天然橡胶中蛋白质的作用

总结鲜胶乳中蛋白质分离和鉴定的研究概况,综述了鲜胶乳中所含蛋白质对胶乳稳定性、混炼胶的硫化特性、硫化胶的力学性能及天然橡胶抗氧老化性能的影响,并为今后开展蛋白质的分离与鉴定,蛋白质自身性能及对天然橡胶影响的研究提供参考价值。     

蛋白质对天然橡胶及其性能影响的研究

天然橡胶(NR)的主要成分为橡胶烃、水、非胶物质,其中非胶物质中蛋白质的含量对其性能的影响最大.本文分析了天然胶乳中的蛋白质的结构,介绍了低蛋白天然胶乳的制备及其性能的研究概况、蛋白质对其硫化及力学性能影响研究现状,并对低蛋白天然胶市场前景进行了分析与展望.     

天然橡胶中蛋白质的研究进展

天然橡胶中含有很大数量的蛋白质,文章从蛋白质在天然胶乳中的生理作用,蛋白质对天然橡胶性能的影响及蛋白质脱除技术三个方面简述了天然橡胶中蛋白质的研究现状。     

恒粘天然橡胶理化性能的研究

用粘度稳定剂处理天然橡胶鲜胶乳和湿杂胶，研究了粘度稳定剂种类及处理方法对橡胶的P0、PRI、MV、氮含量和加速贮存硬化值（△P）等的影响。结果表明，鲜胶乳所制得的恒粘胶经加速贮存后的△P≤1个塑性值，门尼粘度值变化量（△MV）≤3个门尼值。其它性能虽有变化，但均能达到天然生胶标准的要求。自然凝固制得的恒粘胶的P0、PRI和MV相对较高，氮含量相对较低。粘度稳定剂延长了鲜胶乳的凝固时间。粘度稳定剂处理后的杂胶，△P和△MV减少，但恒粘效果不及鲜胶乳制得的恒粘胶。     

天然橡胶中蛋白质总量的测定

凯氏定氮法常用于测定橡胶中的蛋白质含量,此法测定结果准确,重现性好,但操作费时,试剂消耗量大,更简便的方法为：在消化阶段用硫酸钾、双氧水作催化剂,消化分解完成后,固定pH值滴定。     

凝固方法对天然橡胶力学性能的影响

研究了三种不同凝固方法对天然橡胶性能和炭黑/天然橡胶硫化胶力学性能的影响。结果表明,采用十二烷基硫酸钠和氯化钙凝固制得的天然橡胶达到5号标准橡胶的质量,其力学性能比用醋酸凝固所制得的天然橡胶的力学性能要好。     

环氧化天然橡胶贮存性能的差异

对环氧化天然橡胶（ENR）及其胶乳（ENRL）进行了为期2年的贮存试验,考察其外观和主要物理性能的变异状况,探讨了这些性状变异的机理,了解到ENR和ENRL原材料长期贮存,其外以观无明显变化。     

天然橡胶乳液压敏胶粘剂

本文介绍了天然橡胶胶乳压敏胶的基本情况，内容包括基本组成、主要优缺点和改进方法。     

生物酶法催化天然乳胶中过敏蛋白质交联的研究

利用谷氨酰胺转氨酶催化天然乳胶(NRL)水溶性蛋白质(WSP)发生交联,减少天然乳胶中水溶性蛋白质的含量.利用粒径分析、结构表征、十二烷基硫酸钠凝胶电泳实验证明了交联反应的发生.采用这一新技术可以降低天然乳胶制品的过敏性,拓展了其在医疗卫生领域、食品加工等领域的应用空间.     

The utilisation of latex reclaim rubber in natural rubber

Scrap latex products contain rubber hydrocarbon of very high quality, that is only slightly crosslinked. A novel economic technique for converting such latex waste into a processible material is developed. This paper reports the effect of adding this latex reclaim to natural rubber. It is shown that latex reclaim can replace raw natural rubber up to about 50 wt.-% without affecting mechanical properties.     

烷基二硫代磷酸锌（AC-P84）在天然橡胶中的应用

作为一种不产生亚硝胺的环保型绿色促进剂,烷基二硫代磷酸锌有着其它促进剂无可比拟的优势,但以前其应用多见于三元乙丙橡胶。鉴于此,笔者将其应用在天然橡胶中,经过实验对比,发现它与其它常规促进剂相比,有着比较好的硫化焦烧特性,很好的抗硫化返原性;作为副促进剂与次磺酰胺类促进剂有着良好的协同作用。同时通过对力学性能的探讨,确定了其单独使用时的最佳用量。     

Stress softening in natural rubber vulcanizates. Part V. The anomalous tensile behavior of natural rubber

Stress-strain cycling of natural rubber to high strains produces greater softening than amorphous rubbers, but only if the force on the sample is relaxed below a certain value during the cycle. This phenomenon, attributed to crystallization shows why nonrelaxing tests give a longer fatigue life than relaxing tests.     

