Biodegradation of Poly (3-hydroxybutyrate) /Eggshellsystems

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.

Biodegradable polyhydroxybutyrate/cellulose/calcium carbonate bioplastic composites prepared by heat‐assisted solution casting method

“…Figure 3a,b revealed that PHB 100 is relatively smoother than the as‐prepared composites which is consistent with the opacity test results (Figure 2). For PHB 90 CC 10 (Figure 3d,e), the incorporation of CaCO 3 to PHB created heterogeneity in the microstructure surface as observed in the presence of particles (20.0–100.0 μm) which is consistent with literature 18,20 . The CaCO 3 addition to the composites has resulted in a larger size of dispersion phase caused by agglomeration due to the large surface area of the filler, which were unevenly dispersed within the polymer matrix.…”

“…Another abundant and equally cheap natural filler is calcium carbonate (CaCO 3 ). Most of the CaCO 3 can be extracted from eggshells which is primarily 94%–98.5% calcium carbonate 18 …”

“…Similarly, Duangphet et al 20 melt mixed 0%–20% w/w calcium carbonate with PHB to enhance the crystallization growth rate and delay the nucleating process simulation tests on compost and freshwater. Biodegradation tests made under ASTM G160‐03 standard by Sá et al 18 reported outstanding biodegradation rates among PHB‐eggshell systems, having a mass loss rate proportional to that of eggshell filler composition. Hence, in this work, the combination of calcium carbonate and cellulose to PHB is investigated to identify possible advantages in the properties of the resulting PHB‐based material.…”

Study of the hydrolytic degradation of poly-3-hydroxybutyrate in the development of blends and polymeric bionanocomposites

“…The brittleness observed was caused by the increase of the porosity of materials, attributed to the incorporation of the clay and PEG, which possibly altered the hydrophilicity of the polymer resulting in a more degraded material. Sá et al 18 when preparing films of PHB, PEG, and inorganic filler observed a similar behavior by the casting method, where the authors verified the presence of porosity in all systems by scanning electron microscopy. The dim visual aspect can also be explained by the samples refraction index because of water absorption.…”

Desenvolvimento e caracterização de sistemas de nanocompósitos PHB/argila brasileira para encapsulação de ureia.

“…Para mudar essa situação, nos últimos anos foram estudadas alternativas para a obtenção de polímeros biodegradáveis. Também houve interesse de que estes fossem produzidos a partir de fontes renováveis (GODBOLE et al, 2003), devido ao preço flutuante do petróleo, que é a principal fonte de matéria-prima dos polímeros convencionais (SÁ et al, 2018;SIRACUSA et al, 2008), e à sustentabilidade ambiental. Entre os polímeros biodegradáveis, os poliésteres lineares provenientes de ácidos hidroalcanóicos chamados de poli(hidroxialcanoatos) (PHAs) são bons candidatos para substituir os polímeros convencionais (BOYANDIN et al, 2013).…”