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have never been reported so far. Dimethyl sulfoxide (DMSO) and N -methyl pyrrolidone (NMP) as solvents have been used extensively in our production and application, so thermochemical properties of its solution have been studied first by means of a RD
Diffusion in polymers dependence on crosslink density
Eyring approach to mechanism
Abstract
Kinetics of N-methyl pyrrolidone evaporation from swollen photo-crosslinked polyacrylate was monitored thermogravimetrically at temperatures ranging from 323 to 398 K. Crosslink density dependence of evaporation kinetics was investigated in photo-crosslinked polyacrylates with crosslinked density ranging from ≈1.2 × 102 to ≈1.7 × 104 mol m−3 and number of main chain atoms between crosslinks ranging from ≈70 atoms to ≈6 atoms, respectively. As was shown, evaporation kinetics was controlled by the solvent diffusion in polymer. Activation energies of evaporation (diffusion) were deduced from the rate measurements at different temperatures. Apparent activation energy of evaporation decreased from 48.7 to 31.1 kJ mol−1 with crosslink density increase. Activation energy of pure N-methyl pyrrolidone evaporation was 50.6 kJ mol−1. Decrease of the rate of solvent diffusion and unexpected decrease of diffusion activation energy with increase of crosslink density of swollen polymer matrix was explained by decrease in polymer chain segments mobility, as indicated by Eyring’s approach to diffusion in polymers.
Effect of carbon nanotubes’ crystal structure on adsorption kinetics of small molecules
An experimental study utilizing ultra-high vacuum thermal analysis techniques
suspension with SDS (sodium dodecyl sulfate) or NMP ( n -methyl pyrrolidone), for example, is the starting material. Depending on the solvent, the sonication is eventually breaking and debundling the CNTs. The centrifugation is removing amorphous carbon and
flask equipped with a stirrer charged with 3 g CaCl 2 , 3.7 g (0.05 mol)1,3-propanediamine and 100 mL n -methyl-pyrrolidone(NMP). Then the mixture was stirred, when the CaCl 2 dissolved completely, the flask was cooled to 0–10 °C. After that, 10.15 g
-linking agent was purchased from Sigma Aldrich Co and used without further purification. N -methyl pyrrolidone (NMP) and acetic acid solvents (AcOH) were brought from Merck (Germany) and distilled at 250 °C and 60 °C before use, respectively
absorbances A series of phenyl isocyanate solutions with different −NCO concentrations in toluene, butyl acetate, cyclohexanone, pyridine, N -methyl pyrrolidone (NMP), DMF was prepared, and the absorbance of −NCO at 2273 cm −1 was measured with in
