The Effects of Die Shapes and Additives on the Physical and Biodegradable Properties of Biodegradable Cushioning Extruded Foams

摘要

In this study, efforts were focused on the effects of the operating parameters, i.e. die shapes (DS), PVA ratio (PR), additives (AT) on the physical and biodegradable properties of the corn/PVA extrudates. We also evaluated the extrudates as cushioning materials. The process variables were the operating, conditions, die shapes (O, ∞, Δ and 0), PVA ratio (40%, 50%, 60%) and additives [sodium bicarbonate (NaHCO_3), calcium carbonate (CaCO_3) and calcium hydroxide (Ca(OH)_2)]. The experiment is a 4 x 3 x 3 factorial design. Samples of each treatment were collected and the physical, mechanical and chemical properties were measured and analysed using the PROC ANOVA and PROC CORR of the SAS 6.0 software package. The experimental results indicated that: (a) The change of die shapes (DS) had a significant effect on the longitudinal expansion, bulk density, compressibility and biodegradability properties of the extrudates; (b) the change of PVA ratio (PR) had a significant effect on the longitudinal expansion, bulk density and compressibility, but no effect on the biodegradability properties of the extrudates; and (c) the change of additives (AT) had a significant effect on the longitudinal expansion, bulk density and compressibility, but no effect on the spring index of the extrudates.