2026-04-17T04:29:13Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/103162026-02-11T05:10:23Zcom_2072_1033col_2072_452950

Study of the influence of the pressure drop rate on the foaming behavior and dynamic-mechanical properties of CO2 dissolution microcellular polypropylene foams Antunes, Marcelo de Sousa Pais Redondo Realinho, Vera Cristina de Velasco Perero, José Ignacio Universitat Politècnica de Catalunya. Departament de Ciència dels Materials i Enginyeria Metal·lúrgica Universitat Politècnica de Catalunya. POLYCOM - Polimers i compòsits: tecnologia Àrees temàtiques de la UPC::Enginyeria dels materials::Materials plàstics i polímers Polypropylene Mechanics Polipropilè -- Propietats Propietats mecàniques This article presents the preparation of microcellular polypropylene foams produced by a CO2 batch-foaming process and their characterization regarding the influence of the pressure drop rate on the foaming behavior and dynamic—mechanical properties. A polypropylene-based material was prepared by melt-mixing in a twin-screw extruder, cooled, and pelletized and later compression-molded in a hot-plate press to solid discs. These discs were finally foamed inside a high pressure vessel by dissolving CO2 and carefully controlling its sudden decompression drop. The dynamic—mechanical properties of the different expansion ratio-produced PP foams were studied, analyzing the influence of the pressure drop rate and residual pressures on the cellular structure and subsequent dynamic—mechanical behavior of the foams. With increasing the sudden pressure drop by reducing the residual pressure value, higher expansion ratio PP foams were obtained, reaching a maximum value of 3. Only slight differences were observed between foams regarding the cell size (maximum cell size ≈ 100 μm), the foams presenting slightly lower specific storage moduli than that of the solid material, indicating the efficiency of this process in nucleating and generating relatively high expansion ratio foams with a closed-cell type of structure and cell sizes in the micrometer range. Peer Reviewed Postprint (published version) 2010 Article De Sousa Pais, M.; Realinho, V.; Velasco J.I. Study of the influence of the pressure drop rate on the foaming behavior and dynamic-mechanical properties of CO2 diissolution microcellular polypropylene foams. "Journal of cellular plastics", 2010, vol. 46, núm. 6, p. 551-571. 0021-955X https://hdl.handle.net/2117/10316 10.1177/0021955X10382609 eng http://cel.sagepub.com/content/46/6/551.full.pdf+html Restricted access - publisher's policy 21 p. application/pdf