فناوری نساجی (علوم و تکنولوژی نساجی)
سال:1387 | دوره: | شماره: |تعداد مقالات:3

The paper reports the fabrication and characterization of polyacrylonitril (PAN) nanofibers by electrospinning and further development of the as-spun PAN nanofibers into carbon nanofibers. PAN nanofibers as a precursor of carbon nanofibers with diameters in the range of 100–350 nm were prepared by electrospinning of PAN/DMF solution. The aligned electrospun polyacrylonitrile (PAN) nanofibers first stabilized in air at temperature 290oC for 1 hr. We also investigated several carbonization procedures by varying final carbonization temperatures in the range from 800-1000ºC in nitrogen and argon atmospheres and the carbon nanofibers were successfully obtained at 800oC and 1 hr. Morphologies, structures and thermal properties of PAN, stabilized and carbonized nanofibers were investigated by scanning electron microscopy (SEM), infrared spectrometer (IR), thermal gravimetric analysis (TGA). The results obtained from scanning electron microscopy showed that the nanofibers are unidirectional aligned and after stabilization and carbonization the SEM results revealed that the average diameter of the stabilized PAN nanofibers appeared to be almost the same as that of the as-electrospun nanofibers, while the average diameters of the carbonized PAN nanofibers were significantly reduced, and also scanning electron microscopy without any gold coating.

Six new copolyamides CoPAs 7a-f were synthesized through the direct polycondensation reaction of 4,4'-azobenzenedicarboxylic acid 1 with 4,4'-diamino diphenylether 2, 4,4'-diamino diphenylsulfone 3 in the presence of adipic acid 4, fumaric acid 5 and terephthalic acid 6 as a second diacid in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosphite, calcium chloride and pyridine. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses and inherent viscosity. Those CoPAs readily soluble in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrolidone (NMP) and solvents such as sulfuric acid. Thermal properties of the CoPAs 7a, 7b and 7f were investigated using thermal gravimetric analysis (TGA and DTG).

In study presents a CAD/CAM computer system for textile printing design. This computer systems part of an integrated system for graphic design, and includes also structural edition and retrieval tools to exploiting textile printing design. Drawing and some commands for geometrical transformations are specified by means of freehand strokes. Paper describes both user interface and its implementation details. A detailed design example is presented, where an ornamental motive, belonging to a pattern design has been generated by the gesture interface. Then it is integrated in a textile printing design using structural edition CAD/CAM system computer, based on the scientific theory of symmetry groups.