Thermal and UV degradation of polypropylene with pro‐oxidant. Abiotic characterization

Abstract

The oxodegradation of an injection molding grade polypropylene (PP), formulated with 0%, 1.5%, and 3% w/w of a prooxidant additive, was studied. The degradation was conducted in a weathering tester at 60 8C for 40 h. The process was monitored by Fourier transform infrared spectroscopy, standard differential scanning calorimetry, and successive self-nucleation and annealing. Neat PP samples did not exhibit significant changes during the exposure time employed. PP samples with oxo-additive presented similar changes independently of the amount of oxo-degradative additive employed; however, the changes manifested more rapidly in the formulation with higher pro-oxidant content. Fourier transform infrared spectroscopy studies revealed the presence of hydroxyl and carbonyl functional groups whereas differential scanning calorimetry tests showed the decrease in the melting and crystallization temperatures as a consequence of the chain scission and oxidation reactions taking place during exposure. In addition, the induction time (t id ) of the oxo-degradative process was determined for each technique employed and successive self-nucleation and annealing was found to be the most sensitive characterization technique to reveal structural modifications in PP samples. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46088.

Aging Resistance of Biocomposites Crosslinked with Silica and Quercetin

“…According to the spectra presented in Figure 6 and Figure 7 , the most significant changes were detected at a wavenumber of 3400 cm −1 , which represents O-H bonding [ 21 ]. This signal appearing after aging processes is usually related to the formation of unstable hydroperoxides, carboxylic acids or alcohols, as a result of the oxidation process of the material [ 22 ], but is also present in quercetin structures, as well as silica. In ENR-based materials, such groups are able to occur after joining oxygen to the polymer chain or by opening oxirane rings.…”

Chitin- and cellulose-based sustainable barrier materials: a review

“…Degradation is a process in which materials undergo changes in the chemical structure under specific environmental conditions leading to a significant loss in physical and mechanical properties as defined by the American Society for Testing of Materials (ASTM) and International Standards Organization (ISO) [102]. Terms like "oxo," [103][104][105][106][107] "hydro," [39] "photo," [108][109][110] and "chemo" [111] degradable describe abiotic mechanisms of degradation [112]. These processes do not constitute or represent biodegradability, in which microorganisms are present.…”

Actinobacterias Degradadoras De Polipropileno

“…Si bien cerca del 62 % de los productos plásticos se fabrican con PE, el PP presenta el crecimiento interanual de la tasa de consumo más alto del mundo. Este último registró una producción global de 56.44 Mt en 2016, y se espera un aumento para el año 2022 a 75.72 mT (Arráez et al 2018). En 2018, la producción mundial de plásticos alcanzó los 360 Mt (https://www.…”