Search

The microencapsulation of flame retardants can avoid the problems of water absorption and loss. In this paper, hydrophobic microcapsule-encapsulated ammonium polyphosphate (HMAPP) was prepared by ion exchange and Stöber method and applied to the preparation of hydrophobic flame-retardant kraft paper by impregnation. The microscopic morphology and element analysis of the hydrophobic microcapsules tested by TEM and SEM showed that nano-scale particles with a size of about 100 nm have been successfully prepared, and the core–shell structure has been formed. HMAPP constructed a rough structure with low surface energy on the surface of kraft paper and provided the kraft paper with hydrophobic property. The water contact angle of kraft paper reached 122.7 ° after treated by HMAPP, while it also enhanced the physical strength of the paper. Kraft had the self-extinguishing phenomenon after treated by HMAPP, which attached to the surface of kraft paper were heated and melted to release ammonia to dilute combustible gas and oxygen, and formed a flame-retardant layer containing SiO2 particles, phosphoric acid, metaphosphoric acid, pyrophosphoric acid, and carbon flakes on the fiber surface. There were C–C, C–O–C bonds in the carbon layer after flame-retardant treatment, indicating that the pentose contained in fiber has not been completely destroyed. In addition, the presence of Si and P elements in the residual carbon indicates that the decomposed flame retardant adheres to the surface of the fiber to block the heat transfer and flame spread. [ABSTRACT FROM AUTHOR]

Poplar wood underwent a two-step pressure impregnation with phytic acid-iron and epichlorohydrin-chitosan to boost its flame retardancy while mitigating the loss and mechanical performance issues of conventional treatments. Through chelation and grafting reactions, the stable existence of double chelated transition metal network macromolecules (DCMC) inside the wood was promoted under external heating conditions. Flame retardancy tests, thermal stability analysis, characterization of microstructure and element distribution, functional groups and gas composition analysis showed that the limiting oxygen index of the wood after flame-retardant treatment was significantly improved, with DCMC-Poplar reaching 31.9, and it also met the flame-retardant requirements after the anti-leaching test. Compared to Poplar, the peak heat release rate (HRR) of DCMC-Poplar can be reduced by up to 43.4 %. Under nitrogen and air atmospheres, the residual carbon of DCMC-Poplar, 38.53 % and 20.64 % respectively, was significantly higher than that of untreated poplar, retaining a relatively intact microstructure after combustion. DCMC inhibited the spread of flames and heat transfer by promoting rapid carbonization of the wood material to form a strong flame-retardant layer. Fe3+ catalyzed oxidation to fully combustible gases under low oxygen conditions, reducing the harmfulness of smoke during wood combustion. DCMC were successfully grafted into the wood through C-N bonds, improving the flame retardancy of the wood while avoiding the drawbacks of easy loss and mechanical strength reduction of flame retardants. • Double chelated transition metal macromolecules was synthesized inside the micropores of wood. • DCMC-Poplar had a 39.99 % reduction in total heat releasee (THR)relative to Poplar and an increase in char yield to 38.5 %. • The gas emission behaviors had been elucidated. [ABSTRACT FROM AUTHOR]

To improve the flame retardant performance of plywood and reduce the reagent loss and moisture absorption of the flame retardant, a bio‐based supramolecular flame retardant is prepared by vacuum‐pressure impregnation and high‐temperature in situ polymerization in plywood. The best value of bonding strength appears at 170 °C, and the limiting oxygen index (LOI) of 170BF‐B plywood is 42.3%. After hot pressing, the moisture absorption rate of the 170BF‐B veneer is only 18.51%, while the loss resistance rate achieves 83.45%. Its residue at 700 °C is 91.36% higher than that of poplar veneer. In the combustion process, the peak value of heat release rate (PHRR) and heat release rate (HRR) of 170BF‐B plywood are only 10.69% and 37.11% of that of untreated plywood. After combustion, an intumescent flame retardant layer exhibits a graphitization trend. In the flame retardant layer, there are not only functional groups, such as P═O, PO43−, POC decomposed by flame retardant but also characteristic functional groups of wood fiber, like C═O, CH, etc. The prepolymer BF‐B, which is composed of phytic acid, urea, and dicyandiamide polymerized with chitosan or lignocellulose to form a supramolecular flame retardant connected with POC and PON functional groups, thus improving the flame retardant and anti‐loss property by in situ polymerization. [ABSTRACT FROM AUTHOR]

