玻璃钢瓦及平板的大气老化与防护

本文以玻璃钢瓦及平板的大气老化现状及聚保物老化机理为依据，讨论了玻璃钢的老化防护。     

塑料大气老化与人工氙灯老化相关性试验

本试验选取六种通用和工程塑料进行大气老化和人工氙灯老化,采用缺口冲击强度或断裂伸长率保持50％为终止指标,评价其材料的耐候性。试验表明,人工氙灯老化与大气老化结果基本一致,但不同塑料间加速倍率及相关系数差别较大,尚不存在简单而统一的相关性。     

橡胶老化 防护与监测（九）

橡胶老化防护与监测（九）化工部合成材料研究院陈经盛第六章橡胶的老化试验与标准第一节大气老化试验二、动态大气老化试验方法橡胶动态大气老化试验方法，就是使试样模拟橡胶制品的实际使用状态，承受外加的动态应力的反复作用，例如拉伸、压缩或弯曲等变形的作用，并曝...     

橡胶大气老化应力松弛的评价

对８种不同类型的硫化橡胶在大气老化试验时的应力松弛变化进行了探讨。研究结果表明，橡胶的大气老化是一个复杂的化学过程，硫化橡胶的化学应力松弛变化能反映出这种过程的矛盾变化。各种橡胶的应力松弛速率的不同，反映出其耐老化性能的不同，因而硫化橡胶的化学应力松弛可以用来评价橡胶的耐候性。     

硬聚氯乙烯气候老化行为规律研究

通过半硬和硬聚氯乙烯材料（RPVC）户内外气候老化力学性能数据，分析了室内外环境与地区条件对材料气候老化行为的影响，并阐述了材料气候老化规律与材料本身配方、加工工艺条件等的依赖性。探索了材料人工光加速老化与广州户外自然大气老化的相关性，求取了RPVC材料制品冲击强度保留率的线性回归方程，并推算了材料的户外老化寿命。     

橡胶老化 防护与监测（十）

橡胶老化　防护与监测（十）化工部合成材料研究院陈经盛第六章橡胶的老化试验与标准第一节大气老化试验二、动态大气老化试验方法３．试验方法（１）试样曝露用的试样应根据所选的评价指标和相应的测试标准要求来确定。由于光老化首先发生在试样表面，慢慢才侵入到内部，...     

橡胶老化 防护与监测（八）

橡胶老化　防护与监测（八）化工部合成材料研究院陈经盛第六章橡胶的老化试验与标准第一节大气老化试验３．影响试验的主要因素（１）试验地区的气候气候是大气中诸因素的空间分布和时间变化的错综复杂的反应，主要是由太阳辐射、大气环流和地表面的各种物理现象相互作用...     

ABS颜色稳定性的老化试验

未稳定和经稳定ABS的人工加速老化试验，自然大气暴露试验和透过窗玻璃暴露试验，通过颜色和变黄指数变化评价ABS的颜色稳定性。人工加速老化与自然大气暴露有较好的相关性，加速倍率约为7。添加稳定体系能有效地抑制ABS的变黄，并观察到ABS在老化过程中的变白与变黄现象。     

防老剂JOL对并用胶料性能的影响

进行了防老剂ＪＯＬ的单用、并用（与防老剂４０１０ＮＡ）试验，考察了防老剂ＪＯＬ对并用胶料性能的影响。将防老剂ＪＯＬ应用于轮胎胎侧和内层帘布胶料中，对半成品胶料物理性能和轮胎耐久性能进行了考察。试验结果表明，防老剂ＪＯＬ与橡胶行业普遍使用的防老剂Ａ相比，硫化胶的耐热空气老化和大气老化性能均有不同程度的提高，且可降低防老剂原材料成本３９．９７％。     

氯丁橡胶的大气老化及其配方设计

氯丁橡胶的耐大气老化性能在通用型橡胶中仅次于乙丙胶和丁基橡胶，远优于天然橡胶，氯丁橡胶为外皮的电线，电缆，实际使用时间可长达20－30年，充分表明氯丁橡胶的耐候性优良，就广义的耐生来说，应具有耐臭氧，耐紫外线，耐热，耐塞，耐水侵蚀，耐沙蚀及风蚀等性质，其中最主要的是臭氧和光的作用，根据具体的使用环境不同可分为以光老化为主和以臭氧老化为主两种形式，而一般情况下，光和徉氧同时发生作用。     

