Blenda de Polihidróxibutirato(PHB)/Copoliéster Alifático Aromático (AAC) Ecoflex® reforçada com nanofibras de celulose (NFC): análise da resistência mecânica e propriedades químicas

Abstract

Due to increasing use of polymeric materials in society and the large volume of of those materials disposal in nature, the biodegradable polymers have increased interest in research of materials area. The Polyhydroxybutyrate (PHB) is a biodegradable polymer used in this work for preparation of a blend with other biodegradable polymer, the aromatic aliphatic Copoliéster (AAC). The central idea was to obtain a material that maintain good mechanical properties due to resistance of PHB and flexibility of the AAC. The percentages reasons in mass of PHB:AAC used for the prepration of physical mixture were 90:10, 80:20 and 95:5. The blends preparation has employed in a first step a solubilization process using chloroform as solvent and after thermoforming process as final preparation step. Some blends were reinforced with cellulose nanofibers extracted from bamboo (NFC) to form a composite. Some techiniques were used to determine the properties of the blend: analysis of FTIR, SEM, DMTA and optical microscopy. DMA tests in tensile module have shown that the blend offers interesting properties, such as increased flexibility of some blends when compared to the PHB without significant decrease in mechanical strength. The images obtained in SEM showed that there is interaction between the phases present in the blend and that this interaction benefits the miscibility, however the increase in composition of Ecoflex in the blend results on phase separation which can cause changes in the mechanical and chemical properties. The results obtained by DMA analysis on flexural modulus and also the DSC analysis have showed important informations about the the miscibility of blends and the relation of miscibility and temperature. For the composites it became evident that the addition of nanofibers have occasioned in 10 to 15% change in the values of the storage and loss module, making the more rigid material when compared to the bends