环化橡胶共混物的热学性能和热力学参数

上世纪50年代以来,橡胶科学界一直在关注由天然橡胶（NR）、聚丁二烯橡胶（BR）和异戊二烯橡胶（IR）产生的环化橡胶。环化橡胶产品使用在粘合剂、涂料、油墨的配方中,也用于NR的配合来改善其力学性能,环化NR可加入到胎面胶胶料中来改善牵引性能、胎面耐磨性和耐撕裂性。更进一步的是,以这一发现为基础,环化IR可以与氯化丁基橡胶或NR共混,用于轮胎气密层胶料。     

碳酸钙晶须增强炭黑NRNBR橡胶复合材料的研究

天然橡胶（NR）与丁腈橡胶（NBR）共混,共混胶兼并NR物理机械性能及NBR耐油性能,但炭黑补强/NR/NBR橡胶复合材料物理机械性能相比炭黑补强NR橡胶复合材料差。在炭黑补强/NR/NBR橡胶复合材料中,加入碳酸钙晶须旨在增强复合材料物理机械性能,提高其使用范围。本文采用钛酸酯偶联剂对碳酸钙晶须进行改性,研究改性后碳酸钙晶须对炭黑/ NR/ NBR橡胶复合材料性能的影响。结果表明：钛酸酯偶联剂改性后的碳酸钙晶须,表面性能改变,有效提高了碳酸钙晶须与炭黑/NR/NBR橡胶复合材料的相容性。当碳酸钙晶须用量为4份时,复合材料的综合性能最佳,有效改善复合材料Payne效应。     

环氧化天然橡胶和乙烯丙烯酸酯橡胶对白炭黑填充天然橡胶／再生胶粉并用胶性能的影响

就环氧化天然橡胶（ENR）和乙烯丙烯酸酯橡胶（EAA）两组分增容剂对白炭黑填充天然橡胶（NR）／再生胶粉（RRP）并用胶的硫化特性、机械性能、溶胀性和形态进行了研究。结果表明，对于白炭黑填充NR／RRP并用胶，加入ENR／EAA可缩短硫化时间t90，改善加工性能和提高交联密度，还可提高诸如拉伸强度、定伸应力和硬度等机械性能。机械性能的改善是由于加入ENR／EAA两组分增容剂使白炭黑与NR／RRP并用胶之间的交联密度得到提高和相互作用有所改善的缘故。     

橡胶对聚乳酸增韧改性的研究进展

聚乳酸（PLA）具有可降解、生物相容性好、能耗低等优点，但是其存在韧性差、降解速率慢、疏水性、缺乏反应侧链基等特点，限制了PLA的应用范围。橡胶类材料具有优异的弹性与韧性，可作为改善PLA性能的材料。文章概述不同橡胶类型如天然橡胶（NR）、丁腈橡胶（NBR）、丙烯酸酯橡胶（ACM）、硅橡胶（SI）、其他橡胶等对PLA性能的影响。文章综述近年来不同加工工艺下橡胶改性PLA的研究进展，进而提出了橡胶改性PLA面临的困难，指出提高橡胶与PLA之间的界面相容性是未来研究的重点。     

天然橡胶/丁苯橡胶/反式丁戊橡胶并用胶的性能研究

研究反式丁戊橡胶（TBIR）对天然橡胶（NR）/丁苯橡胶（SBR）并用胶性能的影响。结果表明：用15份TBIR替代NR,NR/SBR/TBIR并用胶的NR与SBR相容性改善,拉伸强度和定伸应力略有降低,耐磨性能、耐压缩疲劳性能和耐屈挠疲劳性能提高;用15份TBIR替代SBR,NR/SBR/TBIR并用胶的NR与SBR相容性明显改善,拉伸性能变化不大,耐磨性能、耐压缩疲劳性能和耐屈挠疲劳性能提高;用15份TBIR替代NR/SBR并用胶,NR/SBR/TBIR并用胶的大部分性能介于TBIR单独替代NR与SBR并用胶的性能之间,抗湿滑性能提高,滚动阻力降低;在NR/SBR并用胶中直接加入6份TBIR,NR/SBR/TBIR并用胶的NR与SBR相容性改善,耐磨性能、耐压缩疲劳性能和耐屈挠疲劳性能提高,抗湿滑性能和滚动阻力降低。     

