What is Porosity and Bursting Strength?
Porosity and bursting strength:- Property of containing connected air voids. It is dependent upon the number of voids and their distribution in size, shape and orientation. It indicates how a sheet will respond to fluid penetration eg. In printing paper how printing inks will penetrate and spread. Greaseproof paper must have a very low air permeability/porosity in order to perform propertly. Cigaretter paper must have controlled permeability so as to give a uniform burning rate. Bursting Strength:- A measure of the ability of a sheet to resist rupture when pressure is applied to one of its side. This is one of the oldest tests used by the paper industry and is relatively easy and inexpensive to run for quality control.
