Single-use plastics are expected to disappear, mainly due to the rise of stricter regulations to combat their impact on the environment. As an example, the recent European Directive on Single-Use-Plastics (SUP) will be implemented between 2021 and 2024 and will directly prohibit the use of some SUP. Baby diapers are one of the most used single-used products in our daily lives, and it is estimated that most of the ~4000 diapers that each baby uses in their life go to landfill. Such diapers usually contain superabsorbent polymers (SAP) that are based on acrylic acid-acrylamide mixtures with high water retention capacity, but they are neither bio-based nor biodegradable. In this work, we have developed bio-based superabsorbent aerogels made of cellulose nanofibers (CNF) and propose their potential use in baby diapers. TEMPO-oxidized CNF at different oxidation degrees were prepared and tested. The obtained CNF exhibited higher free swelling capacity (FSC) than the commercial fluff pulp (ranging from 117.62% to 245.21% higher) and also than the diaper absorbent, except for CNF-5 (ranging from 31.56% to 54.55%), even under compression. Overall, the present work shows a case study where CNF could have a potential application with market opportunities.

The present work aims at determining the potential of date palm wastes to be applied as reinforcement in polypropylene. For this, fibers were separated from the raw biomass via mechanical defibration in Sprout Waldron equipment. Then, three different treatment strategies were adopted on the fibers, being (i) mechanical, (ii) chemical with NaOH, and (iii) enzymatical with xylanases and pectinases. Fibers were characterized in terms of chemical composition, morphology and SEM. Additionally, PP was reinforced with date palm fibers and the composites’ stiffness was evaluated. The analysis was performed from a macro and micro mechanical viewpoint. The incorporation of 40 and 60 wt.% of DPF-E enhanced the Young’s modulus of PP by 205 and 308%, respectively. The potential of enzymatically treated fibers to replace glass fibers in composites was studied, exhibiting similar stiffening abilities at 60 wt.% of date palm fiber (6.48 GPa) and 40% of glass fibers (6.85 GPa). The intrinsic Young’s modulus of the fibers was set at values around 16, 20 and 24 GPa for mechanical, chemical and enzymatic fibers. From the micromechanical analysis, the efficiency of the reinforcement as well as the contribution of the length and orientation to the Young’s modulus of the composite was evaluated.

In this study, Young’s modulus of henequen fibers was estimated through micromechanical modeling of polypropylene (PP)-based composites, and further corroborated through a single filament tensile test after applying a correction method. PP and henequen strands, chopped to 1 mm length, were mixed in the presence of maleic anhydride grafted polypropylene (MAPP). A 4 wt.% of MAPP showed an effective enhancement of the interfacial adhesion. The composites were mold-injected into dog-bone specimens and tensile tested. The Young’s modulus of the composites increased steadily and linearly up to 50 wt.% of fiber content from 1.5 to 6.4 GPa, corresponding to a 327% increase. Certainly, henequen fibers showed a comparable stiffening capacity of PP composites than glass fibers. The intrinsic Young’s modulus of the fibers was predicted through well established models such as Hirsch or Tsai-Pagano, yielding average values of 30.5 and 34.6 GPa, respectively. The single filament test performed to henequen strands resulted in values between 16 and 27 GPa depending on the gauge length, although, after applying a correction method, a Young’s modulus of 33.3 GPa was obtained. Overall, the present work presents the great potential for henequen fibers as PP reinforcement. Moreover, relationships between micromechanics models and filament testing to estimate Young’s modulus of the fibers were explored.