The present study deals with the effect of ultrasound on the swelling and dissolution behavior of the cellulose pulp. Hardwood, acid sulfite cellulose pulp sheets were sonicated at different temperatures, operated at a fixed frequency (37 kHz) and power (320 W) to break the intermolecular forces and hydrogen bonds of crystalline region. The obtained samples were evaluated for crystallinity, intrinsic viscosity, molecular weight (MW), molecular weight distribution (MWD) and surface morphology. It was observed that the crystallinity reduced from 61.9 to 18.9% after 20 min of ultrasound treatment at 30 °C, which was equivalent to the swelling at 75 °C for 20 min without the use of ultrasound frequency. It was also found that ultrasound pre-treatment significantly decreased the particle size of the slurry and shortened the dissolution time and temperature requirement without affecting the cellulose solution quality.
A Langmuir film of poly(ethylene oxide) (PEO) has been prepared at the air−water interface using water as the spreading solvent. Unlike the conventional PEO film (prepared using chloroform as the solvent), which exhibits the highest surface pressure of 10 mN/m, the present film attains a surface pressure of 17.5 mN/m at high apparent polymer loading (35 mg/m 2 ).The π−A isotherm of a film prepared at low PEO loading was observed to be similar in nature to the conventional isotherm of PEO, and the surface pressure attained for the film is 10.5 mN/m at a loading of 1 mg/m 2 . The key step in the preparation of the film is to use a higher initial loading of polymer and multiple compression− expansion cycles to induce aggregation and compaction of PEO molecules in the film. The prepared Langmuir films were characterized in term of surface pressure−surface area isotherms, the hysteresis exhibited by these isotherms, and the static dilatational modulus. Article pubs.acs.org/IECR
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