共查询到19条相似文献,搜索用时 125 毫秒
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聚丙烯(PP)微孔发泡材料具有质轻、力学性能较高的特点,PP基体性质、发泡剂种类、发泡制备成型工艺、化学改性方法、共混及填充改性等方法均可以影响发泡材料的泡孔结构及发泡材料的性能。综述了PP微孔发泡材料的制备成型工艺、化学、共混、纳米、填充等改性方法研究进展,指出采用成本低廉、无毒的化学类发泡剂制备泡孔结构良好的PP微孔发泡材料将是今后研究的热点。PP的交联及接枝改性技术,与其它聚合物、填料共混技术是改善泡孔结构、提高泡沫材料发泡性能和力学性能的途径,研究改性材料与PP基体材料的界面相容性问题也是今后的研究方向。 相似文献
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微发泡聚合物材料是泡孔尺寸在微米级的一种新型高分子材料,因其独特的微孔结构能够改善制品的尺寸稳定性、收缩率等问题,已经成为近年来聚合物材料的研究热点。本文综述了微发泡成型研究机理,成型加工参数、纳米填料和发泡剂对微发泡聚合物材料结构与性能的影响,并对众多研究结果进行了分析,提出了未来微发泡聚合物材料的研究领域有待于进一步深入的研究方向,并对微发泡聚合物材料的研究及应用前景进行了展望,提出扩大工业应用的趋势是开发出微发泡聚合物母料来替代物理以及化学发泡。这些基础性的研究工作对于深入理解微发泡聚合物材料的形成机理及后续的应用研究具有非常重要的意义。 相似文献
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采用"二次开模"注射成型工艺制备微发泡聚酰胺6(PA6)材料,研究了不同延时时间对PA6材料发泡行为及力学性能的影响.结果表明:延时时间能有效控制微发泡PA6材料的发泡过程,较短的延时时间内,模具型腔压力下降较大,压力降速率较快,有利于聚合物泡孔成核速率的提高.随着延时时间增加,微发泡PA6材料的泡孔平均直径增大,泡孔... 相似文献
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前言聚氨酯开孔表面活性剂(以下称开孔剂)主要用于聚氨酯各类泡沫塑料,如硬质、半硬质和软质泡沫塑料体系中。开孔剂应用于硬质泡沫塑料,可以制备开孔型硬质泡沫塑料,这种硬泡主要用作空调设备中的过滤材料,建筑中的换气板以及隔音材料等。开孔剂应用于半硬质泡沫塑料,可以降低由于发泡成形速度太快所造成的高闭孔率。在这类泡沫体系中,所用的开孔剂有美国联碳公司的Y-4499及Rohm ScHoass公司的Acrgloid 710等。开孔剂用于软质泡沫塑料时,可以促进和改善制品微孔壁的导通,使发泡反应后期产生更多的开孔性微壁,且能大大地减少制品挤压操作,甚至在相同工艺中, 相似文献
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对聚合物微孔发泡基本过程、机理、聚合物微孔发泡的实施等进行了介绍,同时指出通过嵌段共聚物为载体可以制备纳米孔发泡材料。 相似文献
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聚合物微发泡材料制备技术应用研究进展 总被引:4,自引:1,他引:3
20世纪90年代末,超临界流体(SCF)制备聚合物微发泡材料实现了工业化,这种方法制备的微发泡材料具有非常多的优点,被誉为"21世纪的新型材料"。主要介绍了聚合物微发泡材料应用研究方面的进展,主要涉及聚合物微发泡材料的制备方法及其特点,工艺参数对成型过程的影响及成型设备的特点等方面,重点探讨了非连续方法和连续方法的提出及其发展过程。 相似文献
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在不同工艺条件下用化学注射成型制备了微发泡高抗冲聚苯乙烯(HIPS),分析了泡孔结构参数对HIPS力学性能的影响。结果表明,小的泡孔尺寸、泡孔密度和一致的泡孔尺寸分散度都能增强微孔发泡HIPS材料的力学性能。 相似文献
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将超临界气体发泡技术与化学发泡技术联合用于制备多孔材料。采用碳酸氢钠作为化学发泡剂,将聚己内酯与碳酸氢钠挤出共混之后,使用传统注射成型和微注射成型,进行了发泡实验对比。结果表明,物理化学联合发泡用于制备多孔材料具有可行性,化学发泡剂的加入不仅改善了整体发泡效果,还能够作为气泡成核剂促进物理发泡的质量。对于所得结构在一定程度上表现的泡孔相互连通性进行了讨论,同时对泡孔壁面上出现的“网”状结构进行了分析。气泡在成核生长过程中,对于泡孔壁产生多方向拉伸的作用,相邻气泡共同作用于公共壁面,最终导致壁面部分形成“网”状结构。 相似文献
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Daniel Cuadra-Rodríguez Suset Barroso-Solares Ester Laguna-Gutiérrez Miguel Ángel Rodríguez-Pérez Javier Pinto 《大分子材料与工程》2023,308(10):2300087
The production of open-cell (OC) nanostructures in polymer foams without non-foamed solid skins by gas dissolution foaming has been developed in this work. First, several grades of MAM block copolymer (methyl methacrylate-b-butyl acrylate-b-methyl methacrylate) at high content are employed as heterogeneous phase in poly(methyl methacrylate) for producing OC structures. Atomic force microscopy and extensional rheology are used as methods to understand the main features to obtain OC nanocellular structures. Second, the gas diffusion barrier approach is employed for the first time in polymer blends to avoid the appearance of the solid skins in the borders, which typically appears when the cellular polymer is produced by gas dissolution foaming. The influence of the poly(vinyl alcohol) gas diffusion barrier is analyzed, together with the effect of heterogeneous nucleation provided by MAM copolymer, on the solid skins’ formation. The synergy between both approaches allows obtaining porous nanocellular polymeric films with an OC structure non-constrained by the presence of outer solid skins. 相似文献
