Can Chain-Reaction Polymerization of Octadecyl Acrylate Occur in Crystal?

Octadecyl acrylate was proven to exist in rotator phases, and the mechanism of its chain-reaction photopolymerization was revealed. The polymorphic behavior of octadecyl acrylate was studied by differential scanning calorimeter (DSC) and X-ray diffraction, which concluded that octadecyl acrylate exhibits two rotator phases (<i>R</i>_II and <i>R</i>_I), one orthorhombic crystal phase (<i>C</i>_ort), and one triclinic crystal phase (<i>C</i>_tri) phase. The chain-reaction photopolymerization of four phases of octadecyl acrylate were studied by photo-DSC, and the theoretical possibilities of one-dimension chain propagation in <i>R</i>_II, <i>R</i>_I, and <i>C</i>_ort phases were analyzed by using the molecular dynamics simulation results. Combining the experimental and calculation results, the chain-reaction polymerization mechanism either intralayer or interlayer was discussed and disclosed. The question of whether the chain-reaction polymerization of octadecyl acrylate can occur in crystal was answered, and the reason was explained

0 + 0 = 2: Changeover of Stability and Photopolymerization Kinetics for the Rotator Phase of Long-Chain Acrylate through the Ultra-Addition Effect in Binary Systems

The stability and lowest existing temperature for the rotator phase of long-chain acrylate were improved remarkably simply through the ultra-addition effect of physical blending of two long-chain acrylates, which leads to a wider operation window and better rotator-state photopolymerization. Hexadecyl acrylate (HDA) and tetradecyl acrylate (TDA) were proved existing rotator phase like previously reported octadecyl acrylate (ODA). The binary rotator phase systems were constructed by mixing HDA or TDA with ODA and investigated in detail through thermal analysis, X-ray diffraction, and photopolymerization kinetics. The chain-reaction photopolymerization conversion of the binary system significantly increased to 60% from near 0 for pure acrylate, which realized “0 + 0 = 2”. The mechanism of such an ultra-addition effect was explained on the basis of X-ray diffraction data and calculation of the geometric model. The effect of difference in chain length between two components on this enhancement was studied, and a threshold value was found

Reversible CO₂‑Responsive and Photopolymerizable Prepolymers for Stepwise Regulation on Demand

CO₂-responsive and photopolymerizable prepolymers are designed and synthesized. Their good photopolymerization kinetics and reversible CO₂ and N₂ responses to a bulk state and in a solution are reported. Stepwise modulation is verified in template imprinting. Results reveal that stable and high-resolution patterns can be produced by imprinting liquid prepolymers in CO₂ atmosphere, erased by warm heating, or retained permanently by chemical cross-linking through photopolymerization with the aid of a photoinitiator. By contrast, only blurry patterns are obtained in air

Direct, Rapid, Facile Photochemical Method for Preparing Copper Nanoparticles and Copper Patterns

We develop a facile method for preparing copper nanoparticles and patterned surfaces with copper stripes by ultraviolet (UV) irradiation of a mixture solution containing a photoinitiator and a copper–amine coordination compound. The copper–amine compound is formed by adding diethanol amine to an ethanol solution of copper chloride. Under UV irradiation, free radicals are generated by photoinitiator decomposition. Meanwhile, the copper–amine coordination compound is rapidly reduced to copper particles because the formation of the copper–amine coordination compound prevents the production of insoluble cuprous chloride. Poly­(vinylpyrrolidone) is used as a capping agent to prevent the aggregation of the as-prepared copper nanoparticles. The capping agent increases the dispersion of copper nanoparticles in the ethanol solution and affects their size and morphology. Increasing the concentration of the copper–amine coordination compound to 0.1 M directly forms a patterned surface with copper stripes on the transparent substrate. This patterned surface is formed through the combination of the heterogeneous nucleation of copper nanoparticles and photolithography. We also investigate the mechanism of photoreduction by UV–vis spectroscopy and gas chromatography–mass spectrometry

