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This study explores the utilization of bio-polyol, derived from castor oil modified with waste tire rubber (WTR), in the synthesis of rigid polyurethane-polyisocyanurate foams. Two WTR concentrations (10% and 20%) were incorporated, investigating their impact on foaming, cellular structure, and various foam properties. Response surface methodology assessed the influence of polyol/isocyanate ratios and WTR content on thermal, physical, and mechanical responses. Results indicated significant effects of polyol/isocyanate ratios on thermal and density properties, while WTR content exhibited an opposite trend. Mechanical behavior showed a distinct pattern compared to thermal and physical aspects, suggesting no conclusive correlation between compressive stress variability and polyol/ isocyanate ratio or WTR content. Consequently, the application of these foams depends on specific property requirements, highlighting the potential of sustainable bio-polyols and recycled WTR in replacing conventional petroleum-based counterparts in polyurethane foam production. Highlights * Development of rigid polyurethane-polyisocyanurate foams based on castor oil. * Polyurethane-polyisocyanurate foams modified with waste tire rubber. * Increased isocyanate index impacts thermal stability and density. * Response surface methodology showed variability in compressive stress behavior and the polyol/isocyanate ratio. * For application of polyurethane-polyisocyanurate foams will depend on the desired properties. KEYWORDS castor oil, response surface methodology, rigid polyurethane-polyisocyanurate foams, tire rubber waste, 1 | INTRODUCTION Improper disposal of solid waste is one of the main environmental problems currently faced. (1) With the increase in population and consumption, the amount of waste generated [...]

Photoinduced carbamoylation of ethers using isocyanates as amide sources was accomplished under mild and environmentally friendly reaction conditions. A series of isocyanates were tolerated in this protocol to construct α-amide-substituted ether derivatives with desired yields. The method featured broad substrate scope and good functional group tolerance, which could play an important role in the construction of biological molecules with ethers. [ABSTRACT FROM AUTHOR]

In this paper, a series of cationic polyurethane fluorinated surfactants were synthesized using a series of isocyanates, and 1H, 1H, 2H,2H-tridecafluoro-1-octanol, 2-(dimethylamino)ethanol, and iodomethane as raw materials in a three-step sequential reaction. These fluorinated surfactants exhibited high surface activity and low critical micelle concentration. In addition, these fluorinated surfactants exhibited excellent wetting and emulsification properties at very low concentrations of 0.1 wt%. In addition the cationic polyurethane fluorinated surfactants are compounded into aqueous film-forming foam extinguishing agents, which exhibit excellent fire extinguishing properties. The desirable properties coupled with the simple and green preparation process make this strategy a new way to prepare sustainable alternatives to long fluoroalkyl chain surfactants. A new degradable cationic fluorocarbon surfactant prepared by coupling isocyanate and hydroxyl group was developed and applied to fire fighting. [ABSTRACT FROM AUTHOR]

A nickel‐catalyzed reductive amidation of aryl sulfonium salts with isocyanates for amide synthesis via C−S bond cleavage was developed. The reactions proceeded smoothly at ambient temperature in the presence of nickel catalyst and manganese metal in DMF to give a variety of amides in moderate to good yields with wide functional group tolerance. [ABSTRACT FROM AUTHOR]

The degree of ease of use and the readily observable signals associated with the detection process are critical factors in determining the success of a detection strategy. Considering this perspective, we report the detection of phosgene by modulating the photophysical characteristics of a molecular probe, Xanth-NH2. The probe is non-emissive in nature, but the presence of phosgene facilitates the probe's radiative decay, which enables phosgene detection via fluorescence turn-on change. The fluorescence changes vary linearly with phosgene concentration, contributing to a nanomolar level detection limit for phosgene. Additionally, under a controlled set of conditions, the half-time for the reaction of Xanth-NH2 with phosgene is 68 s. To demonstrate the potential application of Xanth-NH2, probe-loaded paper strips or silica gel were developed as an economic tool for the detection of phosgene in vapor or solution phase. Phosgene detection has been accomplished with a portable UV light source and a smartphone to track minute changes during the detection event. [ABSTRACT FROM AUTHOR]

AbstractWorkplace exposure to diisocyanates like 4,4’-methylene diphenyl diisocyanate can cause occupational asthma (MDI-OA), and the underlying biological pathways are still being researched.Although uncertainty remains, evidence supports the hypothesis that dermal exposure to MDI plays an important role in the development of MDI-OA.Gene expression, proteomics, and informatics tools were utilised to characterise changes in expression of RNA and protein in cultured human HEKa keratinocyte cells following exposure to conjugates of MDI with glutathione (MDI-GSH).RT-qPCR analysis using a panel of 39 candidate primers demonstrated 9 candidate genes upregulated and 30 unchanged.HPLC-MS/MS analysis of HEKa cell lysate identified 18 540 proteins across all samples 60 proteins demonstrate statistically significant differential expression in exposed cells, some of which suggest activation of immune and inflammatory pathways.The results support the hypothesis that dermal exposures have the potential to play an important role in the development of MDI-OA. Furthermore, proteomic and gene expression data suggest multiple immune (adaptive and innate) and inflammatory pathways may be involved in the development of MDI-OA.Workplace exposure to diisocyanates like 4,4’-methylene diphenyl diisocyanate can cause occupational asthma (MDI-OA), and the underlying biological pathways are still being researched.Although uncertainty remains, evidence supports the hypothesis that dermal exposure to MDI plays an important role in the development of MDI-OA.Gene expression, proteomics, and informatics tools were utilised to characterise changes in expression of RNA and protein in cultured human HEKa keratinocyte cells following exposure to conjugates of MDI with glutathione (MDI-GSH).RT-qPCR analysis using a panel of 39 candidate primers demonstrated 9 candidate genes upregulated and 30 unchanged.HPLC-MS/MS analysis of HEKa cell lysate identified 18 540 proteins across all samples 60 proteins demonstrate statistically significant differential expression in exposed cells, some of which suggest activation of immune and inflammatory pathways.The results support the hypothesis that dermal exposures have the potential to play an important role in the development of MDI-OA. Furthermore, proteomic and gene expression data suggest multiple immune (adaptive and innate) and inflammatory pathways may be involved in the development of MDI-OA. [ABSTRACT FROM AUTHOR]

