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以甲基乙烯基硅橡胶为基料、白炭黑为补强填料、羟基硅油为结构控制剂、微球为发泡剂、过氧化二苯甲酰为硫化剂、活性碳酸钙为补强剂制得热硫化发泡硅橡胶。研究了生胶中乙烯基摩尔分数,白炭黑、发泡剂和硫化剂的用量对发泡硅橡胶性能的影响。结果表明,随着乙烯基摩尔分数的增加,发泡硅橡胶的拉伸强度和拉断伸长率先升后降,且当乙烯基摩尔分数为1. 0%时出现最大值,抗弯折性能、硬度和正硫化时间(T_(c90))均逐渐提高,密度先降后升;随着白炭黑用量的增加,发泡硅橡胶的拉伸强度、拉断伸长率先升后降,且当白炭黑用量为35份时出现最大值,抗弯折性能、硬度和密度均逐渐提高;随着发泡剂用量的增加,发泡硅橡胶的抗弯折性能先升后降,拉伸强度、拉断伸长率、密度逐渐降低,T_(c90)逐渐增加;随着硫化剂用量的增加,发泡硅橡胶的抗弯折性能明显提高,拉伸强度和拉断伸长率先升后降,密度、硬度逐渐提高,T_(c90)逐渐缩短。扫描电镜对泡孔结构的分析结果验证了发泡剂用量对硅橡胶性能的影响规律。 相似文献
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使用超临界CO2流体作为发泡剂在不同条件下制得一系列微孔聚碳酸酯(PC)。通过扫描电子显微镜观察分析了各种制备工艺参数对微孔PC泡孔结构和分布的影响。结果表明,饱和阶段的时间超过3.5 h时,试样中的CO2基本达到饱和;饱和阶段压力的增加会使泡孔直径减小,泡孔密度增大;而发泡温度的增加和发泡时间的延长则会使泡孔直径增大,泡孔密度减小。当完全发泡时,试样的泡孔结构在厚度方向上有明显区别:试样表皮部分未发泡,有致密的表皮结构;试样表层附近泡孔直径较小,泡孔密度较大;试样中心处的泡孔直径较大,泡孔密度较小。 相似文献
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以硅烷接枝改性低密度聚乙烯(s-LDPE)对甲基乙烯基硅橡胶/二氧化硅(MVQ/SiO2)混炼胶补强,尿素为物理发泡剂,采用溶析成孔法制备了开孔MVQ/s-LDPE/SiO2泡沫材料,系统研究了MVQ/s-LDPE共混比和尿素发泡剂用量对泡沫材料性能的影响,通过扫描电子显微镜(SEM)对泡沫材料孔结构进行了观察。结果表明:随s-LDPE用量增加,MVQ/s-LDPE/SiO2泡沫材料的邵氏A硬度、拉伸强度和撕裂强度增加,抗压缩变形能力增强,补强作用明显;随发泡剂用量增大,泡沫材料泡孔分布更加均匀,孔隙率增加,力学强度和抗压缩变形能力逐渐降低。 相似文献
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以乙烯-醋酸乙烯酯橡胶(EVM)和聚乳酸(PLA)共混物为基体材料,经模压发泡制备了共混发泡材料。研究了EVM/PLA不同共混比、硫化剂(DCP)、发泡剂(AC)和白炭黑用量以及不同发泡时间对EVM/PLA共混物发泡材料泡孔结构和物理机械性能的影响。结果表明,随PLA组分的减少,白炭黑和DCP用量的增加,泡孔逐渐减小,均匀度增加,孔壁增厚,材料的密度、拉伸强度和拉断伸长率呈升高趋势,发泡倍率呈降低趋势。随发泡剂AC用量的增加,泡孔壁变薄,平均泡孔尺寸变化不大,材料的密度、拉伸强度和拉断伸长率呈降低趋势,发泡倍率增加。随硫化时间的延长,泡孔尺寸变小,孔壁增厚、发泡倍率逐渐下降,拉伸强度先增大后减少,拉断伸长率先下降后上升。 相似文献
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采用3种不同混炼胶,通过化学发泡方法制作了硅橡胶海绵。分别比较了3种海绵的泡孔结构与密度、硬度、拉伸强度、压缩应力松弛、压缩应力应变性能。实验结果表明,混炼胶的性能、海绵的密度是影响海绵材料力学性能的重要因素。 相似文献
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采用模压一步法制备EPDM海绵。研究发泡剂品种和用量对其性能的影响。结果表明,以发泡剂AC,OBSH或H制备EPDM海绵,最佳用量分别为5,5和3份;发泡剂用量为5份时,以发泡剂H制备的EPDM海绵发泡倍率最大。以发泡剂AC/OBSH,AC/H或OBSH/H并用制备EPDM海绵,最佳并用量分别为5,4和2份;发泡剂并用量为5份时,以发泡剂AC/OBSH并用制备的EPDM海绵发泡倍率最大。扫描电子显微镜观察发现.以发泡剂AC/OBSH井用制备的EPDM海绵微孔分散均匀。 相似文献
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采用沉淀白炭黑和高耐磨炭黑作为氟橡胶/硅橡胶共混胶的填料.研究以不同质量比混合的沉淀白炭黑和高耐磨炭黑对氟橡胶/硅橡胶共混胶的硫化特性、门尼粘度、力学性能、耐热老化性能和耐油性能的影响,并通过RPA分析表征填料-填料的相互作用,采用SEM表征白炭黑/炭黑混合填料在氟橡胶/硅橡胶共混胶中的分散性.结果表明,随着混合填料中白炭黑所占比例的增大,氟橡胶/硅橡胶共混胶的硫化转矩升高,焦烧时间(t10)缩短,正硫化时间(t90)延长,门尼粘度增大.氟橡胶/硅橡胶共混胶的力学性能,耐热老化性能和耐油性能都随着混合填料中白炭黑用量增多而提高.RPA分析表明,全部采用白炭黑补强的共混胶Payne效应最明显,炭黑补强的共混胶Payne效应最弱.SEM分析表明,白炭黑在共混胶中分布比炭黑更加均匀,填料聚集体粒径较小. 相似文献
