聚乳酸／幾丁聚醣／非晶性磷酸鈣複合材料之可塑性探討

The purpose of this study was to explore the effects of poly (lactic acid) (PLA)/chitosan/amorphous calcium phosphate (ACP) composites on their shapeable properties. PLA/chitosan/ACP composites containing different proportions of ingredients were prepared by water-washing solidification from an n-methyl-2-pyrrolidone (NMP)/lactic acid/water co-solution. After storing at room temperature for 48 hours, the composites showed swelling and shapeable properties. The water content and yield stress of the samples were measured by thermal gravimetric analysis (TGA) and a rheometer and examined under optical microscopy. Results showed that the composites without ACP had 1000 Pa of yield stress. For composites containing 0.0lwt% of ACP, the water content increased to 42.50wt%. The lowest yield stress was 10.0Pa in 0.30wt% ACP. When the ACP content was 0.30wt% or higher, insoluble ACP particles were observed with optical microscopy. This reveals that the shapeable properties of the PLA/chitosan/ACP composites were closely related to the water content. It was determined that ions released from the ACP interacts with amide groups of the chitosan to form water-absorbing ionic clusters through chelation or electrostatic interactions. These ionic clusters reside within the matrix while the remaining insoluble ACP particles act as a filler; as the amount of ACP increases, the yield stress of the PLA/chitosan/ACP composites also increases.