X射线光谱散射成像在橡胶复合材料中的应用

Ｘ射线映射成像包括吸收射线成像和衍射成像。吸收射线成像已在医学诊断、工业材料无损检测等领域得到广泛应用。衍射成像主要用来揭示具有相当高完整性（低位错密度）的单晶体内部的不规则结构和／或Ｘ射线波动范围,从而使其应用领域受到了限制。为了减少测试试样的局限...     

橡胶防泡剂

橡胶防泡剂是橡胶无压硫化配合体系中的一种功能性助剂。本文介绍了它的作用机理、制备方法、基本性质和主要应用。     

下一代X射线技术

在过去的２５年中,轮胎一直是采用Ｘ光技术进行检验的,目的是测定其内部结构的整体性。轮胎Ｘ光检验系统能够探测到常见的缺陷有：胎体帘布断线、交叉、接头不好、胎圈包布尺寸问题、带束级差及脱空。一般来说,Ｘ光检验系统可包括４个基本组成部分：Ｘ射线发生器、轮胎...     

橡胶填充剂的新发展

本文对近年来橡胶填充剂的发展进行了系统地论述。     

橡胶填充剂的新发展

本文对近年来橡胶填充剂的发展进行了详细的、系统的讨论。     

轮胎用橡胶的元素分析一x射线荧光分析法

轮胎用橡胶的元素分析──Ｘ射线荧光分析法小谷真理奈田代育代石井子著周青山译刘登祥校前言轮胎用橡胶一般应能满足苛刻环境条件的要求。在胶料中添加各种配合剂,例如硫化剂、补强剂、填充剂、软化剂、防老剂和粘合增进剂等乃是为了改善轮胎的耐磨、耐切割、耐疲劳、耐...     

新一代液体硅橡胶

该文介绍Laursilicone新研发单组分液体硅橡胶,这种材料虽然尚处于商业化的早期阶段,但因其具有优良的物理性能和易使用性,未来的市场前景十分看好。     

Next generation of aircraft coatings systems

The current generation of aircraft coatings had its basis in the polymer technologies of the 1970s and the use of chromate-based metal pretreatments and primers. There have been some incremental improvements in the epoxy and polyamide oligomers used in the primers as well as the isocyanates and flexible polyols used in topcoats, plus increases in the volume solids of the coatings to continue minimally meeting environmental requirements, but no truly new technologies have been developed and applied to aircraft coatings since that time. However, because of increasing economic and environmental pressures, this situation will soon change. Also, the U.S. Air Force is seeking a coating system that will have an ultimate lifetime of 30 years for maintenance cost control and fleet sustainability. The first change in the present coatings system will be in the pretreatments plus primers that currently constitute the metal protection system for the high strength Al alloys used for aircraft. For military aircraft, these alloys will continue to be Al 2024 T-3 and Al 7075-T6, heat-treated metals that have phase-separated regions rich in reactive metals such as Cu, Mg, and Zn. There are several new technologies now under consideration for such metal protection including conductive polymers as primers without Cr-based metal pretreatments, sol-gel based pretreatments and primers, plasma polymer metal pretreatments, and organo-modified aluminum oxide particles. Each of these technologies has shown some promise for Cr replacement, but each presently has a weakness that needs to be corrected for immediate usage. For the topcoat system, fluorinated polyols and improved use of UV-absorbers and light stabilizers will probably be the first changes implemented, with ceramer and other new crosslinking systems the most likely next polymer matrix candidates. The target for the entire coatings system is to have drastically improved wet-adhesion due to a covalently bonded system that has a gradient in composition that goes continuously from metal to metal oxide to mixed metal oxide/organic polymer to high-performance UV-stable organic polymer. The materials cost for such a system may be quite high, but the maintenance cost savings will much more than offset these costs. Presented at the 25th FATIPEC Congress, Sept. 19–22, 2000, in Turin, Italy. Department of Polymers & Coatings, Fargo, ND 58105.     

