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Reactive extrusion (REX) of thermoplastic starch: Reactive blending and chemical modification via depolymerization/polymerization

Abstract

This research project proposes the use of reactive extrusion (REX) for the preparation of new materials based on thermoplastic starch (TPS). It is proposed the use of a single screw extruder specifically designed for REX. There are two main objectives; i) to study the reactive blending of starch and other polymers, such as polylactic acid (PLA), polihidroxyalcanoates (PHB and PHBV) and aliphatic polyesters (Ecoflex®), using as compatibilizers diisocyanates, blocked polyisocyanates and/or organic acids and ii) to modify thermoplastic starch during processing by reactive extrusion (REX) by depolymerization followed by reactions with diisocyanates or polyisocyanates and glycerol (repolymerization). The main objective is the preparation of new materials with characteristics different from the conventional TPS, as for example, higher plasticizer permanence, higher compatibility with other polymers, higher water resistance, and lower crystallization. The proponent has experience in thermoplastic starch depolymerization. In this study, glycerol could act as monomer in the re-polymerization or act as internal plasticizer if grafted to the starch backbone. The blocked isocyanates are urethanes formed by the condensation of di- or polyisocyanates with hydroxyl compounds such as phenol, for example. During the processing occurs the break up of the urethane linkage with the formation of free isocyanates which react with the starch or glycerol. The process can be designed in such a way that the deblocking, which occurs typically at 150 oC, takes place only after the water usually present in this kind of mixture is removed in a degassing zone. The by-products of the deblocking can also be eliminated in another degassing zone during REX. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
ALESSANDRA LUZIA DA RÓZ; PRICILA VEIGA-SANTOS; ADRIANE MEDEIROS FERREIRA; THAÍS CRISTINA RIBEIRO ANTUNES; FABIO DE LIMA LEITE; FABIO MINORU YAMAJI; ANTONIO JOSÉ FELIX DE CARVALHO. Water Susceptibility and Mechanical Properties of Thermoplastic Starch-Pectin Blends Reactively Extruded with Edible Citric Acid. MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS, v. 19, n. 1, p. 138-142, Fev. 2016. Web of Science Citations: 5.
ALESSANDRA LUZIA DA RÓZ; PRICILA VEIGA-SANTOS; ADRIANE MEDEIROS FERREIRA; THAÍS CRISTINA RIBEIRO ANTUNES; FABIO DE LIMA LEITE; FABIO MINORU YAMAJI; ANTONIO JOSÉ FELIX DE CARVALHO. Water Susceptibility and Mechanical Properties of Thermoplastic Starch–Pectin Blends Reactively Extruded with Edible Citric Acid. MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS, v. 19, n. 1, p. 138-142, Fev. 2016.
TROVATTI, ELIANE; FELIX CARVALHO, ANTONIO JOSE; GANDINI, ALESSANDRO. A new approach to blending starch with natural rubber. Polymer International, v. 64, n. 5, SI, p. 605-610, MAY 2015. Web of Science Citations: 11.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.
Filed patent(s) as a result of this research project

COMPOSIÇÃO DE ADESIVO APLICADO POR FUSÃO, PROCESSO PARA A PREPARAÇÃO DO MESMO E ARTIGO ADESIVO PI1005124-4 - Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; Universidade Federal de São Carlos (UFSCAR) . Antonio José Felix de Carvalho - November 2010, 10