Cellulose nanofibrils aerogel with enhanced thermal management performance
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Song, Mingyao
issued: 2021-08-31T07:00:00Z
issued: 2020
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: This study aimed to improve the thermal management and mechanical performance of cellulose nanofibrils (CNF) aerogels. We expected that closed-pore structure of CNF aerogel can be gained by Pickering emulsion templating and solvent exchange method, and that paraffin can be encapsulated by CNF to fabricate CNF/Phase change material (PCM) aerogel with excellent stability, super thermal regulation performance, and flexibility. It was also expected that the addition of CNF to prepared emulsion can enhance the structure to further improve the thermal management and mechanical performance. First, CNF aerogels with closed internal pores were successfully fabricated by Pickering emulsion templating and solvent exchange techniques. CNF stabilized oil-in-water Pickering emulsion can be converted into closed pores by sequential solvent exchanging to acetone and tert-butanol, followed by freeze drying from tert-butanol to suppress the formation of large ice crystals. The closed pore was verified by both confocal microscopy and scanning electron microscopy images, and was confirmed to reduce thermal conductivity for aerogel. In addition to the ultra-low thermal conductivity, the CNF/emulsion composite aerogel also demonstrates high performance in properties such as low density, high mechanical properties, superb flexibility, and infrared shielding properties. In addition, robust CNF/PCM aerogels were successfully fabricated with CNF stabilized paraffin by Pickering emulsion templating technique. The CNF/PCM aerogels were ultralight with impressive mechanical properties, which were significantly enhanced by the addition of CNF to the as-formed PCM emulsion. The freeze-dried CNF/PCM aerogels were flexible, and the shape of CNF/PCM aerogel can be well maintained even loaded with a weight of over thousands of times its own weight. The exceptional thermal regulation performance was demonstrated by a series of heating and cooling tests. The CNF/PCM aerogels exhibited excellent shape s…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/75766
note: CELLULOSE NANOFIBRILS AEROGEL WITH ENHANCED THERMAL MANAGEMENT PERFORMANCE by Mingyao Song A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2020 © Mingyao Song, 2020 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Cellulose Nanofibrils Aerogel with Enhanced Thermal Management Performance submitted by Mingyao Song in partial fulfillment of the requirements for the degree of Master of Science in Forestry Examining Committee: Feng Jiang (Assistant Professor, Forestry, The University of British Columbia) Supervisor Philip D. Evans (Professor, Forestry, The University of British Columbia) Supervisory Committee Member Scott Renneckar (Professor, Forestry, The University of British Columbia) Supervisory Committee Member Mohammad Arjmand (Assistant Professor, Mechanical, The University of British Columbia) Additional Examiner iii Abstract This study aimed to improve the thermal management and mechanical performance of cellulose nanofibrils (CNF) aerogels. We expected that closed-pore structure of CNF aerogel can be gained by Pickering emulsion templating and solvent exchange method, and that paraffin can be encapsulated by CNF to fabricate CNF/Phase change material (PCM) aerogel with excellent stability, super thermal regulation performance, and flexibility. It was also expected that the addition of CNF to prepared emulsion can enhance the structure to further improve the thermal management and mechanical performance. First, CNF aerogels with closed internal pores were successfully fabricated by Pickering emulsion templating and solvent exchange techniques. CNF stabilized oil-in-water Pickering emulsion can be converted into closed pores by sequential solvent exchanging to acetone and tert-butanol, f…
has type: Thesis/Dissertation
date issued: 2020-11
is shown at: 10.14288/1.0394085
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/75766