In this paper, a new designed silicon-containing nitrogen and phosphorus flame-retardant system containing ammonium polyphosphate, modified molecular sieve and methylcellulose was used to prepare the flame-retardant corrugated cardboards (FRCCB). The samples before and after treatment were tested for combustion and thermal stability using vertical burning test (VBT), limiting oxygen index (LOI), cone calorimetric test (CCT) and thermogravimetry (TG). To further analyze the flame-retardant properties of the flame-retardant system, the microstructure, surface elements and functional groups of the materials were characterized by the scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the samples were tested to analyze the effect of flame-retardant treatment on the strength. The VBT and LOI tests showed that the samples after the flame-retardant treatment were able to self-extinguish after ignition, achieving the flame-retardant B-1 grade. The CCT tests showed that the total heat release of treated samples was reduced by 49.90%, and the total smoke production was decreased by 27.64%. TG tests showed that the thermal decomposition temperature of FRCCB decreased but the residual carbon content increased largely. FTIR tests showed that the functional group changed at different temperatures. After flame-retardant treatment, a dense carbon layer was formed on the surface of the treated sample, including N, P, Si and Cu, measured by SEM and EDS. Combining with various characterization methods, the flame-retardant system can retard flame by releasing nonflammable gases, forming covers and catalyzing char formation. [ABSTRACT FROM AUTHOR]

The research progress, existing problems and future development of flame retarding modification of bio-based polyurethane are summarized. The work summarized the research status of commonly used methods for preparing bio-based polyurethane, including basic characteristics, application effect and development prospect of various flame retardant agent. At present, vegetable oil-based polyols can effectively replace traditional industrial synthetic petroleum-based polyols as raw materials for the synthesis of bio-based polyurethane. However, there are still some shortcomings in this area that have not been addressed. The defects of polyurethane, such as flammability and smokiness, need to be improved. The practical application conversion rate of research results was not high. The environmental protection and safety performance of bio-based polyurethane can be further improved and enriched. Therefore, more efforts should be put into the above questions, which were all of great significance to the development of polyurethane. The research on retarding modification of polyurethane will have great development space and application value in the future. [ABSTRACT FROM AUTHOR]

In order to address the issues of poor smoke suppression, substrate compatibility, and strong hygroscopicity associated with ammonium polyphosphate, this study employed an in-situ precipitation method to construct a double-shell ammonium polyphosphate microcapsule, with ethyl cellulose and nano-silica serving as shell materials. The microcapsule exhibited improved flame retardancy and fire safety compared to ammonium polyphosphate alone, as evidenced by significant reductions in both maximum heat release rate and total heat release, as determined by thermal-gravimetric analysis (TGA), microcalorimetry (MCC), and vertical burning tests (VBT). Furthermore, the real-time Fourier transform infrared (RT-FTIR), scanning electron microscopy (SEM), and Raman spectrum analyses revealed that the modified kraft paper produced a cross-linked network structure formed by the silica-based substrate and cellulose during combustion, which facilitated the formation of a carbon layer and provided sustained flame retardancy. Physical and hygroscopicity tests demonstrated that the microcapsule exhibited superior compatibility with substrates. Overall, these findings demonstrate that microencapsulation of ammonium polyphosphate effectively addresses the challenges of compatibility and hygroscopicity, while enhancing its flame-retardant efficacy, thus significantly advancing its application in flame retardant materials. [Display omitted] • Compared with APP Kraft, MAPP Kraft has a higher ultimate oxygen index and lower THR and pHRR. • MAPP Kraft has lower moisture absorption than Control Kraft and APP Kraft. • MAPP produce a stabilized flame-retardant layer during combustion, preventing further decomposition of the substrate. [ABSTRACT FROM AUTHOR]

