Effect of the reaction conditions over the yield and properties of methylcellulose obtained from Pinus radiata kraft bleached cellulose

Abstract

Kraft bleached cellulose from Pinus radiata was submitted to methylation reactions in heterogeneous media. After activation with 29% (w/w) NaOH solution, methylation reactions were carried out both with dimethyl sulfate (DMS) and methyl iodide (MI). The effects of the pressing ratio, reaction time and type of methylation agent were studied. The better yields were obtained with dimethylsulphate and the pressing ratio and reaction time were not signficant over the yield. Methylcellulose (MC) of high degree of substitution was extracted with water and the MC of low degree of substitution was extracted with 8%w/w NaOH. Some of the MCs obtained were characterized by viscosity average molecular weight, thermal behavior, degree of substitution, steady shear solution behavior. The MC water extracted obtained under certain reaction conditions showed similar behavior that commercial MC.