The molecular dynamics, with an emphasis on the calorimetric and dynamic glass transitions, of non-isocyanate polyhydroxyurethanes (PHUs) produced by the equimolar polyaddition of polyether-based dicyclic carbonates (P-CCs) and various short diamines was studied. The diamine component consisted of a short aliphatic diamine (1,4-diaminobutane, DAB) and a more complex 'characteristic' diamine. The study was conducted to investigate (i) the chemical structure of the characteristic amine, (ii) its molar ratio, and (iii) the structure and molar mass of the P-CC. Infrared spectroscopy, differential scanning calorimetry, and broadband dielectric spectroscopy were employed. The P-CC, constituting the bulk of the systems, was the most crucial component for the glass transition. The characteristic amine influenced the glass transition as a result of its bulky structure, but also presumably as a result of the introduction of free volume and the formation of hydrogen bonds. The dynamic glass transition (α relaxation) trace in the Arrhenius plots showed a subtle change at a certain temperature that merits further study in the future. The charge mobility was fully coupled with the molecular mobility, as evidenced by dc conductivity being directly proportional to the characteristic frequency of α relaxation. The fluctuation in carbonyl units (β relaxation) was mildly affected by changes in their immediate environment. [ABSTRACT FROM AUTHOR]

Traditional polyurethane coating is prepared by combining isocyanate and polyol, but isocyanate is toxic, which is not conducive to the sustainable development of ecological environment. In this paper, dibutyltin dilaurate (DBTDL) was used as catalyst to synthesize dicyclic carbonate from four different acids and glycerol carbonates. Then, it was gradually polymerized with isophorone diamine (IPDA) and 4,4'-diaminodiphenyl disulfide ether to synthesize self-healing non-isocyanate polyurethane (NIPU). The effects of different acid types on coating forming and self-healing properties of NIPU were studied. Then, polypyrrole modified carbon nanotubes were prepared and physically blended with NIPU to obtain a responsive NIPU gel coating. The results show that NIPU has excellent scratch repair performance at 70°C by optical microscopy; Through the dissolution and re-formation of NIPU by N, N-dimethylformamide, it is proved that the material has repeatable processability and is conducive to the sustainable development of ecological environment; The high precision multimeter proved that NIPU has the responsiveness under different chemical environment of acid, alkali, oxidation and reduction. The coating has broad application prospects in biomimetic technology, biology, electronics and other fields. [ABSTRACT FROM AUTHOR]

In this study, polyurethane (PU) hydrogels were synthesized via mercapto curing reaction to elucidate the effect of molecular interactions between isocyanate and soft segments on the properties of hydrogels. Further, the mesh size, mechanical properties, hydrophilicity, and biological properties of the PU hydrogels were determined. In the isocyanate series, the structural regularity and rigidity of 4,4′‐dicyclohexylmethane diisocyanate (HMDI) favored the formation of hydrogel materials with small mesh size, high modulus, and low water absorption. In contrast, l‐lysine diisocyanate (LDI) favored the materials with large mesh size, low modulus, and good hydrophilicity. In the soft‐segment series, the strong hydrogen bonds of polycarbonate diol (PCDL) favored the formation of materials with small mesh size, dense cross‐link points, and high modulus, whereas weak hydrogen bonds of polytetrahydrofuran ether glycol (PTMG) favored the hydrogel materials with small mesh size, few crosslink points, and low modulus. PU hydrogels exhibit excellent cytocompatibility, anti‐cell adhesion, and anti‐inflammatory properties. Therefore, this study offers valuable insights into understanding the chain structure and macroscopic properties, thus contributing to preparing PU hydrogels with varying performances, as desired. [ABSTRACT FROM AUTHOR]

A facile electrochemical synthesis of selenocarbamates from multicomponent reactions of isocyanides, diselenides, and water is developed here. This strategy provides a mild, direct, and complementary approach for synthesizing selenocarbamates in moderate to excellent yields with good substrate tolerance. The simple undivided cell setting with carbon/Pt electrodes proceeded smoothly. A radical pathway was proposed by preliminary mechanistic research. [ABSTRACT FROM AUTHOR]

Polyurethane foams are materials characterized by low density and thermal conductivity and can therefore be used as thermal insulation materials. They are synthesized from toxic and environmentally unfriendly petrochemicals called isocyanates and polyols, which react with each other to form a urethane group via the displacement of the movable hydrogen atom of the −OH group of the alcohol to the nitrogen atom of the isocyanate group. The following work describes the synthesis of polyurethane foams, focusing on using environmentally friendly materials, such as polyols derived from plant sources or modifiers, to strengthen the foam interface derived from plant precipitation containing cellulose derived from paper waste. The polyurethane foam industry is looking for new sources of materials to replace the currently used petrochemical products. The solutions described are proving to be an innovative and promising area capable of changing the face of current PU foam synthesis. [ABSTRACT FROM AUTHOR]

Isocyanate‐based monomers and polymers have found widespread industrial application; however, the realization of green water‐based products via the preparation of stable isocyanate aqueous emulsions remains challenging. Herein, a series of organosilicon and organofluorine synergistically modified amphiphilic branched polyurethanes (HBWPU), synthesized by grafting perfluorohexyl ethanol semi‐terminated isophorone diisocyanate (IPDI) onto a hydrophilic polyurethane prepolymer, is presented. Subsequently, using a physical mixing method, stable diisocyanate emulsions are fabricated by preparing diisocyanate latex particles with IPDI as the core and hyperbranched water‐based polyurethanes (HBWPU) as the shell. Structural investigations showed that the branching degree and fluorine content of the HBWPU significantly affects the stability of the diisocyanate emulsions. Increasing the degree of branching from 0.34 to 0.86 causes the amount of residual isocyanate (NCO) groups to decrease from 20.1% to 16.7%. In contrast, an increase in the fluorine content from 0% to 17.8% increases the amount of residual NCO groups from 11.5% to 24.6%. Thus, HBWPU can be used as an emulsifier to prepare waterborne diisocyanate cross‐linking agents. Such polyurethane‐coated isocyanate aqueous emulsions can increase the hardness and significantly improve the acetone resistance of hydroxyl polyacrylate resins. [ABSTRACT FROM AUTHOR]

A UV‐ and thermo‐responsive polyurethane‐acrylate prepolymer was synthesized from palm olein (POo) via a non‐isocyanate route. The process included epoxidation of POo, carbonation of epoxidized palm olein (EPOo) into polycyclic carbonate in a solvent‐free and mild condition (100°C, 1 atm), followed by reacting with ethylene diamine and acrylic acid. The chemical structure of the non‐isocyanate polyurethane‐acrylate (NIPUA) prepolymer was elucidated by 1H and 13C nuclear magnetic resonance (NMR) and Fourier transform‐infrared spectroscopy (FTIR), while weight average molecular weight of NIPUA was determined by gel permeation chromatography (GPC). The NIPUA (0–20 wt%) was incorporated with thermoplastic elastomer (TPE) as a plasticizer and cured under UV light and thermal stimulations. The cured NIPUA/TPE films were characterized by FTIR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile strength test. Under UV and thermal stimulations, the NIPUA/TPE demonstrated enhanced tensile properties (elongation at break >1280%, Young's modulus ~25 MPa), thermal properties (lower Tg), lower water contact angle, and shortened curing time as compared with the blank TPE. The 20 wt% NIPUA/TPE films exhibited susceptibility to enzymatic biodegradation and noncytotoxic to HEK 293 cells in vitro, demonstrated it's potential as a UV‐ and thermo‐responsive plasticizer for TPE in manufacturing of medical devices. [ABSTRACT FROM AUTHOR]

