The Effect of Functionalized Cellulose on the Thermal and Mechanical Properties of ABS – and HIPS

Graduate #133
Discipline: Technology and Engineering
Subcategory: Materials Science

Chemar J. Huntley - Tuskegee University
Co-Author(s): Michael L. Curry, Tuskegee University, Tuskegee, AL

An increase in plastic production has contributed to plastic waste being one of the largest municipal solid waste categories in industrial countries. Consequently, plastics leach brominated flame retardants (BFRs) into the atmosphere upon landfill disposal. Therefore, the need for more biodegradable plastic materials has arisen. As a result, labs across the globe have devoted many hours and research dollars to the development of techniques to reduce the impact of such hazardous waste on the environment by using reinforcement fillers, such as cellulose, to increase plastic biodegradability upon disposal. However, the extraction of cellulose from different biomasses is a rigorous process and, often, modification of its structure is needed to obtain the desired chemical and physical structural properties. Therefore, the objective of this research is to functionalize CreaTech cellulose to increase its hydrophobicity and uniform distribution within acrylonitrile-butadiene-styrene (ABS) – and high impact polystyrene (HIPS) – matrix composites. In this research, CreaTech cellulose was oxidized using the Albright-Goldman and Jones methodologies to increase its hydrophobicity and uniform distribution within a thermoplastic-polymer matrix. The polymorphic structure and crystallinity percentage of the cellulose was determined using XRD analysis, while FTIR analysis ensured the introduction of carbonyl-functional groups on the cellulosic structure. After chemical functionalization, the cellulose was incorporated into ABS-HIPS blends, where the thermal and mechanical properties were observed with DMA, DSC, and TGA analyses. TGA determined that a 50:50 ABS-HIPS ratio with 30 wt.% cellulose content was the most thermally stable. However, upon modification via the Jones oxidation methodology, an increase in the thermal stability was observed. Furthermore, DMA analysis proved an increased stiffness at higher cellulose loading contents, but a significant regression in the storage moduli with the incorporation of functionalized cellulose. Therefore, modification of the cellulose improved the thermal properties, but showed a significant decrease in the mechanical properties. Future work includes determining the best functional groups to introduce onto the cellulosic structure that will increase the interaction between the cellulose and polymeric matrix.

Funder Acknowledgement(s): The authors gratefully acknowledge the National Science Foundation under Grant Nos. NSF EPS-1158862, NSF HRD-1137681, NSF IGERT on Sustainable Electronics DGE-1144843, and AGEP HRD-1433005 for support of this research.

Faculty Advisor: Michael L. Curry, currym@mytu.tuskegee.edu

Role: I performed all of the research activities, which included cellulose, chemical functionalization; ABS-HIPS blends preparation; mechanical, structural, and thermal characterization of the cellulose and composite blends; and the correlating calculations for the percent crystallinities and degrees of substitution.