改善丁苯橡胶老化性能的方法

简单介绍丁苯橡胶老化的原理以及主要因素臭氧,其次热氧。主要综述了改善丁苯橡胶静态制品和动态制品的耐臭氧老化性的物理方法,如微晶蜡和表面涂层,以及化学方法,如γ射线辐射交联、化学防老剂、与耐臭氧老化的聚合物共混。阐述了如何改善其耐热氧老化性的方法,包括增加苯乙烯的含量、填充适量炭黑和使用载硫体。     

新型橡胶防护蜡的开发与应用

介绍3种新型橡胶防护蜡XJL系列产品的开发及其应用性能。结果表明：在轿车子午线轮胎胎侧胶中加入新型橡胶防护蜡,硫化胶的物理性能变化不大,耐臭氧老化性能明显提高;当新型橡胶防护蜡用量为2份时,胶料成本较低和产品外观质量较好;10^#和30^#橡胶防护蜡的耐臭氧老化性能优于或相当于国内外同类产品。     

丁苯橡胶老化表观活化能的实验研究

进行了丁苯橡胶在海水中和热空气中的加速老化实验,测试了老化过程中的硬度和拉伸性能,得到了不同指标测定的老化活化能。结果表明：丁苯橡胶在海水中和热空气中老化时,断裂伸长率的表观老化活化能分别为49.65 kJ/mol、62.22 kJ/mol,100%定伸应力变化的表观活化能分别为45.23 kJ/mol、64.35 kJ/mol,硬度的表观活化能分别为85.45 kJ/mol7、3.21 kJ/mol。     

粘土/橡胶纳米复合材料老化性能研究

研究粘土 /SBR及粘土 /NR纳米复合材料的耐热氧老化和耐臭氧老化性能 ,并考察粘土 /SBR纳米复合材料的热失重和气体阻隔性。结果表明 ,粘土 /SBR纳米复合材料的耐热氧老化和耐臭氧老化性能均优于炭黑 /SBR复合材料 ;粘土 /NR纳米复合材料的耐热氧老化性能略优于炭黑 /NR复合材料 ,耐臭氧老化性能与炭黑 /NR复合材料相差不大 ;均匀分散的纳米粘土可提高橡胶的热稳定性和气体阻隔性 ,减缓氧及臭氧在橡胶中的扩散 ,降低橡胶分子链受攻击的几率 ,有利于提高橡胶耐热氧老化和耐臭氧老化性能     

Effects of thermal aging on fatigue of carbon black–reinforced EPDM rubber

Deterioration of the parameters measuring the fatigue of rubber compounds as a result of thermal aging was investigated. The energy to break, tear strength, fatigue life, and fatigue crack propagation rate of EPDM rubber compounds reinforced with three different types of carbon black before and after different periods of thermal aging were measured and compared through a series of static and cyclic loading tests. The experimental results indicated that the fatigue resistance of EPDM rubber compounds with different types of carbon black was consistently reduced because of changes in the molecular structure and crosslink density as a result of thermal aging. Meanwhile, the intrinsic flaws of carbon black–reinforced EPDM rubber compounds after 6 months of thermal aging were smaller, regardless of the type of carbon black. Therefore, the effects of thermal aging on the fatigue of rubber compounds are significant and should be taken into account in designing rubber components. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1244–1251, 2007     

Effects of cyclic compression and thermal aging on dynamic properties of neoprene rubber bearings

The dynamic properties of rubber bearings frequently used as isolators in structures could be significantly deteriorated because of the change of microstructure in rubber caused by cyclic compression and thermal aging. As a result, a catastrophic failure of bridges and buildings unexpectedly occurs when they are subjected to earthquake attack. Here, the dynamic properties of neoprene rubber bearings before and after different cycles of compressive loading or various periods of thermal aging were first measured and compared to each other. On the basis of the experimental results, the effects of cyclic compression and thermal aging on the stiffness, energy absorption, and equivalent viscous damping coefficient of neoprene rubber bearings are investigated. It is found that the deterioration of dynamic properties of neoprene rubber bearings caused by either cyclic compression or by thermal aging is significant and should be taken into account in designing rubber bearings. © 2007 Wiley Periodicals, Inc. JAppl Polym Sci, 2008     

