A new article out of a collaboration between Dr. Ning Yan and Dr. Jing Chen’s labs has been published been published in ACS Applied Polymer Materials written by Xiaobo Xu, Xiaozhen Ma, Xiaolin Wang, Jin Zhu, Jinggang Wang, Ning Yan, and Jing Chen.

You can find this article HERE.

Abstract

Using sustainable biomass feedstock to prepare biobased chemical products is attracting increasing attention. Betulin is a natural cyclic aliphatic diol that can be extracted in large quantities from the bark of birch trees. In this study, a series of bio-based polyurethane (PU) elastomers with excellent mechanical properties, solvent resistance, and thermal stability were synthesized under catalyst-free conditions using betulin and castor oil (CO) as the bio-based polyols. The chemical structure and properties of the bio-based PU elastomers were systematically investigated according to the effect of the hydroxyl ratio between betulin and CO. Due to the presence of abundant hydrogen bonds and rigid ring planes in the PU structure, and a higher cross-link density, the obtained PU elastomers had excellent mechanical properties. They achieved a maximum tensile strength of 31.6 MPa with the tensile strain reaching more than 200% and were able to withstand 1 × 10⁵ times their weight. The thermal decomposition temperature of the betulin-derived PUs was over 300 °C. This study showcased a strategy to synthesize sustainable high-performance PU materials with a high biomass content (>75%).

A new article out of a collaboration between Dr. Ning Yan and Dr. Jing Chen’s labs has been published in Chemical Engineering Journal written by Huihui Wang, Cheng Hao, Tong Shu, Pandeng Li, Tianyi Yu, Longjiang Yu, and Ning Yan.

You can find the article HERE.

Abstract

Janus fabrics are often used for oil/water separation, fog-harvesting, and moisture-wicking clothing due to their unidirectional liquid transport (ULT) ability. However, Janus fabrics are usually mono-functional, and the fabrication process is complex. Moreover, the chemicals used are not green. Herein, a versatile Janus fabric from ramie with ULT, flame retardancy, and moisture-wicking features was fabricated using a facile and sustainable method. Chitosan and phytic acid were rapidly deposited on the surface of fabrics via electrostatic gravitation, and polydivinylbenzene was then used as coating after in situ polymerization. Reverse wettability was achieved on two sides of the Janus ramie fabric after the UV irradiation of one of the sides, which endowed the fabric with ULT ability. Janus ramie fabric exhibited a comparable water vapor transmission rate to that of pristine ramie fabric but a higher water evaporation rate because of its ULT ability, indicating an improved moisture-wicking ability. Furthermore, the Janus ramie fabric displayed a good oil/water mixture separation performance with a separation efficiency of over 98% and good mechanical abrasion and chemical resistance. More importantly, the Janus ramie fabric showed excellent flame retardancy, a self-extinguishing ability, and a high limiting oxygen index of 34.5%, and its heat release rate, heat release capacity, and total heat release rate were significantly lower than those of pristine fabric. Therefore, this versatile Janus ramie fabric demonstrates great potential for various practical applications.

A new article from Ning Yan’s lab has been published in International Journal of Biological Macromolecules written by Mohammad H. Mahaninia, Zhuoya Wang, Araz Rajabi-Abhari, and Ning Yan.

You can find this article HERE.

Abstract

This study reports the fabrication of chitosan-based hydrogels with potential to be applied as a flame-retardant coating on skin or other surfaces. These hydrogels possess remarkable antimicrobial properties that are highly desirable for the protection of epidermises. Hydrogels in this study were prepared via the cross-linking reaction of chitosan with a vanillin-based cross linker containing flame-retarding moieties through Schiff’s base reaction. The synthesized hydrogels possess imine linkages enabling them to self-heal at room temperature. Self-healing abilities offered these hydrogels the ability to protect the skin for a longer time. One flame retarding mechanism of these hydrogels was by retaining the water in their polymeric network; thus, the role of bound and unbound water molecules was studied using DSC and Raman spectroscopy. The hydrogels synthesized in this study retained their flame-retarding properties even after drying due to the charring process that inhibited the pyrolysis process. Therefore, these chitosan-based hydrogels are able to prolong the protection time against fire.

A new article from Ning Yan’s lab has been published in Nano Energy written by Araz Rajabi-Abhari, Mohammad Soltani, Kevin Golovin, and Ning Yan.

