A Tunable Hydrophilic-Hydrophobic, Stimulus Responsive, and Robust Iridescent Structural Color Bionic Film with Chiral Photonic Crystal Nanointerface.

Bio-inspired in nature, using nanomaterials to fabricate the vivid bionic structural color and intelligent stimulus responsive interface as smart skin or optical devices are widely concerned and remain a huge challenge. Here, the bionic flexible film is designed and fabricated with chiral nanointerface and tunable hydrophilic-hydrophobic by the ultrasonic energy perturbation strategy and crosslinking of the cellulose nanocrystals (CNC). An intelligent nanointerface with adjustable hydrophilic and hydrophobic properties is constructed by the supramolecular assembly using a smart ionic liquid molecule. The bionic flexible film possessed the variable hydrophilic-hydrophobic, stimulus responsive, and robust iridescent structural color. The reflective wavelength and the helical pitch of the film can be easily modulated through the ultrasonic energy perturbation strategy. The bionic flexible film by covalent cross-linking has excellent robustness, good elasticity and flexibility. The tunable brilliant structural color of the chiral nanointerface is attributed to the surface charge change of the CNC photonic crystal, which is disturbed by ultrasonic energy perturbation. The bionic flexible film with tunable structure color has intelligent hydrophilic and hydrophobic stimulus response properties. The chiral bionic materials have potential applications in smart skin, optical devices, bionic materials, robots, anti-counterfeiting, colorful displays, and stealth materials.

MFGAN: Multimodal Fusion for Industrial Anomaly Detection Using Attention-Based Autoencoder and Generative Adversarial Network.

Anomaly detection plays a critical role in ensuring safe, smooth, and efficient operation of machinery and equipment in industrial environments. With the wide deployment of multimodal sensors and the rapid development of Internet of Things (IoT), the data generated in modern industrial production has become increasingly diverse and complex. However, traditional methods for anomaly detection based on a single data source cannot fully utilize multimodal data to capture anomalies in industrial systems. To address this challenge, we propose a new model for anomaly detection in industrial environments using multimodal temporal data. This model integrates an attention-based autoencoder (AAE) and a generative adversarial network (GAN) to capture and fuse rich information from different data sources. Specifically, the AAE captures time-series dependencies and relevant features in each modality, and the GAN introduces adversarial regularization to enhance the model's ability to reconstruct normal time-series data. We conduct extensive experiments on real industrial data containing both measurements from a distributed control system (DCS) and acoustic signals, and the results demonstrate the performance superiority of the proposed model over the state-of-the-art TimesNet for anomaly detection, with an improvement of 5.6% in F1 score.

Self-Assembled Nanodot Actuator with Changeable Fluorescence by π-π Stacking Force Based on a Four-Armed Foldable Phthalocyanine Molecule and Its Supersensitive Molecular Recognition.

Designing intelligent molecules and smart nanomaterials as molecular machines is becoming increasingly important in the nanoscience fields. Herein, we report a nanodot actuator with changeable fluorescence by π-π stacking force based on a four-armed foldable phthalocyanine molecule. The assembled nanodot possessed a three-dimensional molecular space structure and multiple supramolecular interactions. The arms of the nanodot could fold and open intelligently in response to environmental molecular stimuli such as natural plant mimosa, which could lead to multiple variable fluorescence emissions. The nanodot was highly sensitive to the biomolecule thyroxine at the molecular level. The accurate molecular recognition and the changeable fluorescence conversion of the nanodot were attributed to multiple supramolecular interactions, including photoinduced electron transfer (PET), intramolecular fluorescence resonance energy transfer (FRET), and π-π stacking of the nanodots, resulting in an intelligent "nanodot machine with folding arms". The self-assembled nanodot actuators with changeable fluorescence have potential applications in advanced intelligent material fields.

A Fast Algorithm for 2D DOA Estimation Using an Omnidirectional Sensor Array.

The traditional 2D MUSIC algorithm fixes the azimuth or the elevation, and searches for the other without considering the directions of sources. A spectrum peak diffusion effect phenomenon is observed and may be utilized to detect the approximate directions of sources. Accordingly, a fast 2D MUSIC algorithm, which performs azimuth and elevation simultaneous searches (henceforth referred to as AESS) based on only three rounds of search is proposed. Firstly, AESS searches along a circle to detect the approximate source directions. Then, a subsequent search is launched along several straight lines based on these approximate directions. Finally, the 2D Direction of Arrival (DOA) of each source is derived by searching on several small concentric circles. Unlike the 2D MUSIC algorithm, AESS does not fix any azimuth and elevation parameters. Instead, the adjacent point of each search possesses different azimuth and elevation, i.e., azimuth and elevation are simultaneously searched to ensure that the search path is minimized, and hence the total spectral search over the angular field of view is avoided. Simulation results demonstrate the performance characters of the proposed AESS over some existing algorithms.

