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Mechanical and surface properties are considered important in governing the physical strength of polymers. A commercially available oxo-biodegradable polymer additive, which has induced surface and mechanical property changes during photo-oxidation in low-density polyethylene (LDPE) films, has been studied. LDPE films containing the oxo-biodegradable additive were irradiated with ultraviolet (UV)-B lamps at 30 ± 1 1C for an extended time period. The changes manifested on the polymer surface and in the mechanical properties were studied with respect to surface wettability, surface morphology using scanning electron microscope, surface topology by atomic force microscopy, functional groups by Fourier transformed infrared spectroscopy, absorbance spectra by UV-visible spectroscopy and elongation at break and tensile strength through mechanical testing. The increase in the wettability and surface-free energy of the irradiated samples was attributed to the formation of hydrophilic groups on the polymer surface by photo-oxidation, which occurs by the exposure of PE to UV irradiation in the presence of air. The degree of reduction in the mechanical strength and surface property modifications in our study are appreciable through the use of an oxo-biodegradable additive added to LDPE film samples.

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Ester-based thermoplastic polyurethane (TPU) nanocomposites were prepared by melt blending at 1908C, using 3 wt% Cloisite 10A (organically modified montmorillonite clay) as the nanoscale reinforcement [TPU(C10A)]. The nanocomposites were subsequently melt-blended with polypropylene (PP) using maleic anhydride-grafted polypropylene (MA-g-PP) as a compatibilizer [in the ratio of 70/30-TPU/PP, 70/25/5-TPU/PP/ MA-g-PP, 70/25/5-TPU (C10A)/PP/MA-g-PP]. Besides giving substantial increase in modulus, tensile strength, and other properties, organoclay reinforcement functions as a surface modifier for TPU hard segment resulting in improved dispersion. The morphology and other characteristics of the nanocomposite blends were investigated in terms of X-ray diffraction, fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, tensile properties, scanning electron microscopy, and atomic force microscopy. The results indicate that the ester-TPU(C10A)/PP/MA-g-PP exhibited better dispersion than other blend systems; abrasion resistance and water absorption resistance were also better for this system.

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