{"title":"Experiments and Modelling of the Expansion of Crosslinked Polyethylene Foams","authors":"A. Mahapatro, N.J. Mills, G.L.A. Sims","doi":"10.1177/0262489319981704002","DOIUrl":null,"url":null,"abstract":"The density of chemically-blown low density polyethylene foam was altered by varying the amount of blowing agent, the degree of cross linking of the polymer, and the foam expansion temperature. A theory is proposed for the equilibrium density, based on the gas pressures in a Kelvin foam structure, and a rubber-elastic analysis of the biaxial stretching of the cell faces. The predicted densities are within 3 kg m -3of the experimental values. For commercial types of LDPE foams, the biaxial stresses in the cell faces are significant, but they only cause a minor increase in the foam density above the free-expansion limit. The molecular orientation in the cell faces must affect the foam properties. The diffusion of the nitrogen gas from the foam is insignificant.","PeriodicalId":9816,"journal":{"name":"Cellular Polymers","volume":"31 1","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cellular Polymers","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1177/0262489319981704002","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATERIALS SCIENCE, BIOMATERIALS","Score":null,"Total":0}
引用次数: 0
Abstract
The density of chemically-blown low density polyethylene foam was altered by varying the amount of blowing agent, the degree of cross linking of the polymer, and the foam expansion temperature. A theory is proposed for the equilibrium density, based on the gas pressures in a Kelvin foam structure, and a rubber-elastic analysis of the biaxial stretching of the cell faces. The predicted densities are within 3 kg m -3of the experimental values. For commercial types of LDPE foams, the biaxial stresses in the cell faces are significant, but they only cause a minor increase in the foam density above the free-expansion limit. The molecular orientation in the cell faces must affect the foam properties. The diffusion of the nitrogen gas from the foam is insignificant.
通过改变发泡剂的用量、聚合物的交联程度和泡沫膨胀温度,改变了化学发泡低密度聚乙烯泡沫的密度。根据开尔文泡沫结构中的气体压力以及对泡孔表面双轴拉伸的橡胶弹性分析,提出了平衡密度理论。预测密度与实验值相差不超过 3 kg m-3。对于商用类型的低密度聚乙烯泡沫来说,泡孔表面的双轴应力很大,但它们只会导致泡沫密度在自由膨胀极限以上略有增加。泡孔表面的分子取向一定会影响泡沫特性。氮气从泡沫中扩散的影响微乎其微。
期刊介绍:
Cellular Polymers is concerned primarily with the science of foamed materials, the technology and state of the art for processing and fabricating, the engineering techniques and principles of the machines used to produce them economically, and their applications in varied and wide ranging uses where they are making an increasingly valuable contribution.
Potential problems for the industry are also covered, including fire performance of materials, CFC-replacement technology, recycling and environmental legislation. Reviews of technical and commercial advances in the manufacturing and application technologies are also included.
Cellular Polymers covers these and other related topics and also pays particular attention to the ways in which the science and technology of cellular polymers is being developed throughout the world.