How latex film formation and adhesion at the nanoscale correlate to performance of pressure sensitive adhesives with cellulose nanocrystals

How latex film formation and adhesion at the nanoscale correlate to performance of pressure sensitive adhesives with cellulose nanocrystals

Description

Emulsion polymerized latex-based pressure sensitive adhesives (PSAs) are more environmentally benign because they are synthesized in water but often underperform compared to their solution polymerized counterparts. Studies have shown a simultaneous improvement in the tack, and peel and shear strength of various acrylic PSAs upon the addition of cellulose nanocrystals (CNCs). This work uses atomic force microscopy (AFM) to examine the role of CNCs in (i) the coalescence of hydrophobic 2‐ethyl hexyl acrylate/n‐butyl acrylate/methyl methacrylate (EHA/BA/MMA) latex films, and (ii) as adhesion modifiers over multiple length scales. EHA/BA/MMA. Thin films with varying solids content and CNC loading were prepared by spin coating. AFM revealed that CNCs lowered the solids content threshold for latex particle coalescence during film formation. This improved the cohesive strength of the films, which was directly reflected in the increased shear strength of the EHA/BA/MMA PSAs with increasing CNC loading. Colloidal probe AFM indicated that the nano-adhesion of thicker continuous latex films increased with CNC loading when measured over small contact areas where the effect of surface roughness was negligible. Conversely, the beneficial effects of the CNCs on macroscopic PSA tack and peel strength were outweighed by the effects of increased surface roughness with increasing CNC loading over larger surface areas. This highlights that CNCs can improve both cohesive and adhesive PSA properties, however, the effects are most pronounced when the CNCs interact favorably with the latex polymer and are uniformly dispersed throughout the adhesive film.
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Year of publication

2021

Authors

Department of Bioproducts and Biosystems

Elina Niinivaara Orcid -palvelun logo - Creator

Alexandra Ouzas - Contributor

Carole Fraschini - Contributor

Emily D. Cranston - Contributor

Marc A. Dubé - Contributor

Richard M. Berry - Contributor

CelluForce Inc. - Contributor

FPInnovations - Contributor

Scholars Portal Dataverse - Publisher

University of British Columbia - Contributor

University of Ottawa - Contributor

Other information

Fields of science

Materials engineering; Nanotechnology

Open access

Open

License

Creative Commons CC0 1.0 Universal (CC0 1.0) Public Domain Dedication

How latex film formation and adhesion at the nanoscale correlate to performance of pressure sensitive adhesives with cellulose nanocrystals - Research.fi