BIOPRODUCTS FROM AGRICULTURAL FEEDSTOCKS
Location: Bioproduct Chemistry and Engineering Research
Title: Starch/polycaprolactone-containing composites reinforced with pre-treated sisal fibers
Submitted to: Composite Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 15, 2011
Publication Date: December 1, 2011
Citation: Compos, A., Teixeira, E., Marconcini, J., Chiou, B., Orts, W.J., Wood, D.F., Mattoso, S., Imam, S.H. 2011. Starch/polycaprolactone-containing composites reinforced with pre-treated sisal fibers. Composite Science and Technology. 15: 89-99.
Interpretive Summary: Starch is a commodity chemical used in a variety of non-food applications. One such application is plastics. However, starch exhibits poor thermal/mechanical properties and is readily susceptible to moisture. Addition of 5-10% treated sisal fibers in composites along with another biodegradable synthetic polymer (polycaprolactone) improved mechanical and thermal properties were observed. This is attributed to more efficient dispersibility of fiber in the matrix and good compatibility between fibers and the matrix polymers, which also led to increased crystallinity that caused composite to be more rigid. Finding new uses for starch and improving its property is critical to US farm economy and also beneficial to American farmers and starch-industry.
Composites based on thermoplastic cornstarch (TPS) and polycaprolactone (PCL) were reinforced with 5, 10 and 20% (wt%) of pretreated sisal fiber. The impact of the addition of sisal fiber on the mechanical, thermal and morphological properties of composites was investigated. Addition of 5-10% fibers in composites exhibited improved mechanical and thermal properties attributed to more efficient dispersibility of fiber in the matrix and good compatibility between fibers and the matrix polymers, which also led to increased crystallinity that caused composite to be more rigid. The DSC and X-ray diffraction studies suggested interaction between polymers in the blend via carboxyl groups in thermoplastic starch-PCL and hydroxyl groups in fibers. An increase in storage energy was also observed from the DMTA studies, indicating mobility reduction in the polymers chains. Crystallization of PCL was apparent in the TPS/PCL blends but not in TPS/PCL composites with the added fibers, suggesting that sisal fibers hindered the crystallization of PCL in composites.