Francys K. V. Moreira, Ph.D. National Nanotechnology Laboratory for Agribusiness (LNNA) Embrapa Instrumentation, São Carlos (SP), Brazil Continuous casting: a soft processing approach to fabricate polysaccharide- based bioplastics Biopolymers & Bioplastics-2015 “Bio World Innovation: Smart, green and environmentally sustainable biopolymers

Background Non-biodegradable plastics – Versatile materials Images from Internet.

Background Non-biodegradable plastics – The “dark side” Images from Internet.

Background 4 Celullose Chitin Pectins Hemicelluloses Starch Carragenan Alginates Polysaccharides Green raw-materials for plastic production

Background Considerable potential for short time applications Biodegradable plastic wraps Edible films Fully biodegradable Relatively cheap Neutral and hydro-soluble Abundant as a natural resource Images from Internet.

Background Blow Molding Extrusion Single Screw Extrusion Twin Screw Extrusion Fiber Spinning Dry Spinning Melt Spinning Wet Spinning Filament Winding Film Blowing Injection Molding Mixing and Compounding Batch Intensive Mixing Twin Screw Extrusion Pultrusion Reaction Injection Molding Spin Coating Transfer Molding.Single Screw ExtrusionTwin Screw ExtrusionDry SpinningMelt Spinning Filament Winding Film Blowing Injection MoldingBatch Intensive MixingTwin Screw Extrusion Reaction Injection Molding Spin Coating * Polymer Processing Methods Images from Internet.

Background Casting as a processing method for biodegradable polymers

Background Casting is not applicable to large scale production Blow Molding Extrusion Fiber Spinning Mixing and Compounding Pultrusion Transfer Molding Injection molding. Casting Image from Internet.

AS A SCALABLE-UP METHOD FOR POLYSACCHARIDE FILM PRODUCTION CONTINUOUS CASTING AS A SCALABLE-UP METHOD FOR POLYSACCHARIDE FILM PRODUCTION

Background Low temperatures involved (90 °C); Precise control of film thickness; Short time-related process (4 min); Applicable for industrial production of biodegradable films. CONTINUOUS CASTING

To determine the suitability of the continuous casting as a processing method for the production of bioplastic films from polysaccharides. GENERAL OBJECTIVE  Study of different polysaccharides;  Rheology of polysaccharide solutions;  Delineation of processing conditions;  Mechanical characterization.

Sample*Concentration range (wt.%) Pectin Chitosan5 - 8 Hydroxypropyl Methyl-cellulose (HPMC) Carboxymethyl-cellulose (CMC)1-2 Corn starch4-10 Alginate_Na Carragenan1-4 Experimental – Polysaccharide samples *HPMC: Methocel E19FG (Dow); Pectin: Citrus Pectin USP-B (CKPelco); Chitosan (Polymar); CMC: Murta Ing.; Starch: Casco TM (Ingredion); Alginate: (GastronomyLab): Carragenan GENUGEL ® (CPKelco) Aqueous polysaccharide solutions used in the CC.

Experimental – Labcoater casting unit* *KTF Devices: (1) – Substrate roll; (2) Foulard of Transport; (3) Coating device; (4) IR pre-dryer; (5) First hot air drying chamber; (6) Foulard of lamination; (7) Lamination roll; (8) Second hot air drying chamber; (9) Collecting roll.

Experimental Mathis KTF-B Coating Device 2 - Doctor Knife Type B 1 - Substrate 3 - Comparative clocks (± mm)

Continuous casting - Step 1: Casting

Continuous casting - Step 2: Drying

Continuous casting - Step 3: Rolling up

CONTINUOUS CASTING - HIGHLIGHTED RESULTS-

HIGHLIGHTED RESULTS Rheological Aspects IDEAL UNDESIRABLE Low viscosity High viscosity Too high viscosity Molecular mass, Solid content HPMC 2 wt.% PEC 8 wt.% CMC 2 wt.% Liquid Gel

HIGHLIGHTED RESULTS Rheological Aspects Flow curves (25 °C) of aqueous HPMC solutions with different concentrations. IDEAL

Rheological Characterization HIGHLIGHTED RESULTS Comparison of flow curves (25 °C) between a HPMC solution (12 wt.%) and pectin solution (8 wt.%)

HIGHLIGHTED RESULTS Rheological Characterization Frequeny sweep at 25 °C: Dependence of storage modulus (G’) and loss modulus (G’’) on the angular frequence for an aqueous HPMC solution (12 wt.%).

HIGHLIGHTED RESULTS SampleConcentration (wt.%) Temperature (°C) Processing speed* (m min -1 ) Film thickness (μm)** Coef. Of variation (%)*** Pectin Chitosan HPMC CMC Starch Alginate Carragenan Summary of the best CC conditions for some polysaccharides *Maximum value; ** Wet solution layer thickness = mm;***n = 10.

HIGHLIGHTED RESULTS Mechanical Characterization Force (N) – deformation (mm) curves of chitosan films with varying thickness. 19 μm 25 μm 34 μm 45 μm 42 μm

HIGHLIGHTED RESULTS Summary of Mechanical Properties* PolymerElastic Modulus (MPa) Tensile Strength (MPa) Elongation at Break (%) Pectin Chitosan HPMC – CMC – Starch LLDPE** – LHDPE** N.D. Data were collected following the ASTM D 882 protocol, cross-head speed of 10 mm min -1 *, load cell of 10 Kgf. A. Prasad, Polymer Data Handbook, J. E. Mark, Ed. Oxford University Press, Oxford, 1999, 524.

Concluding Remarks Continuous casting could be a suitable method for the production of bioplastic films at large scale from any type of polysaccharide; Homogeneous polysaccharide film sheets can be properly fabricated only from liquid- or weak gel-like formulations. Formulations with high solid content are always desirable; The mechanical parameters of the polysaccharide-based bioplastic films can be easily tuned by setting the thickness during the continuous casting process.

CONTINUOUS CASTING - OUTLOOKS-

POLYMER PROCESSING OF DELICATE COMPOUNDS Dr. Tara McHugh, leading scientist in fruit puree edible films for food packaging (WRRC-ARS/USDA).

POLYMER PROCESSING OF DELICATE COMPOUNDS Nori Watermelon Passion fruit Red guava ASTM-D638 Type I specimens for red guava, passion fruit, and watermelon-based bioplastics.

INTENSIFICATION OF BIONANOCOMPOSITES’ PROPERTIES Tensile strength evolution of pectin-hydrotalcite bionanocomposites made by continuous (CC) and bench (BC) casting. Tensile tests were carried out using an Instron Machine at speed of 25 mm min -1. * Bench casting vs. continuous casting *Moreira, F. K. V., Materials Science and Engineering. Thesis (2014), Federal University of São Carlos, Brazil

Luiz H. C. Mattoso Tara McHugh Don Olson Roberto Bustillos Caio Gomide Marcos Lorevice Acknowledgments Scientific Staff Contacts: Francys Moreira Financial Support EMBRAPA FAPESP (Project no 2012/ ) FINEP/MCT CNPq ( CNPq/Sisnano /2013-4) CAPES