2019, Vol. 4, No. 4

Display Method:
Feasibility and Potential of Graphene and Its Hybrids with Cellulose as Drug Carriers:A Commentary
Roshanak MIRAFTAB, Huining XIAO
2019, 4(4): 200-201. doi: 10.12162/jbb.v4i4.013
Mechanism of Preparation of Platform Compounds from Lignocellulosic Biomass Liquefaction Catalyzed by Bronsted Acid:A Review
Kang GUO, Qiyuan GUAN, Junming XU, Weihong TAN
2019, 4(4): 202-213. doi: 10.12162/jbb.v4i4.009
Over the past two decades, research on transforming lignocellulosic biomass into small molecule chemicals by using catalytic liquefaction has made great progress. Notably, in recent years it has been found the production of small molecule chemicals through directional liquefaction of lignocellulosic biomass. Understanding the liquefaction mechanism of lignocellulosic biomass is highly important. In this review, the liquefaction mechanism of lignocellulosic biomass and model compounds of cellulose are described, and some problems and suggestions to address them are described.
Original Research
Converting a Dilute Slurry of Hollow Tube-like Papermaking Fibers into Phase-reversible, Self-healable, and Stretchable Hydrogels
Zhongfei YUAN, Hongjia LIN, Xueren QIAN, Jing SHEN
2019, 4(4): 214-221. doi: 10.12162/jbb.v4i4.011
Commercially, assembly-directed packing of hollow tube-like papermaking fibers with diameters of roughly 10-50 μm into sustainable micro-fibrous bio-assemblies (i.e., cellulosic paper) starts with a dilute fiber slurry. In this process, a huge amount of water is required to disperse and transport fibers, which also facilitates colloidal interactions and formation of inter-fiber bonds. To form bio-assemblies in their dry states, unit operations associated with dewatering and drying are routine practices and treatment of the generated wastewater is a necessity. We herein present a facile, scalable concept of converting fiber slurry into dynamic hydrogels by using chemical additives (similar to papermaking wet-end additives), but without water removal. We used a typical group of additives as an example in an attempt to demonstrate the applicability of the concept. With boron-based dynamic chemistry as a key theoretical foundation, the combination of crosslinking and hydrogen bonding led to the formation of phase-reversible, self-healable, and stretchable hydrogels. Essentially, the characteristics of hydrogels can be facilely tunable, and process parameters such as polymer dosage are rather critical. It is worth noting that fibers can act as a structural skeleton or mechanical support for tailorable design of hydrogels. The concept demonstrated in this study would provide useful insights into value-added utilization of mass-producible biopolymeric fibers in accordance with existing mill facilities. Fiber-based hydrogels would find use in diversified applications:toys, 3D/4D printing materials, soft robots, drug delivery systems, among others.
Physicochemical and Functional Properties of Water Soluble Gum from Wrinkle Floweringquince (Chaenomeles Speciosa) Seeds
Yejun DENG, Lixin HUANG, Caihong ZHANG, Pujun XIE, Jiang CHENG, Xiaojie WANG
2019, 4(4): 222-230. doi: 10.12162/jbb.v4i4.012
Wrinkle Floweringquince (Chaenomeles speciose (Sweet) Nakai) seed, as an unexploited forestry residue, contains considerable amount of bioactive carbohydrates with potential functionality, which was not widely concentrated. The aim of this study is to determine the basic characterizations (molecular weight and functional group), specific components (carbohydrate, protein and uronic acid contents), and functional properties of Chaenomeles speciosa seed gum (CSG). Results indicated that carbohydrate (63.80%), protein (13.69%) and uronic acid (10.30%) contents were achieved. The CSG (average molecular weight, 9.85×106 u) consists rhamnose, arabinose, xylose and glucose in a molar percentage of 29.77:10.54:18.55:15.84, respectively. The Fourier transform infrared (FT-IR) analysis revealed hydroxyl, carboxyl and methyl groups and α-glycosidic linkages are founded in the CSG. The CSG was surface active and its ability to decrease surface tension was comparable to commercial gums. Moreover, the CSG solutions showed pseudoplastic flow behavior under dynamic shear rate at high concentrations. The GSC also presented good emulsifying and foaming properties, indicating the potential of the GSC as bioresource stabilizer and thickener in industry.