A multi-scale layered helical structure composite using the co-dispersion of cellulose nanocrystals and the micro-nano Al sheets and its efficient near-infrared stealth performance.

To design flexible functional materials with high efficiency, light weight, less metal consumption, stable structure for the thermal infrared stealth materials is a great challenge. We hypothesized that the use of crystal materials with different sizes to design composites with a chiral layered helical structure, the layered structures can repeatedly reflect infrared ray. Here, we reported the novel multi-scale layered helical chiral structure composite by self-assembly using the co-dispersion of cellulose nanocrystals (CNC) and micro-nano Al sheets. A new stable interlocking supermolecular structure is formed between the positively charged metal sheet and the negatively charged CNC photonic crystals. Metal sheets and CNC organic crystals were hybridized at the molecular level and form the Pickering-like CNC-Al co-dispersion system. The metal sheets in CNC chiral helical layered structure greatly improve its near-infrared reflection and stealth camouflage. Surprisingly, the CNC/Al composite on the heated glass substrate enabled the temperature drop 23 °C, and made its emissivity in the range of 7-14 µm significantly reduce. The synergetic effect of the Al sheets and the CNCs helical structure greatly improved the thermal infrared reflection and heat insulation properties. It is expected to provide a chiral layered material for the infrared stealth, and pattern camouflage fields.

Exploring the distribution and co-occurrence of rpf-like genes and nitrogen-cycling genes in water reservoir sediments.

Water reservoir sediments represent a distinct habitat that harbors diverse microbial resources crucial for nitrogen cycling processes. The discovery of resuscitation promoting factor (Rpf) has been recognized as a crucial development in understanding the potential of microbial populations. However, our understanding of the relationship between microorganisms containing rpf-like genes and nitrogen-cycling functional populations remains limited. The present study explored the distribution patterns of rpf-like genes and nitrogen-cycling genes in various water reservoir sediments, along with their correlation with environmental factors. Additionally, the co-occurrence of rpf-like genes with genes associated with the nitrogen cycle and viable but non-culturable (VBNC) formation was investigated. The findings indicated the ubiquitous occurrence of Rpf-like domains and their related genes in the examined reservoir sediments. Notably, rpf-like genes were predominantly associated with Bradyrhizobium, Nitrospira, and Anaeromyxobacter, with pH emerging as the primary influencing factor for their distribution. Genera such as Nitrospira, Bradyrhizobium, Anaeromyxobacter, and Dechloromonas harbor the majority of nitrogen-cycling functional genes, particularly denitrification genes. The distribution of nitrogen-cycling microbial communities in the reservoir sediments was mainly influenced by pH and NH4 +. Notably, correlation network analysis revealed close connections between microorganisms containing rpf-like genes and nitrogen-cycling functional populations, as well as VBNC bacteria. These findings offer new insights into the prevalence of rpf-like genes in the water reservoir sediments and their correlation with nitrogen-cycling microbial communities, enhancing our understanding of the significant potential of microbial nitrogen cycling.

Preparation of high-performance monoazo disperse dyes bearing ester groups based on benzisothiazole and their dyeing performance on polyester fabrics.

To obtain high-performance disperse dyes, a series of azo disperse dyes containing different kinds of ester groups based on benzisothiazole were synthesized by the coupling reaction of diazotization of 3-amino-5-nitro [2,1] benzisothiazole with N-substituted aniline compounds bearing different ester moieties. The structures of the synthesized dyes were evaluated using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance techniques (1H-NMR), and MS analysis. UV-Vis spectrophotometry methods were applied to study absorption maxima, molar extinction coefficients, and solvatochromic behaviors of the dyes, and time-dependent density functional theory (TD-DFT) simulations were applied to reveal the nature of the absorption spectrum properties. Polyester fabrics were colored using a high-temperature dyeing method under pressure, and the dyed fabrics exhibited deep and bright intense blue hues. In addition, excellent fastness properties, including washing fastness, sublimation fastness, rubbing fastness, and light fastness, were achieved.

