Excepting bamboo and sungrass, various grass species growing
in the forest lands of Chittagong, Chittagong Hill Tracts and Sylhet
districts of Bangladesh, at present, have practically no use. Five
grass species, namely, Panicum, antidetale, Retz., Themeda arundinacea,
Ridley., Saccharum spontaneum Linn., Thysanolaena maxima, O, Ktze, and
Imperata arundinacea, Cyr., which are available in the area in appreciable
quantities, have been pulped by steaming and soda processes for the
manufacture of insulation boards in equivalent mixtures as well as in
the proportion of their availability in the forests. The pulps obtained
by the steaming process were free-draining but rather dark in colour.
Soda pulps were lighter in colour but comparatively slow-draining.
Yield was high in both the processes.
Rigid structural insulation boards were made both by press-drying
in a hot hydraulic press at low pressure and by cold pressing the
mats and then drying in a force-draft oven. The boards had very
good strength but moderate heat insulating properties, They compared
favourably with the imported ones so far as the moisture resistance
properties were concerned.