The Effects of Phosphotungstic Heteropoly Acid on Degradation Behaviour of Hardened Epoxide Polymers in Near-Critical Water

2013 ◽  
Vol 762 ◽  
pp. 515-519 ◽  
Author(s):  
Yu Yan Liu ◽  
Li Qin Jiang ◽  
Song Quan Wu ◽  
Yu Ting Liu
Keyword(s):  
Decomposition Rate ◽  
Epoxy Resins ◽  
Heteropoly Acid ◽  
Phosphotungstic Acid ◽  
Decomposition Mechanism ◽  
Degradation Behaviour ◽  
Epoxide Polymers ◽  
Catalytic Effects ◽  
Composition Of Products

This paper aims to study the catalytic effects of phosphotungstic acid on the degradation behaviour of E-51/DDM and E-51/MeTHPA epoxy resins. The results show that phosphotungstic acid promotes the decomposition of E-51/DDM and E-51/MeTHPA in different degree. The decomposition rate of E-51/MeTHPA is relatively higher. According to the GC-MS results, the composition of products when phosphotungstic acid is used as the catalyst is complicated, indicating that the decomposition mechanism is complicated.

Heteropoly acid-catalyzed three-component aza-Diels–Alder reaction in a continuous micro-flow system

RSC Advances ◽  
2015 ◽  
Vol 5 (72) ◽  
pp. 58798-58803 ◽  
Author(s):  
Wei He ◽  
Zheng Fang ◽  
Zhao Yang ◽  
Dong Ji ◽  
Kai Guo
Keyword(s):  
Water Absorption ◽  
Heteropoly Acid ◽  
Phosphotungstic Acid ◽  
Flow System ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
System P ◽  
Micro Flow ◽  
Acid Catalyzed

The first direct aza-Diels–Alder reaction catalyzed using phosphotungstic acid combined with a water absorption device in a micro-flow system was reported.

scholarly journals Intercellular Attachment in the Epithelium of Hydra As Revealed by Electron Microscopy

1959 ◽  
Vol 6 (3) ◽  
pp. 343-352 ◽  
Author(s):  
R. L. Wood
Keyword(s):  
Electron Microscopy ◽  
Intercellular Space ◽  
Epoxy Resins ◽  
Phosphotungstic Acid ◽  
Internal Environment ◽  
Prominent Feature ◽  
Cell Surfaces ◽  
Intercellular Spaces ◽  
Two Peaks ◽  
Plasma Unit

In Hydra adjacent epithelial cells are bound firmly to each other by desmosomes of a type not described in detail hitherto. The most prominent feature of these desmosomes is the presence of a series of parallel lamellae which bridge the intercellular space and connect the two apposed cell surfaces directly. These structures, here termed intercellular attachment lamellae, display two peaks of density about 50 A apart. These dense lines appear in some instances to be continuous with the outer dense components of the plasma unit membranes of the attached cells. The presence of prominent lamellae in intercellular attachments is sufficiently distinctive to deserve special terminology; accordingly, the term septate desmosome is proposed. It is noted that septate desmosomes may have been seen in other animals in instances where published electron micrographs show cross-striations or prominent connections in regions of intercellular attachment. It is suggested that septate desmosomes in Hydra, in addition to binding cells firmly to each other, form barriers to the movement of water into intercellular spaces and thus help to protect the organism's internal environment. Observations on the use of phosphotungstic acid for improving contrast in materials embedded in epoxy resins are also recorded.

scholarly journals Synthesis and catalytic activity of Cu–Cr–O–TiO2 composites for the thermal decomposition of ammonium per-chlorate: enhanced decomposition rate of fuel for solid rocket motors

RSC Advances ◽  
2017 ◽  
Vol 7 (21) ◽  
pp. 12486-12495 ◽  
Author(s):  
Harish Kumar ◽  
Prahalad N. Tengli ◽  
Vijay Kumar Mishra ◽  
Pankaj Tripathi ◽  
Dan Bahadur Pal ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Decomposition Rate ◽  
Sol Gel ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Gel Method ◽  
Sol Gel Method ◽  
Solid Rocket ◽  
Catalytic Effects

This study presents the synthesis of Cu–Cr–O·nTiO2 particles via sol–gel method and their catalytic effects on thermal decomposition of AP.

Heteropoly acid in ionic liquid — An efficient and recyclable system for one-pot three-component Mannich reaction

2007 ◽  
Vol 85 (1) ◽  
pp. 77-80 ◽  
Author(s):  
Meghana S Rasalkar ◽  
Sachin V Bhilare ◽  
Amol R Deorukhkar ◽  
Nitin B Darvatkar ◽  
Manikrao M Salunkhe
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Organic Solvents ◽  
Mannich Reaction ◽  
Heteropoly Acid ◽  
Phosphotungstic Acid ◽  
Reaction Medium ◽  
Homogeneous Reaction ◽  
Ambient Conditions ◽  
One Pot

This paper describes a one-pot three-component Mannich reaction, catalyzed by phosphotungstic acid (H3PW12O40), a heteropoly acid in ionic liquid. The catalyst was found to be mild and efficient, and the protocol affords β-amino ketones in good yields under ambient conditions. Several ionic liquids and conventional organic solvents were employed for the reaction. The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) offered the best results in terms of yield of the products. It was observed that a homogeneous reaction medium proved beneficial for the yield of the reaction.Key words: Mannich reaction, β-amino ketones, phosphotungstic acid, ionic liquid, recyclability.