Voltage-dependent anion channels (VDACs) are situated in the outer membrane of the mitochondria and serve as gatekeepers that control metabolite and ion exchange between the cytosol and mitochondria. VDAC1 is one of the most studied members of the VDAC protein family and is overexpressed in multiple types of cancer. However, the specific biological function and regulatory mechanism of VDAC1 in breast cancer remains unclear. The present study investigated the biological role of VDAC1 in breast cancer cells using an MTS assay. The association of clinicopathological features with VDAC1 in breast cancer was analyzed by Gene Expression Profiling Interactive Analysis. The regulatory mechanism of VDAC1 was determined by cell transfection, western blot analysis, reverse transcription-quantitative (q)PCR analysis, chromatin immunoprecipitation (ChIP) and ChIP-qPCR analysis. The results of the present study demonstrated that VDAC1 promoted breast cancer proliferation and was associated with a poor prognosis in patients with breast cancer. Additionally, it was observed that the expression of VDAC1 could be decreased by the bromodomain inhibitor (JQ1), and bromodomain-containing protein 4 (BRD4) was indicated to be a regulator of VDAC1. Furthermore, results suggested that VDAC1 may be involved in the resistance of breast cancer to JQ1. Collectively, the present findings uncovered important aspects of the function of VDAC1 in the tumor progression of breast cancer, and may provide a basis for potential therapeutic strategies for the treatment of breast cancer. [ABSTRACT FROM AUTHOR]

One of the pressing issues in the field of fire safety is the sustainable flame retardancy of polymer materials. Bio-based flame retardants are one of the emerging and promising areas of sustainable flame retardants of the last decade. Tannic acid (TA) is a type of naturally occurring plant polyphenols with a broad source and abundant reserves. In recent years, TA based on textile, steel, and other natural and synthetic polymeric materials has shown great potential for flame retardancy. Depending on the method used and the addition of flame retardants to a flame-retardant system based on TA, various flame retardation modes of action and fire-resistance performances are achieved. This paper reviews the physicochemical properties and thermal properties of TA as well as flame retardancy and fire-retardant mechanism of common polymeric matrixes which are chemically treated by flame retardants (mixture of modified TA and existing flame-retardant additives). Different modes of modification of TA and its roles in flame retardation (e.g., hydrogen bond association, metal ion complexation, carbon source and oxidation resistance) are then worked out in some detail. Achievements in this area have increased our knowledge of the application of TA in the field of flame retardancy and have spurred the development of bio-based flame retardants. [Display omitted] • The application of bio-based substances in flame retardation. • The reaction on the phenolic hydroxyl group of tannic acid was summarized. • Flame retardancy and UV resistance. • The application of tannic acid in flame retardation was systematically described. [ABSTRACT FROM AUTHOR]

Diphenyl carbonate is one of the raw materials used for the synthesis of polycarbonate, and its green and clean production is of great importance to the non-phosgene process for polycarbonate. The production of diphenyl carbonate by transesterification is its representative process route and is considered to be one of the typical examples of a green and sustainable process for chemicals. Since the discovery of the transesterification catalyst for diphenyl carbonate in the 1970s, researchers have been committed to improving its catalytic activity and selectivity and, correspondingly, the reaction engineering process. However, thermodynamic limitations, low activity, low selectivity, and limited stability have been bottlenecks that the transesterification catalyst has not been able to completely overcome, and the improvement of the catalyst is still ongoing. Therefore, this review takes the transesterification reaction of dimethyl carbonate and phenol as a model reaction and, based on a review of the progress in catalyst research on catalytic reaction processes, tries to clarify the structure–activity relationship between catalytic active sites and catalytic performance in homogeneous and heterogeneous catalytic processes and provides an overview of the progress in catalyst synthesis and modification. [ABSTRACT FROM AUTHOR]

