The design of polybenzoxazines from bisphenol alternatives with controlled curing pathways remains a challenge due to the rapid, multi-stage nature of cationic ring-opening polymerization (ROP). This study investigates the synthesis and thermal behavior of a novel piperazine-bridged bisbenzoxazine where all reactive sites on the phenolic core are blocked. Spectroscopic analyses (NMR and FTIR) confirm a complex competition between ring closure and retro-Mannich fragmentation during synthesis. DSC analysis and curing kinetics, evaluated using the Kissinger, Ozawa, and Friedman methods, revealed a profile consistent with a staged mechanism rather than classical benzoxazine curing. Accordingly, an initial formation of a kinetically trapped N,O-acetal network follows a limited amount of thermally triggered rearrangement. Moreover, TGA analysis revealed a low char residue, indicating that the N,O-acetal dominated network is highly susceptible to complete thermal volatilization via retro-Mannich reversal.

This study demonstrates an efficient approach for the photovulcanization of liquid polybutadiene (pBD) under UV-A irradiation by using phenacyl bromide (PhABr) as a dual-action photoinitiator. Spectroscopic analysis such as FTIR and NMR revealed a radical-mediated relatively rapid crosslinking initiated by the homolytic cleavage of PhABr. The solid-state UV-Vis spectroscopy demonstrated high optical transmittance throughout the visible region. Thermal characterization via DSC showed a drastic increment of the glass transition temperature (Tg) from a theoretical baseline (-98 degrees C) to -20 degrees C, with the 10 wt% loading. Mechanical testing confirmed the changes by showing a linear increase in Young's modulus and tensile strength as the material transforms from a viscous liquid into a rigid thermoset. Gel fraction experiments confirmed the formation of a robust 3D network (Gf > 87%). Furthermore, surface analysis (SEM and WCA) provided evidence that the photovulcanization is spatially uniform, producing smooth, defect-free films. A significant drop in the water contact angle from 99 degrees to 86 degrees at higher loadings revealed the increment in surface polarity due to photooxidation.

Poly(vinyl chloride) (PVC) waste valorization is challenged by inert C-C backbones and uncontrolled dehydrochlorination releasing corrosive HCl. To overcome this, we developed a visible-light-driven photothermal halogen atom transfer (XAT) platform using dimanganese decacarbonyl (Mn2(CO)10) that eliminates HX release while enabling tunable dual-pathway upcycling. PVC degradation and grafting were performed under 405 nm LED irradiation, systematically varying atmospheric control (O2 vs. N2), temperature (25-170 °C), and Mn2(CO)10 loading (0-20 mg mL–1). Under O2, the system achieved a 95% Mn reduction (66.4 to 3.5 kDa) via auto-accelerated oxidative β-scission, with zero detectable HCl release confirmed by an AgNO3 trap. Under N2 with vinyl monomers, grafting-from copolymerization yielded PVC-g-PMMA (44.7 wt% PMMA, Mn = 105.6 kDa) and PVC-g-PS (55.0 wt% PS, Mn = 99.0 kDa). Continuous distribution kinetics revealed an autocatalytic rate acceleration. Ultimately, this platform enables switchable PVC upcycling, either controlled degradation to functional oligomers or graft copolymer synthesis, avoiding HCl byproducts while achieving high conversion efficiencies.

The low recycling rates (<1 %) of expanded polystyrene (EPS) and its tendency to fragment into microplastics pose significant environmental challenges, driving the need for cost-effective chemical upcycling strategies. Here, we demonstrate photochemicaldegradation of waste EPS using trichloroisocyanuric acid (TCCA), a common inexpensive (∼$1/kg) pool disinfectant, under UV-A irradiation and oxygen (O2) atmosphere in green ethyl acetate solvent. TCCA serves as Hydrogen Atom Transfer (HAT) reagent, generating reactive chlorine species (RCS) upon photolysis that abstract benzylic C–H bonds in polystyrene, initiating oxidative degradation. GPC results reveal that under optimized conditions, EPS is reduced from 83 kDa to ∼2 kDa (Mn), yielding low-molecular-weight oxygenated oligomers along with value-added aromatic molecules (mainly acetophenone and benzoic acid), quantified by UPLC-TOF. Real-time NMR monitoring and control experiments indicate that photogenerated RCS dominate the degradation mechanism with minor contribution from reactive oxygen species (ROS). The demonstrated photochemical method offers a practical benefit, as the byproduct cyanuric acid, known to act as a strong oxygenation inhibitor, precipitates in ethyl acetate. This straightforward, metal-free approach is an economically viable route to transform waste EPS into valuable chemical feedstocks under mild conditions.

