AO-resistant properties of polyimide fibers containing phosphorous groups in main chains

A series of polyimide fibers containing phosphorus element derived from (3-aminophenyl) methyl phosphine oxide (DAMPO) diamine was exposed to an artificial atomic oxygen environment which simulated the space environment in low earth orbit (LEO). The mass loss, surface morphology, chemical composition, and mechanical properties of the fibers before and after atomic oxygen (AO) exposure were compared in detail with a blank sample. Results showed that the phosphor-containing fibers demonstrated lower mass change and less tensile strength reduction. SEM results showed that the fibers with phosphorous element had relatively dense surface after AO exposure. Meanwhile, XPS results indicated that a passivated phosphate layer, which could protect the following under-layer from attacking by AO, was formed on the surface of the fibers. These results indicated that the incorporation of diamine (DAMPO) into the main chains could protect the fibers for avoiding further erosion from AO exposure. Hence, the phosphor-containing PI fibers exhibits potential application in space fields.     

Preparation of di- and triamides and their application in ion-selective electrodes

The synthesis of a series of non-cyclic di- and triamides each containing ether oxygen atoms is described. The ionophoric properties in an ion-selective PVC-membrane were studied. Some of these ionophores were selective for lithium ions.     

Synthesis of SAPO-41 from a new reproducible route using H3PO3 as the phosphorus source and its application in hydroisomerization of n-decane

In the new reproducible route, phosphorous acid (H₃PO₃) or the mixture of H₃PO₃ and phosphoric acid (H₃PO₄) are used as the phosphorus source to synthesize microporous silicoaluminophosohates. It is found that gels containing H₃PO₃ favor the formation of SAPO-41 materials. With only H₃PO₃ as the phosphorus source, pure SAPO-41 phase can be prepared with high crystallinity. When the mixture of H₃PO₃ and H₃PO₄ is used as the phosphorus source, the crystallization of SAPO-41 can be accelerated. Raman and XRD results show that SAPO-41 can be formed after crystallizing for 12 h. The dosage of the template di-n-propylamine (DPA) can be reduced in the mixed phosphorus source system. The SAPO-41 has been used to prepare catalysts for the hydroisomerization of n-decane. High selectivity of isomerization (89.5%) has been observed even at high conversion (88%) over the Pt/SAPO-41.     

N,N,N′,N′,N″‐Pentamethyl‐N″‐[(trifluorosilyl)methyl] phosphoric triamide. First example of the existence of intramolecular PO→Si coordination bond in the Si‐containing phosphoric triamides

The N,N,N′,N′,N″‐pentamethyl‐N″‐(trifluorosilylmethyl)phosphoric triamide O?P(NMe₂)₂N(Me) CH₂SiF₃ with intramolecular P?O→Si coordination was formed by the reaction of N,N,N′,N′,N″‐pentamethyl‐N″[(triethoxysilyl)methyl]phosphoric triamide with BF₃·Et₂O. Copyright © 2007 John Wiley & Sons, Ltd.     

Efficiency and mechanism of phosphorous antioxidants in Phillips type polyethylene

The stabilising efficiency of three phosphorous secondary antioxidants of different chemical structures (phosphonite, phosphite and phosphine) was compared in a Phillips type polyethylene. The polymer was processed by six consecutive extrusions in the presence of 700 ppm primary antioxidant and 700 ppm phosphorous compound. The consumption of the secondary antioxidant was followed quantitatively by Fourier transform infrared (FTIR) spectroscopy. The properties of the polymer were characterised by FTIR spectroscopy, colour and rheological measurements, as well as by the determination of its residual thermo-oxidative stability. The results of the experiments proved that the chemical reactions occurring in the first extrusion of the polymer are different from those taking place in the further processing operations. The rate of antioxidant consumption and the chemical reactions of the polymer are strongly affected by the type of the phosphorous secondary antioxidant. The analysis of the results indicated that the three stabilisers must act according to different mechanisms. The investigated phosphine showed the best melt stabilising efficiency, while phosphonite was found to protect the polymer most effectively from discoloration.     

