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The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid) was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid) produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM) analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid), promoted by the compatibilizer.

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In this work, we study the surface and electrokinetic properties of asphaltenes and some of their polar fractions. Using different mixtures of pentane/methylene chloride as a precipitant, we obtain four fractions (F1-F4), which contain different proportions of iron, nickel, copper, cobalt, aluminum, and vanadium. Modifications of asphaltenes and fractions F1 and F2 are performed by treatment with the salt form of ethylenediamine tetraacetic acid (EDTA) and, after this, with aqueous solutions of copper sulfate. The results indicate differences in the metal content between fractions before and after the treatments. Besides these differences, we observed differences in the zeta potential measurements and differences in the isotherms at the air/water interface. Our results show that, after the EDTA treatment, asphaltenes and fractions F1 and F2 can retain copper (>200% of the original copper content of the samples). This high copper content of the treated asphaltenes and the F1 and F2 samples is reflected in a change of the electrical charge from a negative charge to a positive charge. The hydrophobic behavior of the samples was analyzed with a Langmuir balance. The results show that the asphaltenes and the F1 fractions are more hydrophilic, with a smaller molecular area, and the F4 fractions are more hydrophobic, with a larger molecular area, before and after EDTA and copper sulfate treatments. Both the zeta potential measurements and Langmuir films of the samples indicate the possibility that EDTA molecules remain attached to the asphaltene molecules.

The impact of chitosan on the natural weathering behavior of two blends obtained by mixing either polyethylene (PE) with chitosan or PE, chitosan and polyethylene‐graft‐maleic anhydride (PEgMA) as a compatibilizer is analyzed. In order to follow the weathering behavior of both the uncompatibilized and compatibilized systems, the blend films are exposed to outdoor conditions for 6 months. The weathering behavior of the films is monitored by mechanical tests, spectroscopic Fourier transform infrared, and morphological analyses at different weathering periods of time. The presence of chitosan in the blends accelerates significantly the degradation of the films. Apparently, PEgMA also accelerates the photo‐oxidation rate of the films. This behavior appears to be related to the photo‐oxidative instability of maleic anhydride, and also to the better dispersion of chitosan in the PE matrix, which is due to the interactions in the PE/chitosan interface caused by the addition of the compatibilizer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41045.