The development of high-performance thermosets with enhanced chemical and mechanical properties is critical for demanding applications. This study reports a novel reactive blending approach to synthesize polybenzoxazine-triazinane copolymers as hybrid thermosets by combining 1,3,5-triazinanes with 1,3-benzoxazines. Polymer networks were prepared via a cost effective and one-pot synthesis using 4,4 '-oxydianiline (ODA) and bisphenol A-aniline-based benzoxazine (BA-a). The resulting BA-a/ODA-PHT hybrids exhibit significantly improved acid resistance and 91 % of their mass retained after 30 days in 0.1 M HCl. In contrast, pristine ODA-PHT retained only 40 % by mass. Additionally, the hybrids show a fourfold increase in adhesion to mild steel (4.61 MPa vs. 0.99 MPa for ODA-PHT) and excellent resistance to aggressive liquids, including hydraulic fluids, motor oil, and jet fuel. Thermogravimetric analysis reveals enhanced thermal stability, with a char yield of similar to 35 % at 800 degrees C for BA-a/ODA-PHT. Spectroscopic and thermal analyses including nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) were used for further characterizations.

Titanium-based metal-organic frameworks (MOFs) (MIL-125 based) were utilized as photocatalysts for the first time, in the successful visible-light-mediated polymerization of monofunctional 1,3-benzoxazines (Bzs). Gel permeation chromatography (GPC) analysis revealed that the resulting model polybenzoxazines (PBzs) exhibited relatively high number-average molecular weights (M n). The photopolymerization process was traced by NMR spectroscopy, evidencing complete monomer conversion with MIL-125 (Ti). Control experiments using UV light or diphenyliodonium hexafluorophosphate demonstrated negligible or no Bz polymerization under the same experimental conditions. To enhance the photocatalytic performance, MIL-125 (Ti) was modified through amine functionalization and silver (Ag) doping, which improved visible-light absorption, as confirmed by UV-vis spectroscopy. Moreover, a mechanism for the photocatalytic polymerization of Bzs was also proposed for which the unique contribution of MIL-125 (Ti) to commence the charge-transfer reaction was highlighted as well.

This study investigates the use of an aluminum-based ionic liquid (Al-N-IL) as a highly efficient catalyst to mitigate the high curing temperatures of benzoxazines. The Al-N-IL catalyst was synthesized in a 1:1 molar ratio of Et3NHCl-AlCl3 and then incorporated at various loadings into three structurally distinct benzoxazine monomers. Differential Scanning Calorimetry (DSC) demonstrated a drastic reduction in the cationic Ring-Opening Polymerization (ROP) temperature for all monomers. Most notably, the peak polymerization temperature (Tmax) for bisphenol A, aniline based monomer was lowered from 238 degrees C to an exceptionally low 133 degrees C. NMR tracking at room temperature showed catalytic latency for a certain time that the Al-N-IL complex is stable and does not liberate free AlCl3 to trigger premature ring opening. Thermogravimetric Analysis (TGA) revealed that while the catalyst significantly lowers the cure temperature, it also exhibits a degradation/evaporation at high temperatures.

