环氧化天然橡胶硫化反应动力学参数的拟合

以2-硫醇基苯并噻唑(M)、N-叔丁基-2-苯并噻唑次黄酰胺(NS)、二硫化四甲基秋兰姆(TMTD)硫为促进剂,采用流变仪测定的环氧化程度为25的环氧化天然橡胶(ENR 25)的硫化曲线,通过用硫化动力学模型和origin 7.5软件对ENR25的硫化曲线进行非线性拟合,计算出ENR25硫化动力学参数,探讨了硫化温度对添加3种不同促进剂硫化的环氧化天然橡胶硫化动力学参数的影响。研究结果表明,选用促进剂NS硫化的ENR25,硫化先驱体形成交联键的反应活性较多,硫化活性中间体形成交联键的趋势较强,交联键降解的速率常数较小,是ENR25的最佳促进剂;交联键的降解反应对硫化温度的依赖性强于硫化先驱体分解反应对温度的依赖性。     

SPSS软件在红粘土性质指标统计分析中的应用

应用SPSS软件,结合贵阳市红粘土的测试数据,描述性统计分析其物理力学性质指标特征,探索性统计各个指标的平均值置信区间.用系统聚类法对红粘土的性质指标进行分类,并探求每类内各指标的相关关系.最后应用SPSS软件的制图功能,绘制贵阳市红粘土在塑性图上的位置图,并寻找其特点.统计分析结果符合实际,为该地区的工程实践提供参考...     

植物油中溶剂残留液上气相色谱分析法

本文主要探讨抽其密闭油样瓶上部气体,用气相色谱法测定食用植物油中溶剂残留的方法.实验结果表明,液上气法对仪器无污染,峰形好、出峰快,操作简便,并与直接油样法进行了比较实验,对同一油样,测定结果很接近.本法回收、准确度和     

几种防老剂对环氧化天然橡胶性能的影响

研究几种常用的防老剂（RD、4010NA、4020、MB）对环氧化程度为25的环氧化天然橡胶（ENR25）的硫化特性、硫化胶的交联网络结构、耐热空气老化性能以及热稳定性的影响。研究结果表明,防老剂的加入有助于促进ENR25的硫化：防老剂4020具有较好的力学性能、最佳的耐热空气老化性能和较好的热热稳定性,是ENR25的最佳的防老剂。     

Effect of neodymium stearate on cure and mechanical properties of epoxidized natural rubber

The effect of neodymium stearate (NdSt) on cure and mechanical properties of expoxidized natural rubber with 25 mol.% epoxida-tion (ENR25) was studied in the concentration range of 0 to 2 phr, and the relationship between structure and mechanical properties of ENR25 vulcanizates was also discussed. Neodymium sterate was synthesized by saponification of stearic acid with newly formed rare earth hydroxide in water medium, and the structure of NdSt was investigated by Fourier transform infrared spectroscopy (FTIR). Crosslinking den-sity of vulcanized natural rubber was studied by equilibrium swelling method. The results indicated that the interaction force between carbox-ylic ion of NdSt prepared in the lab and Nd ion was mainly ionic bond through FTIR analysis. NdSt could accelerate the vulcanization of ENR25 and influence the network structure of ENR25 vulcanizates. The incorporation of 1 phr NdSt for ENR25 vulcanizates showed the op-timal aging resistnce.     

精密低功耗仪表放大器INA118及其应用

ＩＮＡ１１８的美国Ｂ－Ｂ公司生产的精密仪表放大器，它在内部集成了输入保护电路，其增益可由外部可调增益电阻Ｒｇ进行调节。本文介绍了ＩＮＡ１１８的原理、特性及应用电路。     

Thermal degradation of epoxidized natural rubber in presence of neodymium stearate

The effect of neodymium stearate (NdSt) synthesized by saponification method on thermal degradation and thermo-oxidative degradation of expoxidized natural rubber with 25 mol.% epoxidation (ENR25) was investigated by thermogravimetric analysis (TGA), and the structure of ENR25 vulcanized with NdSt after thermo-oxidative decomposition was characterized using Fourier transform infared spectroscopy-attenuated total-reflectance (FTIR-ATR). The thermal degradation kinetic parameters of ENR25 with different loadings of NdSt were determined by Coats-Redfern method. The results showed that the thermal degradation of ENR25 in nitrogen was a one-step reaction regardless of NdSt content, whereas the thermo-oxidative degradation was a multiple-step reaction. The thermal and thermo-oxidative stability of the ENR25 vulcanizates with the addition of NdSt was higher than that of pure ENR25 vulcanizates. The ENR25 vulcanizates with the incorporation of 1 phr (per hundred parts of rubber) NdSt imparted the highest activation energy (E) of thermal and thermo-oxidative degradation. This could be attributed to the many unoccupied orbits in rare earth Nd, which could capture the free radicals and make the epoxide groups stable in the process of thermal and thermo-oxidative degradation for ENR25.     

适用于采动影响区的新型可调式钢管桁架设计研究

随着大量输电线路工程的建设,线路途径采动影响区的比例日益增高.在开采活动的影响下,输电铁塔塔基处地表可能产生移动和变形,造成基础倾斜、杆塔变形等危害.中空防护大板基础已成功应用于特高压直流线路采动影响区,取得了良好的效果和工程应用经验,但其适应地形能力差、开方量巨大、水土流失严重.结合钢构件和长短腿的设计经验,提出将刚...     

硬脂酸钕对环氧化天然橡胶性能的影响

用皂化方法制备了硬脂酸钕,采用傅立叶红外光谱法对硬脂酸钕进行结构表征,采用常规方法与环氧化天然橡胶(ENR)混炼、硫化制得硫化胶,研究了硬脂酸钕用量对ENR的硫化特性与力学性能的影响,采用动态压缩生热仪分析了硬脂酸钕用量对ENR硫化胶的温升特性。研究结果表明:自制的硬脂酸钕结构中羧酸根离子与稀土钕离子间的作用是离子键性质的;随着硬脂酸钕用量的增加,ENR胶料的焦烧时间TS1与工艺正硫化时间T90逐渐缩短,硫化速率指数(CRI)也有所增加,说明硬脂酸钕具有促进ENR硫化的作用;1phr硬脂酸钕使ENR具有较好的力学性能,而且ENR的压缩疲劳温升△T2最低,达到10.7℃。