Cellulose/Poly(meta-phenylene isophthalamide) Light-Management Films with High Antiultraviolet and Tunable Haze Performances

Light-management films are usually fabricated from the petrochemical-based polymers, and developing renewable and biodegradable cellulose-based light-management films with high transparence, tunable haze, and UV-blocking capacity by a facile and large-scale production method is still challenging. Herein, cellulose/poly­(meta-phenylene isophthalamide) (PMIA) light-management films were manufactured by simple blending, which was fit for the large-scale production of cellulose/PMIA films. It was found that the cellulose/PMIA composite films showed tunable haze (14–55%), high transparence (>78%), UV-blocking capacity, and irradiation stability. In addition, the elongation at break and tensile strength of the composite film can be improved to 23.78% and 55.90 MPa compared to those of the native cellulose film (21.94% and 45.83 MPa), ascribed to copious hydrogen bonds between PMIA and cellulose molecules. Hence, the cellulose/PMIA light-management films with enhanced optical and mechanical properties were fabricated successfully, and they showed great potential in flexible displays and energy-efficient buildings

Tough and Strong All-Biomass Plastics from Agricultural and Forest Wastes via Constructing an Aggregate of Hydrogen-Bonding Networks

The development of all-biomass materials to replace conventional plastics has been gradually becoming a focus. However, all-biomass plastics, especially those fabricated from agricultural and forestry wastes, have the obstacles of poor formability and/or low toughness. Herein, we demonstrated a facile, efficient, and easy-to-scale method to significantly improve the formability and toughness of biomass materials via constructing an aggregate of hydrogen-bonding networks, where the relatively weak hydrogen bonding could be sacrificed during stretching. After a continuous preparation process that combined a paper-making process with an in situ welding process, the regenerated cellulose material with a layered microstructure was spontaneously formed. The interlayer hydrogen-bonding interactions could dissipate energy during stretching. As a result, the cellulose plastics were tough and strong. The tensile strength, strain, and toughness reached 154.9 MPa, 57.7%, and 81.76 MJ/m3, respectively, which were markedly higher than those of previous cellulose-based materials. The corresponding cellulose hydrogel exhibited an excellent strength of 9.5 MPa and a high strain of 171.4% also. During this scalable process, a 1-ethyl-3-methylimidazolium acetate (EmimAc) aqueous solution worked as a dispersant and a solvent, and a high solid content of cellulose/EmimAc (20 wt %) was used. Based on such an effective method, various agricultural and forestry wastes, including corn straw, wheat straw, grass, and wood powder, could be directly processed into high-tough all-biomass films, indicating a huge potential in ecofriendly materials, environmental protection, and bioresource utilization

Tough and Strong All-Biomass Plastics from Agricultural and Forest Wastes via Constructing an Aggregate of Hydrogen-Bonding Networks

The development of all-biomass materials to replace conventional plastics has been gradually becoming a focus. However, all-biomass plastics, especially those fabricated from agricultural and forestry wastes, have the obstacles of poor formability and/or low toughness. Herein, we demonstrated a facile, efficient, and easy-to-scale method to significantly improve the formability and toughness of biomass materials via constructing an aggregate of hydrogen-bonding networks, where the relatively weak hydrogen bonding could be sacrificed during stretching. After a continuous preparation process that combined a paper-making process with an in situ welding process, the regenerated cellulose material with a layered microstructure was spontaneously formed. The interlayer hydrogen-bonding interactions could dissipate energy during stretching. As a result, the cellulose plastics were tough and strong. The tensile strength, strain, and toughness reached 154.9 MPa, 57.7%, and 81.76 MJ/m3, respectively, which were markedly higher than those of previous cellulose-based materials. The corresponding cellulose hydrogel exhibited an excellent strength of 9.5 MPa and a high strain of 171.4% also. During this scalable process, a 1-ethyl-3-methylimidazolium acetate (EmimAc) aqueous solution worked as a dispersant and a solvent, and a high solid content of cellulose/EmimAc (20 wt %) was used. Based on such an effective method, various agricultural and forestry wastes, including corn straw, wheat straw, grass, and wood powder, could be directly processed into high-tough all-biomass films, indicating a huge potential in ecofriendly materials, environmental protection, and bioresource utilization

Synthetic Celluloses as Green Fillers for the Enhancement of the Crystallization and Mechanical Properties of Poly(3-hydroxybutyrate-<i>co</i>-3-hydroxyvalerate)

Enzymatically synthetic cellulose is a novel green filler combining the advantage of degradability and environmental friendliness. In this work, poly­(3-hydroxybutyrate-co-3-hydroxyvalerate) [P­(HB-co-HV)] nanocomposites were fabricated using the melt blending technique through the addition of slatted cellulose (SC) or disc-shaped cellulose (DC). The effects of different morphologies and weight contents of cellulose on the crystallization behavior, morphology, and interaction of P­(HB-co-HV) nanocomposites were investigated and analyzed. Compared with neat P­(HB-co-HV), the yield strength and elongation at break of P­(HB-co-HV)/0.1 wt %-SC nanocomposites were increased by 29 and 79%, respectively, while those for P­(HB-co-HV)/0.5 wt %-DC nanocomposites were increased by 34 and 59%, respectively. Differential scanning calorimetry and polarized optical microscopy results demonstrated that cellulose increased the crystallization temperature and decreased the spherulite size of P­(HB-co-HV). Wide-angle X-ray diffraction results illustrated that the growth of the grain and crystal plane was affected by cellulose. Fourier transform infrared spectroscopy results indicated that strong hydrogen bonds were formed at the interface between P­(HB-co-HV) and cellulose. Scanning electron microscopy images revealed the uniform dispersion of cellulose in the polymer matrix. This study entails considerable advantages for the preparation of green nanofillers and the production of biodegradable polymers with excellent mechanical properties for tissue engineering in the presence of small amounts of fillers

Translucent and Anti-ultraviolet Aramid Nanofiber Films with Efficient Light Management Fabricated by Sol–Gel Transformation

Derived from poly­(para-phenylene terephthalamide) PPTA fibers, aramid nanofibers (ANFs) not only inherit the excellent properties of PPTA fibers but also demonstrate the nanoeffects of one-dimensional (1D) nanomaterials, showing great potentials in many emerging fields as building blocks. However, ANF-based materials are usually obtained by vacuum-assisted filtration after the regeneration of ANFs, leading to long cycle times and waste of energy. Moreover, the effects of antisolvents on the structure and property of the obtained ANF-based materials were rarely reported. In this work, an in situ-regenerated continuous production line of sol–gel transformation technology was provided to produce ANF films in a large scale. Moreover, the impacts of coagulation baths (water and ethanol) on the structure and properties of ANF films were investigated systematically. It was found that the coagulation baths had obvious effects on the microstructure and properties of ANF films. As a result, ANF films with high transparency, high anti-ultraviolet capacity, and tunable haze can be fabricated successfully by simply changing the component of the coagulation bath. Particularly, the averaged values of ANF films in the region of 315–400 nm (TUVA) and 290–315 nm (TUVB) are nearly 0%, and the haze of ANF Film 100 can reach as high as 90% at 800 nm when ethanol was used as the first coagulation bath. Meanwhile, ANF films (Film 0) regenerated from water displayed the highest transmittance (78.77% at 800 nm) and tensile strength (102.88 MPa), attributed to their homogeneous structures. Additionally, the transmittance and tensile strength were decreased obviously with the increasing ethanol content in the first coagulation bath. Overall, ANF films showed high tensile strength, good thermal stability, and fire-retardant performance. Herein, the ANF films with many merits demonstrate great promising potential to be used in the light management field