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Coupling in situ generated intermediates with other substrates/intermediates is a viable approach for diversifying product outcomes of catalytic reactions involving two or multiple reactants. Cyclohexanone oxime is a key precursor for caprolactam synthesis (the monomer of Nylon‐6), yet its current production uses unsustainable carbon sources, noble metal catalysts, and harsh conditions. Herein, we report the first work to synthesize cyclohexanone oxime through electroreduction of phenol and hydroxylamine. The Faradaic efficiency reached 69.1 % over Cu catalyst, accompanied by a corresponding cyclohexanone oxime formation rate of 82.0 g h−1 gcat−1. In addition, the conversion of phenol was up to 97.5 %. In situ characterizations, control experiments, and theoretical calculations suggested the importance of balanced activation of water, phenol, and hydroxylamine substrates on the optimal metallic Cu catalyst for achieving high‐performance cyclohexanone oxime synthesis. Besides, a tandem catalytic route for the upgrading of lignin to caprolactam has been successfully developed through the integration of thermal catalysis, electrocatalysis, and Beckmann rearrangement, which achieved the synthesis of 0.40 g of caprolactam from 4.0 g of lignin raw material. [ABSTRACT FROM AUTHOR]

Coupling in situ generated intermediates with other substrates/intermediates is a viable approach for diversifying product outcomes of catalytic reactions involving two or multiple reactants. Cyclohexanone oxime is a key precursor for caprolactam synthesis (the monomer of Nylon‐6), yet its current production uses unsustainable carbon sources, noble metal catalysts, and harsh conditions. Herein, we report the first work to synthesize cyclohexanone oxime through electroreduction of phenol and hydroxylamine. The Faradaic efficiency reached 69.1 % over Cu catalyst, accompanied by a corresponding cyclohexanone oxime formation rate of 82.0 g h−1 gcat−1. In addition, the conversion of phenol was up to 97.5 %. In situ characterizations, control experiments, and theoretical calculations suggested the importance of balanced activation of water, phenol, and hydroxylamine substrates on the optimal metallic Cu catalyst for achieving high‐performance cyclohexanone oxime synthesis. Besides, a tandem catalytic route for the upgrading of lignin to caprolactam has been successfully developed through the integration of thermal catalysis, electrocatalysis, and Beckmann rearrangement, which achieved the synthesis of 0.40 g of caprolactam from 4.0 g of lignin raw material. [ABSTRACT FROM AUTHOR]

The inhomogeneous dispersion caused by carbon nanotube (CNT) agglomeration in composites still needs to be explored, though mechanical properties of the polymer materials can be improved significantly if CNTs were added as a reinforcement. In this work, to explore an effective way to solve the agglomeration problem of CNTs within polycaprolactam (Nylon66), a functionalization strategy to enhance the intermolecular interaction between the caprolactam (CPL) unit molecule and (7,3) single-walled carbon nanotube (SWCNT) was investigated theoretically at the molecular level. Molecular moving behavior and intermolecular interaction energy indicate that the surface functionalization, especially with the –NH2 group, is an effective way to strengthen the interaction between CPL and (7,3) SWCNTs, which highlights the key role of controlled surface functionalization of CNTs in improving its dispersion degree in polycaprolactam. This can be explained by a small interfacial charge-transfer amount, which occurs from the occupied valence band maximum of (7,3) SWCNTs to the occupied highest occupied molecular orbital of the CPL molecule. In this case, the dipole moment of involved molecules plays an important role in the interfacial interaction strength and then increased intermolecular interaction between CPL and functionalized (7,3) SWCNTs, especially incorporating the –NH2 group with larger dipole moment, can be understood. Our results for the functionalization effects on the physical adsorption behavior of organic molecules around (7,3) SWCNTs can provide more useful information for further design and optimization of a SWCNT-based reinforcement. [ABSTRACT FROM AUTHOR]