Thermo-oxidative degradation of novel epoxy containing silicon and phosphorous nanocomposites

Modified epoxy nanocomposites containing silicon and phosphorous was prepared and compared with pure epoxy. The study of thermo-oxidative degradation of modified epoxy nanocomposites and pure epoxy has been utilized by thermal analysis. The thermal stability of modified epoxy nanocomposites is not superior to that of the pure epoxy at low temperature, however, the char yield of modified epoxy nanocomposites is higher than that of the pure epoxy at 800 °C in air atmosphere. The modified epoxy nanocomposites possess better thermal stability at high temperature range. The values of the limiting oxygen index of pure epoxy and modified epoxy nanocomposites are 24 and 32, respectively. This indicates that modified epoxy nanocomposites possesses better flame retardance.By the Kissinger’s method, the activation energies of thermo-oxidative degradation for epoxy nanocomposites are less than those of thermo-oxidative degradation for pure epoxy in first stage of thermo-oxidative degradation. However, the activation energies of thermo-oxidative degradation for epoxy nanocomposites are more than those of thermo-oxidative degradation for pure epoxy in second stage of thermo-oxidative degradation.     

电感耦合等离子体发射光谱法同时测定玻璃中的硫和磷

通过对玻璃试样中硫、磷的分解方法、分析线选择、共存元素光谱干扰和仪器最佳分析条件等方面的研究, 建立了ICP-AES 测定玻璃中硫、磷的方法. 选用紫外区谱线S 181.972 nm、 P 177.434 nm, 避免了基体元素对硫、磷的干扰, 该法能够准确、快速地测定玻璃样品中的硫、磷量, 测定结果的相对标准偏差小于2.9%, 方法的检出限分别为 S 0.07 μg/mL, P 0.08 μg/mL, 已用于玻璃样品的分析.     

An improved procedure for phosphorous fractionation in plant materials exploiting sample preparation and monosegmented flow analysis

Sample treatment procedures were evaluated for fractionation of phosphorous in plant materials (determination of organic and inorganic, soluble and insoluble fractions). The procedures aimed the conversion of different species into orthophosphate, minimizing time, reagent amounts and waste generation. A monosegmented flow system with multicommutation was developed for the spectrophotometric determination of orthophosphate by the molybdenum blue method. Linear response within 0.5 and 25.0 mg L^− 1 P, detection limit of 24 μg L^− 1 P (99.7% confidence level), coefficient of variation of 3.5% (n = 10) and sampling rate of 38 measurements per hour were estimated. Each determination consumes 5.0 mg ascorbic acid and 0.60 mg of ammonium molybdate. Total phosphorous determination can be carried out after microwave-assisted acid digestion by employing 100 mg of plant material and 500 μL of concentrated HNO₃. Extraction of soluble phosphorous can be carried out with water by stirring for 10 min and organic soluble phosphorous can be determined either after microwave-assisted acid digestion or photodegradation in the presence of ammonium persulfate in acid medium. The results for the different fractions agreed with those obtained by ICP OES at the 95% confidence level.     

Controlling surface shallow junction depth by a rapid thermal annealing process with low ambient pressure

We demonstrate the effect of annealing pressure on the redistribution of phosphorus dopants in silicon. The phosphorus concentration in the kink region is dependent on the annealing pressure that enhances the phosphorous transient out-diffusion. The phosphorous in-diffusion in the tail region is suppressed by this transient out-diffusion under low annealing pressure (below the atmosphere), and the surface shallow junction depth is reduced. The phenomenon of dose loss caused by the phosphorous piling-up or sublimation at the surface has an influence on the electrical characteristics and the surface roughness. Moderate annealing pressure can reduce the junction depth and only slightly increase the sheet resistance and surface roughness.     

Polyamidophosphite Complexes of Metals as Catalysts

Interaction between the equimolecular amounts of glycols (diatomic phenols) and phosphorous acid triamides in diglyme or without solvent gives phosphorus-bearing polyamidophosphites. The structure of these compounds was studied by NMR spectroscopy, and it was shown that a partial disproportionation of amidophosphite fragments into phosphite ones can occur in the course of their synthesis. The chemical properties of the obtained compounds are being studied. First rhodium complexes with polyamidophosphite ligands were obtained. These complexes are shown to be more active hydrogenation catalysts than the corresponding low-molecular complexes. 1