| Abstract: | Water-soluble polymers suitable for shrink-resisting wool fabric by a pad–dry sequence can be prepared by the reaction of polyisocyanates with bisulphite salts. This paper examines the relationship between polymer structure and textile properties in these bisulphite adducts, or polycarbamoyl sulphonates (PCS). The reaction of various polyisocyanates with sodium bisulphite was examined. PCS could be prepared only from polyisocyanates with polyether backbones but not from those with polyester, polybutadiene or polycaprolactone backbones. Stable PCS were obtained from aliphatic isocyanates but those from aromatic isocyanates were relatively unstable. The PCS shrink-resisted wool fabric and behaved similarly to the parent polyisocyanates on wool. The polyureas formed on curing were somewhat susceptible to thermal and photo-oxidative degradation but this was improved to an acceptable level by the addition of hindered phenolic antioxidants. |
