Extraction of natural fibers of Catole coconut (Syagrus Cearensis): Application as reinforcing filler in polypropylene‐based composites

• Published in: Polymer composites 2023-09, Vol.44 (9), p.5891-5909
• Main Authors: Nascimento, Emanuel Pereira, Luna, Carlos Bruno Barreto, Ferreira, Eduardo da Silva Barbosa, Santos Filho, Edson Antonio, Siqueira, Danilo Diniz, Wellen, Renate Maria Ramos, Araújo, Edcleide Maria
• Format: Article
• Language: English
• Subjects: Adhesion; composites; Copolymers; Coupling agents; Differential scanning calorimetry; Elongation; Fiber composites; Fourier transforms; Graft copolymers; Impact strength; Injection molding; Maleic anhydride; Mechanical properties; Modulus of elasticity; Polypropylene; PP‐g‐MA; SEBS‐g‐MA; Styrenes; Syagrus Cearensis; Tensile strength; Tensile tests; Thermal stability; Thermodynamic properties; Thermogravimetric analysis; Thermomechanical properties; X-ray diffraction
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.27535

Polypropylene/Syagrus Cearensis fiber composites compatibilized with polypropylene‐graft‐maleic anhydride (PP‐g‐MA) and styrene(ethylene‐butylene)‐styrene copolymer (SEBS‐g‐MA) were successfully produced using a co‐rotating twin‐screw extruder followed by injection molding. The composites were characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The mechanical properties were determined by Izod impact and tensile testing. Thermal properties were obtained by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Heat deflection temperature (HDT) was determined to study the thermomechanical properties of the composites. XRD and DSC indicated the presence of two polypropylene polymorphs: α and β. The unmodified PP/Fiber composites showed an incompatible behavior, presenting low fiber/matrix interaction and poor interfacial adhesion. The poor compatibility led to low elongation at break and impact strength but high tensile strength. PP‐g‐MA coupling agent promoted some adhesion to the PP/fiber interfaces but not enough to improve the impact strength. The composites with PP‐g‐MA exhibited improved tensile modulus and strength. The enhanced PP/fiber interfacial interaction promoted by SEBS‐g‐MA generated a better interplay of mechanical properties, improving impact strength and elongation at break while preserving the elastic modulus and tensile strength. In general, the fibers enhanced the thermomechanical stability of PP, as evidenced by higher HDT values.