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Clean and Green Bioplastic Composites: Comparison of Calcium Sulfate and Carbon Nanospheres in Polylactide Composites
Author(s) -
Sobkowicz Margaret J.,
Feaver Jonathan L.,
Dorgan John R.
Publication year - 2008
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.200800076
Subject(s) - materials science , composite material , differential scanning calorimetry , dynamic mechanical analysis , bioplastic , crystallization , scanning electron microscope , chemical engineering , polymer , ecology , physics , biology , engineering , thermodynamics
Abstract Two environmentally friendly fillers, carbon nanospheres (CNS) derived from cellulose and calcium sulfate anhydrite (CaSO 4 ), a by‐product of the polylactide (PLA) production process, are compared as nucleating agents in commercial‐grade PLA. CNS and CaSO 4 are compounded with PLA using solution blending. Additionally, CaSO 4 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% (CaSO 4 ). 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.