You can find this article HERE.

Abstract

Atmospheric water harvesting provides a promising, sustainable solution for alleviating the ever-growing water and energy crisis. Here, inspired by the Namib desert beetle, a wettability patterned surface was designed to simultaneously harvest water and triboelectric energy from ambient moisture. Indium tin oxide (ITO) conductive glass was coated by environmentally friendly perfluoropolyether (PFPE) polymer brushes to obtain a hydrophobic surface, decorated by hydrophilic patterns. The PFPE brushes enabled the droplet to slide down and served as the tribonegative material. The water and triboelectric energy harvesting performance of the hydrophilic-hydrophobic “patterned water and energy harvesting” (P-WEH) system was then investigated. In this regard, a water collection rate of 703 mg cm^-2 h^-1 was achieved when the P-WEH was placed within an artificial fog. The influence of pattern size and tilt angle, and their relationship with water droplet volume and speed on the triboelectric output, were measured. The effect of the water harvesting area on the output performance of the P-WEH was investigated. The P-WEH with an area of 100 cm² and a tilt angle of 60° exhibited a high output current of 8.15 µA and a maximum output power of 3.35 µW. Finally, the P-WEH was integrated into a four-season greenhouse to demonstrate its application in reducing external water-energy consumption. This study presents insights into the design of simultaneous water and energy harvesting systems and may contribute to building a sustainable society.

A new article out of a collaboration between Dr. Ning Yan and Dr. Jing Chen’s labs has been published in Small written by Xiaozhen Ma, Xiaolin Wang, Honglong Zhao, Xiaobo Xu, Minghui Cui, Nathan E. Stott, Peng Chen, Jin Zhu, Ning Yan, and Jing Chen.

You can find the article HERE.

Abstract

In this work, high-performance, light-stimulation healable, and closed-loop recyclable covalent adaptable networks are successfully synthesized from natural lignin-based polyurethane (LPU) Zn²⁺ coordination structures (LPUxZy). Using an optimized LPU (LPU-20 with a tensile strength of 28.4 ± 3.5 MPa) as the matrix for Zn²⁺ coordination, LPUs with covalent adaptable coordination networks are obtained that have different amounts of Zn. When the feed amount of ZnCl₂ is 9 wt%, the strength of LPU-20Z9 reaches 37.3 ± 3.1 MPa with a toughness of 175.4 ± 4.6 MJ m⁻³, which is 1.7 times of that of LPU-20. In addition, Zn²⁺ has a crucial catalytic effect on “dissociation mechanism” in the exchange reaction of LPU. Moreover, the Zn²⁺-based coordination bonds significantly enhance the photothermal conversion capability of lignin. The maximum surface temperature of LPU-20Z9 reaches 118 °C under the near-infrared illumination of 0.8 W m⁻². This allows the LPU-20Z9 to self-heal within 10 min. Due to the catalytic effect of Zn²⁺, LPU-20Z9 can be degraded and recovered in ethanol completely. Through the investigation of the mechanisms for exchange reaction and the design of the closed-loop recycling method, this work is expected to provide insight into the development of novel LPUs with high-performance, light-stimulated heal ability, and closed-loop recyclability; which can be applied toward the expanded development of intelligent elastomers.

A new article from Ning Yan’s lab has been published in Industrial Crops and Products written by Chuanwei Zhang, Pengfei Zhang, Yanhui Li, S. Nair Sandeep, Jianyong Li, Maocheng Ji, Sixian Peng, Ning Yan, and Fangyi Li.

You can find the article here.

Abstract

Through a single-sided cavity free-form foaming process, composites with open cell structures similar to wood cells were obtained by using corn starch, pulp fiber, and sisal fibers, which was used as the middle layer of the sandwiched composites. Afterwards, more hydrophobic lignin-containing nanocellulose fibrils from pine bark were coated on the surfaces of the open cell composites by high-pressure gun spraying, simulating the bark of wood to impart barrier property to the final product. The water barrier, mechanical property, apparent density, heat insulation, and biodegradability of the sandwich structured bio-composites were characterized. Experimental results indicated that the water contact angle on the surface of the bio-composite was as high as 92°. The apparent density of the bio-composite was very low, at 0.107 g/cm³. The tensile strength of the bio-composites reached 5.3 MPa. After conducting biodegradability tests in soil for 60 days, the bio-composites lost 87 % of its mass.