Unlocking the potential of resuscitation-promoting factor for enhancing anaerobic microbial dechlorination of polychlorinated biphenyls.

Microbial dechlorination of polychlorinated biphenyls (PCBs) is limited by the slow growth rate and low activity of dechlorinators. Resuscitation promoting factor (Rpf) of Micrococcus luteus, has been demonstrated to accelerate the enrichment of highly active PCB-dechlorinating cultures. However, it remains unclear whether the addition of Rpf can further improve the dechlorination performance of anaerobic dechlorination cultures. In this study, the effect of Rpf on the performance of TG4, an enriched PCB-dechlorinating culture obtained by Rpf amendment, for reductive dechlorination of four typical PCB congeners (PCBs 101, 118, 138, 180) was evaluated. The results indicated that Rpf significantly enhanced the dechlorination of the four PCB congeners, with residual mole percentages of PCBs 101, 118, 138 and 180 in Rpf-amended cultures being 16.2-29.31 %, 13.3-20.1 %, 11.9-14.4 % and 9.4-17.3 % lower than those in the corresponding cultures without Rpf amendment after 18 days of incubation. Different models were identified as appropriate for elucidating the dechlorination kinetics of distinct PCB congeners, and it was observed that the dechlorination rate constant is significantly influenced by the PCB concentration. The supplementing Rpf did not obviously change dechlorination metabolites, and the removal of chlorines occurred mainly at para- and meta- positions. Analysis of microbial community and functional gene abundance suggested that Rpf-amended cultures exhibited a significant enrichment of Dehalococcoides, Dehalogenimonas and Desulfitobacterium, as well as non-dechlorinators belonging to Desulfobacterota and Bacteroidetes. These findings highlight the potential of Rpf as an effective additive for enhancing PCB dechlorination, providing new insights into the survival of functional microorganisms involved in anaerobic reductive dechlorination.

Application of Transfer Learning and Feature Fusion Algorithms to Improve the Identification and Prediction Efficiency of Premature Ovarian Failure.

Ultrasound imaging technology has the advantages of noninvasiveness, real-time, low price, and easy operation. It is one of the most used diagnostic tools for early detection and classification of premature ovarian failure. Although the rapid development of computer-aided diagnosis has provided a great help to the ultrasound diagnosis of premature ovarian failure, it still has many limitations and shortcomings, so this paper adopts transfer learning and feature fusion algorithms to improve the identification and prediction efficiency of premature ovarian failure. In this study, the POF group and the control group both adopted a unified scale. From the four aspects of sociological characteristics, past medical history, environmental factors, and living habits, a dedicated person asked and filled out the scale face to face. All patients participating in the experiment underwent ultrasound examinations. In this paper, the bottom-level feature fusion method is used to improve classification performance. The experiment uses 100 epochs. After each epoch training is completed, we used all the data and labels of the target domain to test. All experiments were performed five times, and the result is the average of five experiments. All the results of baseline and direct classification without migration use the average of five experimental results as the result. Migrating the features extracted by the InceptionV3 network has the best performance for predicting premature ovarian failure. Its classification accuracy is as high as 85.13%, and the F1 value is 0.78. The results show that the migration learning and feature fusion algorithms used in this paper can provide reliable predictive analysis and decision support for doctors in the diagnosis of premature ovarian failure.

On Fatigue Detection for Air Traffic Controllers Based on Fuzzy Fusion of Multiple Features.

Fatigue detection for air traffic controllers is an important yet challenging problem in aviation safety research. Most of the existing methods for this problem are based on facial features. In this paper, we propose an ensemble learning model that combines both facial features and voice features and design a fatigue detection method through multifeature fusion, referred to as Facial and Voice Stacking (FV-Stacking). Specifically, for facial features, we first use OpenCV and Dlib libraries to extract mouth and eye areas and then employ a combination of M-Convolutional Neural Network (M-CNN) and E-Convolutional Neural Network (E-CNN) to determine the state of mouth and eye closure based on five features, i.e., blinking times, average blinking time, average blinking interval, Percentage of Eyelid Closure over the Pupil over Time (PERCLOS), and Frequency of Open Mouth (FOM). For voice features, we extract the Mel-Frequency Cepstral Coefficients (MFCC) features of speech. Such facial features and voice features are fused through a carefully designed stacking model for fatigue detection. Real-life experiments are conducted on 14 air traffic controllers in Southwest Air Traffic Management Bureau of Civil Aviation of China. The results show that the proposed FV-Stacking method achieves a detection accuracy of 97%, while the best accuracy achieved by a single model is 92% and the best accuracy achieved by the state-of-the-art detection methods is 88%.