Nylon nanocomposites were prepared by in‐situ ring‐opening polymerization to overcome the problem of poor properties due to the uneven dispersion of the nanoparticles by the traditional melt blending. This high‐performance polyamide 6 (PA6) nanocomposites with high dispersion and strong interface was prepared by grafting PA6 onto the surface of cellulose nanocrystals (CNC). The micromorphology, mechanical, crystalline and thermal properties of the composites were also investigated. Firstly, the hydroxyl group on the surface of CNC reacted with the para isocyanate of toluene diisocyanate (TDI), and the remaining ortho isocyanate was blocked by caprolactam to prepare CNC grafted with caprolactam (CNC‐g‐CL). Then CNC‐g‐CL was used as an activator to prepare cellulose nanocrystal grafted with polyamide 6 (CNC‐g‐PA6) composites by the ring‐opening polymerization of caprolactam on the CNC. The effects of different reaction temperatures, solvent amounts and molar ratios on the grafting rate of CNC‐g‐CL were investigated. The results showed that the highest grafting rate of CNC‐g‐CL with 66.7% was achieved at a reaction temperature of 45°C, 0.1 g/mL CNC in toluene, and a molar ratio of 6 for TDI/CNC. Further, different CNC‐g‐PA6 composites prepared from different CNC content and activator content were explored. For CNC‐g‐PA6 composites, CNC was uniformly dispersed in the PA6 matrix and had a good compatibility with the matrix. CNC exhibited significant reinforcement in the composites with a tensile strength of up to 108 MPa. In addition, the glass transition temperature of CNC‐g‐PA6 was increased to 92°C, which significantly improved the heat resistance of the new composites. Highlights: Effects of reaction condition of CNC and TDI on DSTDI and DSCL were studied.Effects of CNC and activator content on CNC‐g‐PA6 properties were studied.CNC is uniformly dispersed in PA6 with average particle size less than 1 micron.The nylon matrix was significantly strengthened by the addition of CNC.The addition of CNC significantly improved the heat resistance of the composites. [ABSTRACT FROM AUTHOR]

Hexamethylenediamine (HMDA), a crucial precursor of nylon-66, can be synthesized from caprolactam (CPL) via a two-step route involving CPL ammoniation and 6-aminocapronitrile (ACN) hydrogenation. Based on theoretical calculations and experimental screening, mesoporous alumina was selected which served as a highly active and cost-efficient catalyst for CPL ammoniation, catalysing the ring-opening of amides by C–N bond breakage and subsequent amide dehydration to nitrile. A 57.9% CPL conversion and 98.3% ACN selectivity were achieved at 320 °C with stability over 480 hours. The subsequent hydrogenation of ACN using the commercial RANEY® Ni catalyst yielded 100% HMDA, requiring milder conditions and half the hydrogen compared to adiponitrile processes. Overall, this research highlights a green HMDA production pathway, employing CPL as a feedstock. [ABSTRACT FROM AUTHOR]

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The preparation of caprolactam (CPL) from biomass as raw material is a very hot topic of current concern. In this paper, a new way to synthesize CPL from 5-hydroxymethylfurfural (HMF) was proposed, and the catalytic reaction of cyclization of the intermediate 6-hydroxycaproamide (6-HCM) was studied to provide a basis for the synthesis of bio-based CPL. A bimetallic catalyst, Ru–Co/TiO2, was prepared using the impregnation method and characterized using XRD, XPS, H2-TPR, and TEM. The investigation delves into the impact of various parameters, including metal loading, choice of solvent, solvent ratio, catalyst dosage, and reaction time, on the yield of the final product. The findings demonstrate a significant synergistic effect between Ru and Co in the bimetallic Ru5Co6/TiO2 catalyst, leading to improved catalytic performance. Under the optimized reaction conditions (250 °C, 1 MPa N2, 1,4-dioxane: NH3·H2O = 2:1 as the solvent ratio), the conversion rate of 6-HCM reaches 99.0%, with CPL yield of 62.2%. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The authors investigate a new reagent—modified water-soluble polymer of polyvinyl caprolactam (PVCL)—as a collector in flotation of gold-bearing sulfide ore. Modified PVCL is obtained by solid-phase modification of poly(N-vinyl caprolactam) by thiourea. The electron scan and laser microscopy identified adsorption of PVCL at gold grains applied artificially to the surface of polished sections of pyrite. It is found that PVCL facilitates selective aggregation of gold-bearing minerals from fine slime, and more than 99% of gold goes from fine slime to sand at the content of 3.54 g/t. The use of PVCL together with butyl potassium xanthate (PVCL 30 g/t, BPX 200 g/t) in flotation of finely ground gold-bearing ore from the Olimpiada deposit improved the quality of the concentrate: gold content increased from 19.9 to 29.5 g/t and gold recovery increased from 81 to 95%. The joint application of modified PVCL and BPX results in the gold recovery higher by 14%, concentrate quality improved 1.5 times and in the gold content of tailings reduced to 0.15 g/t. [ABSTRACT FROM AUTHOR]