Next generation of low global warming potential refrigerants: Thermodynamic properties molecular modeling

The recent global agreement signed in Kigali to limit the use of hydrofluorocarbons (HFCs) as refrigerants, starting by 2019, has promoted an active area of research toward the development of low global warming potential (GWP) new refrigerants. Hydrofluoroolefins (HFOs) have been proposed as a low GWP alternative to third generation HFC refrigerants, but further work on fully characterizing them and their blends with other compounds is still required to fully assess their performance to replace the ones in current use. In this work, the polar and perturbed chain statistical associating fluid theory coupled with the density gradient theory is used to predict the vapor–liquid equilibrium, isobaric heat capacity, speed of sound, and surface tension of selected HFC and HFO‐based commercial azeotropic blends as fourth generation low GWP refrigerants, seeking for a predictive tool for these properties. © 2017 American Institute of Chemical Engineers AIChE J, 63: 250–262, 2018     

新一代硫酸装置干吸塔除雾器的选择

介绍了在当前技术上作了重大改进的3种新型除雾器的开发.DEMISTER@型713丝网除雾器,在干燥塔中使用可提高效率且具有较低的压力降;FLEXIFIBER(R)BD-LdP布朗扩散型烛式除雾器,在吸收塔中使用可减小压力降且无效率损失;FLEXIFIBER(R)ICK-LF碰撞型烛式除雾器,在干燥塔和二吸塔中使用可延长使用寿命且无效率损失.讨论了每一种类型除雾器的优点和局限性,以帮助管理者作出明智的决策,针对他们的具体要求选择最好的技术,同时也将比较不同选择所预期的安装、检修和操作费用.     

浅谈橡胶防水片材挤出连续硫化生产线管路系统的改进

对防水片材挤出连续硫化生产线的四条管路做了改进。其中的硫化加热管路，设计了一套完整的油加热管路，取代了蒸汽加热管路，用户使用方便，节约能源，外观美丽，经济效益大增。     

Void formation in a filled SBR rubber determined by small-angle X-ray scattering

Two commercial styrene-butadiene (SBR) latexes were used to prepare a model filled material consisting of glassy SBR filler particles about 1000 Å in diameter embedded in a rubbery SBR matrix crosslinked by γ-radiation. When transparent specimens of this material were extended, voiding occurred, as evidenced by stress whitening and greatly enhanced X-ray scattering intensity. More voids were formed at higher rates of extension, but voids disappeared when specimens were relaxed. The effects of filler content and cure time of the matrix on the size and number of voids formed were determined by low-angle X-ray scattering for a constant extension rate and a constant extension ratio λ = 1.6. The number of voids measured by X-ray scattering intensity decreased rapidly with time over the 3-h period of measurement. The number of voids remaining 1 h after extension increased about 40 times as filler content was increased from 15% to 50%. Increasing the cure time from 24 to 96 h increased the number of voids about four times. In contrast, the radius of gyration of the voids formed (250–350 Å) did not depend strongly on time, nor did it depend strongly on the filler content or the cure time of the matrix. Stress relaxation measurements made under the same conditions as X-ray scattering measurements showed effects typical of filled materials. However, the relaxation of stress (which followed a power law decay) was much slower than the decay of the number of voids as measured by X-ray scattering intensity.     

Hysteresis loss in filled rubber vulcanizates and its relationship with heat generation

A relationship between heat generation of filled rubber vulcanizates and hysteresis loss, specific heat, thermal conductivity, modulus, filler loading, structure, and surface area of the filler, the temperature difference between application temperature and glass transition temperature, frequency, temperature difference between the wall and the environment, stress, and stroke amplitude were developed. Styrenebutadiene rubber (SBR) and natural rubber (NR) vulcanizates were used that had variations of loading of carbon black, silica, resin and coupling agent, types of filler, level of curatives, and cure time. The derived equation was verified with a set of a few unknown SBR and NR vulcanizates, and also by varying the stress and stroke amplitudes in the heat generation experiment. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1541–1555, 1997     

A wide-angle X-ray study of the development of molecular orientation in crosslinked natural rubber

Molecular orientation parameters have been measured for the non-crystalline component of crosslinked natural rubber samples deformed in uniaxial tension as a function of the extension ratio and of temperature. The orientation parapeters 〈P₂(cosα)〉 and 〈P₄(cosα)〉 were obtained by an analysis of the anisotropy of the wide-angle X-ray scattering functions. For the measurements made at high temperatures the level of crystallinity detected was negligible and the orientation-strain behaviour could be compared directly with the predictions of molecular models of rubber elasticity. The molecular orientation behaviour with strain was found to be at variance with the estimates of the affine model particularly at low and moderate strains. Extension of the crosslinked rubber at room temperature led to strain-crystallization and measurements of both the molecular orientation of the non-crystalline chains and the degree of crystallinity during extension and relaxation enabled the role of the crystallites in the deformation process to be considered in detail. The intrinsic birefringence of the non-crystalline component was estimated, through the use of the 〈P₂(cosα)〉 values obtained from X-ray scattering measurements, to be 0.20±0.02.