| Pigment printing is a kind of environmentally friendly coloring technology.Organic pigment is widely used in inks,dyeing,printing and other fields because of its high color fastness,bright color,good color chromatography as the coloring particles.There are many problems in pigment printing and dyeing,such as the difficult to disperse in the water system and easily to accumulate in the film after evaporation of water,due to its strong hydrophobicity.In order to ensure the effective attachment of the pigment,it is often necessary to use a large amount of adhesives.It definitely results in a low efficiency in using adhesives and pigments.Moreover,the excessive adhesives cover on the fabric surface,leading to a stiff feeling and a low friction fastness of fabrics,which greatly limit the wide application of pigment printing and dyeing technology.The key points to overcome the above-mentioned problems are to improve the dispersibility of pigment particles in the composite films and further to control the microphase structure of the composite films.In this thesis,we firstly synthesized adhesive pigment micro-/nano-capsules through in situ encapsulation of pigment particles by adhesive copolymers;secondly,the film formation process of micro/nano capsules on the glass or aluminum substrate and the microphase structure of the films were systematically investigated;finally,the attachment of composite film on the fabric surface and the corresponding performance of fabrics were also studied.In order to deeply understand the film formation process,The 3D video microscopy system is used to carry on the direct observation.it is difficult to directly observe the nanoscale pigment capsule film forming mechanism and the film microphase structure formation regularity.The corresponding results can be used to study the mechanism of film formation and the regularity of film microstructures of pigment nano capsule which are difficult to be directly observed.Firstly,the copper phthalocyanine(PB)were efficiently and stably encapsulated in micron-sized polymer capsules(hereinafter referred to as microcapsules)by in situ micro-suspension polymerization by using tricalcium phosphate(TCP)and chitosan(CS)as the dispersants.When using TCP as dispersant,it was found that TCP particles would be in the form of internal and external two-layer structure attached to the monomer droplets.It is suitable for the preparation of high glass transition temperature(Tg)pigment microcapsules because of the weak dispersion ability.When using CS as dispersant,it was found that the protonation degree and hydrophilic-hydrophobic property of CS molecular chains could be easily controlled by adjusting the pH value of aqueous medium.The adsorption efficiency and spreading degree of CS chains on the surface of monomer droplets could be adjusted in a wide range.When the pH value of the system was close to 6.0,CS had a suitable degree of cohesion and hydrophobicity,and therefore,it can disperse and stabilize the monomer droplets in the process of high-speed shear homogenization and micro-suspension polymerization.The film-forming properties of PSA/PB micro capsules were systematically studied using the glass as the substrate.It was found that the coated organic pigment was well dispersed in the film after the capsules made of the styrene-acylate polymer were melted and spread.It meant that the pigment particles could directly disperse in the polymer film without the water dispersed process,after the capsule and the film formlation.Compared with the blended film,the composite film prepared with PSA/PB micro capsules had better coloration effect.Secondly,the nano-sized polymer/pigment capsules(hereinafter referred to as nanocapsule)were prepared by miniemulsion polymerization by using PB cake as the coloring agent.The influences of the preparation parameters on the dispersed state of PB particles in the monomer mixture,the particle size of the monomer droplets and latex particles of miniemulsion,and the morphology and the film-forming performance of the PB-containing capsules were investigated in terms of the homogenization method,the content of the organic pigment,and the type of monomer.The colloidal stability of the miniemulsion system could be well controlled when the content of the pigment was 12 wt% and the mass ratio of BA to styrene were 6:4,respectively.The resulting particles showed a clear capsule morphology and a good film-formation performance.The submicron pigment-containing capsules prepared by our proposed technique have a high potential application in pigment printing and dyeing.Novel P(DMS-SA)/PB pigment nanocapsules were prepared by preloading a silicone monomer,VPDMS,into miniemulsion polymerization systems.The P(DMS-SA)/PB pigment nanocapsules displayed a multiple island phase structure.PB and PDMS were the island phase,while PSA was the sea phase.After the film formation of P(DMS-SA)/PB nanocapsules,the internal phase separation structure was still maintained.The film surface formed a special protrusion structure.The PDMS could enhance the surface hydrophobicity,good color depth,and color uniformity of the capsule film.Finally,a series of organic pigment micro-/nano-capsules prepared by microsuspension polymerization or miniemulsion polymerization were applied into pigment printing of cotton and polyester fabrics.The morphology of microcapsule and printed cotton surface was observed by SEM.The effect of microcapsule morphology on the printing results was investigated in order to understand the film-formation process of microcapsule.It was found that the pigment particles of nanometer level microcapsule were homogeneously and firmly adhered in the thin adhesive layer of the whole fiber surface,attributing to its small particles size and its self-adhesive polymer wall.Thus its K/S value,handle,dry and wet fastness were better than those of the traditional printed fabric and the fabric printed by micrometer level microcapsule.For micrometer level microcapsule,numbers of pigment particles in it could not migrate with the viscous flow of adhesive polymer.Thus a lot of pigment accumulation and discrete adhesive layer were observed on the surface of yarn.In conclusion,the microcapsule morphology as well as the spreadability of pigment particles during film curing process played an important role in the print quality of cotton fabric.Only the pigment microcapsule in a small scale was available to improve the dispersion of pigment particles on fabric surface and simultaneously the binding force of pigment particles with fabrics.P(DMS-SA)/PB nanocapsules have all advantages of PSA/PB.Compared with PSA/PB nanocapsules,P(DMS-SA)/PB nanocapsules could not only attach pigment to the surface of the fabric fibers more firmly,but also cover more efficiently on single fibers.Thus,P(DMS-SA)/PB nanocapsules were subjected to pigment printing could obtain properties such as air permeability,hand feeling,and fastness.Through the researches of this paper,the mechanism of pigment capsules formation by situ polymerization was revealed.Pigment capsules with different particle size and morphology were designed and prepared.The hydrophobic of pigment particles was greatly improved.The study of the capsule's film formation of also revealed the dispersion state of the pigment in the capsule.Comparing with the traditional printed fabric,the K/S value,the handle,the dry and wet rubbing fastness of printed fabric treated by microencapsulated pigments could be better than the former,implying the present of polymeric layer on the pigment particles could remarkably improve the dispersion of pigment particles on fabric surface and simultaneously the binding force of pigment particles with fabric.In conclusion,there are many advantages of organic pigment encapsulation on the pigment printing of cotton and polyester.The conclusions obtained in this thesis may guide the improvement of coloring performance and properties of organic pigment printing and dyeing. |
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