Coupled analysis on heterogeneous oxidative aging and viscoelastic performance of rubber based on multi-scale simulation

An oxidative aging-viscoelastic constitutive model was established to study the coupled heterogeneous oxidation and viscoelastic performance of rubber during aging process. The basic elasticity and viscoelasticity of rubber materials were comparatively considered as the function of ongoing aging. The dynamic compression process of natural rubber at different aging times was analyzed by the finite element method. And then the effects of oxygen uptake, diffusion, and oxidative reactions on the dynamic viscoelasticity of rubber were analyzed. The permeability of the oxygen in natural rubber was determined by means of molecular dynamics simulation. The results reveal that the heterogeneous degradation caused by diffusion-limited oxidation can lead to a complex stress distribution in the natural rubber specimen under dynamic loading condition; the relaxation time and the energy dissipation of the rubber specimen also increased after aging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47452     

Effect of CeO2 on UV aging of composite insulators prepared by template-spraying method

When the silicone rubber composite insulator is exposed outdoors for a long time, it will be affected by high-temperature ultraviolet environments. In order to ensure the operation of silicone rubber composite insulators, a super-hydrophobic composite insulator with antiaging characteristics was prepared by mixing cerium dioxide (CeO₂) with silicone rubber and spraying CeO₂ on the surface of silicone rubber. This article studied the aging characteristics of the base and surface of silicone rubber composite insulator by CeO₂ in ultraviolet environment. The properties of silicone rubber composite insulators before and after aging were tested by mechanics, contact Angle, rolling Angle, bounce, and icing experiments. The aging mechanism of silicone rubber was analyzed by Fourier transform infrared spectroscopy and search engine marketing. This study prepared composite insulators with excellent mechanical, hydrophobic, and antiicing properties. The aging resistance of silicone rubber composite insulators is improved by adding CeO₂ into silicone rubber matrix and spraying CeO₂ on the surface, which also ensure the use of composite insulators in high-temperature ultraviolet environment.     

Numerical study on rubber compounds made of reactivated ethylene propylene diene monomer for fiber reinforced elastomeric isolators

A huge amount of rubber waste coming from tire industry or other sources (eg, weather strips producers) has attracted interest from researchers to investigate the possibility of recycling used rubber for various products, particularly in construction sector. This article presents a series of experimental and numerical investigations to evaluate the feasibility of regenerated synthetic rubber ethylene propylene diene monomer (EPDM) for production of a building seismic isolation system. Four rubber blends using two different sources of regenerated EPDM are considered in this study. The mechanical properties of the recycled rubber under study are evaluated through uniaxial tensile and relaxation tests, considering the accelerated aging effect. Based on several hyperelasticity and viscosity models of rubber available in the literature, several numerical test simulations on rubber compounds and on a prototype of fiber reinforced elastomeric isolators (FREIs) are performed. The test results reveal that the proposed regenerated EPDM compounds can be particularly suitable for the production of unbonded FREIs, especially because they are able to exhibit low/moderate tensile stresses at high-shear strain. The results also show that not all regenerated rubber blends fulfill the durability requirements of rubber for seismic isolation after accelerated aging tests. The durability of the specimens seems to be mainly affected by the choice of the regenerated rubber source.     

Thermooxidative aging mechanism of crumb‐rubber‐modified asphalt

We investigated the thermooxidative aging mechanism of crumb‐rubber‐modified asphalts (CRMAs) by tracing the evolution of the chemical structure and physical properties of CRMA during aging. The chemical structural evolution of crumb rubber (CR) in various aged CRMAs was characterized by measurement of the crosslink structure and composition of extracted CR. The residual asphalt of the aged CRMA was investigated by IR spectroscopy. The physical properties of CRMA were characterized by conventional testing before and after aging. We found that the change in the physical properties of CRMA correlated well with both the evolution of the rubber network and the oxidation of asphalt. The thermooxidative aging resistance of CRMA was improved with increasing CR dosage; this further illustrated that aging promoted the dissolution of CR into asphalt. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43323.