An Explanation of Dyeing Mechanisms in Terms of Non‐polar Bonding

Inadequacies are demonstrated in previous attempts to explain dyeing mechanisms on the assumption of polar forces between dye and fibre. The important part played by non‐polar forces in adsorption phenomena generally is illustrated by examples. It is postulated that such forces are mainly responsible for dye‐fibre attachment and that in aqueous solution they occur between hydrophobic surfaces. The relative importance of hydrophobic and hydrophilic properties in fibres is deduced from their moisture regain figures and is discussed in relation to fibre structure. The properties of dyes are then similarly considered. Thence the dyeing behaviour of each type of fibre is predicted from the postulate that dye substantivity is due to non‐polar forces. It is concluded that this assumption is sufficient to explain the methods adopted for dyeing different fibres and that it eliminates anomalies incapable of explanation on the assumption that dye‐fibre attachment is due to polar forces.