Phenyldiazenyl moiety has been utilized both as a protective and activating group to synthesize C-1-substituted tetrahydroisoquinolines via lithiation–substitution strategy. This reaction sequence involves generation of α-amino carbanions, derived from N -phenyldiazenyl tetrahydroisoquinolines, followed by coupling with various electrophiles, e.g., aldehyde, ketones, alkyl halide, oxiranes, isocyanates, and with in situ generated arynes. Deprotection of the protecting group was carried out under acidic conditions to afford the desired α-substituted products in moderate to good yields. So, triazene as a protecting/directing group and its compatibility with strong bases provide a good synthetic utility for the synthesis of a variety of α-substituted secondary amines via lithiation substitution reaction. [ABSTRACT FROM AUTHOR]

Due to their excellent biocompatibility and biodegradability, aliphatic polyesters are widely used in the biomedical, packaging and agricultural fields, which are usually accessed by the ring-opening polymerization (ROP) of lactones and the catalysts particularly play an important role. Herein a series of quinolinyl-urea catalysts have been synthesized via the reaction between isocyanate and aminoquinoline with an amino group at different substitution positions and characterized. In combination with 7-methyl-1, 5, 7-triazabicyclo[4,4,0]dec-5-ene (MTBD) as a cocatalyst and benzyl alcohol (BnOH) as an initiator, 1-(3,5-bis(trifluoromethyl)phenyl)-3-(quinolin-3-yl)urea (3-QU) was observed to be most active for the ROP of δ-valerolactone (δ-VL). The polymerization conditions were optimized by varying the type of organic base, catalyst concentration and reaction temperature. By changing the ratio of [M]0/[I], linear polyvalerolactones (PVLs) with different molecular weights and narrow molecular weight distribution were prepared. The kinetic and chain extension experiments were carried out to prove the "living"/controllable feature. And the NMR experiments were used to support the proposal of possible mechanism. [ABSTRACT FROM AUTHOR]

A new series of flexible polyamide (PA) aerogels was synthesized using terephthaloyl chloride (TPC), 2,2′-dimethylbenzidine (DMBZ) and cross-linked with an inexpensive, commercially available tri-isocyanate (Desmodur N3300A) at polymer concentrations of 6–8 wt.% total solids and repeating units, n, from 30 to 60. The cross-linked DMBZ-based polyamide aerogels obtained, after supercritically drying using liquid CO2, had shrinkages of 19–27% with densities ranging from 0.12 g/cm3 to 0.22 g/cm3, porosity and surface areas up to 91% and 309 m2/g, respectively, and modulus values ranging from 20.6 to 109 MPa. Evidence suggests that a higher flexibility could be achieved using DMBZ in the polyamide backbone with N3300A as a cross-linker, when compared to previously reported TPC-mPDA-BTC PA aerogels, N3300A-polyimide aerogels, and N3300-reinforced silica aerogels. [ABSTRACT FROM AUTHOR]

The nanocomposites of polythiourethane (PTU) with Fe3O4 were fabricated via an isocyanate-free approach. The nanocomposites simultaneously had the reprocessing, shape memory and photothermal properties. First, a linear PTU carrying a plethora of thiol groups was synthesized via the ring opening polyaddition between a bicyclic trithiocarbonate and a poly (propylene oxide) diamine. In the meantime, the surfaces of Fe3O4 nanoparticles were functionalized with thiol groups. Second, the co-crosslinking between the linear PTU and the thiol-functionalized Fe3O4 was performed via the coupling of thiol radicals with a radical initiator. Notably, the nanocomposites of PTU with Fe3O4 were successfully obtained with the fine dispersion of Fe3O4 nanoparticle in PTU matrix. Compared to control PTU, the nanocomposites displayed the improved thermomechanical properties. More importantly, the nanocomposites had reprocessing properties. The dynamic exchange of disulfide bonds is responsible for the reprocessing behavior. Owing to the crosslinking with disulfide bonds, PTU had shape memory properties. Notably, the incorporation of Fe3O4 nanoparticles was capable of improving the shape memory properties. In addition, the nanocomposites displayed the photothermal properties with the incorporation of Fe3O4 nanoparticles. The photothermal conversion behavior can be utilized to trigger the shape recovery of the nanocomposites under near-infrared light irradiation and in a non-contact fashion. [ABSTRACT FROM AUTHOR]

Carbodiimides are important crosslinkers in organic synthesis and are used in the isocyanate industry as modifier additives. Therefore, the understanding of their formation is of high importance. In this work, we present a theoretical B3LYP/6-31G(d) and SMD solvent model and experimental investigation of the formation of diphenylcarbodiimide (CDI) from phenyl isocyanate using a phosphorus-based catalyst (MPPO) in ortho-dichlorobenzene (ODCB) solvent. Kinetic experiments were based on the volumetric quantitation of CO2 evolved, at different temperatures between 40 and 80 °C. Based on DFT calculations, we managed to construct a more detailed reaction mechanism compared to previous studies which is supported by experimental results. DFT calculations revealed that the mechanism is composed of two main parts, and the rate determining step of the first part, controlling the CO2 formation, is the first transition state with a 52.9 kJ mol−1 enthalpy barrier. The experimental activation energy was obtained from the Arrhenius plot (ln k vs. 1/T) using the observed second-order kinetics, and the obtained 55.8 ± 2.1 kJ mol−1 was in excellent agreement with the computational one, validating the complete mechanism, giving a better understanding of carbodiimide production from isocyanates. [ABSTRACT FROM AUTHOR]

