Property – performance relationships for cellulose nanocrystals in latex nanocomposites

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Property – performance relationships for cellulose nanocrystals in latex nanocomposites Antoniw, Julia Madelaine

Abstract

In recent years, the scale of production and availability of cellulose nanocrystals (CNCs) has increased dramatically to meet the growing demand for sustainably-sourced materials. Paramount to application development is an understanding of how surface chemistry and handling conditions impact the performance of CNCs in suspension. This work defines the colloidal stability window for commercially-produced carboxylated CNCs (DextraCel™) and sulfated CNCs, and presents guidelines for conditions under which CNCs remain colloidally stable with predictable performance. Carboxylated CNCs were found to have a pKₐ of 5.1 ± 0.1 and were colloidally stable at pH 3-11, with less than 5 mM of added NaCl. These guidelines were used to design a bench-scale study to compare CNCs with different surface chemistries and storage methods in the semi-batch emulsion polymerization of poly(butyl acrylate/methyl methacrylate) to produce nanocomposites for pressure sensitive adhesive (PSA) applications. Carboxylated and sulfated CNCs, stored as dried powders or never-dried suspensions, were incorporated into the latex nanocomposites. Extensive characterization revealed that surface chemistry and storage method have a compounded effect on the latex and cast film properties. Never-dried carboxylated CNCs and dried sulfated CNCs imparted high latex viscosity and formed uniform PSA films with the best tack and peel strength (i.e., adhesive properties). Furthermore, surface chemistry governed CNC-CNC interactions, with dried carboxylated CNCs interacting more than dried sulfated CNCs, which promoted latex particle coalescence and correlated to a spike in PSA shear strength (i.e., cohesive properties). Understanding how CNCs with different surface chemistries can affect in situ polymerization may promote their use as “green” property modifiers and will ideally encourage a shift towards water-based polymerization methods in polymer manufacturing; expanding the range of envisioned nano-enhanced and nano-enabled products.

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Title	Property – performance relationships for cellulose nanocrystals in latex nanocomposites
Creator	Antoniw, Julia Madelaine
Supervisor	Cranston, Emily
Publisher	University of British Columbia
Date Issued	2022
Description	In recent years, the scale of production and availability of cellulose nanocrystals (CNCs) has increased dramatically to meet the growing demand for sustainably-sourced materials. Paramount to application development is an understanding of how surface chemistry and handling conditions impact the performance of CNCs in suspension. This work defines the colloidal stability window for commercially-produced carboxylated CNCs (DextraCel™) and sulfated CNCs, and presents guidelines for conditions under which CNCs remain colloidally stable with predictable performance. Carboxylated CNCs were found to have a pKₐ of 5.1 ± 0.1 and were colloidally stable at pH 3-11, with less than 5 mM of added NaCl. These guidelines were used to design a bench-scale study to compare CNCs with different surface chemistries and storage methods in the semi-batch emulsion polymerization of poly(butyl acrylate/methyl methacrylate) to produce nanocomposites for pressure sensitive adhesive (PSA) applications. Carboxylated and sulfated CNCs, stored as dried powders or never-dried suspensions, were incorporated into the latex nanocomposites. Extensive characterization revealed that surface chemistry and storage method have a compounded effect on the latex and cast film properties. Never-dried carboxylated CNCs and dried sulfated CNCs imparted high latex viscosity and formed uniform PSA films with the best tack and peel strength (i.e., adhesive properties). Furthermore, surface chemistry governed CNC-CNC interactions, with dried carboxylated CNCs interacting more than dried sulfated CNCs, which promoted latex particle coalescence and correlated to a spike in PSA shear strength (i.e., cohesive properties). Understanding how CNCs with different surface chemistries can affect in situ polymerization may promote their use as “green” property modifiers and will ideally encourage a shift towards water-based polymerization methods in polymer manufacturing; expanding the range of envisioned nano-enhanced and nano-enabled products.
Genre	Thesis/Dissertation
Type	Text
Language	eng
Date Available	2024-07-31
Provider	Vancouver : University of British Columbia Library
Rights	Attribution-NonCommercial-NoDerivatives 4.0 International
DOI	10.14288/1.0422927
URI	http://hdl.handle.net/2429/83543
Degree	Master of Science - MSc
Program	Chemical and Biological Engineering
Affiliation	Applied Science, Faculty of; Chemical and Biological Engineering, Department of
Degree Grantor	University of British Columbia
Graduation Date	2023-05
Campus	UBCV
Scholarly Level	Graduate
Rights URI	http://creativecommons.org/licenses/by-nc-nd/4.0/
Aggregated Source Repository	DSpace

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UBC Theses and Dissertations

UBC Theses and Dissertations

Property – performance relationships for cellulose nanocrystals in latex nanocomposites Antoniw, Julia Madelaine

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