The intrinsic flame retardant mechanism of bio?based epoxy resin containing pyridazinone structure was explored through resin ablation experiment, scanning electron microscope,X?ray photoelectron spectrometer,thermogravimetry?infrared simultaneous thermal analyzer,and other characterization methods.The results show that compared with the most commonly used petroleum?based bisphenol A epoxy resin, the resultant bio?based epoxy resin is more likely to form a large amount of intumescent carbon layer structure during combustion and release a large amount of non?combustible gases such as CO2 and NH3 with less combustible gases.The intrinsic flame retardant bio?based epoxy resin containing pyridazinone structure exhibits a condensed phase?gas phase synergistic flame retardant mechanism. This study provides new ideas for constructing high?performance intrinsic flame retardant epoxy resin.
In recent years, the global market demand for pressure?sensitive adhesives has shown a steady growth trend. The market demand has reached about 3.5 million tons in 2021, and the estimated size of the global pressure?sensitive adhesive market in 2025 is ＄10 billion. Amid the development of pressure?sensitive adhesive technology and the increase in the application demand for pressure?sensitive adhesives, functionally modified pressure?sensitive adhesives have become a major trend in this field. Acrylate?based pressure?sensitive adhesive is the most widely used pressure?sensitive adhesive at present. Its performance has been improved after modification. Nevertheless, the modification process has some disadvantages, such as environmental pollution and low resource utilization. Since rubber has the advantages of low cost, superb mechanical properties, high and low temperature resistance, and environmental friendliness,and so on.Rubber?modified acrylate?based pressure?sensitive adhesives have become a development trend in this field. This paper summarized the development process of rubber?modified acrylate?based pressure?sensitive adhesives and outlined and compared the types of rubber and the advantages and disadvantages of modified products.
This paper systematically studied the material compatibility, storage stability, and miscibility with diesel fuel of polyoxymethylene dimethyl ethers (PODE n ) from the point of view of its application performance. The results show that the PODE n is generally highly compatible with common metal materials, such as copper, brass, steel, cast iron, cast aluminum, and solder. In comparison, blended diesel fuel with PODE n at a volume fraction of 10% is highly compatible with polyester polyurethane rubber and fluororubber but poorly compatible with nitrile rubber and polyether polyurethane rubber. In the storage stability test conducted at 43 °C for 16 weeks, PODE n demonstrates satisfactory storage stability. Excellent miscibility stability occurs after the blending of automobile diesel fuel with PODE n at a volume fraction of 10%. In general, as a component of blended diesel fuel, PODE n delivers satisfactory application performance.
This paper used a rubber processing analyzer (RPA) to study the effect of different amounts of epoxidized soybean oil and antioxidants on the rheological properties of brominated butyl rubber (BIIR) during the thermal oxidative aging process and discussed the cause of degradation and gel generation of BIIR.The results show that the rheological properties change trend is consistent with the GPC data,which proves that the thermal oxidative aging of BIIR is a process involving both molecular cross?linking and degradation;epoxidized soybean oil and antioxidants can greatly slow down the rate of the gel generation and molecular chain degradation during the aging process of BIIR.Different antioxidants have different anti?aging effects on BIIR.Antioxidant 1076 has a stronger inhibitory effect on oxidative degradation of BIIR than antioxidant 264.
Taking the Bohai Q oilfield as an example, this paper focused on how to improve the effect of liquid production increase in fluvial facies reservoir and counted the effects of measures to increase the production of oil wells in the oilfield in the past five years. The sensitivity of oil wells was analyzed from static and dynamic aspects,and the effects of liquid production increase measures on static and dynamic parameters were studied to analyze the effective timing and scale of increasing liquid production.According to the effect of the measures, classification schemes for the liquid production increase of water?drive reservoir in Bohai fluvial facies were established.The results show that if oil wells in the reservoir are in Class Ⅰ liquid production increase stage (20 000 mD
The properties of alumina supports are the key factors affecting the propane dehydrogenation performance of Pt?Sn/γ?Al2O3 catalysts.In this paper,γ?Al2O3 supports were prepared at three calcination temperatures of 450,650,850 ℃,and the structures and properties of the supports and supported catalysts were systematically studied by XRD,XRF,NH3?TPD,Py?FTIR, CO?FTIR,OH?FTIR,and other characterization methods.The properties of the propane dehydrogenation reaction were evaluated by a fixed?bed micro?reaction evaluation device with online analysis,and the gas?phase product distribution and coking properties were analyzed.The results show that with the increase in calcination temperature,the surface acid content of γ?Al2O3 supports decreases,and calcination at 850 ℃ almost eliminates the weak L acid centers on the surface.This indicates that the number of coordinated unsaturated Al sites on the surface of γ?Al2O3 and surface hydroxyl groups decreases as the calcination temperature grows,which is not conducive to the high dispersion of metal active centers.Both CO?FTIR and TEM results confirm the formation of larger Pt clusters on Pt?Sn/γ?Al2O3?850,and more Pt active phase structure with saturated coordination can promote the occurrence of side reactions such as deep dehydrogenation and reduce the selectivity of propylene products.
Organic sulfides widely exist in natural resources such as petroleum and coal,which have abundant resource reserves.In the petroleum refining industry,the cleavage of C-S bonds is usually required for the desulfurization of petroleum fractions. Among them,the transition metal?catalyzed cleavage reactions of C-S bonds have attracted the attention of researchers owing to the advantages of high efficiency,mild conditions,and low pollution.This review summarizes the progress in transition metal?catalyzed C-S bond cleavage reactions of different types of organic sulfides,and provides insights into Pd,Cu,Ni and Fe catalytic systems and mechanisms.Moreover,the development of such reactions is proposed.
Rare earth complexes of Eu3+ and Nd3+ with pyridine dicarboxylate [Ln(2,6?dipic)(2,6?Hdipic)(H2O)2]?4H2O (Ln: Eu, Nd) were synthesized by hydrothermal method. The structure, magnetism and thermodynamic properties of the complexes were studied by the means of single crystal X?ray diffraction measurement, magnetic test, thermogravimetric analysis and differential scanning calorimetry analysis. The results show that two complexes are isostructural crystallizing in the monoclinic system of space group P21/c. There are two different coordination modes for pyridine?2,6?dicarboxylic acid in the crystals. The complexes exhibit antiferromagnetism with obvious orbital coupling effect. The prepared complexes have good thermal stability.
Tin phosphide (Sn4P3) as the anode material for lithium?ion batteries exhibits high theoretical specific capacity (1.255×103 mA
This paper in situ introduced a mixture of phytic acid,methanol,water,chromium nitrate nonahydrate,N,N?dimethylformamide in polyvinyl alcohol casting solution, where phytic acid and chromium nitrate nonahydrate formed a metal organic framework (MOF) with a three?dimensional structure. Glutaraldehyde was the crosslinking agent to crosslink polyvinyl alcohol into a network structure, and a series of anion exchange membranes with a porous MOF were constructed for fuel cells（MOF@PVA）. During the experiment, the structure and properties of the membranes were optimized by adjusting the Cr3+ content. Characterization and performance test results show that the obtained composite membranes are flat and uniform in morphology, with a large number of pore structures available for OH- migration and retention of water molecules. Additionally, membrane conductivity, water content, and mechanical properties increase with the rising Cr3+ mass fractions. When m(Cr3+)/m(conductive film) is 0.012, the conductivity is the highest, that is 24.9 mS/cm. The membrane conductivity is only reduced by 8% after being immersed in a 3 mol/L NaOH solution at 80
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