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Hollow ceramic spheres are considered as an excellent buoyancy unit for deep-sea applications (> 5,000 m). However, there is no successful commercialization due to the low productivity of conventional slip casting because of the short life span of gypsum molds. In this work, we have developed single-use pulp-based molds for ceramic slip-casting applications. The developed robust pulp mold offers the advantage of being combustible in a controlled manner during the ceramic sintering process. The smooth, wrinkle-free inner surfaces, controlled water swelling, high wettability, and ability to retain shape during wet casting make the molds highly suitable for producing hollow ceramic spheres on an industrial scale. Alumina-based spheres with 52.8 mm diameter, 1.08 mm wall thickness, 0.46 g/cm3 density, and 54% buoyancy were successfully produced in pulp molds after sintering at 1630 °C. The spheres show exceptionally high hydrostatic failure pressures of above 200 MPa (> 20,000 m) and can be safely operated at depths greater than 5,000 m below sea level. We envision this approach to facilitate the mass production of ceramic spheres with the possibility of creating other complex-shaped ceramics via slip casting in pulp-based molds. [Display omitted] • Pulp mold as a replacement for gypsum based mold for slip-casting applications. • Single-use, sacrificial pulp mold for mass production of hollow alumina spheres. • Smooth, wrinkle-free, controllable water swelling and wettability of pulp molds. • Ability to retain pulp mold shape during the wet casting process. • 50 mm spheres of 1 mm thickness, 200 MPa compressive pressure, 54% buoyancy. [ABSTRACT FROM AUTHOR]

Surface modification of micro- and nanofibrillated cellulose (MFC and NFC) under aqueous environment was performed by deposition of poly(styrene- co -maleimide) nanoparticles synthesized by imidization of poly(styrene- co -maleic anhydride) in presence of wax and ammonium hydroxide in variable amounts. Specifically, the influences of fiber fibrillation on nanoparticle formation (i.e., reaction efficiency) and permanent nanoparticle deposition on the fiber surface (i.e., retention) were investigated. The surface modification was mainly governed by the fiber diameter, surface charges and amount of wax. As such, the MFC affected the imidization reaction to a smaller extent (i.e., high reaction efficiency) and was more densely deposited by nanoparticles than NFC (i.e., high retention). Moreover, wax protected the fibers against fibrillation and peeling-off at high temperature and favored nanoparticle deposition. As a result, water contact angles of 142° were obtained for modified MFC in parallel with a surface coverage of 92%. [ABSTRACT FROM AUTHOR]

In this study, a biodegradable film from bacterial biopolymer, i.e., poly (3-hydroxybutyrate-co-4-hydroxybutyrate) or P(3HB-co-4HB) incorporating Thyme essential oil as an antimicrobial agent was developed as an active packaging for shelf-life extension of bread. Thin solvent-cast films containing 10, 20, and 30% v/w of Thyme oil were prepared and studied for the morphological, thermal, chemical, mechanical, barrier, and antimicrobial behaviors. The presence of oil in P(3HB-co-4HB) films and their purity without detectable remains of solvent, i.e., chloroform, was confirmed by infrared spectroscopy. In parallel, the time-bound release of volatile Thyme oil from the films was demonstrated when stored in a controlled environment. The plasticizing effect of Thyme oil in films was evidenced by decreased tensile strength and crystallinity. In contrast, an increase in elongation at break and water vapor permeability of oil films were measured. Finally, the antimicrobial activity of oil films was checked against total bread molds and observed that when bread was sealed in P(3HB-co-4HB) films containing 30% v/w Thyme oil, its shelf-life extended to at least 5 days compared to 1–4 days for the neat film. • Thyme oil completely inhibited the growth of bread molds than other essential oils. • P(3HB-co-4HB) films containing Thyme oil were successfully developed. • Thyme oil influenced the physicochemical and thermal properties of composite films. • Films showed antimicrobial activity against the total bread molds. • The film containing the 30% v/w Thyme oil extended the shelf-life of packed bread. [ABSTRACT FROM AUTHOR]