Multifunctional Polypyrrole-silver Coated Layered Double Hydroxides Embedded into a Biodegradable Polymer Matrix for Enhanced Antibacterial and Gas Barrier Properties
Haibo HUANG, Long MAO, Zhihan LI, Yuejun LIU, Shuhong FAN, Yao JIN, Jianda XIE
2019, 4(4): 231-241. doi: 10.12162/jbb.v4i4.015
In this study, polypyrrole-silver coated layered double hydroxides (LDHs@PPy-Ag) was prepared by chemical polymerization of pyrrole (Py) with silver ions. Silver nanoparticles (AgNPs) could be uniformly reduced onto PPy coatings in situ by redox reaction during simultaneous polymerization process. And LDHs@PPy-Ag/poly(ε-caprolactone) (PCL) nanocomposites were fabricated by solution casting method. It is revealed that spherical AgNPs are loaded on PPy coatings uniformly. Particularly, compared with pure PCL, LDHs@PPy-Ag/PCL nanocomposites with incorporation of only 1 wt% LDHs@PPy-Ag show a 17% increase in tensile strength (36.5 MPa) and a 29% increase in elongation at break (822%). Upon PPy-Ag coatings onto original LDHs, relative permeability of LDHs@PPy-Ag/PCL nanocomposites decreases to 52% with the same addition. Meanwhile, due to the double antibacterial activity of PPy and AgNPs, the antibacterial rate of LDHs@PPy-Ag reaches 100%. And the corresponding LDHs@PPy-Ag/PCL nanocomposites also show outstanding antibacterial activity. Considering the superiority of their comprehensive performance, antibacterial LDHs@PPy-Ag/PCL nanocomposites can be used further for the application as biodegradable polymeric active packaging materials.
Ternary Composite MnO2@MoS2/Polypyrrole from In-situ Synthesis for Binder-free and Flexible Supercapacitor
Dubin DONG, Xiaoxia WANG
2019, 4(4): 242-250. doi: 10.12162/jbb.v4i4.010
MnO2@MoS2/Polypyrrole ternary composite is prepared through hydrothermal methods and a simple oxidation process by using MnO2@MoS2 sheet as the substrate and polypyrrole. The ternary composite serves as an electrode for pseudocapacitor which has more superior electrochemical properties compared with the binary complex. The supercapacitor electrode consists of two dimensional MoS2 layers as load skeleton, MnO2 providing electrochemical performance and polypyrrole improving high electric conductivity. These three components form a compact structure and synergistic effect leads to enhancing sufficient oxidation reduction for supercapacitor performance. Hence, MnO2@MoS2/Polypyrrole structure possesses higher specific capacitance of 490 F/g at a current density of 1 A/g and excellent cycling stability of 90% after 1000 cycles at 1 A/g. Here, Polypyrrole is also used as the bender material, exhibiting mechanical flexibility for electrode. The results of this study provides a simple method to produce an effective material for flexible pseudocapacitor electrodes for higher energy storage devices.
Preparation of Nanolignocellulose/Chitin Composites with Superior Mechanical Property and Thermal Stability
Yushan YANG, Huajie SHEN, Xian WANG, Jian QIU
2019, 4(4): 251-259. doi: 10.12162/jbb.v4i4.014
To resolve the issues of special processing equipment, cumbersome process flow and high cost of the composite material. The poplar wood fiber was used as the raw material, which were effectively crosslinked with chitin by the simple mechanical thermal rubber milling method, then the high performance nanolignocellulose/chitin composite were obtained by the binderless hot-press method. The nanostructure, chemical structure, surface composition, and thermal stability of nanolignocellulose/chitin composites were investigated by the scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric/differential thermogravimetric (TG-DTG), respectively. Results turned out that the nanolignocellulose was laminated by the grinding and the composite material appeared layered structure after the binderless hot-pressing. Chitin/chitosan from crab shell powder can be effectively crosslinked with nanofibrillarized lignocellulose to increase the contact area of surface hydroxyl groups. The static bending strength (MOR), modulus of elasticity (MOE) and internal bonding strength of the nanolignocellulose/chitin composite were 34.13 MPa, 7072 MPa and 0.97 MPa, respectively. Meanwhile, the swelling value of thickness after water absorption was only 9.27%, demonstrating the dimensional stability. According to the profile density distribution, the density of nano-lignocellulose/chitin composites was relatively uniform, which indicates that the preparation process is reasonable. The nanolignocellulose/chitin composite has excellent thermal stability, since the mass loss of pyrolysis process is lower than the untreated binderless fiberboard. In this study, a new and effective methods for preparing composite materials was proposed, which provides some research ideas and theoretical guidance for the efficient development of new nanolignocellulose composite and waste marine arthropod materials.