| 초록 |
Poly(lactic acid) (PLA) and cellulose are difficult to make into foams. This is because the former has a low melt viscosity, and the latter has limited number of solvents for processing. First, cellulose from coffee grounds dissolved in an alkaline aqueous solution. After freezing, it is immersed in cryogenic ethanol and water in order to remove the solvent. The resulting aerogels obtained by freeze drying is put in PLA solution to make PLA/cellulose composites. The cellulose has crystal phases of cellulose ΙΙ. The PLA/cellulose composite has 80% porosity similar to cellulose aerogel. The cellulose foam from coffee grounds has a lower modulus and stress than the foam from filter papers, despite the higher concentration of its stating solution. PLA/cellulose composites have stronger mechanical integrity than cellulose foams. This fabrication method using the cellulose foams with vertical pores like wood can prepare the PLA/cellulose composites with enhanced physical properties. |
