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摘要:本文用实验方法探究EPDM发泡材料硬度与动静比之间的关系,讨论刚度与发泡材料减振性能的关系,判定其减振性。实验表明,随着N330、N550用量的增加,硬度、动静比均呈现增大趋势,填充相同用量N550的胶料的硬度较填充的N330大,而填充N330的胶料的动静比比相应的N550的小;随硫黄用量增加,硬度逐渐增大,动静比则呈现减小的趋势;随DCP用量增加,硬度逐渐增大,动静比则呈现先增大后减小的趋势,且在用量为3份时出现最小值,且DCP硫化的EPDM发泡材料动静比较硫黄硫化的大。为了研究EPDM发泡材料硬度与动静比的关系,我们选择了填充体系、硫化体系,探究硫化特性、门尼粘度、交联密度和发泡倍率与硬度的关联,进而分析了硬度与动静比变化趋势。 相似文献
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研究了加入不同量硫化剂DCBP对硅橡胶发泡材料各项力学及物理性能的影响。结果表明:随着DCBP加入量的不断提高硅橡胶发泡材料的拉伸强度、密度、压缩永久变形升高;发泡倍率降低;断裂伸长率先升高后下降且随着硫化剂用量增加泡孔减小。 相似文献
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填料对乙烯-醋酸乙烯酯橡胶发泡材料性能的影响 总被引:1,自引:0,他引:1
使用无转子发泡硫化仪、RPA橡胶分析仪、体视显微镜以及力学性能测试仪器等研究了白炭黑和炭黑对乙烯-醋酸乙烯酯橡胶(EVM)硫化发泡特性、发泡材料微观结构和性能的影响。结果表明,白炭黑用量较少时,体系焦烧时间和正硫化时间均延长,发泡剂分解速度提高。与相同用量的白炭黑体系相比,炭黑体系不易焦烧,正硫化时间较长,发泡剂分解速度较快。白炭黑体系泡孔质量好于炭黑体系,其中添加30份白炭黑的泡沫材料具有最低密度。RPA分析结果表明,减少白炭黑用量或采用炭黑作填料均能降低体系储能模量(G′)和损耗模量(G″),炭黑体系泡沫材料动态模量具有较强温度敏感性。 相似文献
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研究不同粒径和结构度炭黑填充集成橡胶(SIBR)的性能。结果表明:高结构度的BL系列炭黑和大粒径的炭黑N774均使SIBR胶料的焦烧时间和硫化时间延长;随着炭黑结构度的提高,胶料的门尼粘度和交联密度增大;结构度最高的炭黑BL302填充硫化胶的定伸应力最大,耐老化性能最好;结构度大、粒径小的炭黑BL201填充胶料的Payne效应最强,生热也较大;在0℃下炭黑N774,N660,N550,N330,N220,BL201,BL101,BL302填充硫化胶的损耗因子依次减小,抗湿滑性能下降。 相似文献
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研究氯化聚乙烯橡胶(CM)/废旧三元乙丙橡胶(EPDM)胶粉共混发泡材料的性能,并采用活化剂420等对废旧EPDM胶粉进行活化改性,考察废旧EPDM胶粉改性对共混发泡材料的影响。结果表明:随着废旧EPDM胶粉用量的增大,共混发泡材料的门尼粘度增大,邵尔C型硬度减小,发泡倍率先增大后减小,发泡收缩率减小;废旧EPDM胶粉改性后,共混发泡材料的门尼粘度变化不大,M_H-M_L值增大,发泡倍率略有减小,但物理性能和发泡收缩率改善,且泡孔结构更密实、更完整。 相似文献
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季铵化硅烷的合成与应用 总被引:13,自引:2,他引:13
利用γ-氯丙基三甲氧基硅烷与N,N-二甲基十八胺反应,合成了N,N-二甲基-N-十八烷基氨丙基三甲氧基硅烷季铵盐(BFS),对其抑菌性能及与氨基硅微乳同浴使用的效果进行了测定和研究。结果表明:BFS用量为10g/L条件下,能使整理后的棉织物对金黄色葡萄球菌、大肠杆菌的抑菌率分别达到99.82%和99.12%;而与氨基硅微乳同浴使用,所整理的织物不仅抑菌效果显著,柔软性良好,而且具有舒适的手感;另外,弱酸性使用条件有助于BFS和氨基硅微乳的协同效应,表现出最佳的整理效果。 相似文献
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以 4个不同结构的芳胺为原料 ,经过N 烷基化 ,N 氯乙酰化 ,酯化 ,酯交换反应合成了 4个 2 羟基乙酰胺类化合物 ,它们都是重要的农药中间体。其中N (4 三氟甲基苯基 ) N 异丙基 2 羟基乙酰胺的合成 :控制温度在 10~ 2 0℃ ,向 4 三氟甲基苯胺 ,冰醋酸与丙酮的混合液中慢慢加入硼氢化钾 ,加完后 2 0℃反应 2h得到产品N 异丙基 4 三氟甲基苯胺 ,产率 86 .0 %。升温至40℃ ,向N 异丙基 4 三氟甲基苯胺、甲苯混合液中滴加氯乙酰氯 ,滴完后升温至 75℃ ,通氮气反应 2h得到产品N (4 三氟甲基苯基 ) N 异丙基 2 氯乙酰胺 ,产率 92 .9%。N (4 三氟甲基苯基 ) N 异丙基 2 氯乙酰胺 ,甲醇 ,醋酸钾 ,三乙胺 ,碳酸钾 ,回流反应 17h ,得到产品N (4 三氟甲基苯基 ) N 异丙基 2 羟基乙酰胺 ,产率 88.2 % ,总收率为 70 .5 %。产品结构经质谱和核磁确定 相似文献
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The use of legumes as green manuring crops does involve a potential riskof N leaching losses over the winter period. The susceptibility of cropresidue-derived N to losses and the pre-crop value of a green manuring crop canbe manipulated by proper timing of incorporation into soil. In this study,mineralization of C and N was investigated in a range of low temperatures,including thawing and freezing, that are characteristic to autumn green manureincorporation and its decomposition. The pre-crop effect of green manuring wasfurther tested with spring wheat under field conditions. We hypothesized thatdelaying green manure incorporation in the autumn would reduce the risk of Nlosses from the field and maximize the N transfer to a successive spring wheatcrop. To test the hypothesis, N mineralization was followed in alaboratory experiment where red clover (Trifoliumpratense L.) shoots