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Hemihydrate gypsum (CaSO4.0.5H2O), which is abundantly produced in the region of Araripe in the State of Pernambuco-Brazil, is obtained by calcination of dihydrate gypsum (CaSO4.2H2O). The mineral found at the mentioned site presents a high degree of purity, ranging from 80% to 95%. In spite of this, it finds its main use in the construction industry as a high-quality material of low cost [1-3]. One of the alternatives to add value to gypsum lies in its processing, that is to say, the improvement of its properties [1], or else its chemical conversion into a different material, which in the present case is hydroxyapatite [Ca10(PO4)6(OH)2]. The latter is a biomaterial with chemical and crystallographic similarity to the human bone matrix [4]. The transformation of gypsum into hydroxyapatite allows a great addition of value to the raw material, as the obtained ceramic has an elevated commercial value in comparison to gypsum. The cost of 5.0 g of hydroxyapatite at 99.9% purity is R$ 125.12 [5], whereas a 40 kg bag of gypsum-β costs on average R$ 20.00. Gypsum is a material that is highly moldable when in paste form, allowing solid bodies of previously defined shapes to be obtained [6]. Hydroxyapatite, on the other hand, is difficult to be molded in complex shapes due to its high fragility, which is directly related to the elevated crystallinity of the material [7, 8]. Bearing this in mind, our present aim is the formation of composites with hydroxyapatite (HA) and biodegradable and bioactive polymers, such as PHB (polyhydroxybutyrate), which is a thermoplastic material of the class of polyhydroxyalkanoates, chemically being polyesters with molecular formula C4H6O2. This polymer, Chemical conversion of a solid body of the composite gypsum/ polyhydroxybutyrate in hydroxyapatite/polyhydroxybutyrate

Chemical conversion of a solid body of the composite gypsum/polyhydroxybutyrate in hydroxyapatite/polyhydroxybutyrate