ABSTRACT
Biomass-derived sustainable film is a promising alternative to synthetic plastic, but hampered by strength, toughness and flexibility trade-off predicament. Here, a feasible and scalable strategy was proposed to fabricate strong and flexible lignocellulosic film through molecular reconstruction of cellulose and lignin. In this strategy, polyphenol lignin was absorbed and wrapped on the surface of cellulose fiber, forming strong interfacial adhesion and cohesion via intramolecular and intermolecular hydrogen bonding. Further, covalent ether bond was generated between the hydroxyl groups of lignocellulose to form chemical cross-linking network induced by epichlorohydrin (ECH). The synergistic effect of hydrogen bonding and stable chemical cross-linking enabled the resultant lignocellulosic film (ELCF) with outstanding mechanical strength of 132.48 MPa, the elongation at break of 9.77 %, and toughness of 9.77 MJ·m-3. Notably, the integration of polyphenol lignin synergistically improved the thermal stability, water resistance, UV-blocking performances of ELCF. Importantly, after immersion for 30 d, ELCF still possessed high wet strength of 70.38 MPa, and elongation at break of 7.70 %, suggesting excellent and durable mechanical performances. Moreover, ELCF could be biodegraded in the natural soil. Therefore, this study provides a new and versatile approach to reconstruct highly-performance lignocellulosic films coupling strength, toughness with flexibility for promising plastic replacement.
Subject(s)
Cellulose , Lignin , Biomass , PolyphenolsABSTRACT
A novel transformation from rhamnose-type C-glycosides to 2-cyclopentenones is described. With the promotion of fluoroboric acid, C-glycosides underwent ring opening and subsequent Nazarov cyclization to afford 2-cyclopentenones in good to excellent yields. The solvent and the concentration of acid are crucial to the yield of this transformation.
ABSTRACT
An efficient and stereoselective one-pot, two-step tandem α-arylation of glycals from readily available aryl amines via stable diazonium salts has been developed. Moreover, the stereoselective preparation of the challenging ß- C-glycosyl arenes by the anomerization of α- C-glycosides using HBF4 is also described. This protocol has a broad substrate scope and a wide functional-group tolerance. It can be used for the gram-scale preparation of 3-oxo- C-glycosides, which are versatile substrates for the preparation of many biologically important C-glycosides.
ABSTRACT
The seeds of Amygdalus mongolica contain various constituents including flavonoids and vitamin E, which are known to exert antioxidant effects. However, the safety of the oil extract of this compound is not fully known. The aim of this study was to determine the physicochemical properties of A. mongolica oil, identify the constituents and subsequently assess the effectiveness of utilizing this seed extract in hyperlipidemia as an antioxidant agent. In particular, the toxicity and safety of A. mongolica oil were examined with emphasis on effects on blood lipids level and serum lipid peroxidation using a hyperlipidemia rat model. Treatment with 20 ml/kg A. mongolica oil produced no apparent adverse effects after 14 days in normal female and male rats. A dose of 2.5-10 ml/kg A. mongolica oil administered to hyperlipidemic male rats significantly decreased serum total cholesterol (TC), low-density lipoprotein-C (LDL-C), malondialdehyde (MDA), total cholesterol high-density lipoprotein-C (TC/HDL-C), LDL-C/HDL-C, and atherosclerosis index(AI). In contrast, glutathione (GSH) levels and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly increased. Data demonstrated that A. mongolica oil may be utilized in conditions of hyperlipidemia due to its antioxidant effects.