An interconnected sponge structure and porous surface poly (acrylonitrile-co-methyl acrylate) (P(AN-MA)) microfiltration membranes (MF) were fabricated via thermally induced phase separation (TIPS) by using caprolactam (CPL), and acetamide (AC) as the mixed diluent. When the ternary system was composed of 15 wt.% P(AN-MA), 90 wt.% CPL, and 10 wt.% AC and formed in a 25 °C air bath, the membrane exhibited the highest water flux of 8107 L/m2·h. The P(AN-MA) membrane contained hydrophobic groups (-COOCH3) and hydrophilic groups (-CN), leading it to exhibit oleophobic properties underwater and hydrophobic properties in oil. The membrane demonstrates efficient separation of immiscible oil/water mixtures. The pure water flux of the petroleum ether/water mixture measured 870 L/m2·h, and the pure oil flux of the petroleum tetrachloride/water mixture measured 1230 L/m2·h under the influence of gravity. Additionally, the recovery efficiency of diluents through recrystallization was 85.3%, significantly reducing potential pollution and production costs. [ABSTRACT FROM AUTHOR]

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Upcycling biodegradable polyester waste into value-added chemicals can not only avoid CO2 emissions but also achieve sustainable carbon recycling. Herein, we report a one-pot catalytic process to deconstruct polycaprolactone into 6-aminocaproic acid (EACA) and caprolactam (CPL), two monomers of nylon-6, using aqueous ammonia and Ru catalysts. No additional hydrogen is required, and the total yield of EACA and CPL could reach 90.2% using a ternary catalyst, Ru/CeO2/RGO, at 140 °C. It is verified that 6-hydroxyhexanoic acid and 6-hydroxyhexanoamide are the initial intermediates resulting from polycaprolactone decomposition, which undergo dehydrogenation, amination and re-hydrogenation to transform into EACA and 6-aminohexanoamide over the Ru catalyst. The hydrolysis of 6-aminohexanoamide produces EACA, and the reverse reaction between dehydration of EACA and hydrolysis of CPL results in their coexistence. The protocol demonstrated here provides a novel route to recycle polycaprolactone to valuable chemicals. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) provide a greener approach to reduce the toxicity of ionic liquids (ILs) when altering the behaviour of polymers. DESs have extraordinary properties such as high solubilising abilities, easy preparation, low volatility, good thermal stability, and cost effectiveness, making them suitable for wider applications in biomedical research. DESs can be used for modulating the behaviour of thermo-responsive polymers (TRPs) to provide successful hybrid functionality very near or at room temperature to achieve better stability. The current study is an attempt to achieve this and demonstrates that the presence of choline chloride : lactic acid, 1 : 2 (CC : LA), betaine : lactic acid, 1 : 2 (BET : LA), proline : lactic acid, 1 : 1 (PRO : LA) and urea : lactic acid, 1 : 2 (U : LA) as DESs can change the performance of a thermoresponsive polymer poly(N-vinylcaprolactam) (PVCL). The thermoresponsive behaviour of PVCL was investigated in this study using a variety of techniques, including steady-state fluorescence, Fourier-transform infrared (FTIR) spectroscopy, and UV-visible spectroscopy. Additionally, the LCST values of PVCL were also examined by temperature dependent dynamic light scattering (DLS) which showed a regular decrease in the presence of DES. Dynamic light scattering was also used to better understand the PVCL's aggregation behaviour in the DES environment. Our results show that DESs are generally ionic or polar protic in nature and that they promote hydrophobic interactions among the biopolymeric chains by providing a hydrophobic environment and significantly promoting the hydrophobic collapse of PVCL. It was observed in this study that the structure of DESs plays a major role in altering the lower critical solution temperature (LCST) of PVCL. Our results shows that U:LA provides the least hydrophobic environment due to its polar nature and that BET:LA exerts the most pronounced extent. The intramolecular hydrogen bonding interactions among urea molecules lead to its lower interactions with the surrounding PVCL polymer and the absence of hydrogen bonding in the betaine moiety favours the intermolecular interactions with PVCL and results in a more prominent decrease in the LCST values of the polymer. All DESs successfully modulated the LCST of PVCL through the exclusion of water molecules around the polymer and thus facilitated faster agglomeration. Notably, the LCST of BET:LA reached 27 °C. This study provides us with a new approach for drug carrier applications. [ABSTRACT FROM AUTHOR]

