Solid-state hydrolysis of postconsumer polyethylene terephthalate after plasma treatment

Authors

  • Sandro Donnini Mancini,

    Corresponding author
    1. Department of Environmental Engineering and Department of Control and Automation Engineering, UNESP, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Sorocaba, São Paulo, Brazil
    • UNESP, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Sorocaba, São Paulo, Brazil
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  • Alex Rodrigues Nogueira,

    1. Department of Environmental Engineering and Department of Control and Automation Engineering, UNESP, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Sorocaba, São Paulo, Brazil
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  • Elidiane Cipriano Rangel,

    1. Department of Environmental Engineering and Department of Control and Automation Engineering, UNESP, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Sorocaba, São Paulo, Brazil
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  • Nilson Cristino da Cruz

    1. Department of Environmental Engineering and Department of Control and Automation Engineering, UNESP, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Sorocaba, São Paulo, Brazil
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Abstract

Plasma treatments were applied on the surface of postconsumer polyethylene terephthalate (PET) bottles to increase their wettability and hasten the subsequent hydrolysis process. Sixty-four treatments were tested by varying plasma composition (oxygen and air), power (25–130 W), pressure (50–200 mTorr), and time (1 and 5 min). The best treatment was the one applied in air plasma at 130 W and 50 mTorr for 5 min, as it provided the lowest contact angle, 9.4°. Samples of PET before and after the optimized plasma condition were subjected to hydrolysis at 205°C. Although the treatment changed only a thin surface layer, its influence was evident up to relatively high conversion rates, as the treated samples presented more than 40% higher conversion rates than the untreated ones after 2 h of reaction. Infrared spectroscopy showed that the terephthalic acid obtained from 99% of depolymerization was similar to the commercial product used in PET synthesis. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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