溶菌酶凝固天然橡胶加工性能和力学性能的研究

采用溶菌酶凝固天然胶乳,对凝固后天然橡胶的理化性能、加工性能及力学性能等进行研究,并与酸凝固天然橡胶对照。研究表明,溶菌酶凝固天然橡胶综合性能优异。溶菌酶凝固天然橡胶混炼胶与酸凝固天然橡胶混炼胶相比,弹性模量G’高,损耗因子tanδ小。与酸凝固天然橡胶相比,溶菌酶凝固天然橡胶蛋白质含量高,耐氧老化性能好,硫化速率快,硫化胶交联密度高,力学性能好。     

溶菌酶凝固天然橡胶加工性能和力学性能的研究

采用溶菌酶凝固天然胶乳,对凝固后天然橡胶的理化性能、加工性能及力学性能等进行研究,并与酸凝固天然橡胶对照。研究表明,溶菌酶凝固天然橡胶综合性能优异。溶菌酶凝固天然橡胶混炼胶与酸凝固天然橡胶混炼胶相比,弹性模量G’高,损耗因子tanδ小。与酸凝固天然橡胶相比,溶菌酶凝固天然橡胶蛋白质含量高,耐氧老化性能好,硫化速率快,硫化胶交联密度高,力学性能好。     

不同凝固方式的天然橡胶干胶气味成分分析

分析不同凝固方式制备的天然橡胶干胶的气味成分,为生物凝固应用于生产提供技术参考。用顶空固相微萃取与GC-MS联用检测不同凝固方式处理的天然橡胶干胶的挥发性成分。发现不同凝固方式对天然橡胶干胶的气味组分与含量都有一定影响。不同的鲜胶乳凝固方式对制得的天然橡胶湿凝块气味组分的影响要大于对干胶气味组分的影响。     

凝固方法对天然橡胶性能的影响

本文研究了凝固方法对天然橡胶性能的影响。结果表明:不同凝固方法制备的天然橡胶都达到5号标准橡胶的质量指标,生物凝固的天然橡胶硫化时间较短、硫化胶力学性能较好、而抗老化性能较差,HAc凝固的天然橡胶的硫化时间较长,硫化胶力学性能较差,而抗老化性能较好。     

白糖辅助微生物凝固天然橡胶的特性研究

为提高微生物凝固天然橡胶的性能,采用白糖辅助微生物凝固法制备了一系列白糖辅助微生物凝固天然橡胶,并对白糖辅助凝固胶的性能进行了全面的评价。研究结果袁明,与酸凝固和微生物凝固天然橡胶相比,白糖辅助凝固天然橡胶性能较好,其生胶纯度高,抗老化性能好;硫化胶在老化前后的力学性能都是最好的。其不足之处是,与酸凝固和微生物凝固硫化胶相比,白糖辅助凝固硫化胶的抗老化性能最差。     

镧配合物对天然橡胶的防老化作用

选用自制的镧配合物,采用常规方法与天然橡胶混合、硫化制得硫化胶,测试了胶料的硫化特性、硫化胶的力学性能,研究了天然橡胶硫化胶的耐热氧老化性能。结果表明:镧配合物的加入,有助于改善天然橡胶的硫化特性;添加镧配合物的硫化胶力学性能有明显提高;硫化胶的热氧老化结果显示,镧配合物的加入对天然橡胶有较好的防老化作用,其防老化效果优于工业常用防老剂4010NA。     

凝固方法对胶清橡胶力学性能的影响

研究了3种不凝固方法对胶清橡胶性能和碳黑或CaCO3/胶清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CaCl2凝固胶清制得胶清橡胶具有较好的性能.     

硫化型吸水膨胀天然橡胶的制备研究

采用原位聚合法在天然胶乳中制备出吸水膨胀天然橡胶,并硫化制得硫化型吸水橡胶（WSNR）。傅立叶红外谱图分析发现该原位聚合法能使聚丙烯酸钠接枝到天然橡胶的分子链上;TG和DTG分析表明接枝了聚丙烯酸钠的天然橡胶的热稳定性能有一定的提高;不同硫化体系对吸水橡胶的硫化性能影响考查结果表明：随着硫黄用量的增加,WSNR的吸水性能降低、力学性能得到提高。     

射流凝固制备的天然橡胶性能的研究

利用射流凝固(NR-j)的方法制备天然橡胶,研究了天然橡胶的性能。分析结果可得:射流凝固天然橡胶的溶胶含量较低,杂质含量、灰分含量、氮含量和塑性初值比酸凝固天然橡胶的大,而挥发分和塑性保持率较小。在硫化性能上,射流凝固天然橡胶的硫化速率比酸凝固天然橡胶的速率稍大,硫化胶的强度也大于酸凝固天然橡胶的强度,但其老化后的强度保持率小于酸凝固天然橡胶。     