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Silicone rubber foam was prepared through crosslinking with electron beam irradiation and foaming by the decomposing of blowing agent azobisformamide (AC) in hot air. The crosslinking and foaming of silicone rubber was carried out separately, which was different from the conventional method of chemical crosslinking and foaming. After foaming, the silicone rubber foam was irradiated again to stabilize the foam structure and further improve its mechanical properties. The effects of irradiation dose before and after foaming, and the amount of blowing agents on the structure and properties of silicone rubber foam were studied. The experimental results show that with the increase of AC content, the average cell diameter of silicone rubber foam increases a little, the foam density decreases to a minimum value when AC content is 10 phr. With the increase of irradiation dose before foaming from 10 to 17.5 kGy, the cell nucleation density of silicone rubber foam increases, the average cell diameter decreases, and the foam density increases. With the increase of irradiation before foaming, the tensile strength, tensile modulus, and the elongation at break of the silicone rubber foam increase. Through irradiation crosslinking again after foaming, the foam density is decreased and the mechanical properties of silicone foam are further improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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The morphology of the microcellular ethylene–octene copolymer (Engage) of both unfilled and precipitated silica‐filled compounds was studied from SEM photomicrographs with variation of blowing agent and silica filler loading. The average cell size, maximum cell size, and cell density varies with variation of blowing agent and filler loading. Physical properties similar to relative density, hardness, tensile strength, elongation at break, modulus, and tear strength decreases with blowing agent concentration. The elastic nature of closed cells reduces the hysteresis loss compared to solid compounds. Set properties improve with blowing agent concentration. It is observed that stress relaxation behavior is independent of blowing agent loading (i.e., density of closed cell microcellular vulcanizates). Theoretically, flaw sizes are found to be about 3.08 times larger than maximum cell sizes observed from SEM photomicrographs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 357–366, 2002 相似文献