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Start Over Topic chemical structure Journal carbohydrate polymers
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1. Metal complexed-enzymatic hydrolyzed chitosan improves moisture retention of fiber papers by migrating immobilized water to bound state

Author

Chao Lin, Xuejiao Wang, Shuqin Xia, Khizar Hayat, Huijuan Wang, Muhammad Tahir, Shahzad Hussain, Heping Cui, and Xiaoming Zhang

Subjects
Paper, Polymers and Plastics, Water activity, Chemical structure, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Polyvinyl alcohol, law.invention, Humectant, Chitosan, chemistry.chemical_compound, Hydrolysis, Magazine, Cellulase, law, Papain, Materials Chemistry, Organometallic Compounds, Organic Chemistry, Water, 021001 nanoscience & nanotechnology, nervous system diseases, 0104 chemical sciences, Molecular Weight, Polygalacturonase, chemistry, Wettability, Molar mass distribution, 0210 nano-technology, Hydrophobic and Hydrophilic Interactions, Nuclear chemistry
Abstract

To obtain chitosan (CTS) with narrower molecular weight distribution, CTS with weight-average molecular weight (MW) of 197.30 kDa was first metal complexed and then degraded into five CTSs with MW of 107.90, 56.48, 10.40, 5.67 (CTS-4) and 3.66 kDa. Decrease of MW did not cause a significant change in chemical structure of the residue CTS, but the crystal structure was transformed significantly. The moisture retention increased firstly and then decreased as the MW of CTS decreased. CTS-4 was superior to CTSs with other MW and propylene glycol in terms of the moisture retention. The lower water activity and increase of net isosteric heat were observed in CTS-4, which was due to the migration of immobilized water to a bound-state caused by mounting newly formed chain-end hydrophilic groups per unit weight. CTS-4 could effectively improve moisture retention, showing a potential to substitute commonly used humectant such as propylene glycol.

Published
2019

2. The effect of pulping concentration treatment on the properties of microcrystalline cellulose powder obtained from waste paper

Author

O Okwonna Obumneme

Subjects
Paper, Materials science, Polymers and Plastics, Chemical structure, Infrared spectroscopy, Hydrolysis, chemistry.chemical_compound, stomatognathic system, Materials Chemistry, Composite material, Fourier transform infrared spectroscopy, Cellulose, Paperboard, Organic Chemistry, Refuse Disposal, Microcrystalline cellulose, Kinetics, stomatognathic diseases, chemistry, Chemical engineering, visual_art, Newsprint, visual_art.visual_art_medium, Thermodynamics, Caustic (optics), Powders
Abstract

Microcrystalline cellulose (MCC) powder was isolated from three grades of waste paper: book, Groundwood/Newsprint and paperboard, through the processes of pulping and hydrolysis. Pulping treatment on these grades of waste paper was done using varying concentrations of caustic soda. Effects of the concentration of the pulping medium on the thermal and kinetic properties were investigated. Also determined were the effects of this on the physico-chemical properties. The chemical structure was characterized using an infrared spectroscopy (FTIR). Results showed these properties to be affected by the concentration of the pulping medium.

Published
2013