| 초록 |
Cellulose and poly(lactic acid) (PLA) are biodegradable polymers, but it is difficult to make them into a foam because cellulose has a limited number of solvents and PLA has a low melt viscosity. In this study, we extract cellulose from coffee grounds and prepare foams by a directional melt crystallization method. The refined coffee grounds (RCG) are dissolved in alkaline aqueous solution and frozen with liquid nitrogen. After that we remove the solvent and infiltrate PLA in to the pores of cellulose to make a PLA/RCG foam. The cellulose from the RCG had a cellulose Ⅱ crystal structure, and composite showed vertically structured pores. PLA/RCG foam had a higher modulus than RCG foam and the mass loss rate was slow up to 300 °C upon heating. RCG foam has a hydrophilic surface, but PLA/RCG foam was modified to have a hydrophobic surface due to PLA. PLA/cellulose composite made from coffee grounds has stronger mechanical properties and thermal stability than RCG foam. |
