Effect of sawdust surface treatment and compatibilizer addition on mechanical behavior, morphology, and moisture uptake of polypropylene/sawdust composites

Authors

  • Silvia H.P. Bettini,

    Corresponding author
    1. Department of Metallurgical and Materials Engineering, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, São Bernardo do Campo, São Paulo, Brazil, CEP: 09850-90
    Current affiliation:
    1. Department of Materials Engineering, Universidade Federal de São Carlos, Rodovia Washington Luiz, km 235, São Carlos, São Paulo, Brazil, CEP: 13565-905
    • Department of Metallurgical and Materials Engineering, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, São Bernardo do Campo, São Paulo, Brazil, CEP: 09850-90
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  • Baltus C. Bonse,

    1. Department of Metallurgical and Materials Engineering, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, São Bernardo do Campo, São Paulo, Brazil, CEP: 09850-90
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  • Elis A. Melo,

    1. Department of Metallurgical and Materials Engineering, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, São Bernardo do Campo, São Paulo, Brazil, CEP: 09850-90
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  • Pablo A.R. Muñoz

    1. Department of Metallurgical and Materials Engineering, Centro Universitário da FEI, Av. Humberto de Alencar Castelo Branco, 3972, São Bernardo do Campo, São Paulo, Brazil, CEP: 09850-90
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Abstract

Polypropylene/sawdust composites were investigated to assess the effect of sawdust surface treatment and compatibilizer addition on polymer/fiber adhesion. Two silane coupling agents were used for sawdust surface treatment: vinyl-tris (2-methoxyethoxy) silane and (3-aminopropyl)triethoxysilane. Maleic anhydride grafted polypropylene was used as compatibilizer. Composites were prepared in a corotating twin-screw extruder coupled to a Haake torque rheometer and submitted to tensile and bending tests as well as scanning electron microscopy (SEM). Moisture uptake tests were also performed. Results showed that incorporation of untreated sawdust to polypropylene (PP) caused reduction in composite tensile strength and increase in stiffness. When the only treatment used was surface modification with silane coupling agents, no significant changes were observed in mechanical properties. However, when compatibilizer was added to the composites, tensile strength was increased, and % elongation at break reduced, indicating improved system compatibility. The composite presenting the highest increase in tensile strength was that containing sawdust treated with amino silane in addition to the compatibilizer. SEM analyses corroborated the mechanical property results. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

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