Construction of a Repairable Fixed Porous Catalytic Bed Loaded with Gold Nanoparticles via Multivalent Host–Guest Interactions

The reversible combination between gold nanoparticles (AuNPs) and carriers is crucial for the preparation of a recycle system. Here, a repairable catalytic system was constructed on the basis of AuNPs and porous nickel (PNi) which were combined through the multivalent host–guest interactions between βCD-AuNPs and PNi@IPTS-Azo [β-CD, β-cyclodextrin; IPTS, (3-isocyanatopropyl) triethoxysilane; Azo, azobenzene]. The large specific surface area and connected porous structure of PNi provide a good opportunity to achieve the multivalent interactions between βCD-AuNPs and PNi@IPTS-Azo in the nickel. Additionally, the reaction solution could be catalyzed by flowing over the PNi@IPTS-Azo@βCD-AuNPs substrates. This catalytic model showed a high efficiency close to 95%. Because of the reversible host–guest interactions between β-cyclodextrin and azobenzene, the catalytic system could be regenerated by removing the deactivated AuNPs with UV-light irradiation and recombining new ones through multivalent interactions <i>in situ</i>. This type of catalytic system is regenerative, material-saving, and effective. This system could be expected to be constructed as catalytic fixed beds and applied in industry

Electrooxidation of Methanol on Pt @Ni Bimetallic Catalyst Supported on Porous Carbon Nanofibers

This paper describes the preparation of Ni/Pt/CNFs via electrospinning technology, carbonization process, and chemical reduction method. The structure and composition of Ni/Pt/CNFs were characterized with X-ray diffraction, Raman spectroscopy, nitrogen adsorption isotherms, and X-ray photoelectron spectroscopy. Meanwhile, the morphology was analyzed with scanning electron microscopy and transmission electron microscopy. The electrochemical performance was evaluated by oxygen reduction reaction (ORR), cyclic voltammetry and chronopotentiometry. The results indicated that Pt and Ni nanoparticles were completely reduced in the experimental process and homogeneously distributed on the nanofibers with the average diameters of 3.8 and 17.8 nm, respectively. In addition, the Ni₅₀/Pt/CNFs catalyst showed excellent electrocatalytic performance for ORR and superior specific and mass activities for methanol oxidation (the maximum current density is ca. 10.9 mA cm^–2) and exhibited a slightly slower current decay over time, better than the reference samples which indicated a higher tolerance to CO-like intermediates

Cationic Ring-Opening Photopolymerization of Long-Chain Epoxides in the Rotator Phase: Confirmation, Mechanism, and Combination

Rotator-phase photopolymerization has been developed in the field of free-radical addition polymerization since the photopolymerization in the rotator phase was first proposed, and other mechanisms urgently need to be extended. Herein, four long-chain glycidyl ethers were synthesized, and their polymorphic behavior was studied by differential scanning calorimetry and X-ray diffraction. Among all, the octadecyl glycidyl ether (OGE) and the hexadecyl glycidyl ether (HGE) are proven existing rotator phases. The cationic ring-opening photopolymerization of the OGE in the rotator phase was achieved, and the highest conversion reached 68.6% at 30 °C, which is even higher than that of liquid-state photopolymerization at adjacent higher temperatures (27.2% at 40 °C). The mechanism was discussed and explained with the aid of a molecular dynamic simulation. In order to further develop the cationic ring-opening photopolymerization in rotator phases at relatively low temperatures, three types of long-chain compounds were chosen to separately blend with the OGE to construct binary systems. The conversion of the OGE at 20 °C (17% in the pure OGE system) could be obviously improved in all binary systems, and the maximum conversion could reach 56%. Subsequently, the interactions of different long-chain compounds on the OGE and the effect on polymerization behavior are both discussed

Cationic Ring-Opening Photopolymerization of Long-Chain Epoxides in the Rotator Phase: Confirmation, Mechanism, and Combination

