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New composites based on poly(propylene) as polymer matrix and hemp strands as natural reinforcement have been developed by injection-molding. The materials were previously mixed in a two roll mill to induce the dispersion of the fiber inside the polymer. To improve the adhesion between both components, maleated poly(propylene) was added as coupling agent, at 4% wt/wt with respect to hemp strands. The addition of this amount of this coupling agent to the formulation modified with 40 wt % of hemp strands increases the ultimate tensile strength ( t ) and flexural strength ( f ) up to 49 and 38%, respectively, compared with the composite without coupling agent. The interaction between the surface of hemp strands and the coupling agent was determined by FT-IR spectroscopy assuming that a covalent bond was established, avoiding the adverse effect of the poor compatibility at the interface for this kind of composites.

Low liquid-solid ratio (LSR) can be used to obtain high-content xylo-oligosaccharide (XOS) spend liquor by hot water pretreatment. Developing a technology based on low LSR results in more efficient water usage in the system and thus in lower capital and operating costs. Xylans from xylan rich agro-industrial waste are abundant hemicellulosic polymers with enormous potential for industrial applications. Currently, freeze-dried xylo-oligosaccharides are used as bio-based polymers and hydrolysates containing high xylose contents are converted to several chemical products. In this study, sugarcane bagasse was treated with water at low LSRs and mild temperatures in order to assess the effects of varying the pretreatment conditions on the xylo-oligosaccharide and xylose concentrations, and use a central composite experimental design to optimize the process parameters. The pretreatments were performed in the ranges temperature: 143.3-176.7 °C, time: 20-70 min and LSR: 1 : 1 to 11 : 1 (g g −1 ). The maximum concentrations of xylose and xylan were 13.76 and 36.18 g L −1 (equivalent to 48.29 g L −1 of xylan), respectively, which were achieved by treating bagasse at 170 °C for 60 min, with LSR of 3 g g −1 . The amount of xylan removed under these conditions was almost 57%. The soluble xylan consisted mainly of xylo-oligosaccharides (74 wt% of the identified compound in the spent liquor).