Automotive and industrial design companies have profusely used commodity materials like glass fiber-reinforced polypropylene. These materials show advantageous ratios between cost and mechanical properties, but poor environmental yields. Natural fibers have been tested as replacements of glass fibers, obtaining noticeable tensile strengths, but being unable to reach the strength of glass fiber-reinforced composites. In this paper, polyamide 6 is proposed as a matrix for cellulosic fiber-based composites. A variety of fibers were tensile tested, in order to evaluate the creation of a strong interphase. The results show that, with a bleached hardwood fiber-reinforced polyamide 6 composite, it is possible to obtain tensile strengths higher than glass-fiber-reinforced polyolefin. The obtained composites show the existence of a strong interphase, allowing us to take advantage of the strengthening capabilities of such cellulosic reinforcements. These materials show advantageous mechanical properties, while being recyclable and partially renewable.

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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.

BACKGROUND Poly(ethylene terephthalate) (PET) waste films were treated by cold plasma aminolysis to graft primary amino groups (‐NH2) and the surface biocompatibility of the polymer was improved. Aminated PET waste films were obtained by applying radiofrequency (RF) plasma treatment of either diethylenetriamine (DTA) or ethylenediamine (EDA). Aminolysis was applied during 5, 10 and 15 min at plasma power levels of 150, 175 and 200 W. RESULTS Water contact angle study revealed that the surface of PET waste films became more hydrophilic after plasma treatment, the contact angles decreased as exposure time or plasma power increased. Also, X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) detected signals related to ‐NH2 functional groups at the surface of treated PET films. In relation to the biocompatibility properties of the aminated PET waste films, most of them, do not present hemolytic problems, but those treated with DTA at 150 W for 10 min (PET‐DTA/150 W‐10 min) showed the least hemolytic effect. On the other hand, it was proved that plasma treatment of PET waste films conferred a sterilization effect against Pseudomonas aeruginosa bacteria. CONCLUSIONS The biocompatible properties of PET were improved while the material was sterilized due to the ultraviolet radiation and free electrons generated during plasma treatment. These results suggest that aminated PET waste films have the potential to be used in biological or biomedical applications by taking advantage of ecofriendly technology such as cold plasma and the reuse of waste polymers such as PET from purified water bottles. © 2022 Society of Chemical Industry (SCI).

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