It has been a long‐term challenge to synthesize intrinsically flame retardant polyamide 6 (FRPA6) with high‐molecular weight. In this work, through the ring‐opening polymerization of caprolactam initiated by 9,10‐dihydro‐10‐[2,3‐di(hydroxycarbonyl)propyl]‐10 phosphaphenanthrene‐10‐oxide (DOPO‐ITA), intrinsically flame retardant PA6 with high‐molecular weight was successfully prepared. Its chemical structure, thermal stability, mechanical and combustion properties, as well as the retarding mechanism were thoroughly characterized in detail. The FRPA6 containing 3.0% retardant could achieve a V‐0 rating with an LOI value of 31.2%. An interesting phenomenon was observed during V‐0 tests. The melt drip slowly extended downward to form a long strip after moving fire, which was in favor of its heat release in a short time, thereby effectively prevented it from igniting the cotton. That is, a facile method to prepare intrinsically high‐efficiency fire retardant polymer via ring opening and polycondensation was proposed. [ABSTRACT FROM AUTHOR]

Beckmann rearrangement has been quite successful in the preparation of many medicinally potent scaffolds. In synthetic organic chemistry, the Beckmann rearrangement is quite popular, caprolactam is synthesized from cyclohexanone oxime on a large scale for Nylon‐6 production. The function of numerous catalysts and media in the Beckmann rearrangement has been discussed in depth in this review. In the last 20 years, Beckmann rearrangement catalysis has evolved from a potentially hazardous to a more environmentally friendly catalyst, as a result of greater usage. Catalytic performance and synthetic performance of various catalytic systems have been re‐evaluated in the present review article. [ABSTRACT FROM AUTHOR]

Caprolactam is in high demand in the new materials industry as a monomer for nylon and polyamides. Although the schemes of traditional processes such as hydroxylamine production (hydroxylamine sulphate oxime process, hydroxylamine phosphate oxime process, nitric oxide reduction process) and cyclohexanone production were still involved in the caprolactam production industry, the modern technical adaptations achieved higher atomic utilisation and higher selectivity. In this review, the basic traditional schemes for the production of caprolactam are for the first time presented. The modern technical adaptation, the rectification dehydrogenation of the by-product cyclohexane in cyclohexanone production, was highlighted to achieve an increase in atomic utilisation from 78 % to 98 %. The higher selectivity achieved with membrane separation resulted in a conversion of cyclohexanone of > 99.6 % and a selectivity of cyclohexanone oxime of > 99.5 %. In addition, the progress of the catalysts used in the modern technical adaptation was briefly discussed. This review highlights the modern process with atom economy and high selectivity. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, a modified torque rheometer is used to investigate the volatilization behavior of monomer and oligomers in polyamide-6 (PA6) melt under dynamic film–forming conditions with negative pressure. The surface renewal model is employed to simulate the volatilization behavior. The effects of actual processing factors and simulation results on the volatilization behavior of monomer and oligomer are analyzed comparatively. It is found that the monomer and oligomers removal rate increase continuously with increasing temperature, residence time, and rotational speed. And, the cyclic dimer, which is extremely harmful to spinning, can be removed. It is found that the removal of monomer and oligomers continued to increase with increasing temperature, residence time, and spinning speed. Moreover, cyclic dimers, which are extremely harmful to spinning, are also removed. Additionally, it is discovered that the polycondensation reaction of PA6 results in an increase in the molecular weight and viscosity at lower temperatures (250 °C), while a higher temperature (270 °C) and shear rate (150 r/min) cause a reduction in viscosity and molecular weight. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Catalytic hydrodeoxygenation (HDO) is a promising route to upgrade bio‐oils from plants or pyrolysis to basic chemicals. KA‐oil (cyclohexanol/‐one) is an example of a highly valuable feedstock for the industrial synthesis of caprolactam and perlon, which can potentially be produced via a completely sustainable route. This work investigates the alkaline promoter effects on Ni‐based catalysts for the selective HDO of lignin surrogate guaiacol using mesoporous Ni/MgO and co‐impregnated Ni‐MgO/SiO2 catalysts. Due to preferred demethoxylation by alkaline oxides and their accumulation on nickel corners, responsible for dehydration, conversion, and selectivity for KA‐oil rise. Furthermore, influences of operating parameters are investigated and optimized by design of experiments (DoE), while long‐term stability (24 h) and water resistance remain high. In a final proof of concept, the application of Ni‐CaO/SiO2 was the most promising material (U=93 %, S=86 %), demonstrating a sustainable route from lignin‐based bio‐oil to produce a bulk commodity for caprolactam synthesis. [ABSTRACT FROM AUTHOR]