几种不同凝固方法对天然橡胶性能的影响

对6种不同的凝固方法与酸对照样的性能进行对比,探讨不同凝固方法对天然橡胶性能的影响。结果表明,辅助生物凝固剂凝固胶理化性能优于其它方法;酸对照样的力学性能低于微生物凝固胶;硫化特性和热分析的微生物凝固胶也优于酸对照样;不同的凝固方法对相对分子质量及其分布影响不显著。     

国产脱蛋白天然橡胶的性能及应用

研究国产脱蛋白天然橡胶（DPNR）的性能及其在减震橡胶制品中的应用。结果表明：与普通天然橡胶（NR）相比,DPNR的氮含量较小,压缩生热较低,压缩永久变形较小,弹性和电绝缘性能较好,拉伸强度和拉断伸长率略低,耐老化性能稍差;用国产DPNR为主体材料试制的机车弹性旁承的强化疲劳性能、尺寸稳定性和弹性好,压缩永久变形小。     

橡胶加工分析仪研究环氧化天然橡胶的性能

用橡胶加工分析仪对环氧化天然橡胶进行了温度扫描、频率扫描和应变扫描，并和天然橡胶的响应曲线进行了对比。     

Effect of surface modification of silicon carbide nanoparticles on the properties of nanocomposites based on epoxidized natural rubber/natural rubber blends

Improvement of the properties of rubber nanocomposites is a challenge for the rubber industry because of the need for higher performance materials. Addition of a nanometer‐sized filler such as silicon carbide (SiC) to enhance the mechanical properties of rubber nanocomposites has rarely been attempted. The main problem associated with using SiC nanoparticles as a reinforcing natural rubber (NR) filler compound is poor dispersion of SiC in the NR matrix because of their incompatibility. To solve this problem, rubber nanocomposites were prepared with SiC that had undergone surface modification with azobisisobutyronitrile (AIBN) and used as a filler in blends of epoxidized natural rubber (ENR) and natural rubber. The effect of surface modification and ENR content on the curing characteristics, dynamic mechanical properties, morphology and heat buildup of the blends were investigated. The results showed that modification of SiC with AIBN resulted in successful bonding to the surface of SiC. It was found that modified SiC nanoparticles were well dispersed in the ENR/NR matrix, leading to good filler‐rubber interaction and improved compatibility between the rubber and filler in comparison with unmodified SiC. The mechanical properties and heat buildup when modified SiC was used as filled in ENR/NR blends were improved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45289.     

Controlled degradation of cured natural rubber by encapsulated benzophenone as a photosensitizer

The photodegradation of raw natural rubber and natural rubber compound film were studied using an artificial solar energy simulator. The properties of degraded rubber sheets containing benzophenone (BP) were determined by solution viscosity, ¹H‐NMR, and FTIR analyses. In the case of rubber compounds containing BP, the changes of tensile strength and crosslinking density were determined. It was found that BP could amply accelerate the photodegradation of rubber. To control the release rate of BP, it was necessary to encapsulate BP with urea–formaldehyde as a matrix. The encapsulated BP or capsule was formed by an interfacial polycondensation reaction between formaldehyde and urea. The kinetic of release rate of BP from urea–formaldehyde capsule was markedly observed within 15 days of release time; after that the rate of BP released from urea–formaldehyde microcapsule was very slow. At the same concentration of BP, the degradation rate of rubber compound by adding BP directly was faster than that of the rubber containing encapsulated BP. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 297–305, 2003     

天然虾青素改性白炭黑/天然橡胶复合材料的制备与性能

采用天然虾青素对白炭黑表面进行物理改性，并与天然橡胶（NR）制备成复合材料。利用RPA、DMA、SEM等测试手段对天然虾青素改性白炭黑/天然橡胶复合材料的结构与性能进行表征。结果表明，在硫化特性方面，与未采用天然虾青素改性白炭黑相比，采用天然虾青素改性白炭黑所得胶料的焦烧时间和工艺正硫化时间均缩短，促进了橡胶的硫化过程；在物理力学性能方面，所得硫化胶的拉伸强度基本不变，回弹性和耐磨性明显增加，压缩生热降低；在动态黏弹性方面，所得硫化胶的Payne效应明显降低，填料的分散性在一定程度上得到改善；在动态力学性能方面，所得硫化胶的滚动阻力降低，玻璃化转变温度提高。特别地，在耐老化方面，天然虾青素改性白炭黑/天然橡胶复合材料的耐热空气老化性能明显提高。     