In this work, a two‐step activated swelling technique was effectively employed to successfully synthesize monodisperse porous poly(styrene‐divinylbenzene) (PS‐DVB) particles. Diazoresin (DR) transform an ionic bond into a covalent bond by photoreaction. Under ultraviolet irradiation, DR was used to covalently attach dichlorophenyl isocyanate to sulfonated PS‐DVB microspheres. The novel photo‐crosslinking reaction effectively overcomes the toxicity issues associated with conventional coupling agents and enables green production of chromatographic fillers. Modified PS‐DVB particles were indeed commonly used as filler material for the separation of chiral compounds by high performance liquid chromatography (HPLC). The porous modified microspheres designed effectively separate benzoone, DL‐mandelic acid, 2‐phenylcyclohexanone, ibuprofen, 2‐hydroxyl flavone, DL‐cysteine, chloraniline maleate, hesperidin, and other chiral compounds by 100 mm column. It is noteworthy that the isocyanate‐chitin modified microspheres are effective in separating chiral drugs (1000 μg/mL) within 5 min. Compared with ordinary microspheres, porous isocyanate‐chitin modified microspheres showed better separation efficiency under the same conditions. The enhancement is attributed to the increase in their specific surface area. Consequently, they are a better choice of chromatographic packing matrix. [ABSTRACT FROM AUTHOR]

The introduction of nitrogen‐containing functional groups to chiral polymer backbones enables the tailoring of physical properties and offers opportunities for further post‐polymerization modification. However, the substrate scope of such polymers is extremely limited because monomers having nitrogen‐containing groups can change coordination state with respect to the metal centers, thus decreasing the activity and enantioselectivity and even poisoning the catalyst completely. In this paper, we report our attempts to carry out the asymmetric copolymerization of meso‐epoxide with highly reactive isocyanates. In particular, we found that biphenol‐linked bimetallic Co(III) complexes with multiple chiral centers are very efficient in catalyzing this asymmetric copolymerization reaction, affording optically active polyurethanes with a completely alternating nature and a high enantioselectivity of up to 94 % ee. Crucially, we identified that the steric hindrance at the phenolate ortho position of the ligand strongly influences the catalytic activity and product enantioselectivity. In addition, density functional theory calculations revealed that the highly sterically bulky substituents change the mechanism from bimetallic to monometallic, and result in the unexpected inversion of the chiral induction direction. Moreover, the high stereoregularity of the produced polyurethanes enhances their thermal stability, and they can be selectively decomposed into oxazolidinones. This study offers a versatile methodology for the synthesis of chiral polymers containing nitrogen functionalities. [ABSTRACT FROM AUTHOR]

The first examples of tetrasubstituted conjugated bis‐guanidinate (CBG) supported monomeric and thermally stable gallium dihalides [LGaX2], (X=Cl (Ga−Cl), I (Ga−I)) and dihydride (Ga−H) [LGaH2] (where L={(ArHN)(ArN)−C=N−C=(NAr)(NHAr)}; Ar=2,6‐Et2−C6H3) compounds are reported. The reaction of in situ generated LLi with 1.0 equiv. GaX3 (X=Cl, I) afforded compounds Ga−Cl and Ga−I. The reaction between Ga−Cl and Li[HBEt3] in benzene yielded the dihydride compound Ga−H. All reported compounds (Ga−Cl, Ga−I, and Ga−H) were characterized by NMR, HRMS, and single‐crystal X‐ray diffraction studies. Ga−H was probed for the hydroboration of carbodiimides (CDI), isocyanates, and isothiocyanates with HBpin. Compound Ga−H was also found effective for the catalytic hydroboration of imines, nitriles, alkynes, esters, and formates, affording the corresponding products in quantitative yields. Stoichiometric reactions with a CDI were performed to establish the catalytic cycle. [ABSTRACT FROM AUTHOR]

In this work, a family of bioactive waterborne polyurethanes (WPUs), based on glycerol ethoxylate (GE), hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI), with specific bioactivity on their chemical structures constituted by the amino acids: L-tyrosine (T), L-histidine (H) or L-glutamic acid (Glut), using a mass ratio of each component of 56/29/15%, respectively, was synthesized by a condensation reaction at 80 ºC for 3 h. In the GPC analysis, the P(HDI-T) shows the highest average molecular weight (Mn) (20,264 g mol−1), with a rod-like morphology, with a melting point of 240 ºC and with high resistance to endothermic degradation. IPDI-based WPUs exhibit a rough and amorphous structure, with a glass transition temperature around 120 ºC, regardless of the chemical structure of the amino acid present in their polymeric skeleton. The P(HDI-T) WPU it has the largest particle size. The in vitro biological evaluation reveals that the synthesized WPUs demonstrate to be non-hemolytic materials, benefiting the proliferation of important cells in the healing process such as monocytes and fibroblasts, and that they have antibacterial properties; evidencing that P(HDI-H) and P(IPDI-Glut) allow a 100% in vitro wound closure at 15 days. These novel bioactive synthetic polymers could be useful for the design of smart biomaterials as hydrogels made up of proteins using them as chemical crosslinker, taking advantage of the reactivity of the isocyanate groups. [ABSTRACT FROM AUTHOR]

Non-isocyanate polyurethane (NIPU) is one of the hot spots in the scientific research of polyurethane. In this work, mechanically regulable NIPU were prepared by ring-opening polymerization of cyclic carbonates via diamines. Cyclocarbonates with different functionalities were firstly synthesized by thiol-ene click reaction, which was characterized through nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The controllable mechanical performance of NIPU films was obtained by the structure of the diamines and the functionality of the thiol groups. The results of swelling and differential scanning calorimetry experiments suggested that the control of functionality and reactivity endowed the material with an adjustable crosslinking density. The Young's modulus of the material could be regulated from 51.3 to 765.1 MPa. Furthermore, the studied films also showed good thermal stability. The present study provides some guidance for the preparation of non-isocyanate polyurethane coatings for different application scenarios. [ABSTRACT FROM AUTHOR]

N‐Alkyl‐2‐nitroanilines deoxygenated with tributylphosphine form intermediate 2‐(alkylamino)aryliminophosphoranes, which were subjected, without isolation, to various cyclocondensation reactions with CS2, CO2, alkyl isocyanates, acyl chlorides, anhydrides, or esters. A simple, convenient, one‐pot procedure provided derivatives of unsymmetrically substituted 1‐alkylbenzimidazoles functionalized at C2 in good to excellent yields. The method does not require the use of metals, sensitive catalysts, or pressure. [ABSTRACT FROM AUTHOR]

In the 1H NMR spectra (DMSO-d6) of 1,3-disubstituted ureas containing the 4,7,7-trimethyl-3-oxo-4-oxabicyclo[2.2.1]heptan-1-yl substituent, the signals for the CH2—CH2 moiety appear as an ADMP-type spin system consisting of four doublets of doublets of doublets with chemical shifts in the range from 1.54 to 2.80 ppm. The experiment in CD3OD showed the disappearance of the signal at δ 2.80 and a change in the multiplicity of the other signals, which is indicative of the selective deuterium exchange of one of the four protons of the CH2—CH2 group for a deuterium atom. This allows the selective modification of compounds containing the oxacamphanyl moiety. [ABSTRACT FROM AUTHOR]

