Research Article

Clean and Green Bioplastic Composites: Comparison of Calcium Sulfate and Carbon Nanospheres in Polylactide Composites

  1. Margaret J. Sobkowicz,
  2. Jonathan L. Feaver,
  3. John R. Dorgan

Article first published online: 5 AUG 2008

DOI: 10.1002/clen.200800076

Issue

CLEAN – Soil, Air, Water

CLEAN – Soil, Air, Water

Special Issue: Feedstocks for the Future: Renewables in Green Chemistry

Volume 36, Issue 8, pages 706–713, August 2008

Additional Information

How to Cite

Sobkowicz, M. J., Feaver, J. L. and Dorgan, J. R. (2008), Clean and Green Bioplastic Composites: Comparison of Calcium Sulfate and Carbon Nanospheres in Polylactide Composites. Clean Soil Air Water, 36: 706–713. doi: 10.1002/clen.200800076

Author Information

  1. Department of Chemical Engineering, Colorado School of Mines, CO, USA.

Publication History

  1. Issue published online: 5 AUG 2008
  2. Article first published online: 5 AUG 2008
  3. Manuscript Revised: 16 MAY 2008
  4. Manuscript Received: 19 MAR 2008

Funded by

  • USDA Cooperative State Research, Education, and Extension Service. Grant Number: 2006-35504-16618
  • National Science Foundation. Grant Number: CMMI-0700869

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Keywords:

  • Carbon;
  • Crystallization;
  • Green bioplastic composites;
  • Gypsum; Polylactide

Abstract

Two environmentally friendly fillers, carbon nanospheres (CNS) derived from cellulose and calcium sulfate anhydrite (CaSO4), a by-product of the polylactide (PLA) production process, are compared as nucleating agents in commercial-grade PLA. CNS and CaSO4 are compounded with PLA using solution blending. Additionally, CaSO4 is melt mixed with PLA. Crystallization kinetics are explored using differential scanning calorimetry (DSC) and polarized optical microscopy. Mechanical properties are examined using dynamic mechanical thermal analysis (DMTA) and morphology is determined using field-emission scanning electron microscopy (FE-SEM). It is found that the filler does not increase the PLA crystallization rates significantly at loadings up to 15 wt% (CNS) or 20 wt% (CaSO4). The lack of effect on crystallization kinetics is attributed to the high D-lactic acid content of commercial-grade PLA, and also to poor dispersion of the fillers in the PLA matrix. The glassy shear storage modulus of the composites is found to increase by 50% in the highest weight loadings tested. These clean and green bioplastic composites may be able to offset the use of fossil resource-based materials.

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