共查询到18条相似文献,搜索用时 133 毫秒
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研究了稀土金属硬脂酸盐对PVC的热稳定作用.结果表明,硬脂酸稀土属长期型热稳定剂,与少量硬脂酸锌并用可有效改善其抑制PVC初期着色的效能;不同硬脂酸稀土与硬脂酸锌并用稳定的PVC具有相似的初期色相,但中、长期热稳定性不同,其中镧系金属硬脂酸盐的中、长期热稳定性随镧系原子系数呈现明显的奇偶效应递变规律;硬脂酸稀土具有类似于碱土金属皂的热稳定作用机理. 相似文献
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脂肪酸稀土用作PVC热稳定剂的热稳定性和透明性递变规律 总被引:15,自引:3,他引:12
研究了常见的脂肪酸稀土用作PVC热稳定剂的热稳定性和透明性,结果表明,添加等物质的量的脂肪酸稀土的PVC热稳定性和透明性具有与添加剂熔点一致的递变规律:硬脂酸稀土~棕榈酸稀土~肉豆蔻酸稀土~月桂酸稀土> 癸酸稀土> 辛酸稀土> 油酸稀土。根据这种关系分析,由分子间力递变引起的与PVC基质相容性的递变是添加脂肪酸稀土后PVC热稳定性和透明性递变的主要原因 相似文献
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采用皂化法制备了PVC热稳定剂-硬脂酸钇,并进行了动力学研究。采用单因素实验方法对反应时间、反应温度、盐碱比、氢氧化钠浓度等因素分别对硝酸钇/氢氧化钠盐碱反应和氢氧化钇/硬脂酸皂化反应的稀土转化率的影响进行了考察,并确定了最优工艺条件,建立了动力学模型。实验结果表明,采用改进的新工艺,稀土转化率高达99.50%以上,硬脂酸钇的熔点为118℃。经实验验证,第一阶段硝酸钇/氢氧化钠盐碱反应为二级反应,动力学方程为-dcA/dt=8.56cA^2。第二阶段近似看作氢氧化钇/硬脂酸的皂化反应,符合二级反应特征,动力学方程为-dcA/dt=1666cA^2。采用称重法测定稀土转化率比化学法简单、快速。 相似文献
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以氰尿酸、硝酸镧、氢氧化钠为原料合成了氰尿酸镧,采用正交试验法确定了合理的工艺条件。采用转矩流变仪研究与比较了氰尿酸镧、硬脂酸镧、硬脂酸钙、硬脂酸锌等热稳定剂对PVC的塑化作用。结果表明,氰尿酸镧的最佳合成工艺为70℃、氢氧化钠浓度1.2mol/L、反应时间60min、pH 7;氰尿酸类与硬脂酸类稀土稳定剂复合后对PVC的塑化效果最佳。 相似文献
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稀土热稳定剂在聚氯乙烯塑料中的应用前景 总被引:14,自引:0,他引:14
本文对稀土热稳定剂的发展、应用、特点、稳定机理以及发展前景做了详尽的综述。确定烯土化合物是一种可以替代传统热稳定剂的新型热稳定剂。该稳定剂无毒、价廉、稳定效果好、制品性能优异,具有广阔的应用前景。 相似文献
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ResearchandDevelopmentofRareEarthAdvancedMaterialsinChinaWangDianzuo(王淀佐),WanQun(万群),YangYuchun(杨遇春)(GeneralResearchInstitute... 相似文献
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从热力学的角度阐述了稀土在铜中的反应,综述了国内对稀土在铜及铜合金加工中的应用.适量的稀土在铜和铜合金熔铸中主要起净化作用、变质作用和合金化作用,可以提高热处理温度,增强塑性加工的效果. 相似文献
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《中国稀土学报(英文版)》2017,(12)
To examine the activation of organic acids on the leaching process of ion-adsorption type rare earth ore(IRE-ore), the leaching behavior of rare earth(RE) and zeta potential of IRE-ore were investigated in the absence and presence of carboxylic acids. The results show that all the tested organic acids(acetic acid,malonic acid, citric acid, tartaric acid, succinic acid, and malic acid) can promote RE extraction. At relatively high concentrations of organic acids, the activation efficiency of organic acids on RE extraction is generally consistent with their complexation ability; whereas at their low concentrations, the change of zeta potential on the IRE-ore surface with organic acid concentration and p H has a close association with RE extraction, which indicates that organic acids can impact the surface electrical property of IREore via their adsorption/desorption, and thereby increase/decrease the affinity of RE ions to IRE-ore.Therefore the influence of organic acids on the IRE-ore surface electrical property also plays an important role in RE extraction in addition to their complexation with RE ions. 相似文献
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稀土类稳定剂作为新型发展起来的无毒热稳定剂,热稳定性和持久性均较好,且无毒、环保、价廉,适应当今PVC制品无毒、无污染、高效的发展要求。为此,介绍了稀土热稳定剂的性能特点及发展趋势。 相似文献
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Modification Behavior of Trace Rare Earth on Impurity Phases in Commercial Purity Aluminum 总被引:20,自引:0,他引:20
Modifying effect and mechanism of trace rare earth on Fe(Si)-rich impurity phases in commercial purity aluminum were studied with the aids of SEM, EDAX, TEM, etc. It is found that Ce-rich mixed rare earth (RE) is an effective modifying agent, which makes the coarse Fe-rich impurity phases transform into complex compounds of tiny, sphere/short stick form, thus improving mechanical properties of this material; its modifying mechanism is in that RE gathering in front of solid/liquid interface enters into the impurity phases, forming complex (A1FeSiRE) compounds; or is adsorbed in the impurity phases surface, impeding the growth of impurity phases; however, excessive RE will result in the increasing of RE compounds (secondary phases), and plasticity reduction of this material. Therefore, its addition amount should be less than 0.07% (mass fraction). 相似文献