Extraction of Natural Dye from Aerial Parts of Argy Wormwood Based on Optimized Taguchi Approach and Functional Finishing of Cotton Fabric.

The aerial parts of the Argy Worm Wood (AWW) plant have been used in different Chinese foods as a colorant and a taste enhancer for a long time. Despite its application as a food colorant, it has rarely been considered for the coloration of textiles. Keeping in mind the variation in color strength due to the change in phytochemical contents by seasonal change and other variables, the extraction of AWW aerial parts was optimized using the Taguchi method. Optimization was performed on the basis of total phytochemical contents (phenols, flavonoids, and tannins) in the extracted solutions. For this purpose, two different solvent systems, namely sodium hydroxide/water (NaOH/water) and ethanol/water (EtOH/water), were applied through a simple aqueous extraction method at varying levels of solvent concentration, and extraction temperature and duration. Maximum phytochemicals yield of 21.96% was obtained using NaOH/water system with 9 g/L NaOH/water at 85 °C for 20 min and 25.5% with 75% aqueous ethanol at 85 °C for 40 min. Optimized extracts were characterized by UV-Vis and FTIR spectrophotometry, which showed the presence of multiple phytochemicals in the extracts. The dyeing temperature and time were also optimized. Dyed cotton fabrics showed medium to high colorfastness to washing and excellent antibacterial and UV radiation absorption properties. The effect of pre-mordanting with salts of iron and copper was also studied on the color fastness properties. Cotton fabrics dyed with two different solvent system extracts displayed various shades of brown with NaOH/water, and green with aqueous ethanol with and without pre-mordanting. The present study provides the textile industry with a promising source of functional bio-colorant and a value-adding approach for the AWW plant industry.

Assembly of a Fluorescent Chiral Photonic Crystal Membrane and Its Sensitive Responses to Multiple Signals Induced by Small Molecules.

Chiral liquid crystal materials that are responsive to environmental stimuli are in demand. A chiral photonic crystal membrane based on cellulose nanocrystals (CNCs) was prepared by molecule assembly in the present work. A fluorescent molecule containing a cationic group, [N-(3-N-benzyl-N,N-dimethylpropyl ammonium chloride)-1,8-naphthalimide]hydrazine, was assembled on the surface of the CNCs. The new chiral photonic crystal membrane possesses supersensitive multiresponses to small molecules, such as water and formaldehyde molecules. The appearance, liquid crystal texture, fluorescence, and color of the chiral membrane have sensitive changes induced by small molecules. By increasing RH from 30 to 100%, the reflectance peak of the membrane red-shifted from 498 to 736 nm. In particular, the iridescent texture and fingerprint structure of the membrane could change markedly under trace amounts of formaldehyde, and the chiral membrane can form an extremely sensitive off-on fluorescence switch. The relationship between the fluorescence intensity and the trace concentration of formaldehyde satisfied the linear equation with the association coefficient of 0.9997. The changes in fluorescence and color are visible to the naked eye, and the membrane can quantitatively recognize trace formaldehyde at a molecular level in a humid environment. The mechanism by which the fluorescence switch operates was investigated using density functional theory at the B3LYP/6-31G(d) level. The membrane has potential for use in the fields of advanced functional materials and biomaterials.

Light- and Humidity-Responsive Chiral Nematic Photonic Crystal Films Based on Cellulose Nanocrystals.

Light- and humidity-responsive chiral nematic photonic crystal (PC) films containing cellulose nanocrystals (CNCs) were fabricated. A photoactive polymer with hydrophilic groups, poly-(3,3'-benzophenone-4,4'-dicarboxylic acid dicarboxylate polyethylene glycol) ester, was coassembled with CNCs to form flexible iridescent films with a tunable chiral nematic order. In the coassembly process, the intermolecular hydrogen bonds of CNCs were weakened, which facilitated the fine regulation of the chiral PC nanostructure. The PC films displayed sensitive responses to both light and humidity. With increasing humidity from 30 to 100%, the chiral nematic helix pitch increased from 328 to 422 nm. The color of the PC films changed from blue to green, yellow, orange, and dark red with increasing relative humidity. Over 15 min of light irradiation, the absorption intensity of the films increased gradually. The light and humidity responses of the films were reversible. The films maintained their variable cholesteric liquid crystal texture and helical lamellar structure after light irradiation at different humidities. These PC films are expected to be useful in intelligent coatings and 3D printing.

