Submitted to: Annual Meeting of the Bio Environmentally Degradable Polymer Society
Publication Type: Abstract Only
Publication Acceptance Date: September 20, 1997
Publication Date: N/A
Technical Abstract: Starch based foams are currently being used as loose fill cushioning and have potential for many other uses if mechanical properties could be improved and density and cost reduced. There is, however, relatively little basic information available on how formulation and extrusion parameters affect foam properties. This study examined the effects of added nucleating agent (talc), blowing agents (water, ethanol, propanol), different biodegradable polymers (polyvinyl alcohol, polylactic acid, polycaprolactone, cellulose acetate, polybutylene succinate-adipate, polyester-amide) and extrusion conditions on the density, resilience and compressibility of extruded normal cornstarch loose fill foams. Experimental results indicated that 0.5-1.0% of talc was the optimum range. There was no significant difference among the selected blowing agents as long as water was kept at approximately 18%. Biodegradable polymer type and content played a ver important role. Addition of 10-15% poly(lactic acid) gave the lowest density and most resilient foams. Optimal processing temperature for the twin screw extruder was 185 deg C. Pressure was the most crucial processing parameter. As extrusion pressure increased, foam density decreased and resilience increased. Some samples seem to be promising as commercial products since they possess very low bulk density (e.g. 0.006g/cm**3 or 0.35 lb/ft**3) and reasonable mechanical properties.