Rotator-phase photopolymerization has been developed in the field of free-radical addition polymerization since the photopolymerization in the rotator phase was first proposed, and other mechanisms urgently need to be extended. Herein, four long-chain glycidyl ethers were synthesized, and their polymorphic behavior was studied by differential scanning calorimetry and X-ray diffraction. Among all, the octadecyl glycidyl ether (OGE) and the hexadecyl glycidyl ether (HGE) are proven existing rotator phases. The cationic ring-opening photopolymerization of the OGE in the rotator phase was achieved, and the highest conversion reached 68.6% at 30 °C, which is even higher than that of liquid-state photopolymerization at adjacent higher temperatures (27.2% at 40 °C). The mechanism was discussed and explained with the aid of a molecular dynamic simulation. In order to further develop the cationic ring-opening photopolymerization in rotator phases at relatively low temperatures, three types of long-chain compounds were chosen to separately blend with the OGE to construct binary systems. The conversion of the OGE at 20 °C (17% in the pure OGE system) could be obviously improved in all binary systems, and the maximum conversion could reach 56%. Subsequently, the interactions of different long-chain compounds on the OGE and the effect on polymerization behavior are both discussed

Cationic Ring-Opening Photopolymerization of Long-Chain Epoxides in the Rotator Phase: Confirmation, Mechanism, and Combination

Rotator-phase photopolymerization has been developed in the field of free-radical addition polymerization since the photopolymerization in the rotator phase was first proposed, and other mechanisms urgently need to be extended. Herein, four long-chain glycidyl ethers were synthesized, and their polymorphic behavior was studied by differential scanning calorimetry and X-ray diffraction. Among all, the octadecyl glycidyl ether (OGE) and the hexadecyl glycidyl ether (HGE) are proven existing rotator phases. The cationic ring-opening photopolymerization of the OGE in the rotator phase was achieved, and the highest conversion reached 68.6% at 30 °C, which is even higher than that of liquid-state photopolymerization at adjacent higher temperatures (27.2% at 40 °C). The mechanism was discussed and explained with the aid of a molecular dynamic simulation. In order to further develop the cationic ring-opening photopolymerization in rotator phases at relatively low temperatures, three types of long-chain compounds were chosen to separately blend with the OGE to construct binary systems. The conversion of the OGE at 20 °C (17% in the pure OGE system) could be obviously improved in all binary systems, and the maximum conversion could reach 56%. Subsequently, the interactions of different long-chain compounds on the OGE and the effect on polymerization behavior are both discussed

Cationic Ring-Opening Photopolymerization of Long-Chain Epoxides in the Rotator Phase: Confirmation, Mechanism, and Combination

Rotator-phase photopolymerization has been developed in the field of free-radical addition polymerization since the photopolymerization in the rotator phase was first proposed, and other mechanisms urgently need to be extended. Herein, four long-chain glycidyl ethers were synthesized, and their polymorphic behavior was studied by differential scanning calorimetry and X-ray diffraction. Among all, the octadecyl glycidyl ether (OGE) and the hexadecyl glycidyl ether (HGE) are proven existing rotator phases. The cationic ring-opening photopolymerization of the OGE in the rotator phase was achieved, and the highest conversion reached 68.6% at 30 °C, which is even higher than that of liquid-state photopolymerization at adjacent higher temperatures (27.2% at 40 °C). The mechanism was discussed and explained with the aid of a molecular dynamic simulation. In order to further develop the cationic ring-opening photopolymerization in rotator phases at relatively low temperatures, three types of long-chain compounds were chosen to separately blend with the OGE to construct binary systems. The conversion of the OGE at 20 °C (17% in the pure OGE system) could be obviously improved in all binary systems, and the maximum conversion could reach 56%. Subsequently, the interactions of different long-chain compounds on the OGE and the effect on polymerization behavior are both discussed