Poly(2-oxazoline)s are promising class of polymers that allows several design possibilities. Functional 2-oxazoline monomers with initiator or chain transfer agents allow creating macroinitiators for brush copolymers. In this talk, we will highlight various combinations of 2-oxazolines that are polymerized by cationic ring opening polymerization and acrylates/acrylamides that are polymerized by controlled radical polymerization techniques.

Photoiniferter (PI) is a promising polymerization methodology, often used to overcome restrictions posed by thermal reversible addition-fragmentation chain-transfer (RAFT) polymerization. However, in the overwhelming majority of reports, high energy UV irradiation is required to effectively trigger photolysis of RAFT agents and facilitate the polymerization, significantly limiting its potential, scope, and applicability. Although visible light PI has emerged as a highly attractive alternative, most current approaches are limited to the synthesis of lower molecular weight polymers (i.e. 10,000 g/mol), and typically suffer from prolonged reaction times, extended induction periods, and higher dispersities when high activity CTAs (photoiniferters), such as trithiocarbonates, are employed. Herein, an acid-enhanced PI polymerization is introduced that efficiently operates under visible light irradiation.[1[ The presence of small amounts of biocompatible citric acid fully eliminates the lengthy induction period (21 hours) by enhancing photolysis, rapidly consuming the CTA, and accelerating the reaction rate, yielding polymers with narrow molar mass distributions (Ð ~ 1.1), near-quantitative conversions (>97%), and high end-group fidelity in just two hours.[1] A particularly noteworthy aspect of this work is the possibility to target very high degrees of polymerization (i.e. DP = 3,000) within short timescales (i.e. less than five hours) without compromising the control over the dispersity (Ð ~ 1.1). The versatility of the technique is further demonstrated through the synthesis of well-defined diblock copolymers and its compatibility to various polymer classes (i.e. acrylamides, acrylates, methacrylates), thus establishing visible-light PI as a robust tool for polymer synthesis.[1]

Thermal initiators require elevated temperatures to initiate radical polymerization. The annual energy consumption for plastic production in the USA is about 6% of all the energy used by USA industries. A green chemical reaction should be conducted at ambient temperatures to increase energy efficiency whenever possible. In this paper, commercial radical initiators, such as AIBN, KPS, and BPO, were decomposed at oil-water interfaces without additional heating. Trommsdorff effect was not observed in this polymerization system. Without using controlled radical polymerization techniques, homo, and copolymers with narrow molecular mass distribution (PDI < 1.3) and ultra-high molecular mass (Mw > 1000 kg/mol) can be produced at room temperature. The resulting polymeric materials are more ductile and exhibit better thermal properties.

Reversible addition-fragmentation chain transfer (RAFT) mediated polymerisation-induced self-assembly (PISA) has become a well-recognised and powerful tool for the synthesis of a wide range of nano-objects. Though the technique’s potential is broad, RAFT-PISA has attracted considerable attention for its use in biomedical applications, such as for drug delivery or biosensing.[1] However, to realise high value in these applications, specialised chemistries are often sought for incorporation into the block copolymer to afford abilities such as stimuli response or biological selectivity.[2] A common approach to achieve these functions is to include bespoke monomers, such as methacrylated amino acids[3] or phosphorylcholine,[4] in the RAFT-PISA reaction. Alternatively, the synthesis of PISA nano-objects containing post-polymerisation modifiable sites can offer greater versatility and more combinatorial options to create these target molecules.
N-hydroxysuccinimide (NHS) esters are a class of active esters commonly employed for bioconjugation, due to their selective reactivity towards primary amines.[5] Here, methacrylic acid NHS (NHS-MA) is utilised in RAFT-PISA to yield modifiable and temperature responsive nanoparticles in aqueous media. The copolymerisation of NHS-MA with oligo(ethylene glycol) methacrylate (OEGMEM) was performed to yield water-soluble NHS containing macro-RAFT agents. These temperature responsive macro-RAFTs were then utilised in aqueous emulsion PISA to yield stable micelles, which were subsequently modified with model amine-containing compounds.

Flow reactors attract interest as a tool for rapid synthesis of polymers. It allows also for photo-polymerizations and even automatic set-ups. We focused on ATRP (Atom Transfer Radical Polymerization) for preparation of homopolymers and copolymers in the presence of aerial oxygen. Improved kinetics in polymerization of acrylates and metacrylates with short induction periods encouraged us to test also copolymerizations. Copolymers of methyl methacrylate and polyethylene glycol methacrylate are an example of material designed for an aplication in 3D printing. Second type of copolymers are those prepared by Polymerization Induced Self Assembly in water and alcohol solvents. These copolymers form nanoparticles and other objects suitable for drug delivery or similar applications.

Projects APVV 21-0355 and VEGA 2/0153/25 are acknowledged

Embracing a sustainable future involves transitioning away from the use of fossil fuels in the production of polymer goods. Prioritizing the continuous reuse of polymer products is a crucial stride towards a cleaner planet. Thermoset polymers, such as polyurethanes and epoxy resins, have been extensively used in various applications, leading to a consistent increase in manufacturing. These incredibly durable and heat-resistant materials offer long-lasting, high-performance mechanical capabilities. However, once they have fulfilled their function, these thermoset materials are often difficult to recycle using chemical or mechanical methods. Proper recovery and recycling of these materials are essential to prevent disposal and advance sustainability. As a result, there is a growing interest in recycling these materials to recover and utilize them at the end of their useful life rather than disposing of them.[1-3] Here, we present novel epoxy thermosets based on 1,3,5-triazines that are amenable to recycling, enabling via dynamic aromatic substitution reaction (SNAr) to show the capability of transitioning between polymerized and depolymerized states.[4,5] The polymer exhibited both a high decomposition temperature at 5% weight loss (Td5%) above 250 °C and a glass transition temperature (Tg) above 100 °C. Additionally, the epoxy thermosets demonstrated exceptional mechanical properties, with a high Young’s modulus over 3.0 GPa and a tensile strength in the range of 90 Mpa. The thermosets can be further depolymerized under basic conditions and repolymerized back to the original polymer with identical properties, fulfilling the concept of closed-loop recycling.