Triglycidylamine (TGA) modified soybean protein isolate (SPI) adhesive can increase the bonding strength of soy protein and improve its utilization. In order to study the chemical changes of TGA modified SPI adhesives during the heating process, the curing mechanism of soybean protein adhesives was studied by Fourier transform infrared (FTIR), second derivative infrared (SDIR) and two-dimensional correlation spectroscopy (2D-COS). With the increase of temperature, there were significant differences in the absorption peaks at 1075 cm−1, 1169 cm−1, 1390 cm−1, 1735 cm−1 indicating the active functional groups bared and reacted in the modified SPI, which formed hydrophobic ester, amide groups. Besides, some functional groups were dismissed or weakened such as N–H and –CH 2 - at 3440 cm−1 and 2847 cm−1 respectively. The epoxy ring of TGA opened to cross-link with the amino and hydroxyl groups within the molecular structure of SPI. The addition of TGA can effectively improve the molecular weight of soybean protein and form a network structure, which provides a method for improving the performance of a soybean protein adhesive. • FTIR, SDIR, 2D-COS characterized the curing process of modified soy protein isolate (SPI) adhesive and pure SPI adhesive during heating process. • 2D-COS synchronous and asynchronous graphs indicated that the epoxy group had underwent a ring opening reaction while the temperature was increasing. • The epoxy group of Triglycidylamine (TGA) underwent dehydration synthesis with functions group exposed in the SPI molecule to form a network macromolecule. • 2D-COS can reflect the sequential relationship of different functional groups in the reaction process. [ABSTRACT FROM AUTHOR]

The conversion of ethanol to butadiene catalyzed by modified β zeolites has attracted wide attention. The construction of intracrystalline mesoporosity in β zeolite is a challenging way to improve the catalytic activity. In this work, a surfactant-template strategy was used to construct intracrystalline mesoporosity successfully in the alkali treatment of β zeolite using long-chain quaternary ammonium salt with different alkyl chain length (C10~C16) as the template. The intracrystalline pore size can be adjusted by varying the surfactant alkyl chain length (C10~C16) (1.9–3.4 nm). To get more information about this process, CTAB was chosen as the template in further investigations. The mesoporosity can be generated within 1 h. The BET surface area can reach up to 600 m2/g while the pore volume can reach up to 0.568 cm3/g, which are 1.23 and 1.5 times that of the parent zeolite, respectively. The template action of CTA+ is essential for forming mesoporosity, and CTA+ interacts with the zeolite during the alkali treatment process, protects the zeolite framework from being etched, and does not form a separated mesoporous phase. To demonstrate the effect of intracrystalline mesoporosity on the catalytic performance, Zr-β zeolite was prepared and used as the catalyst for ethanol-acetaldehyde conversion. The hierarchical Zr-β zeolite was prepared using a dealumination-metallization strategy, and both the zeolite crystallinity and the mesoporosity were preserved in this process. The total conversion increased by 10%, while the BD selectivity was well maintained. The catalytic performance showed that the introduction of mesoporosity effectively mitigated decreasing conversion while preserving BD selectivity. Image 1 • Hierarchical β zeolite was obtained via the surfactant-templating strategy. • The intracrystalline pore size could be tailored by the alkyl chain length of the surfactant. • Hierarchical Zr-β zeolite was obtained with preserved crystallinity and mesoporosity. • Mesoporosity in Zr-β zeolite enhanced the catalytic performance for ethanol-acetaldehyde conversion. [ABSTRACT FROM AUTHOR]

Under ultraviolet (UV) light, the salix integra will be faded after being dyed with reactive dyes. In order to study the chemical change in reactive dye on the dyed salix integra during the process of UV light, tri-step infrared spectroscopy is used to analyze the reactive dyes with different UV aging time. The results showed that the change in dye functional groups became more apparent when the UV aging time was increasing. The generation, disappearance or intensity change in peaks at 3432 cm−1, 2918 cm−1, 1632 cm−1, 1563 cm−1, 1501 cm−1, 1398 cm−1 and other wavelengths, which indicated that the unsaturated bonds of azo group, fused ring and cyanyl group in dye molecules were broken or isomerized. With the internal groups of reactive dyes experience electron transition and photooxidation under UV irradiation, the molecular structure will be isomerized and the unsaturated groups become broken simultaneously, which makes the color fade or even disappear. • Ultraviolet aging test was carried out on salix integra after dyed by C.I. Reactive Blue 194 (RB194). • The RB194 was measured by FTIR during the ultraviolet aging process. • The 2D-COS test can help to explain the mechanism of the fading of the dyed salix integra after UV aging. [ABSTRACT FROM AUTHOR]

