Tesis doctoral de Daiyong Ye
Miscanthus, cardoon, and eucalyptus pulps were produced by impregnation rapid steam pulping (irsp) process and bleached by total chloride free (tcf) sequences using hydrogen peroxide and sodium hydroxide. With an increase of pulping severities, accessibilities and reactivities of bleached pulps increased while viscosities and kappa numbers decreased. A novel facile methylation was developed in order to prepare methylcelluloses from wood and annual plants. Each methylcellulose of tcf bleached pulps was synthesized in isopropanol slurry with iodomethane at 600c for 22 hours after the tcf bleached pulp was mercerized in 40% naoh solution for 1 hour. The mercerization and methylation were repeated in order to obtain a higher degree of substitution (ds). Fourier transform infrared (ftir) spectra showed oh groups of cellulose were partially substituted by methoxyl groups. Supramolecular substitution patterns of methylcelluloses were determined by 13c nuclear magnetic resonance (nmr) spectroscopy. Intrinsic viscosities of methylcelluloses were measured in distilled water, 4% naoh solution, or dimethyl sulphoxide (dmso). Rheological properties of methylcelluloses were measured in dmso, 4% naoh solution or distilled water, in which the synthesized methylcelluloses had similar properties as commercial methylcelluloses. Water-soluble and alkali-soluble contents of methylcelluloses were determined by solvent extraction. we used iodomethane to synthesize methylcelluloses from elemental chloride free (ecf) bleached abaca, hemp, flax, jute, and sisal pulps via heterogeneous and homogeneous methylations. The heterogeneous methylation was carried out in isopropanol with iodomethane at 600c for 22h after a ecf bleached pulp was mercerized in excessive 50% naoh solution for one hour at ambient temperature. The homogeneous methylation was carried out in dimethyl sulfoxide with iodomethane at 300c for 48h using a methylcellulose of low degree of substitution.
Datos académicos de la tesis doctoral «Preparation of methylcellulose from annual plants«
- Título de la tesis: Preparation of methylcellulose from annual plants
- Autor: Daiyong Ye
- Universidad: Rovira i virgili
- Fecha de lectura de la tesis: 30/09/2005
Dirección y tribunal
- Director de la tesis
- Xavier Farriol Roiges
- Tribunal
- Presidente del tribunal: Luis Jimenez alcaide
- joan carles Ronda bargalló (vocal)
- teresa Vidal lluci? (vocal)
- jordi Reguant miranda (vocal)