A procedure utilizing [TBA][P(SiCl3)2] as P source for the synthesis of phosphinecarboxamides is presented. The synthesis involves the reaction of [TBA][P(SiCl3)2] with isocyanates. These compounds act as highly effective reagents for the subsequent phosphination of isocyanates, leading to the formation of phosphine(triscarboxamides). This reaction proceeds swiftly under mild and straightforward conditions, making it suitable for a wide range of commercially available isocyanates. [ABSTRACT FROM AUTHOR]

Radiation curing is an excellent option for the economical implementation of coatings while simultaneously producing technically advanced products. Nevertheless, the number of materials used is mainly limited to pure (meth)acrylate and epoxy systems. Polyisocyanurates could be an excellent addition to this range, especially due to their thermal and chemical stability. In this work, through the use of a transition metal‐based photocatalyst, as well as the use of 1,5‐diazabicyclo(4.3.0)non‐5‐en as a co‐catalyst, formulations are presented, which enable pure polyisocyanurates to be used in radiation‐based coating technology. Trimerization with this system using any primary isocyanates worked and consequently thus opened the possibility for aromatic and aliphatic polyisocyanurates. Using monofunctional isocyanates, the theoretical background of trimerization as well as the theoretical enthalpy is evaluated and the possibilities as well as the limitations for poly‐trimerization of polyisocyanurates are analyzed. Finally, photo‐induced catalytic poly‐trimerization of aliphatic isocyanates is used to obtain samples with a Tg in the range of 100 °C and onset of degradation above 400 °C. Thus, for the first time, a framework for the use of isocyanates in the field of photopolymerization and, in particular, in the field of radiation‐based coating of polyisocyanurates is provided for further development. [ABSTRACT FROM AUTHOR]

Purpose: This work presents an environmental assessment of two adhesives to evaluate the replacement of the traditional adhesive (PU) used in the footwear industry by a novel adhesive based on a microencapsulation approach (PUMC) which is more favorable from the safety and technical perspectives. The PU adhesive is polyurethane-based, while the PUMC adhesive is polyurethane-based but with its isocyanate compounds microencapsulated, increasing storage life and reducing risks related to the exposure of workers with the adhesives. Methods: The potential environmental impact of the adhesives was evaluated using the life cycle assessment (LCA) methodology. A detailed process model was developed (both for laboratory and for a pilot-scale implementation) to investigate the environmental impacts associated with these processes. The functional unit was one kilogram of adhesive (PU and PUMC adhesives) produced. A cradle-to-customers' gate approach was defined. The system boundary starts from extraction of resources, through material production, until adhesive use. This includes microcapsule production in the case of the PUMC adhesive. This study investigates the important drivers behind the environmental impacts to help guide commercialization efforts. A scenarios study/sensitivity analysis was conducted to determine the response of the PUMC adhesive system to the variability of the model, scenarios, and parameters. Results: The results show that the PU adhesive environmental impact is due to acetone and polyol consumption in the production stage. In the PUMC adhesive system, acetone consumption and microcapsule production are the major factors responsible for the environmental impact. Polybutylene adipate terephthalate (PBAT), dichloromethane (DCM), and isophorone diisocyanate (IPDI) consumption are the major factors responsible for the environmental impact of the microcapsules' production. A sensitivity analysis was conducted using three alternative scenarios focused on the reduction in material consumption and increase in material recuperation, as well as using an alternative renewable energy source. Although the traditional PU adhesive has a lower impact, it was found that the three alternative PUMC adhesive systems can become comparable to the traditional PU adhesive. Conclusions: This study shows the advance and development of a new technology for microencapsulation of isocyanate in adhesives and its environmental advantages and disadvantages with respect to a traditional product that uses non-encapsulated isocyanate. Finally, it was shown that there is significant potential for minimizing some environmental impacts of the PUMC adhesive, such as optimizing the microcapsules' production stage, increasing the production efficiency to decrease the required material consumption. [ABSTRACT FROM AUTHOR]

Given the enormous safety risks and environmental pollution that restrict the green development of isocyanate produced by phosgene reactions, we propose a new green and intrinsically safe route for synthesizing diisocyanates containing the furan ring from 5-hydroxymethylfurfural. In this work, the following novel reactions have been systematically investigated, including synthesizing a new compound methyl furan-2,5-dimethylene dicarbamate (FDC) using 2,5-bis(aminomethyl)furan (BAF) and dimethyl carbonate (DMC), the selective hydrogenation of FDC to a new compound methyl tetrahydrofuran-2,5-dimethylene dicarbamate (THFDC), and FDC and THFDC catalytic decomposition to produce corresponding furan-2,5-dimethylene diisocyanate (FDI) and tetrahydrofuran-2,5-dimethylene diisocyanate (THFDI). The results showed that CH3ONa could effectively catalyze the synthesis of FDC from BAF and DMC, and the separation yield of FDC was 98.1% under mild conditions including a nBAF : nDMC ratio of 1 : 10 at 70 °C for 4 h. CH3ONa can be recycled up to four times with high stability. A 0.5% Pd/γ-Al2O3 catalyst with low Pd loading was prepared, and it showed high catalytic activity and stability for FDC hydrogenation to THFDC, with a THFDC yield of 99.9% at 100 °C, 2 MPa H2 and 1 h, and the catalyst could be reused after simple treatment with ethanol. The structure–activity relationship of supported Pd catalysts was studied. The conditions for the thermal decomposition reactions of FDC and THFDC were optimized, resulting in FDI and THFDI yields as high as 89.6% and 92.8%, respectively. Owing to the urgent need for raw materials sustainability and environmental friendliness, the brand-new safe pathway for synthesizing FDI and THFDI was constructed, significantly improving the competitiveness of the non-phosgene method in preparing bio-based isocyanate. [ABSTRACT FROM AUTHOR]

The glycolysis process of flexible polyurethane foams containing styrene–acrylonitrile and calcium carbonate as fillers was explored in detail. The use of DABCO as a catalyst allowed us to reduce the catalyst concentration and the polyurethane-to-glycol mass ratio to 0.1% and 1:1, respectively. The glycolysis process allowed us to obtain a high-purity polyol (99%), which can totally replace raw polyols in the synthesis of new flexible polyurethane foams, maintaining the standard mechanical properties of the original one and modifying the ratio of isocyanates employed to correct the closed cell structure caused by the impurities present in the recovered polyol. This isocyanate mixture was also optimized, resulting in a ratio of 30 and 70% of the isocyanates TDI80 and TDI65, respectively. Additionally, the fillers incorporated in the glycolyzed foams were recovered. Both recovered fillers, styrene–acrylonitrile and calcium carbonate, were fully characterized, showing a quality very similar to that of commercial compounds. Finally, the replacement of commercial fillers by the recovered ones in the synthesis of new polyurethane foams was studied, demonstrating the feasibility of using them in the synthesis of new foams without significantly altering their properties. [ABSTRACT FROM AUTHOR]

