共查询到19条相似文献,搜索用时 79 毫秒
1.
自然环境贮存条件下氟硅橡胶的寿命预测 总被引:1,自引:0,他引:1
对氟硅橡胶材料在全国5个典型气候地区万宁、漠河、敦煌、西双版纳和济南进行了库内贮存试验,分析了不同地区自然老化过程和受力状态(压缩率为25%)下材料力学性能的变化情况。结果表明,压缩永久变形保留率可以作为老化寿命的参考指标,以此建立了5个地区氟硅橡胶受力状态下的贮存寿命方程,利用二分法和线性回归估计确定了氟硅橡胶库内贮存寿命方程中的相关参数,并以压缩永久变形保留率下降到50%作为材料的老化指标,在95%的置信水平下,预测出5个地区氟硅橡胶的寿命由短到长依次为:西双版纳419 d、万宁944 d、济南1 043 d、敦煌2 031 d、漠河3 330 d。 相似文献
2.
3.
以压缩永久变形为寿命分析研究对象,研究了常用工况下老化时间对黏弹性阻尼硅橡胶的储能模量、损耗模量及损耗因子的影响,同时采用热空气加速老化试验方法探究了黏弹性阻尼硅橡胶在不同温度(348,363,378,393 K)下压缩永久变形性能保持系数随老化时间的变化规律,并通过对两种老化动力学模型进行研究分析和修正获得了黏弹性阻尼硅橡胶的老化反应速率,此外,还对不同老化动力学模型下老化反应速率对Arrhenius模型的非线性行为进行了分段研究,推测了黏弹性阻尼硅橡胶的储存寿命。结果表明,在室温(298 K)下两种老化动力学模型在储存寿命为10.0 a时的压缩永久变形性能保持系数均为0.60;当选择压缩永久变形性能保持系数为0.50作为失效判据时,黏弹性阻尼硅橡胶的储存寿命分别为20.0 a和19.2 a,使用两种模型所得黏弹性阻尼硅橡胶的储存寿命误差仅为4%。 相似文献
4.
基于高温加速试验的点火药盒贮存寿命预估 总被引:1,自引:0,他引:1
采用高温老化方法,研究了点火药盒的老化失效规律,预估了其贮存寿命。研究结果表明,点火药盒没有早期失效,失效时间分布集中,其失效机理为赛璐珞壳体老化,失效模式为材料力学性能下降导致壳体破坏。点火药盒贮存寿命与温度的关系符合Arrhenius方程。评估结果表明,点火药盒的常温贮存寿命大于12年的设计指标要求。 相似文献
5.
探讨了市售硅橡胶混炼胶(sPF1151)的压缩永久变形性能及其改善对混炼胶力学性能的影响。获得了改善硅橡胶混炼胶压缩永久变形性能的适宜配方和工艺。 相似文献
6.
本文介绍了一些具有优良低压缩永久变形和热老化特性的新型乙烯基硅橡胶胶料,可用作快速硫化硅橡胶垫圈材料和液体注压胶料。 相似文献
7.
发射药加速寿命试验的相关性研究 总被引:5,自引:0,他引:5
用Spearman的秩相关检验法和相关系数法定量地分析了某种发射药温度单应力加速寿命试验与现场贮存试验之间的相关性。结果表明,两者显著相关。给出了相关方程及两者之间的加速系数。 相似文献
8.
9.
低苯基硅橡胶压缩永久变形性能的研究 总被引:1,自引:0,他引:1
比较了不同捏合工艺下热硫化低苯基硅橡胶的压缩永久变形性能。发现捏合时间对低苯基硅橡胶的压缩永久变形性能有显著影响。随着捏合时间的延长,压缩永久变形性能先降后增,当捏合时间达到150 min时,压缩永久变形性能趋于稳定;继续延长捏合时间,压缩永久变形性能变大;随着热空气老化温度的升高,低苯基硅橡胶的压缩永久变形变大,在300℃×12 h条件下压缩永久变形可达100%,基本丧失了回弹能力;随着热空气老化时间的增加,低苯基硅橡胶压缩永久变形变大,在200℃×1 200 h、250℃×72 h、300℃×12 h老化后,低苯基硅橡胶的压缩永久变形达到100%,基本丧失了回弹能力。 相似文献
10.
11.
12.
Effect of gel on crystallization behavior of natural rubber after accelerated storage hardening test
Jintana Yunyongwattanakorn Jitladda T. Sakdapipanich Seiichi Kawahara Masamichi Hikosaka Yasuyuki Tanaka 《应用聚合物科学杂志》2007,106(1):455-461
Crystallization of natural rubber (NR) and purified NR after storage hardening of the rubbers under dried condition with phosphorus pentoxide was investigated by dilatometry and polarized light microscopy. The purified NR was prepared by removing proteins and fatty acid ester groups from fresh NR (FNR) through deproteinization and transesterification, respectively. The rubbers were characterized in regard as gel content, ester content and crosslink density. Nucleation (I) and growth rates (V) of the gel fraction estimated from the number of spherulites and their sizes observed in the course of isothermal crystallization depended on supercooling (ΔT = Tm0 ? T). Tm0 is equilibrium melting temperature and T is absolute temperature. Slope of linear line in a plot of logarithmic V versus 1/TΔT for NR was independent of time for storage hardening, suggesting that the lateral surface free energy and diffusion were little function of branching and crosslinking. The rate of crystallization of FNR significantly decreased when the crosslink density increased. Since the overall crystallization is functions of chain mobility and surface free energy, the slower crystallization of well crosslinked FNR may be attributed to the less chain mobility and small value of Δσ due to the formation of crosslinked and branched entities. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
13.
The dynamic variations of molecular structure and properties of natural rubber (NR) during the accelerated storage have been studied. The results showed that, with the prolonging of the storage time, the average molecular weight and the gel content increased, the width index of molecular weight distribution decreased, the gel size increased gradually, but the crosslinking density of gel fluctuated only within a narrow range. Besides, the initial plasticity increased, whereas the plasticity retention index decreased. The studies with thermal analyses and infrared spectroscopy showed that the thermal degradation temperature dropped, the thermal degradation rate increased, and the thermal stability has decreased after the storage of NR. The molecular structure and properties of NR are in a state of dynamic variation during accelerate storage. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1779–1783, 1998 相似文献
14.
15.
16.
17.
18.
Summary In this paper the relationship of the ageing time to the tensile strength and the ultimate elongation of rubber vulcanizates
was derived from the combination of ageing kinetics with the molecular theory of ultimate tensile strength of elastic networks,
basing on the micro-structure model of rubber vulcanizates. According to this relation, a new simple method for determining
the coefficients (α4) of ageing time and the ageing rate constants (k
4) of rubber vulcanizates from the data of the extension tests was proposed. The accelarated ageing experiments of Butadiene-acrylonitrile
Rubber (BAR) vulcanizates were carried out at the range of temperature 70–110°C in a given period of 1–100 days, and the molecular
parameters were determined by using this new method. It is shown that the experimental results are consistent to the theory. 相似文献