I quite like cooking thesis on health and safety Cotton’s biggest drawback, against its synthetic rivals, was its tendency to crease. This is down to the molecular structure of cotton fibres, which are comprised of long cellulose chains – polymers – held in place end-to-end by hydrogen bonds. Since these links are weak and easily broken, the heat and agitation of washing causes the molecules to shift position, resulting in the wrinkles that are corrected by ironing.