Infiltration Behavior Of Mechanical Alloyed 75 wt% Cu-25 wt% WC Powders Into Porous WC Compacts

In this work infiltration behavior of mechanical alloyed 75 wt% Cu – 25 wt% WC powders into porous WC compacts were studied. Owing to their ductile nature, initial Cu powders were directly added to mechanical alloying batch. On the other hand initial WC powders were high energy milled prior to mechanical alloying. Contact infiltration method was selected for densification and compacts prepared from processed powders were infiltrated into porous WC bodies. After infiltration, samples were characterized via X-Ray diffraction studies and microstructural evaluation of the samples was carried out via scanning electron microscopy observations. Based on the lack of solubility between WC and Cu it was possible to keep fine WC particles in Cu melt since solution reprecipitation controlled densification is hindered. Also microstructural characterizations via scanning electron microscopy confirmed that the transport of fine WC fraction from infiltrant to porous WC skeleton can be carried out via Cu melt flow during infiltration

Proces infiltracji porowatych kształtek WC z wykorzystaniem proszku 75% Cu-25 WC wytworzonego metodą mechanicznego stopowania

In this work infiltration behavior of mechanical alloyed 75 wt% Cu – 25 wt% WC powders into porous WC compacts were studied. Owing to their ductile nature, initial Cu powders were directly added to mechanical alloying batch. On the other hand initial WC powders were high energy milled prior to mechanical alloying. Contact infiltration method was selected for densification and compacts prepared from processed powders were infiltrated into porous WC bodies. After infiltration, samples were characterized via X-Ray diffraction studies and microstructural evaluation of the samples was carried out via scanning electron microscopy observations. Based on the lack of solubility between WC and Cu it was possible to keep fine WC particles in Cu melt since solution reprecipitation controlled densification is hindered. Also microstructural characterizations via scanning electron microscopy confirmed that the transport of fine WC fraction from infiltrant to porous WC skeleton can be carried out via Cu melt flow during infiltration

Development of a new nanofibrous composite material from recycled nonwovens to improve sound absorption ability

Composite structures with various stacking sequences were formed by combining electrospun polyurethane (PU) nanofibers with needle-punched recycled nonwovens from polyester textile wastes and bottles as a new sound absorption material in order to contribute to the solution of noise control and waste generation. PU solutions of 12, 13, 14 and 15 wt % concentrations were prepared for nanofiber optimization studies. Scanning electron microscope (SEM) images showed that the bead free nanofibers were obtained with diameters 296.5 and 509.9 nm from 13 and 15 wt % PU concentrations, respectively. In order to evaluate the potential of nanofibers and nanofiber-recycled nonwoven composites as noise reduction materials; sound absorption coefficients (SACs) were measured and noise reduction coefficients (NRCs) were calculated. The most ideal sample was regarded as the 3.24 mm thick sandwich structure (recycled nonwoven-nanofiber-recycled nonwoven), coded with A250-1320-A250 with a 0.504 NRC value. When the two nanofiber diameters were compared, finer nanofibers (296.5 nm) and finer nanofiber enhanced nonwovens had better NRCs than the thickers (509.9 nm) of the same. The developed composite materials can be regarded as promising sound absorbers. © 2019, © 2019 The Textile Institute

Covalently immobilized tris(triazolyl) methanol-Cu(I) complexes: highly active and recyclable catalysts for CuAAC reactions

Tris(1-benzyl-1H-1,2,3-triazol-4-yl)methanol (3), a highly efficient ligand for CuAAC reactions, has been immobilized onto Merrifield resins through different strategies. The S(N)2-supported Cu complex (8) is stable in water and under air; it is active at low catalyst loadings (1 mol%) and at low concentration (down to 0.125 M) in both aqueous and purely organic media. Resin 8 can be repeatedly reused in 1 : 1 MeOH-water for short reaction times (4 h) with the only precaution of Cu(I) reloading every five cycles

ChemInform Abstract: Covalently Immobilized Tris(triazolyl)methanol-Cu(I) Complexes: Highly Active and Recyclable Catalysts for CuAAC Reactions.

Tris(1-benzyl-1H-1,2,3-triazol-4-yl)methanol (3), a highly efficient ligand for CuAAC reactions, has been immobilized onto Merrifield resins through different strategies. The S(N)2-supported Cu complex (8) is stable in water and under air; it is active at low catalyst loadings (1 mol%) and at low concentration (down to 0.125 M) in both aqueous and purely organic media. Resin 8 can be repeatedly reused in 1 : 1 MeOH-water for short reaction times (4 h) with the only precaution of Cu(I) reloading every five cycles

A Highly Active Catalyst for Huisgen 1,3-Dipolar Cycloadditions Based on the Tris(triazolyl)methanol-Cu(I) Structure

A new tris(1-benzyl-1H-1,2,3-triazol-4-yl)methanol ligand 3 has been prepared by a triple Cu(I)-catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC). Ligand 3 forms a stable complex with CuCl, which catalyzes the Huisgen 1,3-dipolar cycloaddition on water or under neat conditions. Low catalyst loadings, short reaction times at room temperature, and compatibility with free amino groups make 3-CuCl an outstanding catalyst for CuAAC

TRIS(1,2,3-TRIAZOL-4-YL)METHANE ORGANOMETALLIC COMPOUNDS AS CATALYSTS AND PROCESSES USING THEM

Compounds of formula (I) or theirs salts, where Y is a (C1-C4)alkyl biradical and n is 1 or 0; M is Cu, Ag, Au, V, Fe, Zn, Ni, Co, Mn, Ru, or Cr; R1 is a known ring system with 1 -2 rings, isolated or fused; each ring having 5-6 members independently selected from C, N, O, S, CH, CH2, and NH, the rings being saturated, partially unsaturated or aromatic, and optionally being substituted by at least one radical selected: halogen, nitro, cyano, (C1-C4)alkyl, halo-(C1-C4)alkyl, -O-(C1-C4)alkyl. -CO-(C1-C4)alkyl, - COO-(C1-C4)alkyl, -OC(O)-(C1-C4)alkyl, -C(O)NR4R5, -(C1-C4)alkyl-NR4R5, -S- (C1-C4)alkyl, -SO-(C1-C4)alkyl, -SO2-(C1-C4)alkyl, -NHSO2-(C1-C4)alkyl, -SO2- NR4R5, and -NR4R5; R2 is -OR3, wherein R3 is selected from the group consisting of hydrogen, benzyl, and an hydroxyl protective group, or a polymeric support, optionally including a linker; and R4 and R5 are independently H, (C1-C4)alkyl, (C2-C4)alkenyl, or (C2-C4)alkynyl, optionally substituted by at least one radical selected from halogen, nitro, cyano, and amino; are useful as catalyst, in particular, in a process for the preparation of substituted 1,2,3-triazoles