Upcycling of post-industrial starch-based thermoplastics and their talc-filled sustainable biocomposites for single-use plastic alternative

This study utilized post-industrial wheat starch (biological macromolecule) for the development of poly(butylene adipate-co-terephthalate) (PBAT) based thermoplastic starch blend (TPS) and biocomposite films. PBAT (70 wt%) was blended with plasticized post-industrial wheat starch (PPWS) (30 wt%) and reinforced with talc master batch (MB) (25 wt%) using a two-step process, consisting of compounding the blend for pellet preparation, followed by the cast film extrusion at 160 °C. The effect of the chain extender was analyzed at compounding temperatures of 160 and 180 °C for talc-based composites. The incorporation of talc MB has increased the thermal stability of the biocomposites due to the nucleating effect of talc. Moreover, tensile strength and Young's modulus increased by about 5 and 517 %, respectively as compared with the TPS blend film without talc MB. Thermal, rheological, and morphological analyses confirmed that the use of talc in the presence of chain extender at a processing temperature of 160 °C has resulted in an enhanced dispersion of talc and chain entanglement with PBAT and PPWS than PBAT/PPWS blend and PBAT/PPWS/Talc composite films. On the other hand, at 180 °C, the talc-containing biocomposite with chain extender tended to form PPWS agglomerates, thereby weakening its material properties.

Research on Properties of PBAT/CaCO3 Composite Films Modified with Titanate Coupling Agent

High cost, low crystallinity, and low-melt strength limit the market application of the biodegradable material poly (butylene adipate-co-terephthalate) (PBAT), which has become a major obstacle to the promotion of PBAT products. Herein, with PBAT as resin matrix and calcium carbonate (CaCO₃) as filler, PBAT/CaCO₃ composite films were designed and prepared with a twin-screw extruder and single-screw extrusion blow-molding machine designed, and the effects of particle size (1250 mesh, 2000 mesh), particle content (0-36%) and titanate coupling agent (TC) surface modification of CaCO₃ on the properties of PBAT/CaCO₃ composite film were investigated. The results showed that the size and content of CaCO₃ particles had a significant effect on the tensile properties of the composites. The addition of unmodified CaCO₃ decreased the tensile properties of the composites by more than 30%. TC-modified CaCO₃ improved the overall performance of PBAT/CaCO₃ composite films. The thermal analysis showed that the addition of titanate coupling agent 201 (TC-2) increased the decomposition temperature of CaCO₃ from 533.9 °C to 566.1 °C, thereby enhancing the thermal stability of the material. Due to the heterogeneous nucleation of CaCO₃, the addition of modified CaCO₃ raised the crystallization temperature of the film from 97.51 °C to 99.67 °C and increased the degree of crystallization from 7.09% to 14.83%. The tensile property test results showed that the film reached the maximum tensile strength of 20.55 MPa with the addition of TC-2 at 1%. The results of contact angle, water absorption, and water vapor transmission performance tests showed that TC-2 modified CaCO₃ increased the water contact angle of the composite film from 85.7° to 94.6° and decreased the water absorption from 13% to 1%. When the additional amount of TC-2 was 1%, the water vapor transmission rate of the composites was reduced by 27.99%, and the water vapor permeability coefficient was reduced by 43.19%.

Improvement of Interfacial Adhesion and Thermomechanical Properties of PLA Based Composites with Wheat/Rice Bran

The present work aims to enhance the use of agricultural byproducts for the production of bio-composites by melt extrusion. It is well known that in the production of such bio-composites, the weak point is the filler-matrix interface, for this reason the adhesion between a polylactic acid (PLA)/poly(butylene succinate)(PBSA) blend and rice and wheat bran platelets was enhanced by a treatment method applied on the fillers using a suitable beeswax. Moreover, the coupling action of beeswax and inorganic fillers (such as talc and calcium carbonate) were investigated to improve the thermo-mechanical properties of the final composites. Through rheological (MFI), morphological (SEM), thermal (TGA, DSC), mechanical (Tensile, Impact), thermomechanical (HDT) characterizations and the application of analytical models, the optimum among the tested formulations was then selected.