engleski

Influence of inorganic fillers on PLA crystallinity and thermal properties

Polymer composites represent an increasing approach to implement new class of materials for specific application. Polylactide (PLA) is among most widely studied bio-based products during last few decades. That is mainly due to its biodegaradable nature as well as due to a search for the conventional petrol based plastics replacement [1-3]. In this work we have studied thermal behaviour of PLA composites based on three kinds of fillers: Glimmer, Schwerespat and Socal. The concentration of added fillers was: 0.1, 1 and 5 wt %. Composites were prepared using a Brabender plasti-corder at 190 °C. Thermal properties of prepared composites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The glass transition temperature (Tg) of composites is in a range 56 to 61 °C, which is close to a value of PLA matrix (57.7 °C). The obtained results reveal influence of sample's thermal history. Therefore, the second heating run results were compared. All prepared composites display resembling crystallization enthalpies of cold crystallization as well as enthalpies of fusion. Consequently, added fillers provoke disappearance of crystallinity of PLA matrix that was noticeable originally. The results of TGA show increase of thermal stability in all composites. The thermal decomposition onset temperature in PLA matrix is below 260 °C while in some composites it is shifted above 300 °C.

Polylactic acid; DSC; TGA; malt mixing; solution mixing; inorganic filler

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