Light-Induced Production of Reactive Oxygen Species by a Novel Water-Soluble Benzophenone Derivative Containing Quaternary Ammonium Groups and Its Assembly on the Protein Fiber Surface.

Developing an efficient antimicrobial surface has important significance in the field of advanced biomaterials. A novel water-soluble benzophenone tetracarboxylamine derivative containing two quaternary ammonium groups, 3,3'-[4,4'-carbonyl-diphthalimide-]-bis(N-benzyl-N,N-dimethyl-N-propyl-1-aminium)dichloride (BPTCA-N), as a photoactive antibacterial agent was designed and synthesized. The ability of BPTCA-N to generate reactive oxygen species (ROS) in solution was investigated by light-induced activity. Its antibacterial activity in a dark environment or UV exposure was tested on Staphylococcus aureus and Escherichia coli. The influences of different solvents and the pH values on the ability of BPTCA-N to generate ROS were also discussed. BPTCA-N possessed high photoactivity and efficient ROS generation ability. The generation of hydroxyl radicals could be greatly affected by addition of other solvents and H+ or OH-. For the BPTCA-N solution at a concentration of 0.2 mmol/L, the reduction of S. aureus and E. coli could all reach 99.99%. The BPTCA-N compound was assembled onto wool protein fibers. The modified protein fabrics also showed excellent photoactivity and antibacterial property against S. aureus and E. coli. For the wool fabric modified with 30 g/L of BPTCA-N, the reduction of S. aureus could reach 99.91% and that of E. coli was 91.23%. BPTCA-N had the synergistic antibacterial effect of quaternary ammonium salt and benzophenones. It has potential application in the biomedical field as highly effective antimicrobial agent or antimicrobial biomaterial.

Efficient antimicrobial silk composites using synergistic effects of violacein and silver nanoparticles.

Violacein, a natural violet biopigment with efficient bioactivities from Gram-negative bacteria, possesses good affinity to silk fiber and complexes with silver. In this paper, a new approach involving the surface modification of silk fabrics with violacein for the in-situ synthesis of silver nanoparticles (SNPs) was developed. Violacein is used to modify silk material. Subsequently, silk containing bio-violacein was in situ assembled by silver ions and formed SNPs. Functional silk composites (FSC) containing bio-violacein and SNPs were obtained with effective synergistic antimicrobial effects. FSC were characterized by FT-IR spectroscopy, UV-visible absorption spectroscopy, and scanning electron microscopy/energy dispersive spectroscopy, and X-ray diffraction. Exhaustion and amount of violacein on silk fabric were 65.82% and 0.16 g/g, respectively. SNPs were small particles with irregular shapes and sizes <60-70 nm. Antimicrobial activities of the FSC were evaluated against S. aureus, E. coli, and C. albicans. The silk fabric with violacein possessed good antimicrobial activity against S. aureus, with a bacterial reduction of 81.25%. FSC with violacein combined with SNPs integration exhibited good synergistic properties as excellent antimicrobial activities against S. aureus, E. coli, and C. albicans, with microbial reductions of 99.98%, 99.90%, and 99.85%, respectively. FSC not only exhibited the enhanced antimicrobial effects but also exhibited a broadened antimicrobial range.

Functional modification of cellulose fabrics with phthalocyanine derivatives and the UV light-induced antibacterial performance.

Cellulose fabrics were modified with a derivative of copper phthalocyanine (Reactive Blue C.I. 21) by dyeing method. The modified cellulose fabrics exhibited important photoactive property, such as the hydroxyl radicals-generating ability. The UV-vis spectrum, exhaustion rate, fixation rate and grafting quantity of Reactive Blue 21 on the cellulose fabrics were measured and calculated. The chemical structure and morphology of the modified cellulose were characterized. The amount of the produced hydroxyl radicals was measured and the photoactive mechanism was discussed. The UV light-induced antibacterial performance of the modified materials was measured. The modified cellulose exhibited photo-induced antibacterial activity against both Staphylococcus aureus and Escherichia coli.

Lentivirus-mediated miR-23a overexpression induces trophoblast cell apoptosis through inhibiting X-linked inhibitor of apoptosis.