Hexaethylene glycolic vinyl imidazolium (hexaEGVIM) was supported on N-vinyl caprolactam via covalent bonds through simple copolymerization to form poly caprolactam-supported hexaethylene glycol-substituted imidazolium salts (PCLS-hexaEGIM). The resulting heterogeneous PCLS-hexaEGIM promoter was active, selective, and stable for aliphatic nucleophilic substitution reactions using alkali metal salts. The alkali metal salts dramatically enhanced the reactivity of this heterogeneous catalyst with easily isolable higher product yields, reducing the formation of by-products. Therefore, nucleophilic fluorination and other substitution reactions can act as highly efficient catalysts in various sulfonyloxyalkanes and haloalkanes with regard to their corresponding fluorinated products. [ABSTRACT FROM AUTHOR]

Here we report some results on a 3 steps benzene caprolactam process via amination, aniline Hydroxymation and Beckmann rearrangement. The amination proceeds with hydroxylamine trifluoroacetate, with 97% of conversion and selectivity of 90%, catalyzed by V compounds. We achieve 98% of conversion and 95% of selectivity in the hydroxymation of aniline in the presence of hydroxylamine trifluoroacetate, sulfonic resin and Pd/C. While in the absence of the resin, hydrogenation of hydroxylamine trifluoroacetate occurs readily to the ammonium salt. The reaction occurs likely by the exchanged hydroxylamine and the aniline reduction intermediate. The use of hydroxylamine trifluoroacetate, instead of the chloride, favors the sustainability of the process by avoiding the ammonium chloride formation. The absence of salt except those derived from the trifluoroacetic acid allows a complete reuse of the trifluoroacetic acid and the only byproduct is ammonium nitrate obtained by resin regeneration. Beckmann rearrangement of the so produced cyclohexanone oxime occurs easily after diethyl ether evaporation and additions of a solution trifluoroacetic acid acetonitrile in high yield and selectivity. New three steps caprolactam process via benzene amination and aniline hydrogenation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Donghua University (Natural Science Edition) is the property of Journal of Donghua University (Natural Science) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Synthesis of cyclohexanone oxime via the cyclohexanone‐hydroxylamine process is widespread in the caprolactam industry, which is an upstream industry for nylon‐6 production. However, there are two shortcomings in this process, harsh reaction conditions and the potential danger posed by explosive hydroxylamine. In this study, we presented a direct electrosynthesis of cyclohexanone oxime using nitrogen oxides and cyclohexanone, which eliminated the usage of hydroxylamine and demonstrated a green production of caprolactam. With the Fe electrocatalysts, a production rate of 55.9 g h−1 gcat−1 can be achieved in a flow cell with almost 100 % yield of cyclohexanone oxime. The high efficiency was attributed to their ability of accumulating adsorbed hydroxylamine and cyclohexanone. This study provides a theoretical basis for electrocatalyst design for C−N coupling reactions and illuminates the tantalizing possibility to upgrade the caprolactam industry towards safety and sustainability. [ABSTRACT FROM AUTHOR]

Synthesis of cyclohexanone oxime via the cyclohexanone‐hydroxylamine process is widespread in the caprolactam industry, which is an upstream industry for nylon‐6 production. However, there are two shortcomings in this process, harsh reaction conditions and the potential danger posed by explosive hydroxylamine. In this study, we presented a direct electrosynthesis of cyclohexanone oxime using nitrogen oxides and cyclohexanone, which eliminated the usage of hydroxylamine and demonstrated a green production of caprolactam. With the Fe electrocatalysts, a production rate of 55.9 g h−1 gcat−1 can be achieved in a flow cell with almost 100 % yield of cyclohexanone oxime. The high efficiency was attributed to their ability of accumulating adsorbed hydroxylamine and cyclohexanone. This study provides a theoretical basis for electrocatalyst design for C−N coupling reactions and illuminates the tantalizing possibility to upgrade the caprolactam industry towards safety and sustainability. [ABSTRACT FROM AUTHOR]

