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In this work, a custom‐made reactor was developed to treat batches of short wood fibers with plasma. Three different plasma gases were tested: air, methane (CH4) and sulfur hexafluoride (SF6). The latter showed very promising results and was therefore used to prepare additional samples to determine the effects of plasma treatment and conditions on the wood fiber surface properties as well as the adhesion in a polypropylene matrix. As a result, composites made out of fibers plasma treated for 40 min at 60 W demonstrated an increase in the elastic modulus of more than 25%. Scanning electron microscope micrographs of the composites’ fracture surfaces indicated stronger interactions between treated fibers and the matrix. The incorporation of fluorine on treated fiber surfaces, mostly in covalent bonds with carbon, was clearly observed and analyzed by X‐ray photoelectron spectroscopy. The water contact angle on wood specimens treated under similar conditions displayed hydrophobic to superhydrophobic behavior, with contact angles exceeding 130°. POLYM. COMPOS., 39:1468–1479, 2018. © 2016 Society of Plastics Engineers

Despite poly(vinyl chloride) (PVC) being one of the most useful materials available to the fabricator, its inadequate disposal has contributed to strong noneconomic issues based on the allegedly evil effects of chlorine. In this study, we examined the influence of adding starch, a biodegradable bioplastics, to mixtures of PVC plasticized with di(2‐ethylhexyl) adipate (which is susceptible to fungal attack). PVC and its mixtures were assessed by mechanical properties, differential scanning calorimetry, Fourier‐transform infrared spectroscopy, low‐field nuclear magnetic resonance, thermogravimetric analysis, optical microscopy, and degradation in simulated soil. Increasing the amount of starch in the mixtures resulted in greater material stiffness, with a reduction in tensile strength at break (σ) and elongation at break (ɛ). Fourier‐transform infrared spectroscopy and nuclear magnetic resonance showed that there was limited interfacial interaction between components of the PVC mixtures, which agreed with slight phase separation (breakage of the interfaces) and the decrease in the values of σ and ɛ for the mixtures. Samples containing a larger content of starch showed little weight loss after 2, 4, and 6 months in simulated soil, possibly because the starch was encapsulated by the PVC resin. J. VINYL ADDIT. TECHNOL., 22:396–404, 2016. © 2015 Society of Plastics Engineers

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