A procedure has been developed for the synthesis of 3,5-difluoroadamantan-1-yl isocyanate from 3,5-difluoroadamantane-1 carboxylic acid and diphenylphosphoryl azide using a new fluorinating agent, Ishikawa reagent, in one stage of the synthesis. The reaction of 3,5-difluoroadamantan-1-yl isocyanate with aliphatic diamines and trans-4-[(4-aminocyclohexyl)oxy]benzoic acid afforded a series of N,N′-disubstituted ureas and bis-ureas in 43–96% yields. The hydrolysis of 3,5-difluoroadamantan-1-yl isocyanate in the presence of a catalytic amount of DBU gave symmetrical N,N′-bis(3,5-difluoroadamantan-1-yl)urea in 47% yield. A relation between the number of fluorine atoms in the adamantane fragment on the melting points and lipophilicities of the synthesized ureas has been revealed, which makes it possible to control these important properties of ureas as potential enzyme inhibitors. [ABSTRACT FROM AUTHOR]

The synthesis of novel thiazolidinones 6-8A, diazetidenes 9-11A, and ethers 13- 18A was described using 2-aminobenzathiazole and 4-bromophenacyl bromide as starting materials. The reaction of 2-aminobenzathiazole with 4-bromophenacyl bromide afforded the product A1 in 80% yield. Position 5 at the product A1 5-(4- bromophenyl)imidazo(2,1-b)benzothiazole used to form carbaldehyede group A2 under Vilsmeier-Huck conditions. Schiff bases 3-5A were then produced via condensation of A1 various aromatic amines. The products 3-5A were reacted with naphthyl isocyanate and thioacetic acid to give the compounds 6-8A (77-90% yields) and 9-11A (92-97% yields), respectively. The product 2A was reduced with NaBH4 to provide the corresponding alcohol 12A in an excellent yield (97%). This was followed by the reaction with aryl halides via the Williamson reaction to afford the desired ethers 13-18A in yields ranging from 50 to 96%. All of the prepared compounds were characterized by FT-IR spectroscopy, and some of them were characterized by ¹H NMR and 13C NMR spectroscopy. A few products were evaluated for their antifungal, antibacterial, and antioxidant activities. [ABSTRACT FROM AUTHOR]

In this work, isocyanate-based strategy was developed for efficient immobilization of Candida antarctica lipase B (CALB). Of 41 commercial resins, EP109 was chosen and hydrophobized with hydroxyl-terminated polydimethylsiloxane (HTPDMS) for tert-butyl isocyanate (tBIC)-based CALB immobilization due to high loading amount and specific activity. The tBIC-based strategy exhibited shorter immobilization time, higher loading and activity than adsorption strategy by hydrophobic interaction. When compared with free CALB, EP109-HTPDMS-tBIC@CALB owned improved stability (against acid, alkali, and heat) and storability. Subsequently, EP109-HTPDMS-tBIC@CALB was employed in the bio-synthesis of 1,3-diacylglycerol in a solvent-free system with a yield of 76.31%, which was higher than commercial Novozym 435 (53.93%). EP109-HTPDMS-tBIC@CALB exhibited 76.34% of residual activity after 20 repeat uses. [Display omitted] • EP109 was selected from 41 resins and hydrophobized with HTPDMS, ODA, and APTES, respectively. • Candida antarctica lipase B was immobilized on EP109-HTPDMS via an isocyanate-based strategy. • Isocyanate-based strategy showed shorter time, higher loading and activity than adsorption. • The immobilized lipase catalyzed the synthesis of 1,3-diacylglycerol with a yield of 76.31%; • The immobilized lipase owned great reusability with 76.34% residual activity after 20 cycles. [ABSTRACT FROM AUTHOR]

Statistical and block copolymers of n‐hexyl isocyanate (HIC) and 2‐chloroethyl isocyanate (ClEtIC) were synthesized via cοοrdination polymerization employing the half‐titanocene complex [(η5‐C5H5)((S)‐2‐Bu‐O)TiCl2] as initiator. The complex, bearing a chiral substituent, led to optically active products, as confirmed by circular dichroism measurements. The molecular characterization of all products was carried out by NMR and IR spectroscopy and size exclusion chromatography (SEC), while their thermal stability was investigated through differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and differential thermogravimetry (DTG). The reactivity ratios of the two monomers were determined using various graphical methods, as well as the COPOINT program, according to the terminal copolymerization model. Structural parameters, such as the dyad monomer sequences and the mean sequence lengths were calculated as well. In addition, the kinetics of the thermal degradation of the statistical copolymers was studied, and the activation energies of the thermal degradation were calculated employing the Kissinger, Ozawa–Flynn–Wall (OFW), and Kissinger–Akahira–Sunose (KAS) methods. The block copolymers were synthesized by sequential addition of monomers starting from the polymerization of HIC. Well‐defined products were obtained in a controlled way as revealed by SEC, IR, and NMR measurements. [ABSTRACT FROM AUTHOR]

Conventional methods for synthesising polyurethane hydrogels encompass toxic isocyanates and organic solvents, limiting their eco-friendliness and ease of synthesis. In response, this study introduces an innovative approach to synthesising fructose-based non-isocyanate polyurethane (NIPU) hydrogel (FNHG), eliminating the need for isocyanates. Initially, fructose-based NIPU (FNPU) was synthesised using dimethyl carbonate and hexamethylene diamine under mild reaction conditions, paving the way for a greener polyurethane variant. Subsequently, a free radical polymerization technique was employed in an aqueous medium. This process allowed for the integration of poly(sodium acrylate), and N, N-methylene bisacrylamide, leading to to the development of FNHG. Remarkably short gelation time of just 30 min at 60 ℃ was achieved, signifying a significant advancement in the synthesis process. The synthesized NIPU-based hydrogels exhibited outstanding efficiency in the removal of crystal violet (CV) and malachite green (MG) dyes from aqueous media. With an impressive removal efficiency of 96.87% for CV and an astounding 99.8% for MG, these hydrogels demonstrated high effectiveness in remediation efforts. The study's novelty lies in both the synthesis methodology, utilising FNPU, and the exceptional efficiency exhibited by these hydrogels in eliminating diverse dyes from contaminated water. Furthermore, the structure of FNPU was confirmed using FTIR and 1H NMR spectroscopy, adding robustness to our findings. This research not only presents a solution to the limitations of traditional polyurethane synthesis but also demonstrates the potential of fructose-based NIPU hydrogels (FNHG) as eco-friendly and efficient agents for water purification. [ABSTRACT FROM AUTHOR]

