Glycerol triacetate (GTA) was used to plasticize polylactic acid (PLA) in order to enhance its flexibility and to overcome the brittleness. The plasticized PLA and its nanocomposites based on cellulose nanofibers (CNF) were prepared using co-rotating twin screw extruder. The extruded materials were compression molded to films followed by fast cooling to avoid crystallization. GTA plasticizer drastically decreased the glass transition (T<sub>g</sub>) temperature of PLA and the T<sub>g </sub>temperature for the processed plasticized polylactic acid/cellulose nanocomposite was found to be around 38°C. Solid state drawing of the plasticized PLA nanocomposite films was conducted using universal tensile testing machine equipped with temperature chamber. For drawing, rectangular specimens were cut from the compression molded films and uniaxially stretched into tapes of different draw ratio (DR) at a temperature of 35°C and cross head speed of 50 mm/min. The temperature of 35°C was chosen to be just below the glass transition temperature. Also for amorphous material, higher orientation was obtained at a lower draw temperature due to slower chain relaxation. The orientation and its effect on mechanical properties was studied using universal tensile testing machine at room temperature and cross head speed of 5 mm/min. Solid state drawing improved the tensile properties of the nanocomposites and it is expected that the CNF were aligned. Scanning electron micrograph of cryo farctured and tensile fractured specimen of undrawn and drawn (DR=2) cellulose nanocomposite was also performed to study the morphology.

Orientation in uniaxially stretched plasticized polylactic acid/cellulose nanocomposites films

251st National Meeting (2016)

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