Biodegradation of Poly (3-hydroxybutyrate) /Eggshellsystems

Marcel Leiner De Sá,Luis Miguel Araque,Tatianny Soares Alves,Érica Melo De Carvalho,Renata Barbosa,José Francisco Reis Sobrinho,Julienne Calvacante

doi:10.1590/1980-5373-mr-2017-0792

Marcel Leiner De Sá, Luis Miguel Araque + Show 5 more

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https://doi.org/10.1590/1980-5373-mr-2017-0792

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Abstract

In this work, biocomposites of poly (3-hydroxybutyrate) (PHB) / calcium carbonate from Rhea Americana eggshells were prepared and the effects of the addition of the inorganic filler in the polymeric matrix were assessed. The residue (powder) of the eggshell calcined at 400 oC or in natura was inserted into a PHB solution for preparation of films via casting. Powder samples were characterized by X-Ray Fluorescence (XRF), X-Ray diffraction (XRD) and Thermogravimetry (TG/DTG) and films were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) and biodegradation tests according to the ASTM G 160-03 norm: the results were reported as weight loss and visual inspection by optical microscopy (OM). From the results of the XDR, it was perceived that the peaks in the diffractograms of the powder obtained by milling the Rhea Americana eggshells corresponded to the diffraction patterns of the Calcite crystals, which is a calcium carbonate polyform, and that the calcination preserved the crystalline structure, maintaining the calcium carbonate in the samples. For the biocomposites, a peak characteristic to the calcium carbonate in 29.57o was detected, indicating the insertion of the filler to the polymer matrix. Through SEM the presence of small agglomerates, probably due to polymer particles that were not dissolved, was observed for the pure PHB film. With the addition of the filler in natura a greater porosity was formed in the surface of the biocomposite films, and with the calcined filler, homogeneous films with reduced porosity were obtained. From the weight loss and OM results, it was observed that the filler inserted into the polymeric matrix catalyzes the biodegradation process up to 60 days evaluation in different ways, depending on the type of sample used.

Highlights

IntroductionSynthetic polymers are being used in various applications
Nowadays, synthetic polymers are being used in various applications
X-Ray Fluorescence ofin natura and calcined powder Results of the X-Ray Fluorescence analysis for the eggshells of Rhea Americana both in natura and calcined at 400 oC are presented at Table 2, such as the values found in the literature for similar fillers from different sources as reference

Summary

Introduction

Synthetic polymers are being used in various applications. This is due to the low cost, lightweight, high strength and ease of product manufacturing. The main drawback is the disposal causing serious environmental risks when improperly discarded in nature[1,2,3,4]. A way to reduce these environmental risks would be using biodegradable polymers obtained from renewable sources. An important family of biodegradable polymers is the poly (hydroxyalkanoates) - PHAs, which has attracted great attention because they are biocompatible thermoplastics. The PHB - Poly (3-hydroxybutyrate) is the most known among them, which is produced by bacterial fermentation, with mechanical and physical properties similar to the polypropylene. The PHB can be degraded by microorganisms in a short period of time and in different environments, such as soils, rivers, lakes and even in wastewater, generating water and carbon dioxide[3,4,5,6,7,8,9,10]

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