Polymeric graphitic carbon nitride (g-C3N4)-based semiconducting nanostructured materials: Synthesis methods, properties and photocatalytic applications.

A review of polymeric nanocomposite membranes for water purification

Vitrimers are cross-linked polymer networks containing linkages that undergo thermally activated, associative exchange reactions, such that the cross-link density and overall network connectivity are preserved. Polycarbonates are industrially relevant polymers that, to our knowledge, have not yet been explored as vitrimers. We developed hydroxyl-functionalized polycarbonate networks that undergo transcarbonation exchange reactions at elevated temperatures in the presence of catalytic Ti(IV) alkoxides. The rate of transcarbonation within the networks, estimated through stress relaxation experiments, was tuned by adjusting the catalyst loading or hydroxyl group concentration in the networks. The polymer networks exhibit recovery of their tensile strength and plateau storage modulus (71–133%) after reprocessing. In addition to being reprocessable, the networks were hydrolyzed and decarboxylated in aqueous acid to recover 80 wt % of the precursor to the bifunctional cyclic carbonate monomer. These observation...

Reprocessable Acid-Degradable Polycarbonate Vitrimers

Inspired by the self-cleaning and water-repellent properties of plants and animals in the natural world, superhydrophobic and superoleophobic materials develop quickly, and are of great interest in academic and industrial areas. Although various chemicals have been used, silanes and silicones play very important roles in the preparation of superhydrophobic and superoleophobic materials. Approximately 25% of the literature about superhydrophobic and superoleophobic materials is based on silanes and silicones. Thus, we believe that an exhaustive literature review from the viewpoint of silane and silicone chemistry is now pertinent to give an overview of the recent progress about their roles in the preparation of superhydrophobic and superoleophobic materials. First of all, we hope to overview the roles of silanes and silicones in constructing micro-/nanostructures, decreasing the surface energy and/or as binders for the fabrication of superhydrophobic and superoleophobic surfaces. We will then focus on the roles of silanes and silicones in the formation of superhydrophobic and superoleophobic particles, sponges and aerogels. In the conclusions, we will summarize the roles of silanes and silicones in forming superhydrophobic and superoleophobic materials, and the challenges in the field. Overall, this review will hopefully help readers to use silanes and silicones dexterously in the design of novel superhydrophobic and superoleophobic materials.

Roles of silanes and silicones in forming superhydrophobic and superoleophobic materials

The implications of recent advances in carboxymethyl chitosan based targeted drug delivery and tissue engineering applications.

Engineering applications of current thermoset shape memory polymers are limited by three critical issues: demanding fabrication conditions (from 70 to 300 °C temperatures for hours or days), lack of reprocessability or recyclability, and low recovery stress and energy output. To address these problems simultaneously, a new UV curable and vitrimer-based epoxy thermoset shape memory polymer (VSMP) has been synthesized. A 1.1 mm thick VSMP film can be readily cured at room temperature under UV-irradiation (61 mW cm−2) in just 80 s. It possesses 36.7 MPa tensile strength, 230 MPa compressive strength, and 3120 MPa modulus at room temperature. It still has a compressive strength of 187 MPa at 120 °C. The covalent adaptable network (CAN) imparts the VSMP with recyclability, as reflected by two effective recycling cycles (>60% recycling efficiency). In addition, the VSMP exhibits good shape memory properties for multiple shape recovery cycles. With 20% compression programming strain, up to 13.4 MPa stable recovery stress and 1.05 MJ m−3 energy output in the rubbery state are achieved. With good mechanical strength, thermal stability, recyclability, and excellent shape memory properties combined with in situ UV-curing capabilities, the new VSMP is a promising multifunctional thermoset for engineering applications.

Recyclable thermoset shape memory polymers with high stress and energy output via facile UV-curing

Intrinsic healable and recyclable thermoset epoxy based on shape memory effect and transesterification reaction

While thermosets with high mechanical properties and shape memory capabilities have been developed in recent years, two main bottlenecks persist in their intrinsic nonreusability and flammability, especially for those shape memory thermosets used in recycling-required field with high glass transition temperatures (Tg) and thus risky high temperatures to trigger shape recovery. Here, we report a new shape memory epoxy thermoset integrated with excellent fire retardancy, recyclability, high mechanical performance, and 100% shape recovery ratio. The shape memory effect of this new thermoset was directly triggered by high-temperature flame for the first time. Furthermore, the survival thermoset can be recycled by a simple solid-state recycling method and reused as reinforcing fillers for polyester. The highest recycling efficiency reached 85.4%, and the reinforced composite presented about four times higher storage modulus compared to that of neat sample. This work may open a door for application of thermoset...

Multireusable Thermoset with Anomalous Flame-Triggered Shape Memory Effect.

Biomass derivative and recyclability are two major factors in developing sustainable epoxy thermosets that cope with the global oil crisis and climate change. However, the major bottleneck persists...

Biobased Tannic Acid Cross-Linked Epoxy Thermosets with Hierarchical Molecular Structure and Tunable Properties: Damping, Shape Memory, and Recyclability

In this work, we demonstrate the unusual improvement of the tensile actuation of hierarchically chiral structured artificial muscle made of two-way shape memory polymer (2W-SMP) fiber Experimental results show that the chemically cross-linked poly(ethylene-co-vinyl acetate) 2W-SMP fibers possess an average negative coefficient of thermal expansion (NCTE) that is at least one order higher than that of the polyethylene fiber used previously As expected, the increase in axial thermal contraction of the precursor fiber leads to an increase in the recovered torque ( 44 Nmm) of the chiral fiber and eventually in the tensile actuation of the twisted-then-coiled artificial muscle ( 6781±182%) A mechanical model based on Castigliano's second theorem is proposed, and the calculated result is consistent with the experimental result (6417% tensile stroke) The model proves the significance of the NCTE and the recovered torque on tensile actuation of the artificial muscle and can be used as a guidance for the f

Jizhou Fan

Papers

Recyclable thermoset shape memory polymers with high stress and energy output via facile UV-curing

Intrinsic healable and recyclable thermoset epoxy based on shape memory effect and transesterification reaction

Multireusable Thermoset with Anomalous Flame-Triggered Shape Memory Effect.

Biobased Tannic Acid Cross-Linked Epoxy Thermosets with Hierarchical Molecular Structure and Tunable Properties: Damping, Shape Memory, and Recyclability

Artificial muscles made of chiral two-way shape memory polymer fibers