The effect of epoxidized natural rubber on mechanical properties of siliceous earth/natural rubber composites

Siliceous earth (SE) is a kind of mineral consisting of lamellar kaolinite, muscovite (aluminum silicate) and corpuscular silica. Natural rubber (NR) composites containing NR as matrix, epoxidized natural rubber (ENR) as compatibilizer and SE as filler were produced by latex coagulating process and cured using a conventional sulfuric system. Monsanto measurements have shown that the ENR accelerates the vulcanization reaction and gives rise to a marked increase of the torque. The results of physico-mechanical properties of NR vulcanizates show that, when SE modified by silane coupling agent and in the meanwhile adding 4 phr of ENR as compatibilizer, maximum tensile strength, elongation at break, reinforcing index (M300/100) of NR/SE vulcanizates were obtained. The dynamic-mechanical properties exhibit the addition of ENR can enhance wet grip characteristics and reduce rolling resistance by lowering tan δ values at 60 °C and increasing tan δ values at 0 °C of NR compounds. The overall results show that properties of SE-reinforced NR substantially improved by adding ENR as compatibilizer. The addition of silane coupling agent and combining an appropriate amount of ENR would be better choice to improve the properties of NR/SE compounds.     

The effects of natural astaxanthin-modified silica on properties of natural rubber

Natural astaxanthin is a natural substance extracted from algae such as Haematococcus pluvialis. Its molecular structure contains conjugated double bonds as well as keto and hydroxyl groups, and therefore it has high activity. In this research, natural astaxanthin was used to modify the surface of the silica, and its effects on natural rubber vulcanization properties, physical and mechanical properties, dynamic properties, and antiaging properties were studied by means of rubber process analyzer, dynamic mechanical anaylsis, and scanning electron microscopy. The results showed that natural astaxanthin-modified silica could reduce the degree of delayed vulcanization. At the same time, the resilience and abrasion resistance of the obtained vulcanizates were increased. The DIN abrasion volume of the vulcanizates modified and reinforced by the second strategy decreased by 19.2% and 23.6%, respectively; the Payne effect of the natural astaxanthin-modified silica/NR composites was weakened, and the dispersibility of the filler and the compatibility with the rubber matrix was significantly improved. Regardless of which strategy was used to modify the silica, the vulcanizates had a lower rolling resistance. Specially, it could greatly improve the hot air aging resistance property of rubber. Natural astaxanthin as being a renewable feedstock is expected to have a quite broad applications in the rubber industry. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 136, 47287.     

天然橡胶的改性

该文就天然橡胶的物理、化学改性方法进行了综述,分析了天然橡胶的改性技术。     

Reinforcement of natural rubber

In this article, we report on recent investigations on filled natural rubber. These investigations include a mechanical characterization as well as a molecular analysis based on measurements of chain orientation. It is demonstrated that at intermediate strains, the increase in the moduli can be explained by the inclusion of rigid particles in the soft matrix and from molecular interactions between the rubber and the filler. These interactions can be evaluated by equilibrium swelling and by orientational measurements. With regard to the unfilled formulation, carbon black– and silanized‐filled natural rubber exhibit increases in the cross‐linking density ascribed to filler‐polymer links, whereas a large decrease in the orientational level, evidenced by birefringence and by infrared dichroism, is observed when silica is added without any coupling agent. Finally, two specific effects—the Payne and Mullins effects, both related to energy dissipation phenomena—are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2301–2316, 2002     

马来酸酐接枝天然橡胶对纤维素纤维增强天然橡胶复合材料的增容作用

在无引发剂的熔融状态下,利用剪切力将马来酸酐接枝于天然橡胶分子链上,并将马来酸酐接枝天然橡胶(MNR)作为增容剂添加到纤维素纤维增强天然橡胶复合材料中,研究其对复合材料性能的影响.结果表明,在熔融状态下利用剪切力能够发生自由基反应或Diels-Alder反应,将马来酸酐接枝于天然橡胶分子链上而制得MNR.添加了MNR的纤维增强天然橡胶硫化胶的物理机械性能,尤其是定伸强度比未添加MNR的硫化胶有明显提高,应力弛豫程度减小;扫描电镜分析也说明添加MNR使填料与橡胶基质之间有了更强的界面黏合力.