| Polymeric dyes are colored polymers formed by introducing chromophore into the main or side chains of polymers through chemical reactions.They are increasingly becoming a hot research topic because they have many advantages that traditional small molecule dyes do not have(high migration resistance,excellent solvent resistance and high safety).At present,the polymeric dyes with synthetic polymer as the backbone are widely investigated,while little attention has been paid to bio-based polymeric dyes.The development of bio-base polymeric dyes conforms to the green development direction at the time of increasingly serious resource and environmental problems.The aim of this study is to develop cellulose-based polymeric dyes with cellulose macromolecular chain as the backbone,which is expected to broaden the scope of polymeric dyes.This work first explored the dyeing of wood pulp board cellulose in a binary heterogeneous organic solvent system,consisting of dimethyl sulfoxide(DMSO)and ethyl octanoate(EO),which provided which provided an ecological dyeing scheme for the subsequent preparation of cellulose-based polymer dyes.Compared with the dyeing in water system,the solvent system has no obvious dyeing saturation value,and the amount of dyes adsorbed on the fiber increased with the increase of dye concentration in the dye solution,which makes it possible to achieve higher absolute dye fixation than in traditional aqueous dyeing,By adjusting the bath ratio,dye concentration,dyeing temperature,the ratio of DMSO to EO and dyeing processes,reactive yellow 145(RY 145)could be fixed up to 233.72 mg/g,21% higher than the maximum fixation achieved in traditional aqueous dyeing.There is no need to add inorganic salts to promote dye adsorption.The solvent used become miscible above 60? and phase separated when cooled at lowing,convenient recovery and reuse of the excess dyes.The reactive dye will not be hydrolyzed and can be reused in the binary solvent system.Base on the colored wood-pulp.cellulosic dyes were prepared by dissolution and regeneration process followed by homogenization.TEM results reveal that the diameter of30-50 nm and length of several microns.X-ray diffraction and infrared spectrum analysis showed that after cellulose regeneration,the crystal form changed from cellulose type I to cellulose type?,and both the degree of crystallinity and degree of polymerization(DP)decreased noticeably.The effects of the grafting and structure dyes on the solubility of the cellulosic dyes,and the rheological properties were tested.the results show that the dissolution rate of cellulose decreased with increasing grafted dyes.Dyes with multiple active groups lead to incomplete dissolution,because of their cross-linking with cellulose.The regenerated cellulose suspension shows gel-like behavior and shear thinning.Finally,the cellulose-based polymeric dyes were used to color polymer fibers by dope dyeing.The results show that the color depth of the regenerated cellulose/polylactic acid(CRC/PLA)composite fiber increases with the increase of the content(1-2 wt%)of cellulosic dyes.When the addition is 2 wt%,the K/S can reach 8.53.the addition of the cellulose-based polymeric dyes can enhance the tensile strength of regenerated cellulose/polyvinyl alcohol(CRC/PVA)and regenerated cellulose/polyacrylonitrile(CRC/PAN)composite fiber.When 1wt% cellulosic dye was added,the breaking strength of CRC/PVA composite fiber was 327.8 MPa,and that of the CRC/PAN composite fiber was 54.0 MPa,respectively.When the addition is 2 wt%,the breaking strength of CRC/PLA composite fiber was 54.4 MPa,which is increased by 30.6% compared with pure PLA fiber.The polymeric dyes prepared in this study not only have the rich color of small molecule dyes and the processability of polymeric material,but also have the biocompatibility and green renewable characteristics of cellulose.Its development not only opens up some ideas for the development of polymeric dyes,but also expands the application scope of cellulose materials. |
PDF Full Text Request