BR/NR并用胶在隔震橡胶支座中的应用

研究顺丁橡胶（BR）/天然橡胶（NR）并用比对并用胶性能的影响,并将并用胶用于隔震橡胶支座,考察其对隔震橡胶支座力学性能及温度相关性的影响。结果表明：与NR胶料相比,BR/NR并用胶的加工性能更优,耐低温性能更好,热空气老化性能基本不变,拉伸强度和撕裂强度随着BR/NR并用比的增大逐渐减小;NR与BR并用对隔震橡胶支座的力学性能不利,对温度相关性有利。     

石墨烯改性船用橡胶隔振器的研制及应用试验

针对船用橡胶隔振器对高强度、高导热、低蠕变及低生热的综合要求,通过采用超临界二氧化碳流体技术,并使用不同前驱体和载体及偶联剂表面改性等方法分别制备了氧化石墨烯（GO）和天然鳞片石墨烯（NG）母粒,通过混炼和硫化工艺研究及优化GO和NG的添加量,分别制得了2种改性的天然橡胶（NR）和丁腈橡胶复合材料,并测试了改性NR复合材料在橡胶隔振器产品中的隔振效果。结果表明,与未改性橡胶材料相比,改性橡胶材料的综合性能明显得到改善;与使用未改性橡胶制得的隔振器产品相比,由改性橡胶制得的隔振器产品的隔振效果得到改善,当静态承载能力保持不变的时候,其固有频率降低了8.7%,蠕变下降了40.0%。此外,在隔振系统试验中,实测低频段的隔振效果有所改善。     

天然橡胶胶料的耐低温性能研究

研究天然橡胶（NR）胶料的耐低温性能。结果表明：NR胶料的耐低温性能可以通过橡胶并用、改变填充剂和增塑剂种类、调整硫黄用量等方式进行提高。玻璃化温度低且与NR相容性好的增塑剂可以改善胶料的耐低温性能;选用低结构度炭黑可以明显改善胶料的耐低温性能;加入树脂对胶料的耐低温性能不利;促进剂并用对胶料的耐低温性能基本无影响,但硫黄用量对胶料的耐低温性能影响很大。     

环氧化天然橡胶对累托石/炭黑/天然橡胶纳米复合材料性能的影响

研究环氧化天然橡胶（ENR）对累托石（REC）/炭黑/天然橡胶（NR）纳米复合材料性能的影响。结果表明：REC/炭黑/NR纳米复合材料中填料分散均匀,REC片层呈纳米级分散;ENR改善了REC与橡胶基体间的界面相互作用,增大了复合材料交联密度,从而显著提高了复合材料的力学性能、抗切割性能和耐磨性能,且各性能增幅随ENR用量的增大而增大。     

钼系高乙烯基聚丁二烯橡胶在输送带胶料中的应用

研究钼系高乙烯基聚丁二烯橡胶（HVBR）与天然橡胶（NR）并用在输送带胶料中的应用。结果表明,HVBR/NR并用可改善输送带胶料的加工性能,基本不影响胶料的物理性能,可明显增大输送带胶层与纤维帘布的剥离强度,特别是热氧老化后HVBR/NR并用胶层的剥离强度明显大于NR单用胶层,HVBR的应用优势明显。     

Preparation and characterization of maleic anhydride-grafted desulfurization rubber powder by free-radical polymerization

