The use of a large number of traditional organic foam materials using petrochemical resources as raw materials has aggravated the depletion of such resources and their wastes are difficult to degrade in the natural environment, which seriously pollutes the environment. In contrast, biodegradable foam is biocompatible, biodegradable and renewable, and is an environmentally friendly material that has received extensive attention. This paper compares foaming technologies, principles, applications,advantages and disadvantages of extrusion foaming, molding foaming and freeze-drying foaming, and introduced the influence of foaming process on material properties and application, and thus it has great development potential to prepare high-performance biodegradable foam by using natural polymer compounds or other renewable resources to simulate the microscopic and chemical network structure of natural foam. Then, this review summarizes the related research status on natural foam, bionic green foam and biomass foam, and focused on discussing research progress of plants and wood, non-isocyanate and lignocellulosic foams. Furthermore, the typical foaming formula compositions and functions are analyzed.It is pointed out that the further exploration of green medium, plasticity improving and formula is the future development and research direction of biodegradable foaming materials.

Interfacial interaction enhancement between biodegradable poly (butylene adipate-co-terephthalate) (PBAT) and microcrystalline cellulose (MCC) to improve mechanical properties has always been a considerable challenge. Herein, a series of copolyesters (MCP) to solve the above problem are prepared from terephthalic acid, adipic acid, 1, 4-butanediol, MCC, glycerol, and citric acid via atmospheric pressure esterification–polycondensation–reduced pressure esterification. The crystallinity of MCP-1 (1 wt

Exploring and fabricating smart actuating materials that strike the perfect balance between humidity response and mechanical integrity (especially wet tensile strength) via reasonable structural design and simple yet low-cost preparation is critical for biomimetic devices, soft robotics, artificial muscles and generators, but it remains challenging. Herein, inspired by the structure of natural nacre, we demonstrated a robust yet highly sensitive composite film-based humidity actuator composed of carboxymethyl cellulose (CMC), MXene nano-sheets, and multivalent aluminum ions (Al3+) via a facile evaporation-induced self-assembly method. The synergistic reinforcing effects of MXene nanosheets and Al3+ through hydrogen and ionic bonding as well as the densely hierarchical microstructure endow the composite film with both an ultrahigh mechanical strength (273.6 MPa), a desirable toughness (7.95 MJ/m(3)) and even an impressive wet tensile strength (154.2 MPa) at 97 % humidity. Interestingly, the unique laminated structure and water-induced swelling effect of CMC and MXene synergistically enable the composite film with large shape deformation, sensitive actuation (less than 2.3 s) and exceptional cycling stability (over 1500 cycles) upon exposure to humidity gradients. Based on the above merits, the composite film actuator can be well constructed to simulate a flying dragonfly, human finger, artificial muscle, and has also been preliminarily employed as a moist-electric generator, which provides new insight for designing comprehensive composite film-based actuators and reveals their extensive applications.

In this work, a simple, economic and effective one step process in which sodium sulfide is used as a modifier and a source of sulfate doping has been proposed to fabricate sulfur-doped silicate materials (SATP).

TOCNs were blended with cellulose acetate (CA) to fabricate a high water flux ultrafiltration membrane.

Homogeneous tritylation of cellulose in 1-allyl-3-methylimidazolium chloride (AmimC1) ionic liquid with triphenylmethy chloride as regents, pyridine or 1-butylimidazole (BIM) as base was investigated, and subsequent acetylation of the 6-0-functionalized products was further studied. The structure of products was analyzed by FTIR and C-13 NMR spectroscopy and base influences on the structure were discussed as well. The solution with pyridine as base underwent heterogeneous-homogeneous-heterogeneous process and the obtained trityl cellulose (TC) had organized structure with trityl group located completely at C-6 position of cellulose with maximum DStrityi of nearly 1. In the case of BIM as base, the solution was homogeneous for the whole reaction, but the highest DStrityi was about 0.22, with trityl group located not only at position 6 but also partially at position 2. Subsequent acetylation of the TC led to products with a preferred functionalization of the unprotected secondary OH-groups. (C) 2014 Elsevier Ltd. All rights reserved.