kevlar is one of the fbers which is used in heavy industrial productions such as, shipping, military and weaving for reinforcement of composites. initial polymer of kevlar or poly(para-phenylene terephthalamide) is an oriented liquid crystal polymer. existence of aromatic group in the main chain leads to formation of rigid-rod molecules in the polymer, high strength and high modulus in it is fb...

Chemical cross-linking of gelatin is achieved using a thermosensitive reactive copolymer based on N-isopropylacrylamide (NIPAM). The copolymer bears 5 mol % acrylic acid units which form amide bonds with the amino groups of gelatin in the presence of a water-soluble carbodiimide. The cross-linking reaction occurs only below the LCST congruent with 34 degrees C (lower critical solution temperatu...

knowledge of physiological and environmental factors is important for foragegrass production. festuca ovina is a grass species adapted to azerbaijan region climate,iran. this species is a valuable source for forage production and soil conservation.nitrogen (n), phosphorus (p) and potassium (k) are three most important plant nutrients.the aims of present study were to investigate the effects of ...

to investigate the effects of drought stress and different combinations of animal manure with super absorbent polymer on yield and yield components of corn, a split plots design was conducted based on a randomized complete block design with 3 replications in fars agricultural research center in 2007. irrigation treatments were assigned as the main factor in three levels: 70, 105 and 140 mm evap...

In this study, (3-mercaptopropyl) trimethoxysilane (MPTMS) modified silica nanoparticles (SiO2-MPTMS) were successfully prepared. The average size of SiO2-MPTMS was measured by Dynamic Light Scattering (DLS) as 341 nm in ethanol, while Scanning Transmission Electron Microscopy (STEM) analyzes confirmed that the nano-sized and revealed their shapes spherical. Then, 3D nanocomposite hydrogels pre...

Excessive water production through fractures become an important problem in oil exploration of fractured reservoirs. For this purpose, polymer gels were prepared by crosslinking of aqueous solutions of polymer and crosslinker for the purpose of water management in high water cut fractured reservoirs. A copolymer of sulfonated polyacrylamide was used as polymer and chromium triacetate (Cr(OA...

Background: There are various methods to read out responses of a polymer-gel dosimeter, among which the Magnetic Resonance Imaging (MRI) technique is the most common one. Optimizing imaging protocols can have significant effect on the sensitivity and the dose resolution of polymer gel dosimeters. This study has investigated the effects of the number of echoes (NOE) and the echo time spacing (ES...

Due to the importance of nanoparticles stability in industrial applications, in this research, stability of laponite nanoparticles dispersions containing different concentrations of sodium sulfonated polyacrylamide (SPA) was investigated in electrolyte media for oil reservoirs applications. In this regard, effect of parameters such as polymer concentration, temperature, and ionic strength were ...