The changes in structural properties of high density polyethylene films (HDPE), low density polyethylene films (LDPE), biodegradable polyethylene (PE-BIO), and oxodegradable polyethylene (PE-OXO) films exposed to UV-B radiation were studied. The carbonyl(ICO)and vinyl(IV)index, the crystalline phase fraction, and the dichroic ratio were used to evaluate the photooxidation of these polymers. The results obtained show that LDPE and HDPE undergo a major degree of oxidation and an increase in the crystalline phase fraction comparing to PE-BIO and PE-OXO. If the LDPE and HDPE are pretreated by an accurate radiation UV-B dosage before its different commercial uses or in its final disposition, they can become an option for biodegradable material without the necessity of adding organic agents or photosensitizers.

This work presents the results by irradiating fresh Portland cement pastes with CO₂ laser, at powers of 1.6, 2.0, and 2.4 W, at different water‐to‐cement (w/c) ratios 0.4, 0.45, and 0.5. Raman spectra show the evolution and accelerated growth of the main hydration products through the intensity changes of the Raman signal. The Raman shifts reveal that the C‐S‐H, CH, AFt, and CaCO₃ bands are detected in a shorter time, which means that the setting times are also reduced. The detected band of calcium carbonate, which is due to the incorporation of limestone during the grinding process, shows that it is responsible largely for the acceleration in the reactions during the hydration of the cement. The Raman signals of the hydration products of nonirradiated cement pastes present a delay in their evolution with respect to the irradiated pastes. The curves obtained from the Raman spectra can be used to model the mechanism of hydration as well as to understand the setting process.

Pleurotus ostreatus is a wood-decaying fungus capable of producing key enzymes for lignin degradation. Laccase (Lcc), manganese peroxidase (MnP), lignin peroxidase (LiP), and unspecific peroxygenase (UnP) activities of P. ostreatus grown on a wheat straw infusion medium enriched with malt extract and yeast extract (SMY) were studied. Growth kinetics and enzymatic parameters were also determined. Glucose medium was used as a control. The specific growth rate of P. ostreatus in SMY (0.62 h⁻¹) was more than twice as high as that shown in the control (0.24 h⁻¹). This fungus produced 5-fold higher biomass (15.7 g/L) in SMY medium than in the control (3 g/L). Lcc, MnP, LiP and UnP activities were approximately 67-,19-,11-, and 17-fold greater in SMY (3106, 4082, 1564, and 1883 U/L, respectively) than in the control (46, 213, 143, and 112 U/L respectively). P. ostreatus constitutively produced all the studied enzymes; however, the presence of wheat straw infusion components (i.e. phenolic compounds) in SMY enhanced the enzymes production. This is believed to be the first study to examine UnP production by P. ostreatus in an enriched natural medium. UnPs have been reported as promising enzymes for degradation of hazardous pollutants; however, there is still little information about their production.

Thermooxidation of LDPE films by CO₂ laser radiation, 10.6 μm, was characterized by Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The formation of carbonyl and hydroxyl functional groups onto LDPE films was dependent on the fluency of CO₂ laser. IR absorption of vinyl groups and C-O bond present in alcohols showed a decrease and an increase, respectively, indicating that CO₂ laser radiation causes simultaneous formation and accumulation of hydroperoxides in LDPE films; furthermore, crystallinity of LDPE films irradiated with CO₂ tends to increase. So, CO₂ laser radiation is able to oxidize the LDPE films, obtaining a PE with similar spectroscopic properties to that of PE-BIO by a physical process.