One-step synthesis of a cyclic 2,17-dioxo[3,3](4,4') biphenylophane and first preparation of a microporous polymer network from a macrocyclic precursor by cyclotrimerization

A high-temperature-triggered crosslinking reaction to achieve excellent intrinsic flame retardancy of organic phase change composites

The host-guest composite that integrates a porous scaffold and organic phase change materials (PCMs) features high energy density and customizable function, promising for advanced thermal storage/utilization. However, highly flammable organic PCMs are prone to severe combustion in porous structures, making it challenging for traditional flame-retardant methods to balance fire safety and latent heat. Herein, a high-temperature-triggered crosslinking reaction between the host and guest is designed using a polybenzoxazine-based aerogel (PB-1) and benzoxazine-based PCMs (C-dad). At high temperatures, the ring-opening polymerization (ROP) of C-dad can be initiated by and reacted with the phenolic groups of PB-1 to form a polybenzoxazine copolymer monolith with an improved char yield and intrinsic low flammability and without using the typical flame-retardant components. This enables the obtained composite (PB-1/C-dad) to well balance latent heat (145.3 J g-1), char yield (a char residue of 13.1% at 600 °C), and flame retardancy (a peak heat release rate of 231 W g-1), outperforming the representative flame-retardant modified polymer/organic PCM complexes reported in the literature. This thermal-triggered mechanism allows PB-1/C-dad to be repeatedly and stably used within the working temperature and activates its flame retardancy when exposed to open flames. The proposed host-guest crosslinking strategy is believed to inspire the development of inherently nonflammable phase change composites for safer thermal management.

Triphenylamine-anthraquinone based donor-acceptor conjugated microporous polymers for photocatalytic hydroxylation of phenylboronic acids

Triphenylamine-based donor-acceptor conjugated microporous polymers, namely PTPA-AQ and PTPA-AM, were synthesized for the first time via Suzuki-Miyaura coupling of tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-amine as a donor with 2,6-dibromoanthracene-9,10-dione and 2,2'-(2,6-dibromoanthracene-9,10-diylidene)dimalononitrile acceptors for efficient visible-light driven oxidative hydroxylation of various phenylboronic acids. The dimalononitrile derivative having greater acceptor ability showed tunable photophysical properties of PTPA-AM (lower band gap of 1.47 eV and better exciton separation efficiency) as well as porosity (lower Brunauer-Emmett-Teller (BET) surface area of 43 m² g^-1). PTPA-AQ having higher BET surface area (400 m² g^-1), suitable HOMO-LUMO positions and an optimal band gap (1.94 eV) showed better photocatalytic activity for the hydroxylation with yields up to 96%.

Phosphate based new organic polymer networks for efficient dye sorption and catalyst loading for chemo-selective reactivity

Phosphate-based porous organic polymers adsorb small cationic dyes efficiently and host gold nanoparticles for catalytic reduction of electron rich nitroaromatics.

Solution-processable porous graphitic carbon from bottom-up synthesis and low-temperature graphitization

It is urgently desired yet challenging to synthesize porous graphitic carbon (PGC) in a bottom-up manner while circumventing the need for high-temperature pyrolysis. Here we present an effective and scalable strategy to synthesize PGC through acid-mediated aldol triple condensation followed by low-temperature graphitization. The deliberate structural design enables its graphitization in situ in solution and at low pyrolysis temperature. The resulting material features ultramicroporosity characterized by a sharp pore size distribution. In addition, the pristine homogeneous composition of the reaction mixture allows for solution-processability of the material for further characterization and applications. Thin films of this PGC exhibit several orders of magnitude higher electrical conductivity compared to analogous control materials that are carbonized at the same temperatures. The integration of low-temperature graphitization and solution-processability not only allows for an energy-efficient method for the production and fabrication of PGC, but also paves the way for its wider employment in applications such as electrocatalysis, sensing, and energy storage.

Synthetic modulation of micro- and mesopores in polycyanurate networks for adsorptions of gases and organic hydrocarbons

Synthetic modulation of pores sizes in polycyanurates from 1.17 to 17.3 nm was achieved by varying geometrical shape, size and number of functional groups of monomers. The relationships between porous structure and adsorptions of gases and organic hydrocarbons were studied.

Microporous Polymer Networks Made by Cyclotrimerization of Commercial, Aromatic Diisocyanates

The cyclotrimerization of commercial, aromatic diisocyanates allows for the formation of monolithic, microporous polymer networks with S_BET surface areas up to 1300-1500 m²/g. The process has been up-scaled for production of 100 g batches. The monolithic materials show a promising potential for the removal of lipophilic components from aqueous mixtures.