Zr based metallosilicalites, especially Zr‐ß, is promising catalyst for the conversion of ethanol to 1,3‐butadiene, which is considered to be a sustainable alternative to petroleum steam cracking. However it is suffering from deactivation derived from coking and unsatisfied catalytic activity derived from deficient Lewis acidity. For these issues, a dissolution‐recrystallization process through tetraethyl ammonium hydroxide treatment (TEAOH) for enhancing porosity and Lewis acidity of Zr‐ß zeolite was developed in this study. A balance of dissolution and recrystallization existed in this process, which was produced by OH− etching and templating of TEA+ ions, creating additional mesoporosity. Zirconium active sites maintained tetrahedral coordination, while the Lewis acidity was enhanced by creating higher proportion open sites in framework. The recrystallized Zr‐ß exhibited higher catalytic activity and stability in the conversion of ethanol‐acetaldehyde to butadiene due to the compromise of microporosity and mesoporosity, as well as the appropriate enhancement of Lewis acidity. [ABSTRACT FROM AUTHOR]

In this work, Ta was firstly reported as an efficient promoter of MgO–SiO2 for the conversion of ethanol and acetaldehyde to 1,3-butadiene. The doping of Ta into MgO–SiO2 forms Ta–O–Si bonds and generates more strong Lewis acid sites, which not only promote the aldol condensation reaction but also significantly facilitate the Meerwein–Ponndorf–Verley reduction, the total conversion around 80% which drops to 65% after 24 h. In addition, the catalyst showed desirable stability in 24 h long-term stability evaluation, the selectivity remained stable at 80%. [ABSTRACT FROM AUTHOR]

Introduction: Medulloblastoma (MB) is a malignant pediatric brain tumor that arises in the cerebellar granular neurons. Sonic Hedgehog subtype of MB (SHH‐MB) is one of the major subtypes of MB in the clinic. However, the molecular mechanisms underlying MB tumorigenesis are still not fully understood. Aims: Our previous work demonstrated that the receptor for activated C kinase 1 (Rack1) is essential for SHH signaling activation in granule neuron progenitors (GNPs) during cerebellar development. To investigate the potential role of Rack1 in MB development, human MB tissue array and SHH‐MB genetic mouse model were used to study the expression of function of Rack1 in MB pathogenesis. Results: We found that the expression of Rack1 was significantly upregulated in the majority of human cerebellar MB tumors. Genetic ablation of Rack1 expression in SHH‐MB tumor mice could significantly inhibit MB proliferation, reduce the tumor size, and prolong the survival of tumor rescue mice. Interestingly, neither apoptosis nor autophagy levels were affected in Rack1‐deletion rescue mice compared to WT mice, but the expression of Gli1 and HDAC2 was significantly decreased suggesting the inactivation of SHH signaling pathway in rescue mice. Conclusion: Our results demonstrated that Rack1 may serve as a potential candidate for the diagnostic marker and therapeutic target of MB, including SHH‐MB. [ABSTRACT FROM AUTHOR]

• Zr-BEA zeolite has good acetaldehyde aldol condensation selectivity to crotonaldehyde (over 85%). • Zr site coverage and pore blocking are the dominant reasons for the deactivation mechanism. • Carbonaceous deposits are mainly unsaturated aldehydes, unsaturated ketones, and aromatic species. Zr-BEA zeolite was introduced to the aldol condensation of acetaldehyde and showed high crotonaldehyde selectivity (over 85%), but it suffered from rapid deactivation, where the conversion of acetaldehyde decreased from 16.4% at 1 h to 6.5% at 8 h. The spent Zr-BEA zeolites at different time-on-stream (TOS = 1, 2, 4, 6, and 8 h) were characterized by SEM, XRD, XPS, FT-IR, TGA, N 2 physical adsorption, and GC–MS to understand the deactivation mechanism. Pore blocking and Zr active site coverage caused by carbonaceous deposits were both responsible for the deactivation. Furthermore, the main carbonaceous species were unsaturated aldehydes, unsaturated ketones, and aromatic compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

