From biomass resources to functional materials: A fluorescent thermosetting material based on resveratrol via thiol-ene click chemistry

Fabrication of stable solid fluorescent starch materials based on Hantzsch reaction

In this paper, a series of fluorescent starches were prepared simply and effectively by Hantzsch multi-component reaction (MRC). These materials showed bright fluorescence emission. Notably, due to the existence of polysaccharide skeleton, starch molecules can effectively inhibit the common aggregation induced quenching effect caused by the aggregation of conjugated molecules in traditional organic fluorescent materials. Meanwhile, the stability of this material is so excellent that the fluorescence emission of the dried starch derivatives would not destroy after boiling at a high temperature in some common solvents, and even brighter fluorescence can be stimulated in alkaline solution. In addition to fluorescence, starch was also endowed with hydrophobic property by one-pot method connecting long alkyl chains. Compared with native starch, the contact angle of fluorescent hydrophobic starch increased from 29° to 134°. Furthermore, the fluorescent starch can be prepared into film, gel and coating by different processing methods. The preparation of these Hantzsch fluorescent starch materials provide a new way for the functional modification of starch materials and has great application potential in detecting, anti-counterfeiting, security printing and other related fields.

Phase Change Energy Storage Material with Photocuring, Photothermal Conversion, and Self-Cleaning Performance via a Two-Layer Structure

Compared with the thermal curing process, the photocuring process has advantages such as high efficiency and less energy consumption. However, the preparation of photocurable phase change materials (PCMs) with photothermal conversion and self-cleaning properties is challenging due to the conflict between the transparency required by the photocurable resin system and the opacity deduced by the large number of fillers required by photothermal conversion and the negative effect of filler steric hindrance on the reaction rate and crystallinity. In this work, a "thiol-ene" click chemical reaction induced using UV was used to prepare photocurable PCMs, followed by spraying a carboxylated multiwalled carbon nanotube (CCNT) suspension (with ethyl acetate) onto the surface to achieve an effective two-layer composite of the PCM and CCNTs, by which the rough surface of the PCM and the interaction offered by the hydrogen bonds on the interface of the PCM and the CCNTs provide sufficient adhesion for the two phases. The "thiol-ene" cross-linked polymer network provided shape stability as a support material. 1-Octadectanethiol (ODT) and beeswax (BW) were encapsulated in the cross-linked polymer network as phase change components, providing phase change latent heat. The CCNT layer provided excellent photothermal conversion and self-cleaning properties. The experimental results show that the latent heat of the PCM can reach 124.2 J/g, the water contact angle is 144°, the photothermal conversion efficiency reaches 75%, and it has significant self-cleaning performance. To the best of our knowledge, this is the first report on a photocurable PCM with photothermal conversion and self-cleaning properties.

Analysis of 3E (Energy-Economical-Environmental) for Biogas Production from Landfill: A Case Study

Nowadays, generating energy is discussed as a paramount option in waste management, because the share of energy from waste is increasing annually. The ever-increasing need for energy and limitations of using fossil resources, and also the increase in environmental pollution from consuming these resources have made the use of renewable energies of especial importance. In this research, we first studied renewable energies, followed by technologies related to the biogas system. Biogas systems have been referred to by landfill and discussed comprehensively in this scheme for utilization. For this purpose, the input source of this system is considered as the volume of garbage in the city of Germi as the study area. In the next step, the amount of garbage produced in this city was extracted and the Landfill software was used for methane production potential assessment from this system and the Homer software was used for economic analysis and reliability evaluation. The most important results are payback period, which is about 10 years, and the amount of electricity produced per year, which is 11658.265 MWh.

Outstanding flame retardancy for poly(vinyl alcohol) achieved using a resveratrol/tannic acid complex

Resveratrol/tannic acid-poly(vinyl alcohol) (RETA-PVA) blends have been prepared by compression molding using poly(vinyl alcohol), tannic acid and resveratrol as raw materials. The effects of different resveratrol/tannic acid ratios on the flammability of RETA-PVA blends have been studied. The flammability of the RETA-PVA blends was assessed using cone calorimetry, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Results indicate that RETA-PVA molecules occur through hydrogen bonding and RETA-PVA blends are amorphous. The glass transition temperature for RETA-PVA-2 is the highest among all blends and the peak of heat release rate and smoke production rate for RETA-PVA is 38.4% and 43.9% lower than that for PVA, respectively. With the addition of resveratrol, the residual amount of RETA-PVA after complete combustion is greatly increased, to 30 times that for PVA, indicating that RETA-PVA blends display excellent flame retardant properties.

The rigid molecular structure of biobased resveratrol/tannic acid (RETA) complex increases the residual amount of RETA-poly(vinyl alcohol) after complete combustion.

Aggregation-Induced Emission Fluorescent Gels: Current Trends and Future Perspectives

The development of fluorescent gels, if not the current focus, is at the center of recent efforts devoted to the invention of a new generation of gels. Fluorescent gels have numerous properties that are intrinsic to the gel structure, with additional light-emitting properties making them attractive for different applications. This review focuses on current studies associated with the development of fluorescent gels using aggregation-induced emission fluorophores (AIEgens) to ultimately suggest new directions for future research. Here, we discuss major drawbacks of the methodologies used frequently for the fabrication of fluorescent gels using traditional fluorophores compared to those using AIEgens. The fabrication strategies to develop AIE-based fluorescent gels, including physical mixing, soaking, self-assembly, noncovalent interactions, and permanent chemical reactions, are discussed thoroughly. New and recent findings on developing AIE-active gels are explained. Specifically, physically prepared AIE-based gels including supramolecular, ionic, and chemically prepared AIE-based gels are discussed. In addition, the intrinsic fluorescent properties of natural gels, known as clustering-triggered fluorescent gel, and new and recent relevant findings published in peer-reviewed journals are explained. This review also revealed the biomedical applications of AIE-based fluorescent hydrogels including drug delivery, biosensors, bioimaging, and tissue engineering. In conclusion, the current research situation and future directions are identified.

A bio-based low dielectric material at a high frequency derived from resveratrol

An efficient strategy to design and synthesize a low dielectric material at a high frequency of 5 GHz derived from renewable resveratrol.

Building biobased, degradable, flexible polymer networks from vanillin via thiol–ene “click” photopolymerization

A new biobased allyl ether monomer with acetal groups is synthesized from renewable vanillin for building flexible transparent thiol–ene networks with good degradability under mild acidic conditions.

The Use of Click-Type Reactions in the Preparation of Thermosets

Click chemistry has emerged as an effective polymerization method to obtain thermosets with enhanced properties for advanced applications. In this article, commonly used click reactions have been reviewed, highlighting their advantages in obtaining homogeneous polymer networks. The basic concepts necessary to understand network formation via click reactions, together with their main characteristics, are explained comprehensively. Some of the advanced applications of thermosets obtained by this methodology are also reviewed.