Pilot scale production of thermoplastic starch/bentonite nanocomposites and their blends with polystyrene

LEANDRO LUDUEÑA; VERA ALEJANDRA ALVAREZ; ANDRÉS TORRES NICOLINI; MARÍA PAULA GUARÁS; LEANDRO LUDUEÑA; VERA ALEJANDRA ALVAREZ; ANDRÉS TORRES NICOLINI; MARÍA PAULA GUARÁS

Lyon

Conferencia; 32nd International Conference of the POLYMER PROCESSING SOCIETY; 2016

UNIVERSIDAD DE LYON (UNIVERSIDAD DE LYON)

The nonbiodegradability of most plastics has caused many environmental problems. This fact has carried to an increased use of biodegradable polymers for industrial applications. The development of new materials for industrial applications consists of different stages. The first one is the design of synthesis routes and new material properties at laboratory scale matching the application requirements. Once this step is completed, the next step is the scaling of processes. In recent times, the development of starchbased products has a growing interest. Nevertheless, the TPS has low stability in high moisture conditions and has a fragile nature. The mechanical properties of TPS can be greatly enhanced with the addition of a small amount of nanoclays (usually less than 10 wt%). In addition, blending TPS with other polymers has been used. Polystyrene (PS) is a polymer widely used in thermoformed products. TPS/PS blends could meet partial biodegradability, mechanical properties stability, and improved processability. The aim of this work is to scale up the synthesis of TPS nanocomposites and their blends with PS in order to obtain partial biodegradable products by thermoforming. Corn starch was used in powder form. The plasticizer used was glycerol. PS was purchased from INNOVA. Natural bentonite from Minarmco S.A. was used as nanoreinforcement. TPS/clay nanocomposites (TPS5B): corn starch, glycerol, stearic acid and 5wt.% of bentonite were extruded and pelletized in a twin screw extruder of D=18mm and L/D=25D at 25 rpm and 120/130/130/140/140ºC. TPS5B/PS and TPS5B/LDPE blends: blends 50/50 wt.% of TPS5B/PS were prepared by twin screw extrusion at 25 rpm. The temperature profiles used were 150/170/180/190/190. TPS5B/PS blends were thermoformed in a vacuum assisted machine.