Sandwich panel biocomposite of thermoplastic corn starch and bacterial cellulose.

Inadequate disposition and long period for degradation of Petroleum-derived polymers promote damages in the environment, which could be minimized by the use of biodegradable polymers such as starch and cellulose. Films of thermoplastic corn starch (TPS) and bacterial cellulose (BC) were used to produce sandwich panel biocomposite. RXD, SEM and FTIR were used to verify the transformation of TPS from native corn starch. TPS/BC is flexible and transparent, but it is less transparent that TPS and BC due to its multilayer format. TPS/BC presented similar thermal events to TPS and BC samples and thermal stability similar to TPS. The FTIR spectrum of the TPS/BC showed bands observed in the BC and TPS spectra. BC, TPS and TPS/BC showed faster water absorption in the initial stage reaching a stability at about 50 h and presenting Fickian behavior. TPS/BC showed lower water absorption and a good adhesion between the phases observed by SEM images, which can be associated to hydrogen interactions in the interface improving mechanical properties. TPS/BC showed an increase of about 3.6 times in the tensile strength compared to TPS, indicating that BC is a good reinforcement for TPS.

Odor characterization of post-consumer and recycled automotive polypropylene by different sensory evaluation methods and instrumental analysis.

Despite the growing interest of the automotive industry in using recycled polymers, their undesired odor is limiting their application in vehicles' interior components. To get deeper insights into its causes, this study aimed at characterizing the odor of post-consumer and recycled automotive polypropylene with different contents of talc and an anti-fogging additive. Samples were evaluated by different sensory methods currently applied by the automotive industry (GMW 3205 and VDA 270), which confirmed, that they are not feasible for reuse in interior automotive applications. As these odor evaluations are usually performed by non-trained panelists and do not allow a detailed description of the samples' single odor qualities, sensory evaluation according to ISO 13299 was performed by trained panelists. Samples showed medium-high odor intensities rated from 5.1 to 5.6, and a general dislike of the odor with hedonic ratings from 1.8 to 2.6 (scale 0-10). Their odor profiles correlated well with the odorants identified by chemo-analytical characterization using gas chromatography-olfactometry (GC-O) and two-dimensional GC-O coupled with mass spectrometry (2D-GC-MS/O). An array of odorants with benzene and phenolic structures were identified as potential contributors to the samples' overall smell and are likely to originate from degradation of additives commonly used in automotive components. While the addition of talc or anti-fogging additive did not significantly improve the odor of the samples, the description of the samples' smell and the identification of odor-active compounds related to it allow the development of avoidance strategies for the manufacturing of neutral smelling products intended for vehicles' interior applications.

Recycling of viscose yarn waste through one-step extraction of nanocellulose.

Textile manufacturing industries generate large amounts of viscose yarn waste (VW) that causes serious environmental pollution. In this study, VW was used as raw material to successfully extract nanocellulose (NC) in a facile one-step extraction process, without any pretreatment. Different hydrolysis reaction times (5-60 min) were employed, and the extracted material was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopies, atomic force microscopy, and thermogravimetric analysis. Interestingly, it was possible to obtain NC in only 5 min of reaction without any pretreatment and with an increase of 50% in the crystallinity, which was attributed to the pretreatments VW undergone in textile industry that swell cellulose chains and make them more accessible to further reactions. The higher crystallinity index was observed after 30 min of reaction (87%), and through microscopy, it was verified that the morphology of the VW was completely changed to irregular nanoparticles with average size of 42 nm. The obtained NC showed interesting properties to be used in several potential applications, including stabilization of oil/water Pickering emulsions. These results indicate that VW is an attractive source to obtain NC, making the extraction of NC from VW a value-added alternative to recycle this textile waste.

Isolation and characterization of cellulose nanocrystals from pineapple crown waste and their potential uses.

Pineapple crown is an important source of cellulose that is still going to waste because of the lack of knowledge about their economic uses. The isolation of cellulose nanocrystals (CNC) from pineapple crown leaf (PCL) wastes arises as an important alternative to use PCL wastes in high value-added applications, and has not been reported yet. In this study, CNC were successfully extracted from PCL wastes using chemical treatments followed by acid hydrolysis using sulfuric acid. FTIR results confirmed the removal of the non-cellulosic compounds of PCL through the mercerization and bleaching treatments. SEM and AFM showed that the diameter of PCL fibers was reduced from 18 µm to 39 nm after the hydrolysis reaction, resulting in CNC with rod-like shape. The obtained CNC showed cellulose I crystalline structure with high crystallinity index (73%). The thermal degradation of CNC started at 124 °C, what was attributed to the presence of surface sulfate groups identified by elemental analysis. The high hydrophilicity of CNC was verified by its high moisture content and absorption. The results showed that the CNC isolated from PCL have interesting properties to be used in many liquid media applications, besides their use as reinforcement in nanocomposites.