Strategy for Obtaining Bimodal Bubble Size Distribution in Water Blown Polyurethane Foams

Niyogi, Debdarsan and Kumar, R and Gandhi, KS (2015) Strategy for Obtaining Bimodal Bubble Size Distribution in Water Blown Polyurethane Foams. In: INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 54 (42). pp. 10520-10529.

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Abstract

Polyurethane foams with multimodal cell distribution exhibit superior mechanical and thermal properties. A technique for generating bimodal bubble size distribution exists in the literature, but it uses supercritical conditions. In the present work, an alternative based on milder operating conditions is proposed. It is a modification of reaction injection molding (RIM), using reactants already seeded with bubbles. The number density of the seeds determines if two nucleating events can occur. A bimodal bubble size distribution is obtained when this happens A mathematical model is used to test this hypothesis by simulating water blown free rise polyurethane foams. The effects of initial concentration of bubbles, temperature of the reactants, and the weight fraction of water are studied. The study reveals that for certain concentrations of initial number of bubbles, when initial temperature and weight fraction of water are high, it is possible to obtain a second nucleation event, leading to bimodal bubble size distribution.

Item Type:	Journal Article
Publication:	INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	24 Nov 2015 06:02
Last Modified:	24 Nov 2015 06:02
URI:	http://eprints.iisc.ac.in/id/eprint/52812

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