{"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":1,"journal":{"name":"Accounts of Chemical Research","volume":null,"pages":null},"PeriodicalIF":16.4000,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Accounts of Chemical Research","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1177/0262489319981704002","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","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:
Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance.
Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.