Agricultural and Biosystems Engineering Publications

Campus Units

Agricultural and Biosystems Engineering, Materials Science and Engineering, Horticulture, Center for Industrial Research and Service (CIRAS)

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

2015

Journal or Book Title

Green Chemistry

Volume

17

First Page

380

Last Page

393

Research Focus Area(s)

Biological and Process Engineering and Technology

DOI

10.1039/C4GC01482K

Abstract

Adipic anhydride-plasticized soy protein (SP.A) was blended with poly(lactic acid) (PLA) at two concentrations (50/50 and 33/67) and was evaluated for use as a sustainable replacement for petroleum plastic in horticulture crop containers. Following the discovery that SP.A/PLA blends provide additional functions above that of petroleum plastic for this application, the present study evaluates the biodegradation behavior of these materials in soil and describes the substantial improvements in sustainability that result from the additional functions (intrinsic fertilizer and root improvement of plants) and the end-of-life option of biodegradation. After being buried in soil for designated time intervals, the residual degraded samples were analyzed to determine morphological and thermal properties at sequential stages of biodegradation. Samples were characterized by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The results indicated that there was a compatible system between SP.A and PLA in the melt. Incorporation of SP.A accelerated the biodegradation rate of this binary blend significantly compared with pure PLA. Prior to the degradation process, both the glass transition temperatures and melting temperatures of the blends containing SP.A decreased as the concentration of the soy protein increased. With increasing degradation time of the blended samples in soil, the glass transition temperatures increased in the early stages of biodegradation then decreased, a trend associated with the decrease in the molecular weight of the blends as a result of biodegradation. In addition, the thermal stability of blends increased gradually with increasing degradation time, suggesting faster biodegradation loss of the soy component of the SP.A/PLA blends. These results support the use of soy-based polymer blends for horticulture crop containers and provide data for evaluating their use as sustainable materials for other potential applications.

Comments

This is a manuscript of an article published as Yang, Shengzhe, Samy A. Madbouly, James A. Schrader, Gowrishankar Srinivasan, David Grewell, Kenneth G. McCabe, Michael R. Kessler, and William R. Graves. "Characterization and biodegradation behavior of bio-based poly (lactic acid) and soy protein blends for sustainable horticultural applications." Green Chemistry 17, no. 1 (2015): 380-393. DOI: 10.1039/C4GC01482K. Posted with permission.

Copyright Owner

The Royal Society of Chemistry

Language

en

File Format

application/pdf

Published Version

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