The green revolution in plastics should be accelerated due to growing sustainability concerns. Here, we develop a series of chemically recyclable polymers from the first reported cascade polymerization of H2O, COS, and diacrylates. In addition to abundant feedstocks, the method is efficient and air-tolerant, uses common organic bases as catalysts, and yields polymers with high molecular weights under mild conditions. Such polymers, structurally like polyethylene with low-density in-chain polar groups, manifest impressive toughness and ductility comparable to high-density polyethylene. The in-chain ester group acts as a breaking point, enabling these polymers to undergo chemical recycling through two loops. The structures and properties of these polymers also have an immeasurably expanded range owing to the versatility of our method. The readily available raw materials, facile synthesis, and high performance make these polymers promising prospects as sustainable materials in practice. 相似文献
Room-temperature phosphorescence (RTP) polymers, whose emission can persist for a long period after photoexcitation, are of great importance for practical applications. Herein, dynamic covalent boronic ester linkages with internal B−N coordination are incorporated into a commercial epoxy matrix. The reversible dissociation of B−N bonds upon loading provides an efficient energy dissipation pathway for the epoxy network, while the rigid epoxy matrix can inhibit the quenching of triplet excitons in boronic esters. The obtained polymers exhibit enhanced mechanical toughness (12.26 MJ m−3), ultralong RTP (τ=540.4 ms), and shape memory behavior. Notably, there is no apparent decrease in the RTP property upon prolonged immersion in various solvents because the networks are robust. Moreover, the dynamic bonds endow the polymers with superior reprocessablity and recyclability. These novel properties have led to their potential application for information encryption and anti-counterfeiting. 相似文献
Although closed-loop recycling of dynamic covalent bond-based plastics does not require catalysts, their mechanical strength and chemical stability remain a major concern. In this study, closed-loop recyclable poly(aryl imine) (PAI) plastics with high mechanical strength and excellent chemical resistance are fabricated by copolymerizing aromatic amines and aromatic aldehydes through dynamic imine bonds. The resulting PAI plastic with a tensile strength of 58.2 MPa exhibits excellent chemical resistance and mechanical stability in acidic and basic aqueous solutions and various organic solvents. The PAI plastics can be depolymerized in a mixed solvent of tetrahydrofuran (THF)/HCl aqueous solution through the dissociation of imine bonds, and the monomers can be facilely recovered with high purity and isolated yields due to the solubility difference between the aromatic amines and aromatic aldehydes in selective solvents. The efficient closed-loop recycling of the PAI plastic can also be realized through monomer conversion because the hydrolysis of the aromatic aldehydes generates aromatic amines. The recovered monomers can be used to re-fabricate original PAI plastics. This PAI plastic can be selectively recovered from complicated mixed polymer waste streams due to the mild depolymerization conditions of the PAI plastic and its high stability in most organic solvents. 相似文献
The present paper covers the synthesis and characterization of several intermediate products, monomer, and polymers. 3-{ 2-[ 4-( 4-Nitrophenylazo ) phenoxy] ethyloxycarbonyl} propanoyloxy (2-hydroxy) propyl acrylate (4) was prepared by the ring-opening reaction of glycidyl acrylate with the monoester of succinic acid (3). The polymers (5) with different molecular weights were prepared by the free-radical polymerization. The polymers (5) had liquid crystalline behavior without decomposition as revealed by DSC, optical microscope. 相似文献
Click Chemistry, a modular, rapid, and one of the most reliable tool for the regioselective 1,2,3-triazole forming [3+2] reaction of organic azide and terimal alkyne is widely explored in various emerging domains of research ranging from chemical biology to catalysis and medicinal chemistry to material science. This regioselective reaction from a diverse range of azido-alkyne scaffolds has been well performed in both intermolecular as well as intramolecular fashions. In comparison to the intermolecular metal (Cu/Ru/Ni) variant of ‘Click Chemistry’, the intramolecular click tool is little addressed. The intramolecular click chemistry is exemplified as a mordern tool of cyclization which involves metal-catalyzed (CuAAC/RuAAC) cyclization, organo-catalyzed cyclization, and thermal-induced topochemical reaction. Thus, we report herein the recent approaches on intramolecular azide-alkyne cycloaddition ‘Click Chemistry‘ with their wide-spread emerging applications in the developement of a diverse range of molecules including fused-heterocycles, well-defined peptidomemics, and macrocyclic architectures of various notable features. 相似文献
While D-glucose is the natural substrate of aldose reductase (AR) in the polyol pathway, the Km value of D-glucose against AR is large. A glucoamide 1 was designed as a tool to investigate whether AR has a strong affinity for the open form of D-glucose. Glucoamide 1 was synthesized in high yield by modification of the reaction condition for click chemistry. It was found that our modified condition was applicable for highly polar alkynes and gave coupling products in excellent yield (90% to 100%). Although weak inhibitory activity against AR was observed, kinetic studies showed that AR does not accept glucoamide 1 in its active site. 相似文献