The objective of the article was to enhance the recycling value of solid waste rubber by surface functionalization of desulfurized rubber powder using a one-pot method based on free-radical polymerization theory. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscopy, and elemental analysis were used to characterize the maleic anhydride-grafted desulfurized rubber powder, and the grafting mechanism was also investigated. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that maleic anhydride was grafted onto the desulfurized rubber powder. Thermogravimetric analysis indicated that the maleic anhydride-grafted desulfurized rubber powder and desulfurized rubber powder possessed different thermal properties and structure. The results of scanning electron microscopy and elemental analysis illustrated that the surface of the desulfurized rubber powder was covered with a layer of fold-like maleic anhydride polymer. The mechanism of grafting desulfurized rubber powder with maleic anhydride may be achieved by replacing the active α-H on the methylene group of the desulfurized rubber macromolecule chain.     

天然橡胶织物胶膜胶料配方设计

根据天然橡胶织物胶膜制品对胶料的要求,作者进行了天然橡胶L9（34）胶料的正交配方设计,研究分析了硫化体系、粘合体系及增塑剂用量对天然橡胶性能的影响,制定了综合性能优良的天然橡胶配方。对正交优化后的配方还进行了硫化温度、硫化压力工艺参数试验。结果表明,硫化温度对配方的影响较大,硫化压力对配方的影响较小。     

On the compatibility of polysaccharide/maleic copolymer blends. II. Thermal behavior of pullulan‐containing blends

The compatibility of pullulan with maleic acid/vinyl acetate copolymers in the solid state in the form of thin films was studied with thermogravimetry, differential scanning calorimetry, infrared spectroscopy, and optical microscopy. With respect to morphology, blends with a content of pullulan greater than 85 wt % exhibited an even distribution of finely dispersed particles. The thermal properties were dependent on the mixing ratio, and the interactions between components were quite pronounced in the pullulan‐rich blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1782–1791, 2002     

A computer-aided experimental setup for studying sorption kinetics

A novel rubber blend system has been developed that is self-vulcanizable. No rubber chemical was required for vulcanization, and the mixing operation could be completed in less than 14 min. Such a clean rubber blend system can be reinforced by carbon black filler, and physical properties are comparable to those of conventional rubber vulcanisates. Differential scanning calorimeter studies and dynamic mechanical analysis show that neoprene and carboxylated nitrile rubber are not miscible at the segmental level.     

Functionalized liquid polyisoprene as a promising toughening agent for poly(lactic acid): Combining stiffness and toughness

Liquid polyisoprene rubbers (LIR) containing anhydride and carboxylic groups along their chains were successfully employed as toughening agent for poly(lactic acid) (PLA) without great influence on the stiffness of the matrix. In fact, the addition of 5% of these functionalized LIR resulted in an improvement of toughness and impact resistance of more than 2000%, whereas the reduction of the yield stress stayed in the range of 12%. No significant variation of the Young modulus was observed for the modified PLA samples. The effect of the LIR on the rheological and thermal properties of PLA was also investigated. The glass transition temperature obtained from dynamic-mechanical analysis of the PLA matrix was not affected by the addition of 10% of the liquid rubber. The scanning electron microscopy analysis revealed a significant decrease in the rubber domains for the blends containing LIR functionalized with anhydride groups. Finally, the modified PLA with anhydride-functionalized LIR was able to produce transparent film with outstanding mechanical performance than neat PLA, making this material a good option for food packaging.     

SEM/EDX studies of the influence of a cobalt adhesion promoter on the interface between rubber skim compounds and tire steel cord

The failed interfaces between natural rubber skim compounds and tire steel cord used as tire cord adhesion test (TCAT) specimens have been studied by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis in order to understand the influence of cobalt boroacylate in the rubber compound as an adhesion promoter. SEM studies indicated a mixture of cohesive failure in the rubber and interfacial failure between the rubber and the brass coating. Cobalt boroacylate leads to more cohesive failure of the rubber (about 88% of the cord area covered by the rubber compared with 73% by the control), due to its degradative effects on rubber. EDX analysis of the failed cord and rubber surfaces at various points gave the concentrations of copper, zinc, cobalt, iron, silicon, sulfur, oxygen, and carbon. Assuming van Ooij's model of interfacial sulfide film formation over the brass (Cu/Zn) layer and analyzing the EDX results, it is clear that the failure occurs at the Cu/Zn and Cu_xS/ZnS sub-layers.     

