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  • Fabrication of hollow polym...
    Padilha, Carlos Eduardo de Araújo; Nogueira, Cleitiane da Costa; Matias, Stephanie Caroline Bivar; Costa Filho, José Daladiê Barreto da; Souza, Domingos Fabiano de Santana; Oliveira, Jackson Araújo de; Santos, Everaldo Silvino dos

    Colloids and surfaces. A, Physicochemical and engineering aspects, 10/2020, Letnik: 603
    Journal Article

    Display omitted •LNPs were prepared by pH-shifting of soda lignins obtained from GCF and CC.•Pickering emulsions stabilized by LNP reached high E48 values (> 40 %).•The LNP recycling step did not affect the manufacture of polymer microcapsule.•GCF-LNP-coated hollow PCL microcapsule showed stability in dry ambient.•GCF-LNP showed high performance in removing emulsified oil (> 90 %). Lignin-based materials have been explored as a way to minimize dependence on petroleum products and consolidate valorization schemes of lignocellulosic biomass. Soda lignins have peculiar properties and can generate lignin nanoparticles (LNP) with the potential ability to solve emulsification/demulsification problems. The present study focuses on the use of soda LNPs for fabrication of polymer microcapsules via Pickering emulsion template and for removing emulsified oil from aqueous environment. Structural characteristics of lignins recovered from corn cob (CC) and green coconut fibre (GCF) were evaluated after analyses of chemical composition, thermal degradation and infrared spectroscopy. Both LNPs were obtained by pH-shifting method and showed low absolute values of zeta potential. LNPs provided good emulsification capacity (emulsification index > 40 % at 5.00 g/L LNP) and micrometer-scale droplets in oil-water Pickering emulsions. LNPs have been successful as a stabilizing agent in the preparation of microcapsules of poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL), in which size was strongly dependent on the LNP concentration. Hollow PCL microcapsules were manufactured by stabilization with GCF-LNP, but did not show to be stable in experiments involving CC-LNP. In addition, the tendency of soda LNPs to form aggregates was used as a mechanism to remove emulsified oil, which made it possible to remove up to 90.6 % for CC-LNP and 94.4 % for GCF-LNP experiments.