A study on morphology and physical properties of natural–acrylic rubber blends

Morphology and physical properties of natural–acrylic rubber blends were investigated as a function of blend compositions and mixing methods. In the first method, the masticated natural rubber was cross‐blended with the acrylic rubber for 15 min, followed by a sequential addition of vulcanizing chemicals (ZnO, stearic acid, MBT, sodium stearate, and sulfur), and the mixing was terminated within 15 min. In the second method, the masticated natural rubber was premixed with its relevant vulcanizing chemicals (excepting the sulfur) for 7 min, followed by blending it with the acrylic rubber and sodium stearate for 20 min. Finally, the sulfur was added and the mixing was continued for further 3 min before termination. The resulting blends were vulcanized to their optimum cure time in a compression mold. The rubber sheet was cut into a dumbbell‐shaped specimen, and tensile properties were determined at a cross‐head speed of 500 mm/min. The morphology of the blends was examined with scanning electron microscopy (SEM). The SEM specimen was prepared by cryo‐fracturing, followed by staining with OsO₄. It was found that all of the rubber blends were immiscible, as shown by there being two separated phases in the SEM micrographs. The result was in a good agreement with that from a thermal analysis (using a differential scanning calorimeter), which showed two glass transition temperatures. Morphology of the rubber blends changed from a cocontinuous morphology to a dispersed particle morphology as the natural rubber content was increased from 20% to 80% by weight. Increasing the natural rubber content enhanced tensile properties of the rubber blends at the expense of their oil and heat resistance. Most of these properties being examined seemed to be unaffected by the mixing method, with the exception of the retention of tensile strain after aging. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1532–1539, 2002     

甲基丙烯酸铈的制备及其补强天然橡胶性能研究

制备甲基丙烯酸铈[Ce(MAA)_3],并对其补强天然橡胶(NR)性能进行研究。结果表明:Ce(MAA)_3的粒径为20μm左右;硫化后,胶料中Ce(MAA)_3的粒径明显减小,分散效果较好,与橡胶的相界面作用增强;在一定范围内,随着Ce(MAA)_3用量增大,Ce(MAA)_3补强NR硫化胶的拉伸强度和撕裂强度增大,Ce(MAA)_3用量为40份时,其补强效果较好。     

Effects of different drying methods on the microstructure and thermal oxidative aging resistance of natural rubber

In this work, the wet natural rubber granules were dried by hot air and by microwave at 115°C, respectively; the morphological structures of dried natural rubber granules were studied by using a scanning electronic microscope, whereas the thermal oxidative properties of dried natural rubber granules were investigated by comparison of variation in properties before and after aging, and the changes in the thermal oxidative decompose temperatures. The results showed that it needed 13.47 min for microwave drying and 210.00 min for hot air drying to reduce the moisture content of wet natural rubber to the required value. The granules of natural rubber dried by microwave were of rough surfaces and the cutting traces produced during the processing of wet natural rubber remained on the natural rubber surface; whereas, the natural rubber granules dried by hot air were of smooth surfaces, and the cutting traces produced during the processing of wet granules disappeared. The thermal oxidative resistance of vulcanized natural rubber dried by microwave improved significantly. The initial plasticity (P₀), plasticity retention index, and thermo‐oxidative decomposition temperature of natural rubber dried by microwave were higher than those of natural rubber dried by hot air. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

硅藻土/天然橡胶复合材料的性能研究

利用环氧化天然胶乳作为硅藻土的界面改性剂,制备了硅藻土/天然橡胶复合材料,通过无转子流变仪、电子万能材料试验机和橡胶动态压缩生热仪,研究了复合材料的硫化特性,物理机械性能和温升特性。结果表明,硅藻土/天然橡胶复合材料的焦烧与正硫化时间随着硅藻土含量的增加,先增后减;最大与最小扭矩随硅藻土含量的增加而增加;硅藻土/天然橡胶复合材料的拉伸与撕裂强度均有提高,当硅藻土含量为4phr时,拉伸强度最高,为28.5MPa;当硅藻土的含量为2phr时,撕裂强度最高,为37.9N/mm;由于硅藻土的加入,材料的内生热显著降低。     

无卤阻燃型天然橡胶的研究

该文研究了阻燃剂种类和用量对天然橡胶硫化胶的阻燃性能、力学性能和硫化特性的影响。结果表明：单用氢氧化铝时,随着用量增加,硫化胶阻燃性能上升,但力学性能有所下降,氢氧化铝用偶联剂A151表面改性处理后,硫化胶力学性能有所改善;红磷作为阻燃剂用量比较少,在提高硫化胶阻燃性的同时可改善其力学性能;氢氧化铝、红磷和三氧化二锑并用可产生较好的阻燃协同效果,同时会加快橡胶的硫化速度。