(691c) Novel Carbon Nanospheres Derived from Cellulose
The use of nanometric reinforcing fillers to enhance the properties of both conventional and biodegradable polymers has been proven in recent years. Some of the most extensively studied nanocomposites consist of silicate clay1, metal fillers2, and carbon nanotubes in corn and soy based plastics. These nanocomposite materials exhibit considerable improvements in tensile strength, heat distortion temperature, and modulus. As worldwide concern for resource sustainability grows, with an accompanying escalation of prices, it is now imperative to develop polymer nanocomposites with renewable fillers as opposed to those with mined materials. This desirable strategy for raw material substitution is fully consistent with the 12 principles of Green Chemistry3.
Recent advances in both bioplastics4 and carbon nanoparticle production technology5 have increased the economic viability of producing nanocomposites entirely from renewable resources. Homogenous samples of hollow carbon nanospheres, produced onsite at the Colorado School of Mines campus via laser pyrolysis of cellulose, have been isolated and characterized for surface functionalization and solubility characteristics. Methods of isolating the carbon nanospheres include ultrasound assisted solvation using a range of solvents. Best practices for disaggregating the nanospheres are being explored to facilitate their use in making biobased plastic nanocomposites. Transmission electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, light scattering, and suspension and dispersion studies are being performed to understand the novel, highly functional, and potentially valuable carbon nanomaterials. Exploiting the surface chemistry allows polylactide chains to be chemically grafted to the nanoparticle surfaces to constitute the class of nanocomposites under investigation.
1. Ray, S. S.; Bousmina, M., Biodegradable polymers and their layered silicate nanocomposites: In greening the 21st century materials world. Progress in Materials Science 2005, 50, 962-1079. 2. Nicolais, L.; Carotenuto, G., Metal-Polymer Nanocomposites. 2005. 3. Anastas, P. T.; Warner, J. C., Green Chemistry: Theory and Practice 1998. 30. 4. Herring, A.M.; McKinnon, J.T.; McCloskey, B.D.; Filley, J.; Gneshin, K.W.; Pavelka, R.A.; Kleebe, H.J.; Aldrich, D.J., A novel method for the templated synthesis of homogeneous samples of hollow carbon nanospheres from cellulose chars. J. American Chemical Society 2003, 125, 9916-9917. 5. Dorgan, J.R.; Braun, B.; Wegner, J.R.; Knauss, D.M., Poly(lactic acids) ? A brief review. ACS Symposium: Degradable Polymers and Materials ? Principles and Practice 2006, Chapter 3.