Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.769650
Title: Foam templated macroporous polymers and polymer composites
Author: Song, Wenzhe
ISNI:       0000 0004 7658 740X
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2019
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Abstract:
A blowing agent and stabiliser free method - foam templating method - has been introduced to manufacture bio-based epoxy foams. In order to widen the potential applications of the foam templated macroporous polymers, three major challenges have been successfully addressed in this thesis: (i) increase the porosity of the foam templated macroporous polymers above the state of the art; (ii) enhance the fracture resistance and impact toughness of the foam templated macroporous polymers; and (iii) improve the mechanical performance of the foam templated macroporous polymers. The thesis starts from increasing the porosity of foam templated macroporous polymers. By using heat-induced bubble expansion, the porosity has been successfully increased from 71% to 85% without introducing any blowing agents or stabilisers. Correspondingly, the compressive modulus and strength decrease from 231 MPa and 5.9 MPa to 58 MPa and 1.9 MPa. The influence of the curing conditions on the mechanical properties and the deformation of the pores based on in-situ SEM micro-compression test are also discussed. Hollow elastomeric microspheres are used to enhance the fracture resistance and impact toughness of the foam templated macroporous polymers. A 15% increase in critical stress intensity factor and 33% increase in Charpy impact strength are achieved, and the failure behaviour of the epoxy foams changes from catastrophic failure to progressive failure. More importantly, the compressive properties of the toughened epoxy foams are not compromised. Short carbon fibres are used to improve the mechanical properties of the foam templated macroporous polymers. After short mixing time of 20 s, the carbon fibres are still mostly in tow form, and 58% and 10% increase in compressive modulus and strength along the fibre orientation direction are observed. By optimising the mixing process and prolonging the mixing time to 2 min, the single carbon fibres are successfully individualised from the original fibre tows, leading to more significant improvement - 165% and 53% increase in compressive modulus and strength. The highest compressive modulus and strength achieved are 845 MPa and 14.8 MPa.
Supervisor: Lee, Koon-Yang Sponsor: Imperial College London ; China Scholarship Council (CSC)
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.769650  DOI:
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