Conjugated conductive polymers (CCPs) are promising electrode materials for next-generation supercapacitors (SCs), yet their scalable and eco-friendly synthesis remains a challenge. Here, we report a light-driven, in-situ polymerization of EDOT onto polydopamine (PDA@PEDOT), offering a sustainable, photoinitiated route for high-performance SC electrodes. Using an organic, environmentally safe photoinitiator and ethanol as a green solvent, this method achieves uniform PEDOT deposition on PDA with minimal energy input. Using a three-electrode method, the resulting PDA@PEDOT electrode exhibits exceptional electrochemical performance, including a high specific capacitance of 275 F g-1 at 1.0 A g-1, an energy density of 34.04 W h kg-1, and excellent adhesion properties. The synergistic non-covalent interactions between PDA's amine, catechol, quinone functionalities and PEDOT are credited to enhance ion transport through the electrode, improving SC efficiency. These exceptional properties, alongside strong adhesion and uniform deposition of PEDOT on PDA, demonstrate the novelty of the advanced photopolymerization approach. Our eco-friendly photopolymerization method paves the way for sustainable, high-performance SC electrode fabrication, bridging the gap between sustainable chemistry and next-generation energy storage.

This study reports a novel photoactive benzoxazine monomer containing a phenacyl pyridinium salt moiety (PPyr_PA-SbF6), which is designed to initiate cationic ring-opening of benzoxazines upon light exposure. For the purpose, the synthesis of the precursor pyridine-functionalized benzoxazine (P-Pyr) and its subsequent conversion to phenacyl pyridinium salts were successfully achieved. The chemical structures of benzoxazines were confirmed by spectroscopic analyses (1H NMR, 13C NMR, FTIR). Photophysical studies demonstrated the photoactivity of P-Pyr_PA-SbF6, evidenced by UV photobleaching and NMR analysis. Differential Scanning Calorimetry (DSC) showed that UV irradiation (360 nm) significantly reduced the self-curing temperature and enthalpy of P-Pyr_PA-SbF6 itself. Furthermore, P-Pyr_PA-SbF6 exhibited effective thermal and photo-assisted catalytic activity for polymerizing a conventional monofunctional benzoxazine monomer (P-a). Light pretreatment of P-a blends containing P-Pyr_PA-SbF6 substantially lowered the curing onset temperatures (e.g., from 222 degrees C for neat P-a to 146 degrees C with 10 mol% salt) and reduced the activation energy (Ea) for P-a polymerization. These findings reveal P-Pyr_PA-SbF6 as a promising system for achieving controlled, lower-energy curing of polybenzoxazines via light induction.

In this study, we synthesized benzophenone-based main chain polybenzoxazine (BP-PBz) as a type II macroinitiator and this initiator was used to synthesize acrylate-based polybenzoxazine copolymers. BP-PBz effectively initiated the polymerization of methyl methacrylate (MMA) and poly(ethylene glycol) diacrylate (PEGDA), resulting in either polybenzoxazine-grafted-poly(MMA) or crosslinked polybenzoxazine networks. Polymerizations of the formulations were performed upon photolysis at ca. 300 nm. The obtained polymers retained their oxazine functionality and subsequent thermal curing was applied successfully at relatively lower temperatures than conventional benzoxazines. The precursors are shown to have a dual curable character that could be beneficial for deep curing purposes. The synthesized polymers were characterized using various techniques, including nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), ultraviolet-visible (UV-Vis) spectroscopy, and thermogravimetric analysis (TGA), along with differential scanning calorimetry (DSC).

A straightforward approach is employed to synthesize methylene-bridged poly(hetero aromatic)s based on furan, pyrrole, thiophene, and thiophene derivatives. The process involves an electrophilic aromatic substitution reaction facilitated by a visible light-initiated system consisting of manganese decacarbonyl and an iodonium salt. The approach mainly relies on the formation of halomethylium cation, the attack of this cation to heteroaromatic, regeneration of methylium cation on the heteroaromatic, and reactivity differences between halomethylium and heteroaromatic methylium cations for successful polymerizations. This innovative synthetic strategy lead to the formation of polymers with relatively high molecular weights as the stoichiometric imbalance between the comonomers increased. Accordingly, these newly obtained polymers exhibit remarkable fluorescence properties, even at excitation wavelengths as low as 330 nm. Moreover, by harnessing the halogens at chain ends of homopolymers, block copolymers are successfully synthesized, offering opportunities for tailored applications in diverse fields. A straightforward method is described for synthesizing methylene-bridged poly(heteroaromatic)s using furan, pyrrole, thiophene, and thiophene derivatives. The process involves an electrophilic aromatic substitution reaction initiated by visible light with manganese decacarbonyl and an iodonium salt.image