Copper‐catalyzed decarboxylation of peroxides in the presence of O‐methyl‐N‐nitroisourea provides an access to O‐methyl‐N‐alkylnitroisoureas, an underdeveloped class of nitrogenated compounds, which can be regarded as isocyanate surrogates and find useful as AB‐type monomers, for polyurethane synthesis. [ABSTRACT FROM AUTHOR]

α,β‐aromatic lactams are highly abundant in biologically active molecules, yet so far they cannot be radiolabeled with short‐lived (t1/2=20.3 min), β+‐decaying carbon‐11, which has prevented their application as positron emission tomography tracers. Herein, we developed, optimized, and applied a widely applicable, one‐pot, quick, robust and automatable radiolabeling method for α,β‐aromatic lactams starting from [11C]CO2 using the reagent POCl3⋅AlCl3. This method proceeds via intramolecular Friedel‐Crafts acylation of in situ formed [11C]isocyanates and shows a broad substrate scope for the formation of five‐ and six‐membered rings. We implemented our developed labeling method for the radiosynthesis of the potential PARP1 PET tracer [carbonyl‐11C]DPQ in a clinical radiotracer production facility following the standards of the European Pharmacopoeia. [ABSTRACT FROM AUTHOR]

N‐Heterocyclic ylides are important synthetic precursors to rapidly build molecular complexity. Pyrazolium ylides have largely been unexplored, and we demonstrate their diverse utility in this report. We show that these readily accessible building blocks can be used to construct different heterocyclic skeletons by varying the coupling partner. Indolizines can be formed via an N‐deletion type mechanism when reacting pyrazolium salts with electron deficient alkynes. 1,2‐Dihydropyrimidines can be formed via a rearrangement mechanism when reacting pyrazolium ylides with isocyanates. These reactions enable access to valuable heteroarenes without the need for transition metal catalysis, high temperatures, or strong bases. [ABSTRACT FROM AUTHOR]

The reaction of Ti(NMe2)4 with the salan ligand precursor H2N2O2H2 led to the formation of [(L*)Ti(NHMe2)2] (L*=N2O24−) that forms [(H2N2O2)TiCl2] upon reaction with two equiv. of Me3SiCl. [(L*)Ti(py)2] was obtained from the reaction of [Ti(NtBu)Cl2(py)3] with the sodium salt H2N2O2Na2. Treatment of [(L*)Ti(NHMe2)2] with two equiv. of tBuNCO led to the insertion of the isocyanate molecules into the Ti−Nsalan bonds with the formation of [{L*(N(tBu)CO)2}Ti]. Conversely, the reaction of [(H2N2O2)Ti(OiPr)2] with two equiv. of tBuNCO led to the insertion of one isocyanate molecule into a Ti−Nsalan bond with the formation of [{(HN2O2)(N(tBu)CO)}Ti(OiPr)]. Computational studies were performed to gain insight into the reactivity of isocyanates with salan‐based Ti(IV) complexes. [ABSTRACT FROM AUTHOR]

Many years of foundry practice and much more accurate analytical methods have shown that sands with organic binders, in addition to their many technological advantages, pose risks associated with the emission of many compounds, including harmful ones (e.g., formaldehyde, phenol, benzene, polycyclic aromatic hydrocarbons, and sulfur), arising during the pouring of liquid casting alloys into molds, their cooling, and knock-out. The aim of this research is to demonstrate the potential benefits of adopting inorganic binders in European iron foundries. This will improve the environmental and working conditions by introducing cleaner and more ecological production methods, while also ranking the tested binders studied in terms of their harmful content. The article pays special attention to the analysis of seven innovative inorganic binders and one organic binder, acting as a reference for emissions of gases from the BTEX (benzene, toluene, ethylbenzene, and xylenes) and PAHs (polycyclic aromatic hydrocarbons) groups and other compounds such as phenol, formaldehyde, and isocyanates (MDI and TDI) generated during the mold pouring process with liquid metals. The knowledge gained will, for the first time, enrich the database needed to update the Reference Document on The Best Available Techniques for the Smitheries and Foundries Industry (SF BREF). [ABSTRACT FROM AUTHOR]

This study developed a kind of PEG-crosslinked O-carboxymethyl chitosan (O-CMC–PEG) with various PEG content for food packaging. The crosslinking agent of isocyanate-terminated PEG was firstly synthesized by a simple condensation reaction between PEG and excess diisocyanate, then the crosslink between O-carboxymethyl chitosan (O-CMC) and crosslinking agent occurred under mild conditions to produce O-CMC–PEG with a crosslinked structure linked by urea bonds. FT-IR and 1H NMR techniques were utilized to confirm the chemical structures of the crosslinking agent and O-CMC–PEGs. Extensive research was conducted to investigate the impact of the PEG content (or crosslinking degree) on the physicochemical characteristics of the casted O-CMC–PEG films. The results illuminated that crosslinking and components compatibility could improve their tensile features and water vapor barrier performance, while high PEG content played the inverse effects due to the microphase separation between PEG and O-CMC segments. The in vitro degradation rate and water sensitivity primarily depended on the crosslinking degree in comparison with the PEG content. Furthermore, caused by the remaining –NH2 groups of O-CMC, the films demonstrated antibacterial activity against Escherichia coli and Staphylococcus aureus. When the PEG content was 6% (medium crosslinking degree), the prepared O-CMC–PEG−6% film possessed optimal tensile features, high water resistance, appropriate degradation rate, low water vapor transmission rate and fine broad-spectrum antibacterial capacity, manifesting a great potential for application in food packaging to extend the shelf life. [ABSTRACT FROM AUTHOR]

