共查询到19条相似文献,搜索用时 156 毫秒
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对微孔发泡材料制备技术的研究进展进行了综述,对微孔发泡技术的基本原理、常用发泡剂和微孔发泡材料的制备方法等方面进行了详细的介绍和分析。微孔发泡材料的制备大体上可分为间歇法、注射成型法和连续挤出法,各种方法各有其优点和适用的领域。 相似文献
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振动力场下超微孔塑料发泡技术的研究 总被引:9,自引:3,他引:6
超微孔塑料是一种新型的高分子材料,与传统的泡沫塑料相比具有很多优异的性能.本文分析了影响超微孔塑料发泡挤出质量的因素,并从影响超微孔发泡挤出质量的动态因素出发,为了提高超微孔发泡挤出的质量,提出了一种超微孔塑料发泡挤出的新技术,即把振动力场引入到超微孔塑料发泡挤出的全过程的技术. 相似文献
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开孔型聚合物微发泡材料研究进展 总被引:1,自引:0,他引:1
通过回顾目前几种微孔材料成型的主要方法,介绍了微发泡成型技术用于制备开孔型微孔材料的必要性。讨论了关于开孔型聚合物微发泡材料制备技术及研究方法的几种思路,分别是不相容聚合物共混、泡孔合并模型、熔融挤出发泡、开孔剂法和气体浓度阈(值)等方法,这些方法的微孔成型机理各不相同,所制备的材料微观结构也各有特点。文献分析表明:微发泡成型方法用于开孔型微孔材料的制备是一种非常有前景的技术。 相似文献
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在简要回顾了微孔塑料基本特征的基础上,重点讨论了微孔发泡塑料的注射成型机理、工艺特点及主要影响因素;并特别介绍了几种国内外微孔塑料注射成型加工工艺的最新技术动态以及其主要的工作原理。最后,就微孔塑料注射成型技术的工艺特点,以及性能优点介绍了几种典型应用。 相似文献
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为拓宽微孔注塑制品的应用范围,需要改善其表面质量,降低其翘曲变形。模腔气体反压技术、模腔被动控温技术、微孔共注塑技术、泡孔成核速率控制技术、微孔注射压缩成型技术和快速热循环微孔注塑技术等可有效改善微孔注塑制品的表面质量。模腔气体反压技术、微孔共注塑技术和调整加工参数可进一步降低微孔注塑制品的收缩率和翘曲,提高制品的尺寸精度。本文较系统介的绍了这些技术和方法。 相似文献
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Microllular plastics are cellular polymers characterized by cell densities greater than 109 cells/cm3 and cells smaller than 10 μm. One of the critical steps in the continuous production of microcellular plastics is the promotion of high cell nucleation rates in a flowing polymer matrix. These high nucleation rates can be achieved by first forming a polymer/gas solution followed by rapidly decreasing the solubility of gas in the polymer. Since, in the processing range of interest, the gas solubility in the polymer decreases as the pressure decreases, a rapid pressure drop element, consisting of a nozzle, has been employed as a continuous microcellular nucleation device. In this paper, the effects of the pressure drop rate on the nucleation of cells and the cell density are discussed. The experimental results indicate that both the magnitude and the cell density are discussed. The experimental results indicate that both the magnitude and the rate of pressure drop play a strong role in microcellular processing. The pressure phenomenon affects the thermodynamic instability induced in the polymer/gas solution and the competition between cell nucleation and growth. 相似文献
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This study has created a new way of microcellullar processing PET thin sheet foam using a conventional hydraulic press by compression molding and by setting the temperature of press plates differently. Comparing this study with our previous work, the emphasis is on the difference of plate temperature. The nonisothermal condition is used to control the foaming agent decomposition to lead to more uniform cell size microcellular foam. A variety of cell sizes, cell densities, and relative densities are obtained as a consequence of the different foaming temperature, time, pressure, and foaming agent content via isothermal and nonisothermal conditions. The effect of isothermal and nonisothermal foaming on the cell size, cells density, and relative density has been discussed. The electrical properties of the microcellular poly(ethylene terephthalate) (PET) samples prepared in nonisothermal foaming have been investigated. The experimental results show that the microcellular PET foam has lower dielectric constant and dielectric loss and higher electric resistivity than unfoamed PET. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1698–1704, 2004 相似文献