Cross-linked EVOH containing dynamic silyl ether bonds with improved toughness and processability have been prepared by taking advantage of both ethylene vinyl alcohol (EVOH) and benzoxazine chemistry. For that, the cross-linked EVOH was synthesized through a trans etherification reaction between siloxane mono-functional benzoxazine and pendant hydroxyl groups on ethylene vinyl alcohol (EVOH) copolymer. The precursor EVOH copolymer was obtained by hydrolysis of the commercially available and inexpensive ethylene - vinyl acetate copolymer (EVA). The chemical structures of polymers were analyzed by proton nuclear magnetic resonance ( 1 H NMR) spectra and Fourier transform infrared (FTIR) spectroscopy. The curing and thermal stability were researched by using differential scanning calorimetry (DSC) and a thermogravimetric analyzer (TGA), respectively. The mechanical properties via the stress - strain analysis were examined to identify the effect of the benzoxazines with the silyl ether group on the toughness and self-healing ability of the modified EVOH.

Upcycling/recycling of waste polymers to reduce the exponentially increasing plastic pollution is an environmental subject of great importance. Accordingly, in this work, we propose the use of an "all-in-one" photolytic hydrogen atom transfer (photo-HAT) reagent (phenacyl bromide) that can in situ generate bromine radicals, acetophenone, HBr, and H2O2, resulting in a total of four well-established, potent intermediates for the photodegradation/photodepolymerization of waste polystyrene (PS) foam. Under ambient conditions, using ethyl acetate solvent and the stated photo-HAT catalyst, waste PS (M-n > 120 kg/mol) breaks down to oligomers with less than eight styrene units (M-n < 0.76 kg/mol) and to several organic compounds, such as aromatic ketones, oxygenated alkenes in conjunction with acetophenone and trace benzoic acid. A plausible reaction mechanism demonstrating the role of each in situ generated intermediate involved in this photodegradation is proposed. Herein, we present an efficient metal-free photo-oxidative degradation method for commercial PS using a cheap organic reagent at ambient sustainable conditions. Ultimately, this study provides a promising alternative to recent waste polymer valorization methods involving toxic transition metal salts and halogenated solvents.

Two-dimensional (2D) materials have great potential in macromolecular synthesis, yet there are some areas that still need to be explored, such as anionic polymerization. In this study, we present the first example of photoinduced anionic polymerization of ethyl-2-cyanoacrylate (ECA) using 2D graphitic carbon nitride (g-C3N4) as an active photocatalyst responsive to visible light. Our results demonstrate that particularly the mesoporous structure of g-C3N4 can initiate polymerization through the generation of electron-hole pairs upon exposure to visible light. To have a better insight into mechanistic pathways, several experiments, including control experiments, are conducted. The obtained polymers and the synthesized g-C3N4 materials are characterized comprehensively by chromatographic, thermal, and spectroscopic techniques. Accordingly, this study demonstrates an innovative process that can offer several advantages over traditional polymerization methods, including the ability to initiate polymerization at ambient temperatures and achieve high polymerization rates.

The strategy for the preparation of polyisobutylene-based block copolymers via mechanistic transformation from cationic to radical polymerization is reported. This strategy involves the synthesis of 2-bromo-2-methylpropanoyl-terminated difunctional polyisobutylene macroinitiator (BiBB-PIB-BiBB) via consecutive cationic polymerization, in situ preparation of hydroxyl-terminated polyisobutylene and its acylation by 2-bromo-2-methylpropanoyl bromide. The Mn2(CO)10-triggered photo-induced radical polymerization of styrene in bulk using this macroinitiator leads to the formation of multiblock copolymer, while predominantly triblock copolymer is generated during the polymerization of methyl methacrylate. The possibility to functionalize the polyisobutylene by pyrene via photo-induced radical addition of 1-bromomethyl pyrene in the presence of Mn2(CO)10 is also demonstrated in this work. This study reports a new method for polyisobutylene (PIB)-based block copolymers. It utilizes a difunctional PIB macroinitiator prepared via cationic polymerization and acylation. Photo-induced radical polymerization of macroinitiator with Mn2(CO)10 forms multiblock copolymers with styrene and triblocks with methyl methacrylate. Additionally, this work demonstrates the efficient functionalization of PIB with pyrene moieties via photoinitiated radical addition. image