Tris(hydroxymethyl)phosphine oxide, (HOCH2)3PO (THPO), is recognized as an efficient flame-retardant polyol and a derivative of PH3 – an environment-friendly, halogen-free source for phosphorus compounds and polymers. Synthesis and industrial production of THPO are based on straightforward oxidation of tris(hydroxymethyl)phosphine, (HOCH2)3P (THP), or neutralized tetrakis(hydroxymethyl)phosphonium chloride (THPC), or sulfate (THPS), by air/O2 or H2O2. In alkaline aqueous media, THP is oxidized by water with liberation of H2. As an alcohol, THPO readily reacts with isocyanates, epoxides, aziridines, and carboxylic acid derivatives, and is widely used as crosslinker or chain-extender to produce flame-retardant polyurethanes, polyethers, polyesters, and composite materials. Similarly, with compounds containing E–Cl bonds (E = P, Si, and S), THPO forms a variety of flame-retardant P/E-compounds or polymers. Condensation of THPO with phenols proceeds via cleavage of a P–C bond of THPO and liberation of CH2O that leads to flame-retardant THPO-phenol resins. With functionalized alkyl halides, THPO forms tris(alkoxymethyl)phosphine oxide monomers containing, for example, pendant allyl, propargyl, or silane groups. Halogenation of THPO leads to tris(chloromethyl)phosphine oxide, (ClCH2)3PO, or tris(bromomethyl)phosphine oxide, (BrCH2)3PO, useful for syntheses of multifunctional organophosphorus compounds, for example, tris(aminomethyl)phosphine oxide, (NH2CH2)3PO, and phosphorus-containing podands. Similar to THPO, tris(hydroxymethyl)phosphine sulfide, (HOCH2)3PS, is used in preparation of flame-retardant components for polymers, and, in synthesis of asymmetric phosphorus compounds. [ABSTRACT FROM AUTHOR]

Acacia auriculiformis seed oil (ASO) contains linoleic acid (72%) and vernolic acid, which are capable of rendering it as a salient resource for coating applications. In this investigation, ASO a non-conventional source, was first converted to its fatty acid (AFA), followed by aminolysis and esterification to produce an AFA-based polyester amide resin (APEA), using toluene as an azeotropic solvent. Structural confirmation of APEA was performed by FTIR-ATR and 1HNMR spectroscopy. The AFA and APEA resin were characterized and compared with conventional soybean oil-based polyester amide resins (SPEA). The thermal stability of SPEA (270 °C) and APEA (274 °C) resins was determined and compared. Films were produced by curing the resins with melamine–formaldehyde and aliphatic poly-isocyanate and characterized by mechanical, and chemical resistance tests. These tests revealed that APEA has enhanced chemical resistance and scratch hardness than SPEA. The surface morphology of PEA resins was determined by Scanning electron microscopy (SEM) which shows PEA is compatible with these curing agents that contain different true solvents (based on polarity). To study the corrosion resistance properties, a paint primer was formulated with the resins and 5% zinc phosphate. The metal content of the cured primer film was analyzed by Inductively coupled plasma-optical emission (ICP-OE) spectroscopy. All the findings prove that ASO-based PEA exhibited better performance than the soya-based PEA. The APEA can be used as binders in coating formulations to improve the mechanical as well as corrosion resistance properties. [ABSTRACT FROM AUTHOR]

AbstractCancer and antibiotic-resistant bacterial infections are significant global health challenges. The resistance developed in cancer treatments intensifies therapeutic difficulties. In addressing these challenges, this study synthesised a series of N,N′-dialkyl urea derivatives containing methoxy substituents on phenethylamines. Using isocyanate for the efficient synthesis yielded target products 14–18 in 73–76% returns. Subsequently, their antibacterial and anticancer potentials were assessed. Cytotoxicity tests on cancer cell lines, bacterial strains, and a healthy fibroblast line revealed promising outcomes. All derivatives demonstrated robust antibacterial activity, with MIC values ranging from 0.97 to 15.82 µM. Notably, compounds 14 and 16 were particularly effective against the HeLa cell line, while compounds 14, 15, and 17 showed significant activity against the SH-SY5Y cell line. Importantly, these compounds had reduced toxicity to healthy fibroblast cells than to cancer cells, suggesting their potential as dual-functioning agents targeting both cancer and bacterial infections.

Atopic dermatitis (AD) is a chronic inflammatory skin condition increasing in industrial nations at a pace that suggests environmental drivers. We hypothesize that the dysbiosis associated with AD may signal microbial adaptations to modern pollutants. Having previously modeled the benefits of health-associated Roseomonas mucosa, we now show that R. mucosa fixes nitrogen in the production of protective glycerolipids and their ceramide by-products. Screening EPA databases against the clinical visit rates identified diisocyanates as the strongest predictor of AD. Diisocyanates disrupted the production of beneficial lipids and therapeutic modeling for isolates of R. mucosa as well as commensal Staphylococcus. Last, while topical R. mucosa failed to meet commercial end points in a placebo-controlled trial, the subgroup who completed the full protocol demonstrated sustained, clinically modest, but statistically significant clinical improvements that differed by study site diisocyanate levels. Therefore, diisocyanates show temporospatial and epidemiological association with AD while also inducing eczematous dysbiosis.

The germylone dimNHCGe (5, dimNHC=diimino N‐heterocyclic carbene) undergoes a [2+2] cycloaddition with isocyanates RNCO (R=4‐tolyl or 3,5‐xylyl) to furnish novel alkyl carboxamido germylenes 7 (R=4‐tolyl) and 8 (R=3,5‐xylyl), featuring a C−C bond between the former carbene carbon and the isocyanate moiety. Heating a mixture of 8 with 4‐tolyl isocyanate to 100 °C results in isocyanate metathesis, demonstrating reversible C−C bond formation on the reduced germanium compound. DFT calculations suggest that this process occurs via the reductive dissociation of isocyanate from 8 that regenerates the parent Ge(0) compound 5. [ABSTRACT FROM AUTHOR]

The development of comprehensive optical self-healing polyurethane polymers for smart optical devices presents a significant challenge due to the trade-off between intrinsic self-healing capability and mechanical strength. This study focuses on the synthesis of versatile photoluminescence supramolecular polymers that integrate self-healing ability, mechanical strength, and fluorescence responsiveness. The incorporation of hydrogen bonds and disulfide bonds into the dynamic hard domain results in the optimal polymer exhibiting impressive mechanical properties (strength, 27.0 MPa; toughness, 132.1 MJ m-3; elongation at break, 1450%), as well as a conspicuous self-healing efficiency (surface scratches disappear within just 1 min). Furthermore, the transparent (transparency >97%) and colorless polymers demonstrate aggregation-induced emission, characterized by intense cyan fluorescence that transitions to subdued blue fluorescence upon stretching under 365 nm irradiation. Proof-of-concept experiments demonstrate that screen-printed fluorescent patterns, based on as-prepared fluorescence ink associated with dual-mode upconversion emission, are able to successfully encode fluorescence information, and can be integrated into the self-healable 3D optical devices. The self-healing optical devices designed with versatile polymers and featuring diversified patterns offer a promising direction for the advancement and application of future self-healing materials. [ABSTRACT FROM AUTHOR]