Organomediated polymerization

Communications Chemistry is pleased to introduce a Collection of articles focused on organomediated polymerization. Here, the Guest Editors highlight the themes within and look towards the future of this research field.

Organocatalytic ring-opening polymerization (ROP) is a versatile method for synthesizing well-defined polymers, however, precision synthesis of polysiloxanes remains challenging due to a mismatch in polarity between initiators, monomers, and polymers and the formation of scrambling products. Here, the authors describe a binary organocatalytic ROP of hexamethylcyclotrisiloxane employing organic bases as catalysts and (thio)urea as cocatalysts, achieving solubilization of multifunctional silanol initiators and 90% monomer conversion.

Polyphosphoesters (PPEs) are versatile polymers utilized in tissue engineering, as electrolytes, or flame retardants, but copolymers of different PPE subclasses are hardly explored. Here, the authors report general protocols for the organocatalyzed copolymerization of four different PPE subclasses, resulting in copolymers with varying amphiphilicity and gradient strength.

To meet the rising demand for sustainable and simple polymer syntheses, organocatalytic polymerizations are a powerful tool. Here, the authors report the quasi-alternating polymerization of oxirane monomers at room temperature and in solvent-free conditions catalyzed by potassium acetate complexed by 18-crown-6 ether, leading to well-defined polyethers with varied comonomer content and low dispersity values.

Stereoregular polymers exhibit improved thermal and mechanical properties, making the development of enantioselective polymerization catalysts of significant importance. Here, the authors summarize catalyst design strategies and synthetic routes for enantioselective polymerizations of degradable or recyclable polymers from racemic monomers.

Vat-polymerization 3D printing (3DP) enables the high speed printing of precise and intricate 3D models, yet it inevitably produces highly crosslinked polymers that are not easily degradable or recyclable. Here, the author highlights recent work that realizes the formation of fully degradable polymers based on organocatalytic vat-ring-opening photopolymerization 3DP.

Polyurethanes find versatile applications in our daily lives, e.g., as coatings, foams and adhesives, but non-hazardous synthesis routes with renewable feedstocks are urgently needed. Here, the authors report an organocatalytic synthesis route towards non-isocyanate polyurethanes using terpenes as renewable starting materials.

Chemical depolymerization is a promising approach to recycle plastic waste, but complete depolymerization is energy-intense. Here, the authors show upcycling of mixed plastic waste to highly-crosslinked, reprocessable vitrimers through incomplete depolymerization using glycerol as a cleaving agent.

Although depolymerization methods for various commodity plastics and several engineering plastics have been developed, such methods for robust super engineering plastics that have very high heat and chemical resistance are nearly unexplored. Here, the authors report the catalytic depolymerization-like chemical decomposition of oxyphenylene-based super engineering plastics such as polyetheretherketone, polysulfone, and polyetherimide using thiols via selective carbon–oxygen main chain cleavage to form monomer-type molecules, namely electron-deficient arenes with sulfur functional groups and bisphenols.

Microbial enzymes are capable of degrading certain synthetic polymers, with most polyethylene terephthalate (PET) degrading enzymes known to derive from bacteria or fungi. Here, the authors describe an archaeal originating feruloyl-esterase PET46 enzyme with a flexible lid domain and PET degradation capability.

To solve the environmental disaster that is generated by legacy plastics accumulation, researchers are looking to design plastics with enhanced end-of-life options, but many circular plastics do not meet industrial requirements. Here, we highlight a metal-free approach to produce chemically recyclable poly(1,3-dioxolane) with ultra-high molecular weight and comparable properties to one of the most produced plastics, polyethylene.

Polyetheretherketone (PEEK) is an important super engineering plastic utilized in industries owing to its thermal stability and mechanical strength, however, its robustness hinders chemical recycling. Here, the authors report the depolymerization of insoluble PEEK using sulfur nucleophiles via carbon–oxygen bond cleavage and then treatment with organic halides to form various dithiofunctionalized benzophenones and hydroquinone monomers.