Supercritical carbon dioxide (scCO2) processed thermoplastic starch (scCO2 aTPS), cellulose nanofiber (CNF) modified scCO2 aTPS (scCO2 aTPS100CNF0.02) and glutaraldehyde (GA) modified scCO2 aTPS100CNF0.02 (scCO2 aTPS100CNF0.02GAx) foams were prepared for the first time using scCO2 as a blowing agent during their foaming processes. The expansion ratio, cell density, moisture resistance, and compressive strength (σc) retention properties of each foam series were considerably improved with increasing scCO2 pressure during the foaming processes. The expansion ratios and cell densities of each scCO2 aTPS100CNF0.02GAx foam series were increased considerably to a maximum value, as the GA content approached an optimum value. The optimal scCO2 11TPS100CNF0.02GA1.6 foam material exhibited a high expansion ratio and cell density at approximately 50 and approximately 8 × 108 cells/cm3, respectively. Compared with corresponding aged scCO2 aTPS and scCO2 aTPS100CNF0.02 foam specimens, considerably better moisture resistance and σc retention properties were observed for scCO2 aTPS100CNF0.02GAx foam specimens, when they were modified with the corresponding optimum GA content. The moisture resistance and σc retention for optimal prepared scCO2 7TPS100CNF0.02GA0.4, scCO2 9TPS100CNF0.02GA0.8 and scCO2 11TPS100CNF0.02GA1.6 foam materials improved further with increasing scCO2 pressure. Possible reasons accounting for the highly expansion ratio, moisture resistance, and σc retention properties for scCO2 aTPS100CNF0.02GAx foams are presented.
All Science Journal Classification (ASJC) codes
- Polymers and Plastics