Preparation and Properties of Poly(Lactic acid) Foam Containing Rubber Wood Sawdust and Chitosan

Abstract

The objectives of the present work were to prepare porous polymeric from poly(lactic acid) compounded with rubber wood sawdust (RWS) and chitosan (CH) by typical compression molding using chemical blowing agent for studying physical, mechanical and thermal properties, and to preliminarily investigate suitability of the obtained foams for bone scaffold application. Azodicarbonamide and zinc oxide was used as a chemical blowing agent and an accelerator, respectively. Poly(ethylene glycol) (PEG) was used as a plasticizer. Surface treatment of RWS was applied. Foam samples were classified into 3 types: (1) PLA/RWS foams, (2) PLA/PEG/CH foams and (3) PLA/CH/RWS foams. It was found that all the foams were closed-cell. Factors affecting foam morphology and physical properties (average pore size, void fraction (%VF) and density) were particle size and surface treatment of RWS and concentration of CH and PEG. These factors also affected the mechanical properties and thermal degradation of the foams. Foams contained smaller average pore size/%VF and higher density showed higher mechanical properties. The thermal degradation temperature determined from TGA technique of all three foams was lower than that of PLA foam. In-vitro degradation and cytotoxicity tests were applied to Foam 1 and 2. The in-vitro degradation was reported as % weight loss of the samples which tested for 2 months. Noticeably, average pore size, %VF and density affected % weight loss of both foams. The % weight loss of Foam 1 depended on its formulation. The % weight loss of all formulae of Foam 2 was significantly lower than that of PLA foam. Cytotoxicity was evaluated by cell proliferation obtained from cell culturing of MG63 (osteoblast-liked cell) for 7 days. All of Foam 1 and 2 showed non-cytotoxicity confirmed by the increment of cell proliferation throughout the cell culture. Keywords: Poly(lactic acid), chitosan, sawdust, scaffold, PLA foam, cytotoxicity