Studies on the electrical properties of agricultural residue papers II. Electrical properties of rice straw paper and its blends with cotton stalks and wood

Electrical properties for paper samples made from unbleached and bleached r ice straw pulps, as well as from blends of bleached rice straw with cotton stalks and wood pulps, were studied. The influence of paper sizing, i.e. ad dition of resin and alum was also taken into consideration. Dielectric cons tant epsilon', dielectric loss epsilon " and sc. electrical conductivity, w ere measured at frequency OQ-20000 Hz at 110 degrees. influence of chemical composition of rice straw pulp on the electrical properties was studied an d discussed. Despite purification due to bleaching, the dielectric constant of bleached rice straw paper was lower than that of the unbleached paper. This was attributed to the high ash and silica content in the unbleached pu lp. Sizing raised the dielectric constant of paper but the dielectric loss increased. Comparing unsized paper made from bleached pulps, it was found t hat wood paper and rice straw paper possessed close values of dielectric co nstants, amounting to about 9.5. The dielectric constant of cotton stalks p aper was relatively lower: dielectric loss was better for wood pulp. Blends of bleached rice straw with bleached wood and with bleached cotton stalks showed higher values of the dielectric constant than paper from wood alone. However, dielectric loss was better for wood paper.