizates prepared with mixing Scheme 2 were 4.3 MPa lower than vulcanizates from Scheme 1, whereas Scheme 3 was lower than Scheme 1 with 8.5 MPa. The aging results of the vulcanizates from all the mixing schemes were found impressing. The activation energy and free energy change were highest for Scheme 1 whereas the extent of cyclohexanone and acetone penetrations were the lowest with Scheme 1, signifying well crosslinked and ketone resistant vulcanizates.     

Effect of Mixing Schemes on Physico-Mechanical,Aging Properties,and Permeability of Aldehydes through Blends of Natural Rubber and Low Molecular Weight Natural Rubber

This article reports on the physico-mechanical properties, chemical resistance, aging properties, sorption, diffusion, and permeability of aldehydes (acetaldehyde and formaldehyde) through vulcanizates from blends of natural rubber (NR) and low molecular weight natural rubber (LMWNR) compounded by three different mixing schemes. The compounding ingredients were mixed with the two mentioned rubbers using three different mixing schemes by adopting the semi-efficient sulphur vulcanization compounding formulation. In scheme 1, the natural rubber and LMWNR were first mixed before adding the compounding ingredients. In scheme 2, the compounding ingredients were first mixed with the NR before adding the LWMNR and in scheme 3, the compounding ingredients were first mixed with the LMWNR before adding the NR. The physico-mechanical results of the vulcanizates showed that changes in the mixing schemes significantly influence the tensile properties of the vulcanizates. The tensile strengths of the vulcanizates prepared with mixing scheme 2 were 3.5 MPa lower than vulcanizates from scheme 1, whereas scheme 3 was lower than scheme 1 by 7.8 MPa. The aging result of the vulcanizates from all the mixing schemes were found to be similar. The activation energy and free energy change were highest with scheme 1 whereas the extent of acetaldehyde and formaldehyde penetrations were lowest with scheme 1, signifying a well crosslinked and aldehyde-resistant vulcanizate.     

TBIR改性NR硫化胶的研究

研究了两种牌号反式-1,4-丁二烯-异戊二烯共聚橡胶(TBIR)改性天然橡胶(NR),结果表明,10~50份TBIR与NR共混,并用胶焦烧时间(t10)和工艺正硫化时间(t90)略有延长。相比NR硫化胶,NR/TBIR并用硫化胶力学强度保持在较高范围,屈挠疲劳性能大幅度提高,其中NR/TBIR-20=50/50硫化胶一级屈挠疲劳寿命可提高28.6倍,六级屈挠疲劳寿命可提高11.9倍。DMA结果表明,NR与TBIR具有优异的相容性。RPA及DMA 结果均表明NR/TBIR并用硫化胶具有更低的滚动阻力。综合可知,TBIR是一种高性能的合成橡胶新材料,可显著改善NR的综合性能。     

Effect of adhesive‐coated glass fiber in natural rubber (NR), acrylonitrile rubber (NBR), and ethylene–propylene–diene rubber (EPDM) formulations. II. Effect of cyclic loading,abrasion, and accelerated aging

Treated glass fibers (RICS, 3 and 6 mm in length) were added at a concentrations of 10, 20, and 30 phr in natural rubber (NR), nitrile rubber (NBR), and ethylene–propylene–diene comonomer (EPDM) formulations, in both plain and carbon black mixes. The compounds were mixed in two‐roll mill and were evaluated for their resistance to hot‐air aging, abrasion, compression set, Goodrich heat buildup, De Mattia fatigue, and for NR mixes, adhesion in the tensile mode. The vulcanizates of the three rubbers showed resistance to hot‐air aging. Abrasion resistance was poor for NR, and it improved with carbon black addition in the presence of treated glass fiber in NBR. In carbon‐black‐added EPDM vulcanizates, the abrasion resistance and fatigue resistance were better. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1124–1135, 2004