Application Of Modified Sodium Alginate In Phthalocyanine Pigment Dispersion And Printin

Paint printing is a simple process with short printing procedures.However,there are problems such as poor pigment dispersion stability and insufficient adhesion of the binder to the pigment,as well as high energy consumption due to the need for high temperature baking and the impact on the quality of the fabric.Sodium alginate(SA)is the most used natural polymer in the modern textile industry and has a large number of easily modified groups distributed on its long chain.In this study,SA was oxidised using sodium periodate and then grafted with cinnamamide via Schiff base reaction to obtain hydrophobically modified SA(HMSA),and the structure of HMSA was determined by FT-IR,1HNMR and XPS analysis.The dispersion stabilization of phthalocyanine pigments and polyurethane acrylate(PUA)by HMSA complexed with sodium dodecyl sulphate(SDS)was systematically investigated and the effect on the UV-curable printing effect of the pigments on cotton fabrics was studied.Firstly,tests on particle size,zeta potential and light scattering stability revealed that the pigment dispersions reached their highest stability when the HMSA to SDS ratio was 30%.The degree of aggregation(S_T)and degree of settling(R)tests revealed that HMSA significantly enhanced the p H,salt and temperature stability of the pigments.This enhancement effect was particularly evident under acidic conditions,with pigment aggregation levels of 47.43%and 8.49%for blank and added HMSA.Although H~+reduces the electrostatic repulsion on the surface of the dispersion,HMSA still provides some spatial repulsion for the pigments to inhibit collisions and contact between pigment particles.Secondly,the effect of HMSA on PUA emulsification and curing film formation properties was investigated.The results showed that HMSA resulted in smaller and more homogeneous droplets(112.4 nm)and an increase in the absolute potential value of the emulsion(63.2 m V).In addition,the water wetting angle of PUA light-cured films was slightly reduced by HMSA,but the reactive double bond in HMSA increased the cross-linkage of the cured films and enhanced the resistance to acids and alkalis and alcohols.Finally,the encapsulation of phthalocyanine pigments in PUA/HDDA hybrid emulsions was achieved based on HMSA and SDS.The effect of the mixed monomer content on the properties of the pigment capsules was investigated,and the structure of the pigment capsules was analysed by TEM,thermogravimetric analysis,FTIR spectroscopy and XPS.The results show that the pigment particles can be encapsulated on the surface of the fabric,reducing the chance of shedding during rubbing and washing,and effectively improving the colour fastness.In addition,the effect of pigment capsule printing on the properties of cotton fabric such as strength,hydrophobicity and breathability was investigated...