Preeclampsia (PE) is a pregnancy-specific disorder representing a major cause of maternal and perinatal morbidity and mortality. MicroRNAs (miRNAs) have emerged as critical regulators in PE. However, the precise role of miRNAs in PE remains poorly understood. In this study, we aimed to investigate the potential role of miR-23a and the underlying mechanism in regulating trophoblast cell apoptosis. We found a significant increase of miR-23a expression in placental tissues from PE patients. Lentivirus-mediated miR-23a overexpression significantly induced apoptosis in trophoblast cells in vitro. X-linked inhibitor of apoptosis (XIAP) was identified as a target gene of miR-23a by bioinformatics analysis and dual-luciferase reporter assay. Overexpression of miR-23a significantly inhibited XIAP expression. Knockdown of XIAP also induced trophoblast cell apoptosis. Moreover, restoration of XIAP expression significantly abolished the miR-23 overexpression-induced trophoblast cell apoptosis. Taken together, our study demonstrates that miR-23a induces trophoblast cell apoptosis by inhibiting XIAP, which may contribute to PE. Our findings provide novel insights into understanding the pathogenesis of PE and suggest a potential therapeutic target in PE.

UV Light-Induced Generation of Reactive Oxygen Species and Antimicrobial Properties of Cellulose Fabric Modified by 3,3',4,4'-Benzophenone Tetracarboxylic Acid.

3,3',4,4'-Benzophenone tetracarboxylic acid (BPTCA) could directly react with hydroxyl groups on cellulose to form ester bonds. The modified cotton fabrics not only provided good wrinkle-free and ultraviolet (UV) protective functions, but also exhibited important photochemical properties such as producing reactive oxygen species (ROS) including hydroxyl radicals (HO(•)) and hydrogen peroxide (H2O2) under UV light exposure. The amounts of the produced hydroxyl radical and hydrogen peroxide were measured, and photochemical reactive mechanism of the BPTCA treated cellulose was discussed. The results reveal that the fabrics possess good washing durability in generation of hydroxyl radicals and hydrogen peroxide. The cotton fabrics modified with different concentrations of BPTCA and cured at an elevated temperature demonstrated excellent antimicrobial activities, which provided 99.99% antibacterial activities against both E. coli and S. aureus. The advanced materials have potential applications in medical textiles and biological material fields.

Preparation of multi-functional cellulose containing huge conjugated system and its UV-protective and antibacterial property.

A novel Schiff base containing huge azo conjugated system and reactive groups, 3,5-bis{2-hydroxyphenyl-5-[(2-sulfate-4-sulfatoethylsulfonyl-azobenzol)methylene amino]}benzoic acid (BHSABA) was applied to modify cellulose. Exhaustion and grafting reactive rate, and grafting quantity of BHSABA on cellulose were calculated. The chemical structure of the modified cellulose was characterized and thermal degradation and morphology were also investigated. The UV protection and antibacterial properties were measured. With increasing the concentration of BHSABA, grafting quantity of BHSABA on cellulose increased from 1.52 × 10(-2)mmol/g to 5.08 × 10(-2)mmol/g. The multi-functional cellulose fabrics had excellent UV-protective property, which possessed very high UPF value and very low ultraviolet transmittance. The UPF values exceeded 50 and the ultraviolet transmittances were all less than 1%. They also exhibited moderate activity against Staphylococcus aureus and after 10 times washing still maintained antibacterial activity. The onsets of degradation slightly decreased. With increasing the grafting quantity of BHSABA on cellulose, mass loss yields of the residues increased. The morphological structure had no noticeable change.

Multifunctional finishing of cotton fabrics with 3,3',4,4'-benzophenone tetracarboxylic dianhydride: reaction mechanism.

Aqueous solutions of 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BPTCD) were successfully employed in treatment of cotton fabrics to bring multiple functions onto the cotton cellulose. The overall reaction mechanism of the chemical finishing process was investigated. Results revealed that the dianhydride groups of BPTCD were hydrolyzed to tetracarboxylic acid groups, and the acid could directly react with hydroxyl groups on cellulose under the catalyst sodium hypophosphite to form ester bonds. Such a mechanism is different from the mostly recognized formation of anhydride from polycarboxylic acid and then esterification between the anhydride with hydroxyl groups. FTIR, DSC and thermogravimetric analyzer (TGA) were employed in the analysis of the reactions, respectively.