聚合物气体辅助挤出成型研究进展

Progress on Polymer Gas-Assisted Extrusion Molding

挤出成型是聚合物加工领域出现得较早且应用最广泛的技术之一,聚合物传统挤出成型过程中存在的挤出胀大、扭曲变形等问题严重阻碍了该技术的进一步发展及推广应用。聚合物气辅挤出是本世纪初发展起来的一种新型成型工艺,通过在口模内壁与熔体表面间形成稳定的气垫膜层,使熔体以完全滑移非粘着方式挤出成型,改善了口模内熔体的流场分布,从而有效减小甚至消除了传统挤出过程中存在的影响制品质量的固有问题。该技术因具有节能、环保、改善制品质量等优良特性,自问世以来即受到聚合物加工领域诸多学者的广泛关注,相关研究成果对丰富和发展聚合物成型理论及其加工技术的进一步推广应用均具有重要的科学意义和工程价值。文中综述了聚合物气辅挤出成型问世以来国内外研究进展,主要介绍了该技术的成型机理和成型装置,气体辅助单层挤出、双层共挤、微管挤出及气垫膜层等方面的研究方法与研究成果,并在综述现有的研究基础上展望了气辅挤出成型的研究趋势。

Extrusion molding is one of the earliest and most widely used technologies in the polymer processing field.But there are some problems in the traditional extrusion,such as die swell,distortion and deformation.The further development and application of the polymer extrusion molding are seriously restrained.Polymer gas-assisted extrusion is a new molding process developed at the beginning of this century.A stable gas layer is formed between the die inner wall and the melt surface and the polymer melts are extruded in a fully slip and non-adhesive manner for the lubrication of gas layer.The melt flow field distribution is improved in the polymer gas-assisted extrusion molding and the inherent problems are effectively reduced or even eliminated affecting the traditional extrusion product quality.The gas-assisted extrusion technology has been widely concerned after being invented by many scholars because of its excellent characteristics such as energy saving,environmental protection and improving product quality.And the research results about it have important scientific significance for enriching and developing polymer molding theory.It will also promote the further development and application of the technology.The research advances of gas-assisted extrusion molding technology were summarized in China and other countries in this paper.The gas-assisted extrusion molding mechanism and equipment were introduced.The research methods and results were reviewed about gas-assisted extrusion,gas assisted co-extrusion,gas-assisted micro-tube extrusion and gas layer.And the research trends of gas-assisted extrusion were prospected.