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Monitoring the continuous manufacture of a polymeric foam via a thermokinetic-informed acoustic technique

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journal contribution
posted on 01.06.2021, 09:10 by Joseph Holt, Carmen Torres, Paul Conway
Polymer foams are difficult to characterise due to rapidly evolving physical features from liquid to porous solid. Swift changes in volume, porosity and moduli render many techniques challenging for the characterisation of the foam curing during a manufacturing process. A technique that employs the longitudinal speed of sound of an ultrasonic signal, informed by a thermokinetic model, is proposed as an in-situ, in-line, non-destructive and continuous monitoring tool during production of rigid polyurethane foams. This study demonstrates that speed of sound measurements are suitable for: (i) continuous characterisation of different foaming stages in the polymer reaction and curing; (ii) determining the degree of cure for the continuous monitoring of foams, and (iii) predicting mechanical properties (i.e. stiffness and Poisson’s ratio) of cured foam samples. The validity of this monitoring technique is confirmed by comparison with well-established methods that use physical characteristics (e.g. expansion rate, electrical properties), thermo-kinetic models and mechanical testing. This method positions itself as a monitoring tool and convenient method for determining material stiffness during production.


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  • Mechanical, Electrical and Manufacturing Engineering

Published in

Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering


SAGE Publications


AM (Accepted Manuscript)

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This paper was accepted for publication in the journal Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering and the definitive published version is available at [insert DOI link]. Users who receive access to an article through a repository are reminded that the article is protected by copyright and reuse is restricted to non-commercial and no derivative uses. Users may also download and save a local copy of an article accessed in an institutional repository for the user's personal reference.

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Dr Carmen Torres-Sanchez. Deposit date: 28 May 2021

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