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Abstract Polystyrene (PS) is one of the least recycled large‐volume commodity plastics due to bulkiness of foam products and associated contaminants. PS recycling is also severely hampered by the lack of financial incentive, limited versatility, and poor selectivity of existing methods. To this end, herein we report a thermochemical recycling strategy of “degradation‐upcycling” to synthesize a library of high‐value aromatic chemicals from PS wastes with high versatility and selectivity. Two cascade reactions are selected to first degrade PS to benzene under mild temperatures, followed by the derivatization thereof utilizing a variety of acyl/alkyl and sulfinyl chloride additives. To demonstrate the versatility, nine ketones and sulfides of cosmetic and pharmaceutical relevance were prepared, including propiophenone, benzophenone, and diphenyl sulfide. The approach is also amenable to sophisticated upcycling reaction designs and can produce desired products stepwise. The facile and versatile approach will provide a scalable and profitable methodology for upcycling PS waste into value‐added chemicals. 

Abstract Rechargeable aqueous Zn−MnO₂batteries are promising for stationary energy storage because of their high energy density, safety, environmental benignity, and low cost. Conventional gravel MnO₂cathodes have low electrical conductivity, slow ion (de‐)insertion, and poor cycle stability, resulting in poor recharging performance and severe capacity fading. To improve the rechargeability of MnO₂, strategies have been devised such as depositing micrometer‐thick MnO₂on carbon cloth and blending nanostructured MnO₂with additives and binders. The low electrical conductivity of binders and sluggish ion (de‐)insertion in micrometer‐thick MnO₂, however, still limit the fast‐charging performance. Herein, we have prepared porous carbon fiber (PCF) supported MnO₂cathodes (PCF@MnO₂), comprised of nanometer‐thick MnO₂uniformly deposited on electrospun block copolymer‐derived PCF that have abundant uniform mesopores. The high electrical conductivity of PCF, fast electrochemical reactions in nanometer‐thick MnO_2,and fast ion transport through porous nonwoven fibers contribute to a high rate capability at high loadings. PCF@MnO₂, at a MnO₂loading of 59.1 wt %, achieves a MnO₂‐based specific capacity of 326 and 184 mAh g⁻¹at a current density of 0.1 and 1.0 A g⁻¹, respectively. Our approach of block copolymer‐based PCF as a support for zinc‐ion cathode inspires future designs of fast‐charging electrodes with other active materials. 

Abstract High‐performance polymers have been concomitant with advanced technology for half a century. With the advancement of synthetic chemistry, the recent development of high‐performance polymers has provided superior properties and enabled wide applications. This article reviews recent research progress in aromatic high‐performance polymers. Particularly, we focus on the synthesis and processing of polyimides, as well as the application in gas separation membranes. We begin with a brief introduction to highlight important history and physiochemical characteristics of polyimides. Then, we review the various synthesis methods, followed by recent advances for improving processability. Finally, we evaluate the use of high‐performance polymers in gas separation membranes with focus given to the key issues of plasticization and aging. Overall, the information presented herein provides an up‐to‐date overview of high‐performance polymers, polyimides particularly, and serves as a guide for further research involving the applications in membrane technologies. 

Abstract Poly(ether imide) (PEI) from polycondensation of 2,2‐bis[4‐(3,4‐dicarboxyphenoxy) phenyl] propane dianhydride (BPADA) andm‐phenylenediamine (mPD) is a type of high‐temperature engineering thermoplastics that have high glass transition temperature and outstanding mechanical properties. Owing to its wide use in many fields including automotive, aircraft, and electronics, the research of PEI has surged in the last few decades. As science and technology continue to progress rapidly, there is a growing demand for PEIs with better properties. Although a few approaches have successfully improved the properties of PEI, it is recognized that these approaches require complex procedures and are uneconomical. Contrastingly, end‐group modification of PEI is highly effective, simple, and economical. Over the last few years, our group has extensively studied the methods for improving the properties of PEI through end‐group modification. The end‐group moieties and polymer blocks introduce multiple hydrogen bonding, electrostatics, and microphase separation to PEI. In this article, we first classify the end groups based on their characteristics. Then, we compare their effects on the properties of PEIs, including thermal, rheological, mechanical, optical, flame‐retardant, and morphological, and discuss the roots of these effects. The in‐depth comparisons and discussion generate principles to guide the synthesis of PEIs with tailored properties by modifying the end groups. This timely article will provide insights into the synthesis of other novel high‐temperature polymers and entice endeavors to develop novel end groups. 

Abstract Graphene holds promise for thin, ultralightweight, and high‐performance nanoelectromechanical transducers. However, graphene‐only devices are limited in size due to fatigue and fracture of suspended graphene membranes. Here, a lightweight, flexible, transparent, and conductive bilayer composite of polyetherimide and single‐layer graphene is prepared and suspended on the centimeter scale with an unprecedentedly high aspect ratio of 10⁵. The coupling of the two components leads to mutual reinforcement and creates an ultrastrong membrane that supports 30 000 times its own weight. Upon electromechanical actuation, the membrane pushes a massive amount of air and generates high‐quality acoustic sound. The energy efficiency is≈10–100 times better than state‐of‐the‐art electrodynamic speakers. The bilayer membrane's combined properties of electrical conductivity, mechanical strength, optical transparency, thermal stability, and chemical resistance will promote applications in electronics, mechanics, and optics. 

ABSTRACT Ternary block copolymer (BCP)‐homopolymer (HP) blends offer a simple method for tuning nanostructure sizes to meet application‐specific demands. Comprehensive dissipative particle dynamic (DPD) simulations were performed to study the impact of polymer interactions, molecular weight, and HP volume fraction (φ_HP) on symmetric ternary blend morphological stability and domain spacing. DPD reproduces key features of the experimental phase diagram, including lamellar domain swelling with increasingφ_HP, the formation of an asymmetric bicontinuous microemulsion at a critical HP concentration , and macrophase separation with further HP addition. Simulation results matched experimental values for and lamellar swelling as a function of HP to BCP chain length ratio,α = N_HP/N_BCP. Structural analysis of blends with fixedφ_HPbut varyingαconfirmed that ternary blends follow the wet/dry brush model of domain swelling with the miscibility of HPs and BCPs depending onα. Longer HPs concentrate in the center of domains, boosting their swelling efficiencies compared to shorter chains. These results advance our understanding of BCP‐HP blend phase behavior and demonstrate the value of DPD for studying polymeric blends. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2019,57, 794–803 

Polystyrene is a staple plastic in the packaging and insulation market. Despite its good recyclability, the willingness of PS recycling remains low, largely due to the high recycling cost and limited profitability. This review examines the research progresses, gaps, and challenges in areas that affect the recycling costs, including but not limited to logistics, packaging design, and policymaking. We critically evaluate the recent developments in upcycling strategies, and we particularly focus on tandem and hydrogen‐atom transfer (HAT) upcycling strategies. We conclude that future upcycling studies should focus on not only reaction chemistry and mechanisms but also economic viability of the processes. The goal of this review is to stimulate the development of innovative recycling strategies with low recycling costs and high economic output values. We hope to stimulate the economic and technological momentum of PS recycling towards a sustainable and circular economy.