共查询到20条相似文献,搜索用时 109 毫秒
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利用木瓜蛋白酶凝固天然胶乳制备了不同氮含量的天然橡胶(NR-P),研究了NR-P的生胶理化性能和混炼胶硫化特性,以及硫化胶的物理机械性能、压缩疲劳生热和动态力学性能,并与酸凝天然橡胶(NR-A)进行了对比。结果表明,随着氮含量的降低,NR-P的塑性初值先降低再趋于稳定,塑性保持率则稍有下降;混炼胶的硫化速率增大;硫化胶的300%定伸应力和拉伸强度均呈现先增大后稍有减小的趋势,压缩温升和滚动阻力都基本呈现减小趋势。与NR-A相比,NR-P的氮含量较低,但其塑性初值较高而塑性保持率稍低,硫化速率及拉伸强度也优于NR-A。当含氮质量分数处于0.18%~0.23%时,NR-P具有较快的硫化速率,较好的物理机械性能、压缩疲劳生热性能和动态力学性能。 相似文献
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利用射流凝固(NR-j)的方法制备天然橡胶,研究了天然橡胶的性能。分析结果可得:射流凝固天然橡胶的溶胶含量较低,杂质含量、灰分含量、氮含量和塑性初值比酸凝固天然橡胶的大,而挥发分和塑性保持率较小。在硫化性能上,射流凝固天然橡胶的硫化速率比酸凝固天然橡胶的速率稍大,硫化胶的强度也大于酸凝固天然橡胶的强度,但其老化后的强度保持率小于酸凝固天然橡胶。 相似文献
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高性能浇注型聚氨酯弹性体的耐热性能 总被引:2,自引:1,他引:1
用不同结构的多元醇和二异氰酸酯合成了一系列浇注型聚氨酯弹性体(PU),研究了PU的物理机械性能、耐热性和动态力学性能.结果表明,当二异氰酸酯选为对苯二异氰酸酯(PPDI)、扩链剂为1,4-丁二醇(BD)时,不同结构的多元醇制备PU的耐热性从优到劣依次为聚己内酯二醇体系,聚己二酸1,4-丁二醇酯体系,聚碳酸酯二醇(PCD)体系,聚四亚甲基醚二醇体系;当多元醇选取PCD、扩链剂为BD时,不同结构的二异氰酸酯制备PU的耐热性从优到劣依次为1,5-萘二异氰酸酯(NDI)体系,对苯二异氰酸酯(PPDI)体系,3,3'-二甲基联苯-4,4'-二异氰酸酯(TODI)体系,4,4'-二苯基甲烷二异氰酸酯(MDI)体系;TODI、NDI制备PU的动态力学性能优于PPDI和MDI制备的PU. 相似文献
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CPVC加工性能和冲击性能的改进 总被引:1,自引:0,他引:1
研究了加工助剂和冲击改性剂对CPVC性能的影响,试验结果表明:润滑型ACR加工助剂能有效提高CPVC的加工性能,AMS的最佳用量为1~2份,MBS(用量以8份为宜)对CPVC的增韧效果较好。 相似文献
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The optical properties of conventional, free-radical polymerized low density polyethylene (LDPE) blown films are due essentially to surface irregularities that develop during fabrication. Past studies have shown that the extent to which these irregularities occur (and therefore optical properties) correlates well with the melt elasticity of the resin. Specifically, it has been shown that resins with higher melt elasticity result in films with poorer optical properties. However, it was recently reported that the optical properties of film blown from a Sci of three generically similar LDPE resins were found to correlate with the crystallization kinetics of the resins. Specifically, it was reported that the resins that exhibited faster crystallization rates produced films with better optical properties. This present work shows, however, that this apparent correlation is only coincidental. It has been shown that resins exhibiting faster crystallization rates do not necessarily result in films with better optical properties. On the other hand, it has been shown that resins with higher melt elasticity consistently result in films with poorer optical properties. 相似文献
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M. Imran Zainuddin S. Tanaka R. Furushima K. Uematsu 《Journal of the European Ceramic Society》2010,30(16):3291-3296
Two types of granules were fabricated from a flocculated slurry (dispersant: 0.3 wt%) and a dispersed slurry (dispersant: 1.0 wt%), respectively. The slurry properties affected the packing density and morphology of the granules markedly; the granules obtained from the flocculated and dispersed slurries have spherical and dimpled shapes with densities 50.2 and 54.0%, respectively. A new crossed polarized microscopy showed a direct influence of slurry property on the packing structure of particles in the granules. The packing structure of particles affected the deformation behavior of granules; the loosely packed particles in the spherical granules make them easily deformable and the highly packed particles in the dimpled granules make them resistant against deformation. 相似文献
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R. C. Hoseney 《Journal of the American Oil Chemists' Society》1979,56(1):A78-A81
Although much has been learned about the gluten protein complex in the past 50 years, we still do not know why gluten proteins
form a dough. We are left pointing out how gluten differs from other proteins, and offering a few tentative hypotheses.
