High strength retention of cellulose fibers crosslinking with synthesized low-molecular-weight copolymers of itaconic acid and acrylic acid

1,2,3,4-Butanetetracarboxylic acid (BTCA) can cause significant strength loss to cotton fabrics, but it has been proven that a flexible molecular structure could benefit the strength in our previous study. In this research, more flexible copolymers [P(IA–AA)] were synthesized with itaconic acid (IA) and acrylic acid (AA) and creatively used as a formaldehyde-free crosslinking reagent for cotton fabrics to replace BTCA. The optimal synthetic conditions of P(IA–AA) were recommended as that the molar ratio of IA:AA and reaction time were 1:1 and 3 h, respectively. The structure of P(IA–AA) was characterized with proton nuclear magnetic resonance spectroscopy, mass spectroscopy and Fourier transform infrared spectroscopy. Results provided evidence that the P(IA–AA) was synthesized with two IA and two AA molecules (molecular weight was 406). Through careful selection, the optimal anti-wrinkle finishing conditions were P(IA–AA) concentration of 160 g/L, pH value of 2.1, curing temperature of 180 °C, and curing time of 2 min. By comparing with IA, BTCA, citric acid (CA), and copolymers of maleic acid (MA) and AA [P(MA–AA)] in the similar conditions, the P(IA–AA)-treated fabrics showed the highest tearing strength retention of 59.30% and whiteness index of 77.60, and the wrinkle recovery angle of the P(IA–AA)-treated fabrics (245.1° ± 0.85°) was comparable with that of the CA-treated ones (244.7° ± 4.30°). Additionally, by separating the strength loss caused by degradation (TSLD) from that caused by crosslinking (TSLC), the P(IA–AA)-treated fabrics presented about 10% less TSLD than P(MA–AA)-treated ones with a comparable TSLC.