Polymers such as polyacetylene, which have an extended π-electron system in their backbone, or like poly(p-phenylene) consist of a sequence of aromatic rings are excellent insulators in their native state and can be transformed by oxidation or reduction in the solid state into conductive CT-complexes which exhibit metal-like conduction characteristics. The chemical and physical processes involved and the reasons for the observed quasimetallic conductivity are not yet fully understood. The real structure of these materials in chemical and physical terms, i. e. their complicated morphology and texture, as well as the results available on the structure-property relationships of the “organic metals” must be considered when discussing their properties. In other words, a discussion of conductive polymers should be based on what is known of the highly conducting CT-complexes of low-molecular weight compounds. The discovery of the highly conducting polymer complexes has opened up a new interdisciplinary field of research which borders on polymer science, solid-state and semiconductor physics and on organic solid-state chemistry. It is hoped that this area will lead to numerous novel materials and technical applications. 相似文献
In this study, a series of comb-like methoxy polyethylene glycol (MPEG) functionalized polyurethanes (PUs) (PU–g–MPEG) were successfully prepared via ‘click’ chemistry and polyaddition reaction. The copper catalyzed Huisgen 1,3-dipolar cycloaddition was firstly carried out between 3,5-bis(hydroxymethyl)-1-propargyloxybenzene (PBM) and methoxy polyethylene glycol azide (MPEG–N3) to obtain MPEGylated diol PBM (MPEG–PBM). Then, the comb-like PUs having MPEG located on the backbones (PU–g–MPEG) were synthesized through the polyaddition of MPEGylated diol PBM and hexamethylene diisocyanate (HDI). Fourier transform infrared (FTIR), 1H NMR spectroscopy, size exclusion chromatography (SEC), and thermo gravimetric analyses (TGA) were used to characterize these synthesized MPEG-functionalized comb-like PUs (PU–g–MPEG). Compared with PU without MPEG grafts, PU–g–MPEG show a better wettability. 相似文献
Post-polymerization modification (PPM) offers a versatile approach for engineering multifunctional polymers, but this advantage has not been fully exploited to fabricate multifunctional liquid crystal polymers (LCPs). Here, we design a facile synthetic approach towards multifunctional LCP by combining the ring-opening metathesis polymerization (ROMP) with PPM, in which ROMP helps to prepare a reactive LCP precursor with high molecular weight, and PPM provides a facilitation to introduce functional groups into the precursor. Consequently, a photo- and humidity-responsive linear LCP (LLCP) is demonstrated to show the potential of this synthetic strategy to diversify functions of the LCPs. Under light irradiation and humidity changes, the deformation modes of the LLCP films are converted to complex shapes (bending, twisting, and curling). The obtained dual-responsive LLCP with high molecular weight possesses excellent processability and recyclability, making it possible to construct 3D shape actuators with programmable deformation behaviors under light/humidity. 相似文献
In the past decades click chemistries including thiol chemistries have found wide applications in the synthesis of well-defined polymers. In this research, a click-declick strategy based on the oxidation of heteroaromatic thioethers and the substitution reactions between the oxidized groups and thiols, is proposed for the synthesis of the cleavable polymers. In proof-of-concept experiments, block copolymers (BCPs) and star-like polymers are synthesized by thiol-phenylsulfone substitution reactions, and heteroaromatic thioethers are produced at the junction points of the BCP chains or on the crosslinking sites of the star-like polymer. The thioethers can be oxidized to heteroaromatic sulfoxides or sulfones, depending on the oxidization condition. It is demonstrated that both sulfoxides or sulfones can have base catalyzed nucleophilic substitution reactions with thiols, leading to the cleavage of the polymers. 相似文献
Porous organic polymers (POPs) with high porosity and tunable functionalities have been widely studied for use in gas separation, catalysis, energy conversion and energy storage. However, the high cost of organic monomers, and the use of toxic solvents and high temperatures during synthesis pose obstacles for large-scale production. Herein, we report the synthesis of imine and aminal-linked POPs using inexpensive diamine and dialdehyde monomers in green solvents. Theoretical calculations and control experiments show that using meta-diamines is crucial for forming aminal linkages and branching porous networks from [2+2] polycondensation reactions. The method demonstrates good generality in that 6 POPs were successfully synthesized from different monomers. Additionally, we scaled up the synthesis in ethanol at room temperature, resulting in the production of POPs in sub-kilogram quantities at a relatively low cost. Proof-of-concept studies demonstrate that the POPs can be used as high-performance sorbents for CO2 separation and as porous substrates for efficient heterogeneous catalysis. This method provides an environmentally friendly and cost-effective approach for large-scale synthesis of various POPs. 相似文献
A combination of a thiol‐Michael addition reaction and a free radical mediated thiol–ene reaction is employed as a facile and efficient approach to carbosiloxane dendrimer synthesis. For the first time, carbosiloxane dendrimers are constructed rapidly by an orthogonal click strategy without protection/deprotection procedures. The chemoselectivity of these two thiol–ene click reactions leads to a design of a new monomer containing both electron‐deficient carbon–carbon double bonds and unconjugated carbon–carbon double bonds. Siloxane bonds are introduced as the linker between these two kinds of carbon–carbon double bonds. Starting from a bifunctional thiol core, the dendrimers are constructed by iterative thiol–ene click reactions under different but both mild reaction conditions. After simple purification steps the fifth dendrimer with 54 peripheral functional groups is obtained with an excellent overall yield in a single day. Furthermore, a strong blue glow is observed when the dendrimer is excited by a UV lamp.