Furfurylated wood has many advantages, such as decay resistance, dimensional stability, hardness, etc. However, furfurylation increases the brittleness and decreases the flexural resistance of wood, which greatly limits its application. Therefore, caprolactam (CPL) is incorporated with furfuryl alcohol (FA) to improve the performance of furfurylated wood. In this study, an FA and CPL combinational modifier was used to treat masson pine (Pinus massoniana Lamb.) earlywood and latewood. The synergistic interaction of both components with the wood cell walls was systematically evaluated via microstructural, chemical, and thermal analysis using scanning electron microscopy (SEM), infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometry (XPS), and differential scanning calorimetry (DSC). The SEM images showed that polymerized modifiers were distributed in tracheids, ray cells, and pits, with a higher degree of distribution in latewood tissues. The FA-CPL co-treatment led to the highest degree of distribution in cell cavities as well as of cell wall swelling. The results of the weight percentage gain (WPG) of modified wood agreed with the SEM findings that the FA-CPL co-treatment could more effectively increase the WPG than individual modification. The results of FTIR and XPS revealed that FA and CPL might chemically bind with each other as well as react with lignin and hemicellulose in the cell walls during the curing process. In addition, the interactions between modifiers and cell walls were slightly different for earlywood and latewood. DSC analysis indicated that the wood hygroscopicity decreased and the thermal stability improved after modification. [ABSTRACT FROM AUTHOR]

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The effects of compound plasticizer urea/caprolactam (UC) on the diffusion behavior of water in mixtures with poly(vinyl alcohol) (PVA) were studied using a Molecular Dynamics (MD) simulation method. Five simulation models of PVA composites with different plasticizer contents were constructed to investigate the variation of the intermolecular interaction as well as the diffusion behavior of water molecules. Results showed that the predominant interaction between the functional groups of UC and PVA consisted of hydrogen bonds. As the plasticizer content increased, diffusion coefficients of water in PVA systems increased due to the comparably weak diffusion resistance. It was also found that the rotation of the PVA chains and the small molecules became faster with increasing UC content, and the relaxation time became shorter. [ABSTRACT FROM AUTHOR]

In this work, glass fiber reinforced polyamide 6 (GF/PA6) composites were fabricated by vacuum bagging (VB) process. An experimental platform for VB process of continuous fiber reinforced polyamide 6 composites was constructed in combination with the in-situ polymerization characteristics of caprolactam. The differences in properties such as crystallinity, reaction conversion rate and mechanical properties of the composites produced by the two infusion strategies were investigated. The results showed that the composites fabricated by isothermal infusion had high crystallinity and good internal homogeneity. Compared with isothermal infusion, the mechanical properties of composites fabricated by non-isothermal infusion were higher. At a curing temperature of 150 °C, the mechanical properties of the composite were enhanced at the outlet than the inlet. Flexural strength and ILSS had been improved by 13.2% and 16.3%, respectively. The flexural strength and flexural modulus were 273.7 MPa and 14.2 GPa, respectively. ILSS of the composites reached a maximum value of 47.3 MPa at 170 °C. [ABSTRACT FROM AUTHOR]

Stimuli-responsive hydrogels are one type of smart hydrogel, which can expand/contract in water according to changes in the surrounding environment. However, it is difficult to develop flexible shapeshifting behaviours by using a single hydrogel material. This study exploited a new method to utilise single and bilayer structures to allow hydrogel-based materials to exhibit controllable shape-shifting behaviours. Although other studies have demonstrated similar transformation behaviours, this is the first report of such smart materials developed using photopolymerised N-vinyl caprolactam (NVCL)-based polymers. Our contribution provides a straightforward method in the fabrication of deformable structures. In the presence of water, the bending behaviours (vertex-to-vertex and edge-to-edge) were achieved in monolayer squares. By controlling the content and combination of the NVCL solutions with elastic resin, the bilayer strips were prepared. The expected reversible self-bending and self-helixing behaviours were achieved in specific types of samples. In addition, by limiting the expansion time of the bilayer, the layered flower samples exhibited predictable self-curving shape transformation behaviour in at least three cycles of testing. These structures displayed the capacity of self-transformation, and the value and functionality of the produced components are reflected in this paper. [ABSTRACT FROM AUTHOR]

Polylactic acid is a polyester polymer, which is recyclable and renewable as well. Membrane made of polylactic acid is acquiring attention nowadays due to its superior properties and versatility in application. This review primarily explains various synthesis routes of polylactic acid membrane and its applications. Sometimes, in membrane synthesis, polylactic acid is used with some other copolymers such as caprolactam, ethylene glycol to obtain the required functionality or property for its specific application. Some copolymers that find it helpful with polylactic acid for membrane synthesis are also discussed here with its specificity and enhanced properties. In this review, precise and detailed PLA membrane structure and its degradation mechanism is discussed. [ABSTRACT FROM AUTHOR]