High-temperature curing is a major limitation for the widespread use of benzoxazine resins. This study explores two strategies to reduce curing temperatures using minimal sulfur content (1-5 wt%): ziram catalysis and light activation. Both approaches effectively promoted curing at lower temperatures compared to traditional methods. The ziram-activated system achieved an activation energy as low as 83 kJ/mol, while the UV-activated system reached 63 kJ/mol. Furthermore, the UV-activated sulfur system exhibited improved thermal stability, particularly for cresol-based benzoxazines. The curing processes of monomers with catalysts were traced using various techniques, including nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), along with differential scanning calorimetry (DSC).

Phenacyl bromide has been explored as a new Norrish Type I photoinitiator for radically polymerizing methyl methacrylate and styrene monomers. A straightforward radical photopolymerization method using UVA light for the synthesis of chain-end functional poly(methyl methacrylate) and polystyrene has been developed. The process has been refined for both bulk and solution photopolymerizations. Chain-end functionalization was demonstrated by the formation of block-copolymers of the bromine-ended homopolymers, utilized as macroinitiators, resulting in an increase in the molecular weight of the corresponding precursor, observed by gel permeation chromatography (GPC). Block copolymerization was initiated by radicals generated at the chain-ends by a halogen-atom transfer reagent, namely, dimanganese decacarbonyl (Mn2(CO)10). This simple light-induced method is promising for the additive manufacturing field such as vat photopolymerization, stereolithography, digital light processing as it yields chain-end functional materials that can be further processed.

This study introduces a straightforward and efficient route for synthesizing self-healable polybenzoxazine networks by utilizing dynamic imine bond exchanges under mild conditions. The process involves combining polyethylenimines with aldehyde-functional bisbenzoxazine, which was produced from vanillin, using a Sc(OTf)(3) catalyst and subjecting them to moderate heating at 150 degrees C. Remarkably, the resulting polybenzoxazine films exhibit good self-healing capabilities at low temperatures and pressures, without requiring any additional additives to facilitate the healing process. The degree of recovery was assessed through tensile tests, while rheologic measurements were utilized to analyze stress relaxation and activation energy of dynamic bonding, providing insights into the self-healing process. Additionally, comprehensive spectral characterizations and investigations of thermal behaviors were conducted to gain a deeper understanding of the material's properties and performance. Moreover, the polybenzoxazine networks demonstrated enhanced hydrolysis stability compared to conventional imine-based systems, benefiting from the specific Mannich linkages and inherent hydrophobic nature of polybenzoxazines.

The influence of nanoscale confinement on the thermally induced ring-opening polymerization (ROP) of three different monofunctional benzoxazines (Bzs) was highlighted for the first time. The Bzs were solution-loaded or blended in/with a titanium-based metal-organic framework (MOF), i.e., MIL-125-based. The successful infiltration of the Bzs within the MOF was confirmed through comprehensive analyses using FTIR, BET, and DSC techniques. Remarkably, the nanoconfinement exhibited exceptional promotion of the Bzs ROP, resulting in a significant decrease in the onset temperature of the corresponding exotherms of as much as 127 degrees C for the nonsubstituted monomer. GPC traces revealed that high-molecular-weight polybenzoxazines (PBzs) were formed when fluorine-substituted Bz polymerized in the MOF-confined nanospaces. The catalytic role of nanoconfinement was further supported by analyzing the effective activation energy through the isoconversional method of Starink. ROP of the Bz-MIL-125 blend, where the effect of nanoconfinement was absent, demonstrated the catalytic role of MIL-125 with a less pronounced impact compared to the nanoconfined system.