were incubated at 4–8 °Cfor 40–80 days to simulate early autumn, delayed autumn and late autumnincorporation of a green manuring crop, followed by an incubation at–2 °C or at –2 °C to+4 °C for 25 days to simulate winter conditions. In asimultaneous field experiment, we measured the effect ofdelayed autumn incorporation of common vetch (Vicia sativaL.) green fallow on spring wheat performance. In the laboratoryexperiment, significant N mineralization during incubation wasdetected when simulating both early autumn and delayed autumn incorporation. Incontrast, no net N mineralization was detected when simulating lateincorporation. In the field experiment, the N supply fromsoil to spring wheat was higher in the late and delayed incorporationtreatmentsthan in early or spring incorporation of green manure. Late incorporationalso produced most wheat grain. We conclude that different amounts of N becomeavailable to wheat, depending on the time of incorporation of green manureresidues in soil. This difference is due to temperature. Late or delayedincorporation of green manure residues has the potential to reduce thesusceptibility of mineral N to leaching and yields more N available to asubsequent crop. 相似文献
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T.M. Egelkraut D.E. Kissel M.L. Cabrera G.J. Gascho W. Adkins 《Nutrient Cycling in Agroecosystems》2004,68(3):235-242
Research on corn and winter wheat has shown that a critical N concentration in the grain exists above which a yield response to N fertilizer is unlikely. This indicator can be used for post-harvest evaluation of N sufficiency and for mapping N availability in the field, which may be helpful for making future N fertilizer decisions. The purpose of this study was to determine if a critical N concentration in the seed exists for cotton. The study was conducted in the Georgia Coastal Plain during 1998, 1999, and 2001, using a different variety of cotton in each year. In 1998, 12 N fertilizer rates ranging from 38 to 203 kg ha–1 were applied to Delta Pineland 90 at three locations within one field that differed in soil organic matter and clay concentration, and in 1999 and 2001, 6 N fertilizer rates ranging from 22 to 179 kg ha–1 were applied to Stoneville 474 and Delta Pineland 458 in a different field. At all locations, the N concentration in the cottonseed increased linearly with increasing N fertilizer rates. Maximum yields were obtained at less than maximum seed N concentration. Lower seed N concentrations indicated some degree of N deficiency. Based on these results, it appears that a critical N concentration of 35 g kg–1 exists for cottonseeds, above which no yield response to N fertilizer is likely. Information on the spatial distribution of cottonseed N concentrations could therefore help to evaluate the adequacy of N fertilization for cotton, thereby providing a basis for adjustment of N fertilization rates in future crops. 相似文献
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双硫化魔芋寡糖素的合成 总被引:1,自引:0,他引:1
魔芋葡甘寡聚糖与二硫化碳和二甲胺进行双硫化加成反应制备了双硫化魔芋寡糖素(DS-OKGM)。魔芋葡甘寡聚糖与二硫化碳反应得到二硫代魔芋葡甘寡聚糖甲酸钠(SDFO);二甲胺与二硫化碳在碱性条件下反应得到N,N-二甲基二硫代氨基甲酸钠(SDDC);SDF0和SDDC反应得到双硫化魔芋寡糖素。通过正交实验优化了反应条件。DSOKGM对魔芋软腐病、山药炭疽病、小麦赤霉病、梨黑斑、棉花黄萎、稻瘟等细菌均有抑制作用,具有诱导植物产生植保素的作用,是一种潜在的新型生物农药。 相似文献