Presentation Title

Characterization of Well-Dispersed Carbon Nanofiber/Cellulose Nanocrystal Polymer Composites

Faculty Mentor

Stuart J Rowan

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

HARBESON 68

Session

POSTER 1

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

While easily processible and lightweight, neat polymers have limited applications as structural or electronic materials. Addition of carbon nanofiber (CNF) fillers provides both mechanical reinforcement and excellent thermal/electrical properties, allowing for high-performing conductive nanocomposites that retain the beneficial attributes of polymers. However, CNFs are prone to aggregation during composite fabrication and processing due to van der Waals interactions, and even dispersion within the matrix is crucial for enhancing said material properties. To prevent formation of CNF aggregates in thermoplastic polyurethane (TPU) composites, we have incorporated TEMPO-oxidized cellulose nanocrystals (CNCs) at varying compositions to coat each fiber with a negative charge and increase electrostatic repulsion. WAXS/SAXS, DMA, and DSC were used to characterize the effect that strain and CNC content, both above and below the percolation threshold, had on ordered phase formation and alignment of composite components. Preliminary results suggest that strain induces polymer crystallization and alignment of hybrid polymer-filler ordered phases along the tensile axis. There also appeared to be a notable difference in the effect of CNC content on formation of certain ordered phases and overall composite crystallinity when comparing compositions above and below the CNC percolation threshold. This work confirms we are able to access well-dispersed CNF/CNC nanocomposites, and will better inform our understanding of future thermal and electrical conductivity studies.

Summary of research results to be presented

Strain induced crystallization of neat TPU observed through DSC and DMA. WAXS spectra of composite films varying in CNC composition show several crystalline peak area trends (neat TPU, neat CNF, CNC-TPU, and overall crystallinity) with apparent plateau at the CNC percolation threshold. A CNC-CNF ordered phase seems to appear once the CNC percolation threshold has been reached. SAXS confirms alignment of polymer chains along tensile axis and suggests a possible shish-kebab like CNF-TPU structure.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

Characterization of Well-Dispersed Carbon Nanofiber/Cellulose Nanocrystal Polymer Composites

HARBESON 68

While easily processible and lightweight, neat polymers have limited applications as structural or electronic materials. Addition of carbon nanofiber (CNF) fillers provides both mechanical reinforcement and excellent thermal/electrical properties, allowing for high-performing conductive nanocomposites that retain the beneficial attributes of polymers. However, CNFs are prone to aggregation during composite fabrication and processing due to van der Waals interactions, and even dispersion within the matrix is crucial for enhancing said material properties. To prevent formation of CNF aggregates in thermoplastic polyurethane (TPU) composites, we have incorporated TEMPO-oxidized cellulose nanocrystals (CNCs) at varying compositions to coat each fiber with a negative charge and increase electrostatic repulsion. WAXS/SAXS, DMA, and DSC were used to characterize the effect that strain and CNC content, both above and below the percolation threshold, had on ordered phase formation and alignment of composite components. Preliminary results suggest that strain induces polymer crystallization and alignment of hybrid polymer-filler ordered phases along the tensile axis. There also appeared to be a notable difference in the effect of CNC content on formation of certain ordered phases and overall composite crystallinity when comparing compositions above and below the CNC percolation threshold. This work confirms we are able to access well-dispersed CNF/CNC nanocomposites, and will better inform our understanding of future thermal and electrical conductivity studies.