Phosphotungstic Acid, Silicotungstic Acid and Silicon Tungsten-Cobalt Heteropoly Acid with Bovine Serum Albumin Interaction

2013 ◽  
Vol 652-654 ◽  
pp. 722-725
Author(s):  
Wei Yang Shen ◽  
Min Xin Song ◽  
Jian Qiu Chen ◽  
Rui Xin Guo
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Heteropoly Acid ◽  
Phosphotungstic Acid ◽  
Silicotungstic Acid ◽  
Buffer Solution ◽  
Solution Ph ◽  
Uv Absorption Spectroscopy ◽  
Tris Buffer Solution

The interactions of bovine serum albumin (BSA) with phosphotungstic heteropoly acid (PW), silicon tungsten heteropoly acid (SiW) and silicon tungsten-cobalt acid (SiWCo) were studied by fluorescence spectroscopy and UV absorption spectroscopy at Tris buffer solution (pH = 7.40). It was found that the fluorescence quenching of PW, SiW and SiWCo with BSA was static and the binding constant, binding site and the thermodynamic parameters were calculated at 298 and 310K. In addition, the conformations of BSA impacted by PW, SiW and SiWCo were researched using synchronous fluorescence. The results showed that PW, SiW and SiWCo all could interact with BSA but they had not changed the conformation of BSA.

Degradation Behaviour and Kinetics of UV Cured Epoxidised Soybean Oil Derivatives

2011 ◽  
Vol 230-232 ◽  
pp. 94-98 ◽  
Author(s):  
Mohammad Rahmah ◽  
Syuhaimi Ab.Rahman Mohammad ◽  
Mohamed Shaktur Khaled ◽  
Nawi Norwimie ◽  
Faiza Mohd Ahmad
Keyword(s):  
Renewable Resources ◽  
Epoxy Resins ◽  
Raw Materials ◽  
High Price ◽  
Degradation Behaviour ◽  
Uv Curable ◽  
Sustainable Resources ◽  
Oil Derivatives ◽  
Uv Curable Resin ◽  
Kinetics Of

Green resins based from sustainable resources are a requirement nowadays to replace non environmental coatings. Low (VOC) content epoxy which competes with conventional well established coating and high price could be derived from oil. UV curable resin is typically low VOC systems and offer advantages of rapid ambient cross linking and more energy efficient. Epoxy resins must have fast curing and low shrinkage upon cure which will give advantages to devices performance but epoxy resins are expensive and hence renewable resources from vegetable or non food oil can be used as raw materials.

scholarly journals Poly (Triethylene Glycol Methyl Ether Methacrylate) Hydrogel as Carriers of Phosphotungstic Acid for Acid Catalytic Reaction in Water

2021 ◽  
Author(s):  
JunJie Zhu ◽  
Takehiko Gotoh ◽  
Satoshi Nakai ◽  
Nao Tsunoji ◽  
Masahiro Sadakane
Keyword(s):  
Polymer Composite ◽  
Methyl Ether ◽  
Catalytic Reaction ◽  
Heteropoly Acid ◽  
Phosphotungstic Acid ◽  
Triethylene Glycol ◽  
Glycol Dimethacrylate ◽  
Triethylene Glycol Dimethacrylate ◽  
Reaction In Water ◽  
Glycol Methyl Ether

An H3PW12O40-polymer composite was synthesized from a mixture of triethylene glycol methyl ether metacrylate monomer, triethylene glycol dimethacrylate crosslinker, and H3PW12O40. The heteropoly acid molecules were trapped in the hydrogel...

Ultrastructure and Staining of Developing Elastic Tissue

1971 ◽  
Vol 29 ◽  
pp. 244-245
Author(s):  
E. N. Albert
Keyword(s):  
Fine Structure ◽  
Phosphotungstic Acid ◽  
Staining Method ◽  
Rat Aorta ◽  
Uranyl Acetate ◽  
The Other ◽  
Elastic Fibers ◽  
Elastic Tissue ◽  
Lead Citrate ◽  
New Born

Silver tetraphenylporphine sulfonate (Ag-TPPS) was synthesized in this laboratory and used as an electron dense stain for elastic tissue (Fig 1). The procedures for the synthesis of tetraphenylporphine sulfonate and the staining method for mature elastic tissue have been described previously.The fine structure of developing elastic tissue was observed in fetal and new born rat aorta using tetraphenylporphine sulfonate, phosphotungstic acid, uranyl acetate and lead citrate. The newly forming elastica consisted of two morphologically distinct components. These were a central amorphous and a peripheral fibrous. The ratio of the central amorphous and the peripheral fibrillar portion changed in favor of the former with increasing age.It was also observed that the staining properties of the two components were entirely different. The peripheral fibrous component stained with uranyl acetate and/or lead citrate while the central amorphous portion demonstrated no affinity for these stains. On the other hand, the central amorphous portion of developing elastic fibers stained vigorously with silver tetraphenylporphine sulfonate, while the fibrillar part did not (compare figs 2, 3, 4). Based upon the above observations it is proposed that developing elastica consists of two components that are morphologically and chemically different.

Relationship between golgi apparatus and axonal reticulum in sympathetic ganglion cells

1978 ◽  
Vol 36 (2) ◽  
pp. 598-599
Author(s):  
J. Quatacker ◽  
W. De Potter
Keyword(s):  
Golgi Apparatus ◽  
Sympathetic Ganglion ◽  
Phosphotungstic Acid ◽  
Ganglion Cells ◽  
Low Ph ◽  
Dense Core ◽  
Dense Core Vesicles ◽  
Large Dense Core Vesicles ◽  
Cervical Ganglia ◽  
Axoplasmic Reticulum

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).

Epoxy Resin Embedment

1968 ◽  
Vol 26 ◽  
pp. 100-101
Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Light Microscope ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Tissue Preservation ◽  
Resin System ◽  
Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

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