Contribution No. 955. Department of Grain Science and Industry, Kansas Agricultural Experiment Station, Manhattan, KS 66506. 相似文献
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研究了不同因素包括相转移催化剂、磺化度、中和度、中和用阳离子及增塑剂等对磺化乙丙橡胶离聚体的熔融流动性及力学性能的影响。结果表明,在合适条件下可得到Brabender扭矩为35~40Nm、拉伸强度为20~28MPa、断裂伸长率为500%~600%、永久变形小于10%的热塑性弹性体 相似文献
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G. Centi 《Catalysis Today》2000,56(4):443-453
The behavior of fresh and aged EUROCAT V2O5–WO3/TiO2 SCR catalysts in the (I) oxidative dehydrogenation of light alkanes, and conversion of (ii) propan-2-ol, (iii) NO in the presence of propene and oxygen, (iv) propane and propene and (v) chloropropane is reported to analyse possible modifications of the catalyst properties during use and give a more comprehensive general picture of its surface and reactivity properties. 相似文献
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Aiying Li Jieyun Chang Kaiquan Wang Lude Lu Xujie Yang Xing Wang 《Polymer International》2006,55(5):565-569
A highly branched polystyrene (HBPS) was synthesized via the copolymerization of 4‐(chloromethyl) styrene with styrene using the self‐condensing atom transfer radical polymerization method. The addition of HBPS as a melt modifier for polycarbonate (PC) was attempted. Melt flow properties, mechanical properties, thermal properties and morphology of the blends were studied. The results showed that a significant drop in the blend viscosity occurs immediately on addition of HBPS. Impact strength, tensile strength and glass transition temperature (Tg) of all the blends have not been significantly reduced compared with those of pure PC. The TGA analyses showed that an initial weight loss temperature of all the blends is above 458 °C and slightly low compared with that of pure PC, but all the blends still have excellent thermal stability. Morphological studies using SEM showed that a two‐phase morphology is characteristic of all the blends, with more or less spherical droplets of the minor HBPS phase dispersed in the continuous PC phase. Copyright © 2006 Society of Chemical Industry 相似文献
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At OAO Zapadno-Sibirskii Metallurgicheskii Kombinat (ZSMK), research is undertaken to improve the optimization of coking batch.
The basic approach, proposed by specialists from OAO Nizhne-tagil’skii Metallurgicheskii Kombinat, employs the coefficient
K
opt, which characterizes the deviation of the batch from its optimal composition. The coking properties of the OAO ZSMK coal
batch over the last few years are analyzed. After laboratory and industrial coking of batch with different K
opt, the strength and reactivity of the resulting coke is investigated. Evaluation of coke-grade coal in terms of its rank according
to State Standard GOST 25543-88 proves inadequate, since coal of the same rank may differ markedly in coking properties. A
method is established for assessing the optimality of the coal batch at OAO ZSMK. 相似文献