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Design and Characterization of Anisotropic Foams from Lignocellulosic Biomass.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Design and Characterization of Anisotropic Foams from Lignocellulosic Biomass./
作者:	Venkata, Ramakrishna Aravind Kumar Trovagunta.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	182 p.
附註:	Source: Dissertations Abstracts International, Volume: 83-11, Section: B.
Contained By:	Dissertations Abstracts International83-11B.
標題:	Mechanical properties. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29071254
ISBN:	9798426867185

Design and Characterization of Anisotropic Foams from Lignocellulosic Biomass.
Venkata, Ramakrishna Aravind Kumar Trovagunta.

Design and Characterization of Anisotropic Foams from Lignocellulosic Biomass. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 182 p.

Source: Dissertations Abstracts International, Volume: 83-11, Section: B.

Thesis (Ph.D.)--North Carolina State University, 2021.

This item must not be sold to any third party vendors.

The growing environmental concerns associated with the production of petrochemicalderived plastic foams for cushioning applications and their end-of-life necessitate the development of renewable bio-based materials. Lignocellulosic biomass, such as wood consisting of natural biopolymers, has been recognized as an attractive raw material for bio-based value-added products. Inspired by the hierarchical, anisotropic structure of wood and existing synergistic interactions between its constituting biopolymers, the combination of lignin and cellulose nanomaterials (CNMs) was herein explored for the design and characterization of anisotropic foams as an alternative to petrochemical-derived cushioning applications.Two key research aspects were studied as part of this dissertation work. The first part of the research was focused on understanding the optimal processing conditions for cellulose nanofibrils (CNFs). CNFs have shown great potential to form lightweight, porous, self-standing foams. Additionally, CNF suspensions are also capable of templating, i.e., providing scaffolds to low molecular weight or brittle materials for hybrid composites. The fibrillation degree of the CNF suspensions, i.e., the extent to which the cellulosic fiber has been mechanically sheared to their micro-and nanoscale analogs, is key for controlling and tuning the properties of CNF-based materials. Presently, there exists research gaps on the how the processing of cellulose fibers, e.g., sources, pulping process and pre-treatment, alters the overall properties of the CNFs produced. To this end, the research objective was to understand the importance of varying the mechanical prerefining conditions on the fibrillation of softwood kraft pulp and hardwood kraft pulp cellulose fibers into CNFs. The CNF fibrillation degree was considered with the study of the properties of the CNF suspensions and corresponding anisotropic foams.The second aspect of this dissertation work was to develop and explore the structure-property relationships of anisotropic lignin-based foams. The intrinsic features of stiffness and rigidity reinforcement of lignin in wood can be desirable for the design of mechanically robust foams. However, foams with lignin weight fractions beyond 50 wt% have resulted in brittle and friable materials. To address this challenge, the optimally produced CNF suspensions were used to provide scaffolds to lignin to create bi-component composites useful for foam applications. The compressive mechanical performance of the composite foams was evaluated by varying lignin to CNFs weight ratio as well as by varying the sulfonation degree of the lignin. Lastly, to understand the end-of-life of the composite foams in comparison to the cushioning plastics, biodegradation in marine inoculum was performed.Mechanical pre-treatment was necessary to ease the fibrillation process of cellulose fibers. The optimal fibrillation conditions of the CNFs were achieved by controlling the pre-refining conditions at low energy consumption of the main mechanical treatment. CNFs provided scaffolds to lignin to engineer mechanically strong composite foams. Furthermore, these anisotropic ligninbased composite foams showed comparable compressive modulus values to the commercial isotropic cushioning plastics foams.The findings of this dissertation work are promising with the potential for strong compressive performance for cushioning applications and pave the way for a renewable and sustainable alternative to petrochemical-derived foams.

ISBN: 9798426867185Subjects--Topical Terms:

3549505
Mechanical properties.

Design and Characterization of Anisotropic Foams from Lignocellulosic Biomass.
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245 1 0 $a Design and Characterization of Anisotropic Foams from Lignocellulosic Biomass.
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500 $a Source: Dissertations Abstracts International, Volume: 83-11, Section: B.
500 $a Advisor: Kelley, Stephen S;Lavoine, Nathalie.
502 $a Thesis (Ph.D.)--North Carolina State University, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a The growing environmental concerns associated with the production of petrochemicalderived plastic foams for cushioning applications and their end-of-life necessitate the development of renewable bio-based materials. Lignocellulosic biomass, such as wood consisting of natural biopolymers, has been recognized as an attractive raw material for bio-based value-added products. Inspired by the hierarchical, anisotropic structure of wood and existing synergistic interactions between its constituting biopolymers, the combination of lignin and cellulose nanomaterials (CNMs) was herein explored for the design and characterization of anisotropic foams as an alternative to petrochemical-derived cushioning applications.Two key research aspects were studied as part of this dissertation work. The first part of the research was focused on understanding the optimal processing conditions for cellulose nanofibrils (CNFs). CNFs have shown great potential to form lightweight, porous, self-standing foams. Additionally, CNF suspensions are also capable of templating, i.e., providing scaffolds to low molecular weight or brittle materials for hybrid composites. The fibrillation degree of the CNF suspensions, i.e., the extent to which the cellulosic fiber has been mechanically sheared to their micro-and nanoscale analogs, is key for controlling and tuning the properties of CNF-based materials. Presently, there exists research gaps on the how the processing of cellulose fibers, e.g., sources, pulping process and pre-treatment, alters the overall properties of the CNFs produced. To this end, the research objective was to understand the importance of varying the mechanical prerefining conditions on the fibrillation of softwood kraft pulp and hardwood kraft pulp cellulose fibers into CNFs. The CNF fibrillation degree was considered with the study of the properties of the CNF suspensions and corresponding anisotropic foams.The second aspect of this dissertation work was to develop and explore the structure-property relationships of anisotropic lignin-based foams. The intrinsic features of stiffness and rigidity reinforcement of lignin in wood can be desirable for the design of mechanically robust foams. However, foams with lignin weight fractions beyond 50 wt% have resulted in brittle and friable materials. To address this challenge, the optimally produced CNF suspensions were used to provide scaffolds to lignin to create bi-component composites useful for foam applications. The compressive mechanical performance of the composite foams was evaluated by varying lignin to CNFs weight ratio as well as by varying the sulfonation degree of the lignin. Lastly, to understand the end-of-life of the composite foams in comparison to the cushioning plastics, biodegradation in marine inoculum was performed.Mechanical pre-treatment was necessary to ease the fibrillation process of cellulose fibers. The optimal fibrillation conditions of the CNFs were achieved by controlling the pre-refining conditions at low energy consumption of the main mechanical treatment. CNFs provided scaffolds to lignin to engineer mechanically strong composite foams. Furthermore, these anisotropic ligninbased composite foams showed comparable compressive modulus values to the commercial isotropic cushioning plastics foams.The findings of this dissertation work are promising with the potential for strong compressive performance for cushioning applications and pave the way for a renewable and sustainable alternative to petrochemical-derived foams.
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