• For the first time, ethenone is used as acylation reagent to achieve the acylation reaction of anisole catalyzed by resin. • The activation path of ethenone to acylium ion is clarified. • The high activity of ethenone over traditional acylation reagents is verified by calculation. Ketene compounds with the specific structure (>C=C=O) have been widely used for over 110 years and already become a research hotspot. This study proposes a reaction route to produce aromatic ketone by using ethenone as a new acylation reagent, and offers a novel catalytic direction in the field of Ketene Chemistry: acylation of ketenes. The results show that ethenone can react with anisole to form acylation compounds, where the formation of acylium ion from ethenone is the key step. The easy activation of ethenone provides a new insight and breakthrough direction for the application of ketene compounds in acylation reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based flame retardants such as chitosan and tannic acid are applied. • The addition of transition metal Cu reduces smoke release. • Flame retardants have no negative effect on physical and mechanical properties. • Flame-retardant wood also has anti-mildew and antibacterial properties. Utilizing bio-based flame retardants like chitosan (CS) and tannic acid (TA) is an effective way to enhance the flame retardancy of wooden products. In this work, the poplar wood was impregnated with composite flame retardants containing CS, TA, Cu (CH 3 COO) 2 ·H 2 O and silane coupling agent (KH550). When KH550 bound these substances together to form a stable compound, a highly efficient flame-retardant wood (wood/CTA-Cu-Si) was prepared under vacuum pressure impregnation. The results of the functional group test show that bio-based flame retardants have been successfully synthesized. The limiting oxygen index (LOI) of the treated sample was reached 31.5%, the sample also passed the V-0 grade in the UL-94 vertical burning test, and in the Cone colorimeter test, the total smoke release was reduced by 50.2% compared to that of the Control. The energy dispersive spectroscopy proved that Cu and Si elements were evenly distributed in the wood before and after combustion. Raman spectra of the residues after the burning of treated wood were compared and it was found that the degree of graphitization of wood/CTA-Cu-Si was significantly increased, which I D / I G reached 1.85. After impregnation, the flame-retardant treated wood sample exhibited no negative effect on mechanical properties. The flame-retardant mechanism was probed and summarized as the Cu and Si synergistic promotion on charring and suppression on heat and smoke release. Simultaneously, the existences of Si-C, Si-O and Si-N strengthened the char layer and enhanced flame retardancy of poplar wood. Such resulted poplar wood with flame retardancy will be an excellent application prospect as engineering biomaterial. [ABSTRACT FROM AUTHOR]

Zr-β zeolites were modified with second metals to catalyze the conversion of ethanol/acetaldehyde to 1,3-butadiene. The incorporation of Ta increases the Lewis acidity of Zr-β zeolite, resulting in higher catalytic activity than that of In, Y and Ce. Furthermore, the Zr-β zeolite that was first incorporated with Zr and then Ta with a Ta/Zr molar ratio of 1.5 exhibited greater catalytic activity of 57% conversion and 75% selectivity. Activity descriptors were proposed to calculate the reactivity of key reaction steps, which served as evidence that Ta incorporation enhances the aldol condensation and MPV reduction reaction activity, thus improving catalytic performance. [Display omitted] • The metals Zr and Ta were sequentially incorporated into the framework of β zeolite. • The second metal Ta was incorporated into the Zr-β zeolite to establish new Lewis acid sites. • The strengthening Lewis acidity is contributed to enhancing the activity of aldol condensation and MPV reduction. • A mathematical descriptor was defined to analyze the reactivity of aldol condensation and MPV reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • The complex FTS reaction network on Co 2 C was analyzed by first-principles based microkinetic modeling. • The formation pathways of major products including oxygenates and hydrocarbons were determined. • The model-predicted product distribution as a function of temperature can reflect experimental findings. • Degree of selective control (DSC) was used to quantify the inherent variation in catalytic performance. Cobalt carbides (Co 2 C) have been recognized as crucial active phases in emerging applications for direct producing high-value chemicals including oxygenates and olefins from syngas. A mechanistic understanding of the complex nature of the surface reactions on Co 2 C is vital but remains incompletely investigated. In this work, a comprehensive reaction network analysis on Co 2 C(1 1 1) facet by first-principles-based microkinetics modeling reveals pathways for generating methane, ethane, ethylene, acetaldehyde, ethanol and C3 + products, and the model-predicted product distribution as a function of temperature can reflect experimental observations. The competition between the formation of hydrocarbon and oxygenates was analyzed in detail, on both an energetic and microkinetic basis. The elementary reaction steps that control the selectivity of desired products were quantitatively determined using the concept of degree of selectivity control (DSC). Underlying mechanisms for chain growth and product formation were discussed, altogether to provide a better understanding of Fischer − Tropsch synthesis on cobalt carbides. [ABSTRACT FROM AUTHOR]

