Development of novel polymeric cross-linkers for wrinkle-resistant finishing of cellulosic fabrics

Abstract

The present work lays down some new ways, by which promising cellulose reactive cross-linkers can be developed based on utilising naturally available acids as the building blocks. Citric acid (CA) and malic acid (MA) have been focused. Two approaches, i.e., azeotropic polycondensation and bulk polycondensation, have been adopted and studied to synthesise the corresponding well-defined polymers from them with a series of co-reactants such as multifunctional alcohols, poly(ethylene glycol)s (PEG)s, and itaconic acid (IA). It was found that when the multifunctional alcohols were used, dendritic polymers with different numbers of polyacid arm segments can sucessfully be produced in reasonably high yields. In case of (PEG)s, polyacids with linear-dendritic structures were yielded. The way involving IA can enable the formation of linear polyacids with additional functionality. FTIR and NMR analyses have been conducted to verify the polymer composition and architecture. A comprehensive wrinkle-resistant finishing study was carried out to evaluate the cross-linking performance of the newly developed polymers comprised of various compositions and architectures. The resultant performance of dendritic polyacids with various numbers of reactive CA and MA moieties were evaluated in term of wrinkle recovery performance of the modified cotton substrates. Meanwhile, linear-dendritic structure was capable of furnishing strength retention of the modified substrate. In particular, poly(malic acid) capped with IA (PMA-IA) has a strong cross-linking effect to cellulose chains. Upon impregnation of PMA-IA, cellulosic fabric improves substantially in wrinkle-recovery performance. The vinyl moiety on the polymer is polymerisable, which can give hand to building higher network density under a condition with potassium persulfate (K2S2O8). The combined effect proved to promote better wrinkle-resistant performance along with an improved retention in mechanical properties for the cross-linked system. The effects of finishing variables such as polymer concentration, catalyst concentration, pH, and treatment temperature and time have been deeply studied in connection to the FTIR-ATR analysis on the modified materials. The findings in this study could help alleviate the drawbacks of conventional wrinkle-resistant treatment used in the industry.