Smart PVCL‐based nanogels for photosensitizers were prepared following the thermo precipitation methodology. PVCL‐based imprinted and non‐imprinted NGs are reported with different percentages of N,N′‐methylenebisacrylamide (BIS) as crosslinker agent. Zn(II)phthalocyanine (ZnPc) is employed as a model photosensitizer and incorporated as a template molecule for imprinted NGs or it loads post‐synthesis for non‐imprinted NGs. In order to analyze the chemical structure, NGs were characterized using infrared microscopy. Hydrodynamic diameter was determined by dynamic light scattering. The phase transition temperature was measured by UV–vis spectroscopy. The phase transition temperature and Dh values were regulated by the percentage of crosslinker and the presence of the photosensitizer as a template or post‐synthesis load. In all cases, the yields were acceptable and the smart nanodevices were stable. [ABSTRACT FROM AUTHOR]

The supply, demand and price trend of caprolactam industry in China in recent 5 years are studied. In 2021, the domestic caprolactam production capacity is 5 580 kt, the output is about 4 060 kt, the imports is about 106 kt, the exports is about 3.6 kt, and the apparent consumption is about 4 160 kt. The price trend of caprolactam is mainly affected by cost and supply and demand structure. It is estimated that the domestic caprolactam production capacity is expected to reach 8 790 kt, and the market competition will further intensify by 2026. It is suggested that the industry should effectively strengthen caprolactam technology investment and technological innovation, coordinate the development plans and policies of caprolactam and PA6 chips industry, enhance the value of sulfur in ammonium sulfate and strengthen the promotion of PA6 products. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have developed a method for synthesizing novel helical amide derivatives. Nucleophilic primary amines were inserted into benzo-fused 2,2′-biphenoquinones to form helical amides containing seven-membered rings. When optically pure primary amines were used in this reaction, a mixture of two amide diastereoisomers was obtained and separated into diastereomerically pure products by high-performance liquid chromatography. In contrast, the reaction of enantiomerically pure benzo-fused 2,2′-biphenoquinones with achiral aliphatic primary amines afforded enantiomerically pure helical amides with stereospecificity and retention of configuration. [ABSTRACT FROM AUTHOR]

Poly(N-vinylamide) derivatives were synthesized to improve the performance of kinetic hydrate inhibitors (KHIs). In this work, we synthesized poly(N-vinylformamide) (PNVF) and poly(N-vinylcaprolactam) (PVCap) by free radical polymerization with several commercial chain transfer agents (CTAs), which afforded a few thousand Mn. The structures of synthesized PNVF and PVCap were then investigated by 1H NMR and MALDI-TOF/MS spectrograms. KHI properties of the synthesized PNVF and PVCap polymers were also evaluated by the high-pressure slow constant cooling KHI test method. Some of the tested polymers showed a better KHI effect than PVCap. [ABSTRACT FROM AUTHOR]

Biochar-based Fe–Ce bimetallic Fenton-like heterogeneous catalyst was prepared and applied to the degradation of wastewater produced during the synthesis of caprolactam (wastewater-CPL) in the presence of micro-nano bubbles (MNB). The prepared materials were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS), which confirmed the successful loading of Fe and Ce and the formation of Fe2O3 and CeO2. The treatment effects of different reaction systems were compared, indicating that biochar-based catalyst + H2O2 + MNB system had the best treatment effect that the COD removal rate can reach 93.26%. The influencing factors of the system were discussed, and finally it was concluded that the condition of Fe:Ce was 3:1, hydrogen peroxide concentration was 1.2 M, pH was 2, catalyst dosage was 1 g/L, and temperature was 35 ℃. The treatment effects of adding MNB were compared; the treatment effect of MNB + H2O2 on wastewater was about 60% higher than that of H2O2 alone. The reusability of the catalyst was determined, and it was observed that high catalytic performance could be retained after five cycles. Finally, the water quality of the effluent was analyzed, and it was proved that the treatment of wastewater-CPL had a good effect. This study provided a new idea for the treatment of wastewater-CPL. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, doxorubicin (Dox)-encapsulated poly(vinyl caprolactam) (PVCL)-based three-dimensional nanogel networks were developed and were crosslinked with disulfide linkages. The nanogels degrade rapidly to low molecular weight chains in the presence of the typical intracellular concentration of glutathione. Doxorubicin (Dox) was successfully encapsulated into these nanogels. The nanogels have a high drug loading of 49% and can be tailored to 182 nm to deliver themselves to the targeted cells and release Dox under dual stimuli conditions, such as redox and temperature. By evaluating cell viability in the HepG2 cell line, we observed that Dox-loaded nanogels effectively killed the cancer cell. Fluorescence microscopy results show that the nanogels could easily be internalized with HepG2 cells. The results confirm that the nanogels destabilized in intracellular cytosol via degradation of disulfide bonds in nanogels networks and release of the Dox nearby the nucleus. These carriers could be promising for cancer drug delivery. [ABSTRACT FROM AUTHOR]