• PA-Fe chelate forms a flame-retardant layer with a high degree of graphitization. • Fe 2 O 3 can effectively catalyze the conversion of unsaturated gases. • The crosslinking reaction between PA and TDI enhances the mechanics of MPCs. The applicability of wood-plastic composites has attracted great attention due to the improved sustainability. However, the fabrication of wood-plastic composites with excellent flame retardance and smoke suppression without compromising the mechanical property remains a great challenge. In this study, marigold straw (MS)-polyurethane (PU) composites (MPCs) were treated with phytic acid (PA) as a flame retardant and iron oxide (Fe 2 O 3) as a smoke suppressor. The oxygen index of the proposed Fe/TMS (treated marigold straw)/PU/PA-10 composite was 27.8, and the total heat release was 12.02 MJ/m2. Fe 2 O 3 and PA formed a mesh chelate in the form of a coordination bond, which provided a highly graphitized solid flame-retardant layer during the combustion process, improving the high-temperature stability of Fe/TMS/PU/PA-10. In addition, Fe 2 O 3 can effectively catalyze the conversion of unsaturated gases, such as CO, into CO 2. This is essential to suppress the smoke release and also avoid the production of toxic gases. The phosphate group of PA is cross-linked with the -NCO group of TDI (2,4-Toluene diisocyanate), thus significantly enhanced the physical properties of MPCs. This study provides an environmentally friendly approach to enhancing the flame retardancy and smoke suppression of MPCs. [Display omitted] [ABSTRACT FROM AUTHOR]

Metallosilicates with isolated framework metal sites as well as Lewis acidity, e.g., Zr- β zeolite, is proven to be one of the most active for the conversion of ethanol to 1,3-butadiene (ETB), which is a potential process for sustainable butadiene production. However the development process of isolated Zr sites in *BEA framework and their structure–activity relationship in ETB process are still under debate. In this work, three post-synthetic procedures, Liquid Phase Incorporation (LPI), Solid State Ion Exchange (SSIE), and Direct Loading were applied for isolated framework Zr sites development, and the procedure as well as catalytic performance and mechanism were systematically investigated. The isolated framework sites could be developed by Liquid Phase Incorporation (LPI) process, where calcination was the key step for Zr-O-Si bond formation, thus representing Zr incorporation into *BEA framework, accompanying the absence of Zr ion exchange. Isolated Zr framework site was the active site in ETB process, for the strong Lewis acidity upon Zr incorporation. DRIFT and TPSR results revealed that the MPV reduction of crotonaldehyde on Zr site was rate-determining in ETB process. [Display omitted] • Isolated Zr sites in *BEA framework development via LPI process was investigated. • Zr-O-Si bond formation occurred in calcination, while ion exchange was absent. • Isolated Zr sites showed better ETB activity, MPV step was rate-determining. [ABSTRACT FROM AUTHOR]

Based on manually collected data, we investigate the effects of internationalization on corporate social responsibility (CSR) in Chinese firms. We find that the internationalization is positively related to CSR scores. The results are robust when we address the endogeneity, and use alternative measurements of the dependent and independent variables. Furthermore, we find internationalization significantly improves the CSR performance when the quality of the host country's institutional environment is better and the firms are state-owned enterprises, business-to-consumer firms, and operate in socially sensitive industries. This indicates that legitimacy is the main motive for Chinese multinational companies to engage in more CSR. • Internationalization level is positively related to CSR scores in China. • Internationalization improves MNC's CSR when host country's institution is better. • Internationalization significantly improves the SOEs' CSR performance. • Internationalization improves CSR of firms in socially sensitive industries. • Legitimacy is the main motive for MNCs to engage in more CSR. [ABSTRACT FROM AUTHOR]