Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization

Frontal polymerization is a proven energy-saving and rapid method of synthesizing polymers with good mechanical properties. With a small energy input, a reaction front propagates rapidly through the sample, transforming monomer (liquid or soft gel) into polymer (stiff solid), and is self-sustained b...

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Main Author: Li, Xuanhe
Other Authors: Cohen, Tal
Format: Thesis
Published: Massachusetts Institute of Technology 2023
Online Access:https://hdl.handle.net/1721.1/147324
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author Li, Xuanhe
author2 Cohen, Tal
author_facet Cohen, Tal
Li, Xuanhe
author_sort Li, Xuanhe
collection MIT
description Frontal polymerization is a proven energy-saving and rapid method of synthesizing polymers with good mechanical properties. With a small energy input, a reaction front propagates rapidly through the sample, transforming monomer (liquid or soft gel) into polymer (stiff solid), and is self-sustained by heat released from the polymerization reaction itself. A thermo-chemical coupled model has been proposed to describe the frontal polymerization process, and recent experiments have shown that such coupling could lead to an unstable propagating front. However, the influence of mechanical forces has been absent in previous analyses of frontal polymerization, which could be significant considering local volume change caused by thermal expansion and chemical shrinkage as the front propagates. In this thesis, we will explore the mechanical behavior and potential thermal-chemo-mechanically coupled effects that may emerge during frontal polymerization of soft gels. We will show that non-uniform residual stress distribution could be generated due to differences in thermal and chemical properties on both sides of the propagating front. Our experiments further confirm that the emergence of stress could in turn influence the propagation of front, and our model describes such coupling effects to predict the dynamics of a propagating front in agreement with experimental observation. Our findings suggest that the mechanical effects need to be taken into consideration for industrial applications of frontal polymerization at large scales.
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spelling mit-1721.1/1473242023-01-20T03:09:26Z Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization Li, Xuanhe Cohen, Tal Massachusetts Institute of Technology. Department of Mechanical Engineering Frontal polymerization is a proven energy-saving and rapid method of synthesizing polymers with good mechanical properties. With a small energy input, a reaction front propagates rapidly through the sample, transforming monomer (liquid or soft gel) into polymer (stiff solid), and is self-sustained by heat released from the polymerization reaction itself. A thermo-chemical coupled model has been proposed to describe the frontal polymerization process, and recent experiments have shown that such coupling could lead to an unstable propagating front. However, the influence of mechanical forces has been absent in previous analyses of frontal polymerization, which could be significant considering local volume change caused by thermal expansion and chemical shrinkage as the front propagates. In this thesis, we will explore the mechanical behavior and potential thermal-chemo-mechanically coupled effects that may emerge during frontal polymerization of soft gels. We will show that non-uniform residual stress distribution could be generated due to differences in thermal and chemical properties on both sides of the propagating front. Our experiments further confirm that the emergence of stress could in turn influence the propagation of front, and our model describes such coupling effects to predict the dynamics of a propagating front in agreement with experimental observation. Our findings suggest that the mechanical effects need to be taken into consideration for industrial applications of frontal polymerization at large scales. S.M. 2023-01-19T18:45:31Z 2023-01-19T18:45:31Z 2022-09 2022-10-05T13:46:03.636Z Thesis https://hdl.handle.net/1721.1/147324 In Copyright - Educational Use Permitted Copyright MIT http://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology
spellingShingle Li, Xuanhe
Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization
title Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization
title_full Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization
title_fullStr Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization
title_full_unstemmed Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization
title_short Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization
title_sort investigation of thermo chemo mechanically coupled phenomena in frontal polymerization
url https://hdl.handle.net/1721.1/147324
work_keys_str_mv AT lixuanhe investigationofthermochemomechanicallycoupledphenomenainfrontalpolymerization