Thermoplastic vulcanizates (TPVs) based on high‐density polyethylene (HDPE), ethylene–propylene–diene terpolymer (EPDM), and ground tire rubber (GTR) were dynamically vulcanized with dicumyl peroxide (DCP). The polymer blend was composed of 40% HDPE, 30% EPDM, and 30% GTR, and the concentration of DCP was varied from 0.3 to 3.6 parts per hundred rubber (phr). The properties of the TPVs were determined by evaluation of the gel fraction content and the mechanical properties. In addition, IR spectroscopy and differential scanning calorimetry analysis were performed as a function of the DCP content. Decreases in the Young's modulus of the blends and the crystallinity of HDPE were observed when the content of DCP was greater than 1.8 phr. The results regarding the gel content indicate that the presence of DCP promoted the crosslinking of the thermoplastic matrix, and optimal properties were obtained with 1.5% DCP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39901.

Ground tire rubber (GTR) was modified by sulfuric acid in order to improve its compatibility with and reinforcement of a polypropylene (PP) matrix. Polymer composites PP/GTR were prepared by melt mixing at different concentrations, with a maximum of 50 wt % of GTR. Studies by Fourier transform infrared spectroscopy (FTIR), surface specific area by BET (Brunauer, Emmett, and Teller), and scanning electron microscopy were used to characterize the untreated GTR and treated GTR, while the mechanical and thermal properties of the PP/GTR composites were assessed to understand how the surface treatment of GTR affected the mechanical and thermal properties of the composite PP/GTR. FTIR revealed the presence of sulfonic groups on the surface of sulfuric acid–treated GTR, and BET analyses showed an increase of about 625% in the specific surface area as a result of the high porosity produced by the treatment. In all composites containing treated GTR, a higher Young's modulus was obtained than for composites containing untreated GTR. Particularly, an increase of about 275% in the Young's modulus was obtained in composites with treated GTR (40 wt %) against that containing untreated GTR. However, a more significant reduction of the elongation at break was observed in composites containing treated GTR than in those containing untreated GTR. Also, an increase of the crystallization temperature of PP as a function of GTR was observed by differential scanning calorimetry, but the crystallinity of the composites was reduced by the addition of both untreated and treated GTR. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44858.

This study aims to investigate changes in the structural properties of alkali/acid‐ultrasound modified Agave fibers and their performance immersed on a polyvinyl alcohol (PVA) matrix with plasticizer during melt mixing processing. Structural analysis revealed that ultrasound enhances the effectiveness of the conventional alkaline/acid treatments to modify fibers since the simultaneous treatment increased the partial removal of lignocellulosic components, water molecules, and amorphous regions which improved their processability on a PVA matrix. Specific energy consumption values indicated that during melt mixing the modified fibers required more energy to expose the chains of cellulose fraction to function as an interaction site for PVA chains. Once the mixture was homogenized, the fiber‐matrix interactions promoted high viscosity, friction, and mechanical stress in the chamber. Therefore, the modified fibers restricted the interaction between plasticizer and PVA in the obtained films, resulting in a highly structured, and reinforced network, increasing the storage modulus as dynamic mechanical analysis indicated. These findings highlight a feasible way to valorize Agave fibers and allow the understanding of the matrix‐fiber interactions during melt mixing processing, useful to predict the structural and mechanical properties of the films.

Thermoplastic vulcanizates (TPVs) based on high density polyethylene (HDPE), ethylene propylene diene terpolymer (EPDM) were reinforced with ground tyre rubber (GTR) modified with sulfuric acid and dynamically vulcanized with dicumyl peroxide (DCP). TPVs were composed by 40% of HDPE, 30% of EPDM and 30% of GTR at 50 and 100 mesh and the concentration of DCP was varied from 0.3 to 3.6 parts per hundred rubber (phr). The properties of the TPVs containing GTR were determined by infrared spectroscopy, gel content and differential scanning calorimetry (DSC) analyses. The mechanical properties of the composites were also obtained. An increase of about 207% in the Young's modulus was obtained in blends containing GTR modified with sulfuric acid (GTR‐SA) in relation with blends containing pristine GRT. Good compatibility of compounds containing GTR‐SA was observed, GTR‐SA presented high specific area as a consequence of the modification with sulfuric acid. POLYM. COMPOS., 39:229–237, 2018. © 2016 Society of Plastics Engineers

The viscoelastic and mechanical performance of sustainable raw materials on biodegradable matrices provide insights into how to develop and improve materials that contribute to the circular economy. Thus, we aim to evaluate the effect of conventional (acid or alkali) and dual (alkali/acid‐ultrasound) treatment on Agave fibers, as well as their rheological and micromechanical performance on polyvinyl alcohol (PVA)‐based composites. TGA results indicate that the treatments promote the removal of moisture, waxes, pectin, hemicellulose, and lignin from the fibers to different extents. PVA matrix containing modified fibers exhibits low viscosity, flux index, and critical shear values, indicating a high interaction and dispersion of the filler in the matrix. Furthermore, tensile tests and theoretical predictions of micromechanics‐based finite element analysis show evidence that the modified fiber type provides a different stress transfer ratio () than in the matrix, which changes Young's modulus values. The results indicate that Agave fibers modified by dual treatment are a useful filler to produce soft or stiff PVA composites when looking for potential applications in the mobility industry or other fields like the packaging.