胶料热物性对微波加热硫化温度场的影响

采用闪光导热分析仪和差示扫描量热仪对异戊橡胶(IR)在硫化过程中的热物性参数进行测量,得出热导率和比热容随温度的变化规律。同时采用ANSYS有限元分析软件对IR进行三维建模,并对其微波加热硫化过程进行数值模拟,得到热导率和比热容恒定或随温度变化等4种情况下胶料内部的焦耳热密度分布和温度分布。结果表明,热导率变化对胶料温度分布影响不大,而比热容变化的影响较大。     

硅橡胶耐高温用含铈聚硅氧烷的制备及应用

本文以硅氧烷、氢氧化钾、无水氯化铈为原料,制备了一种与硅橡胶结构相似的含铈硅氧烷(PSC)。研究PSC用量、硅氧烷种类以及不同耐热添加剂对硅橡胶耐高温性能的影响。通过红外光谱对PSC结构进行表征,力学测试、热重分析、扫描电镜研究其加入硅橡胶前后的性能。结果表明：在250℃×24h和300℃×8h热老化条件下,随PSC用量增加,硅橡胶的拉伸强度、断裂伸长率和撕裂强度先增加后降低,硬度基本保持不变,PSC加入量为5%时,材料具有最佳的力学强度。PSC在硅橡胶中分散均匀,其加入起后始分解温度提高了250℃。     

Devulcanization of Natural Rubber Vulcanizates by Mechanochemical Process

Using a suitable disulfide-based devulcanizing agent, which cleaved the sulfur cross-links in vulcanized rubber at high temperature, devulcanization of gum natural rubber was carried out. High sulfur and medium sulfur, as well as low sulfur–containing rubber vulcanizates were used to study the cleavage of sulfidic bonds. The cure characteristics and mechanical properties of vulcanized natural rubber and revulcanized natural rubber were studied. Thermal properties of the rubber were analyzed by thermogravimetric analysis (TGA), which indicates that the onset degradation temperature further increased on revulcanization with higher amount of disulfide. The properties of the revulcanized natural rubber increased with increasing disulfide concentration, also the mechanical properties of the devulcanized natural rubber were increased by decreasing the sulfur content in the original rubber vulcanizate. From the rheometric study increases in optimum cure time were observed when ground rubber vulcanizates were treated with higher amounts of disulfide. The scanning electronic microscopy (SEM) study suggested the change in failure mechanism as influenced by the type of cross-linking present and the devulcanizing agent used. From infrared (IR) spectroscopy it was observed that the oxidation of the main polymeric chain did not occur at the time of high temperature milling.     

Study of flame-retarded silicone rubber with ceramifiable property

Fire-resistant ceramifiable silicone rubber composites with excellent comprehensive property were prepared in this paper. Silicone rubber was used as the base polymer, aluminum hydroxide, magnesium hydroxide, zinc borate, and glass frits were additives. The flammability and thermal stability properties, essentially focusing on the use of the limiting oxygen index and thermogravimetric analysis, were all studied. Besides, the ceramic residues were also studied by mechanical testing, scanning electron microscopy, and X-ray diffraction. The ceramifying silicone rubber could achieve a limiting oxygen index value of 34.8%, and the flexural strength of ceramic residues formed at 800°C was 9.7 MPa. The residue of composites was approximately 58.6% at 700°C, which is significantly higher than that of neat silicone rubber. The scanning electron microscopy analysis depicted that a dense structure was formed as formed.