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Bubble nucleation and growth are the key steps in polymer foam generation processes. The mechanical properties of foamed polymer are closely related to the size of bubbles created inside the material. Thus, it is necessary to study how to improve mechanical strength by producing extremely fine bubbles inside polymer resin. We developed a theoretical framework to help produce uniformly distributed microcellular bubbles and experimentally verified the theoretical analysis results using an injection molding machine modified to make microcellular foaming products. 相似文献
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As the use of plastics has increased in various industries, research on microcellular plastics has increased as well. The microcellular foaming process helps produce lighter plastic and reduces material consumption. This process also affects the optical properties. The primary purpose of this study is to measure the visible changes occurring in polymer samples by comparing changes in the samples before and after the microcellular foaming process. To measure the changes in color characteristics, colored PC samples were utilized for the experiments. Changes in the color characteristics were indicated using the Munsell color system. 相似文献
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以化学发泡注塑成型技术为主线,在二次开模条件下制备微发泡聚苯乙烯(PS)及微发泡聚丙烯(PP);通过流变性、加工性分析了树脂本征特性对PS及PP发泡行为的影响。结果表明:本征特性对气泡的长大和定型过程、气体扩散具有明显的影响;熔体强度越高的材料,阻碍泡孔长大的趋势越明显,所得到的泡孔越细小而均匀;PS具有合适的熔体强度和熔体流动速率(MFR),发泡质量较理想,泡孔直径和泡孔密度分别为41.4μm、8.7×106个/cm3;PP(K9026)熔体强度较低,而熔体流动速率过大,发泡质量明显降低,泡孔直径和泡孔密度分别为65.94μm、5.82×105个/cm3。 相似文献
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In the development of weapons, the current trend is to replace incombustible constituent elements with combustible ones. The traditional porous combustible objects are composed of nitrocellulose as energetic component, which is highly sensitive and inflammable. Formulations composed of high content RDX and inert polymer binder were employed to replace the tradional ones. This paper reports the fabrication process of microcellular combustible objects with skin‐core structure using supercritical CO2 (SC‐CO2) as foaming agent. The objects were foamed in designed foaming molds with expansion ratios of 1.1, 1.2 and 1.35. The influence of foaming temperature, saturation pressure, expansion ratio and RDX content on porous structure was investigated by scanning electron microscopy (SEM). Thermogravimetric analysis was conducted and the results revealed a two‐stage decomposition process of RDX and binder. Performance in terms of heat resistance and moisture resistance was evaluated and compared with the traditional ones. A comparative study indicated that microcellular combustible objects are superior to traditional ones in respect of their survivability. 相似文献