Cationic dyeable polyamide 6 (CD-PA6) fiber, as a novel functional polyamide 6 (PA6) fiber, conforms to people's requirements for fashion clothing. However, due to the limitation of the hetero-end groups after caprolactam hydrolysis, it is difficult to introduce comonomers into the PA6 molecular chain to prepare PA6-based polymers with a certain molecular weight and maintain the original physical properties and spinnability. In this paper, through molecular design of PA6 segments, 5-sulfoisophthalic acid monosodium salt (5-SSIPA) was introduced into PA6 by copolymerization, and a CD-PA6 masterbatch with an addition amount of 10 wt% was prepared. CD-PA6 were prepared by blending with pure PA6 with masterbatch technology. The melt-spinning method was used to prepare CD-PA6 filaments, and they were woven into fabrics. The results show that the CD-PA6 masterbatch and PA6 have good blending compatibility. CD-PA6 filaments and fabrics maintain the excellent physical properties of PA6. When the addition amount of 5-SSIPA is 3%, the dye uptake rate of the cationic pigment exceeds 90%, and it has color affinity and excellent color fastness. [ABSTRACT FROM AUTHOR]

The basic structure,types,properties and future research directions of polyamide thermoplastic elastomer are reviewed,and the synthesis method of polyamide thermoplastic elastomer is emphasized. The synthetic methods of polyamide thermoplastic elastomers mainly include the following: dibasic acid synthesis method, isocyanate synthesis method, anionic polymerization synthesis method, one-step synthesis method, transesterification method, dynamic vulcanization process. For each synthesis method, the existing problems are explained separately, and solutions to the corresponding problems are proposed. As a new type of thermoplastic elastomer, polyamide elastomer has excellent physical and chemical properties, such as good flexibility, high tensile strength, high low-temperature impact resistance, chemical resistance and weather resistance, and easy processing molding, applicable to various fields, is a major mainstream of thermoplastic elastomers in the future. At present, my country's demand for polyamide elastomers is increasing year by year,but the domestic industrialization of the elastomers has not yet been popularized. Therefore, it is of great value to develop a green, environmentally friendly and industrialized synthetic process in the future. [ABSTRACT FROM AUTHOR]

Caprolactam wastewater (WCP), which is generated during the production of caprolactam, contains high contents of NO3− and inorganic P and is considered to be difficult to treat. In this study, Arthrospira platensis was used to remove N and P from WCP. Culture conditions and wastewater addition were optimized to relieve the inhibition effects of WCP. The results show that A. platensis growth and photosynthetic activity were inhibited depending on WCP concentrations. The inhibition rates were enhanced as the culture time increased under batch mode. However, the fed-batch mode significantly minimized the negative impact on A. platensis, which is beneficial for removing N and P from WCP by Arthrospira. After 10 d of cultivation of A. platensis in a 25 L circular photobioreactor in fed-batch addition of WCP (1.25% mixed WCP (v/v) each day), the average biomass productivity reached 17.48 g/(m2·d), the maximum protein content was 69.93%, and the N and P removal ratios were 100%. The accumulation effect of WCP inhibition on algal growth was not observed under this culture condition. Fed-batch cultivation of A. platensis is a promising way for bioremediation of WCP with high N and P removal efficiencies and high value-added biomass production. [ABSTRACT FROM AUTHOR]

In this work we studied the reactivity of the Trifluoroacetic acid hydroxylamine system in the one step salt free synthesis of amides from ketones. A particular regards was paid to the caprolactam synthesis because of its industrial relevance. Synthesis, reactivity and characterization of the hydroxylamine trifluoroacetate is given. Fast oximation reaction of several ketones was gained at room temperature (1 h of reaction quantitative conversion for several ketones). In the same reactor, by raising the temperature at 383 K, the Beckmann rearrangement of the so obtained oximes is easily accomplished in the presence of three equivalent of TFA. The possibility of obtaining the trifluoroacetate of the hydroxylamine with a modified nitric acid hydrogenation reactions was verified, too. Reuse of solvent and trifluoroacetic acid is easily achieved by distillation. Salt free one-pot caprolactam and amides process catalyzed by CF3COOH, in the presence of NH2OH TFA as the oximation agent. [ABSTRACT FROM AUTHOR]