Preparation Of Multifunctional Microcapsules Via Pickering Emulsion And Their Application In Textile

Functional textiles are the main research focus in the textile industry,and some textiles with functions such as aromatic slow-release,uv resistance,super hydrophobic,energy storage,intelligent color change and so on have attracted much attention.At present,most functional textiles in the market only have a single function,so the design and preparation of textiles with various special functions has become the mainstream of development.In textile functional finishing,many unique advantages of microcapsule finishing show great potential.First,microcapsules can encapsulate active substances(including essence,phase change materials,dyes,flame retardants,etc.)to play a role of slow release and isolation;Secondly,microcapsules are easy to be precisely regulated in size,shape and chemical surface to adapt to textile finishing.At present,most of the preparation methods of multifunctional microcapsules are complicated and time-consuming,which is difficult to large-scale application.Pickering emulsion method refers to the preparation of multifunctional microcapsules using solid particles instead of traditional emulsifiers to stabilize Pickering emulsion.As a newly developed technology,this technology has been widely used.In this thesis,functional inorganic nanoparticles were employs as Pickering emulsifier to stabilize the oil phase containing polymeric monomer and another active substance,and to initiate polymerization of monomer to form microcapsule shell material,and to prepare multifunctional microcapsules.The multifunctional microcapsules prepared are applied in outdoor textiles,energy storage textiles and anti-counterfeiting textiles,which are divided into the following three parts:(1)Preparation of multifunctional microcapsules with fragrance releasing,superhydrophobicity and UV resistance by Pickering emulsion and their applicationTiO₂ nanoparticle was modified by 1H,2H,2H-perfluorooctyltriethoxysilane and UV absorbers Tinuvin 1130 for improving the amphiphilic property and additional performance.Multifunctional microcapsules with osmanthus fragrance oil(OFO)as core materials and hexanediol diacrylate(HDDA)/modified titanium dioxide(TiO₂)as shell materials were prepared via Pickering emulsion photopolymerization.The microcapsules are strawberry and core-shell structure and then blended with waterborne silicone resin to form multifunctional fabric coatings.The preparation process is rapid and environmentally friendly.The coated fabric can keep fragrance releasing for 85 days at room temperature condition,which showed slow releasing performance of fragrance.Meanwhile,due to perfluorooctyltriethoxysilane and ultraviolet absorbers Tinuvin 1130 grafting on the TiO₂ nanoparticles in the shell of microcapsules,the coated fabric not only exhibits excellent superhydrophobicity with high water contact angle(WCA)(158.6^o)and low sliding angle(SA)(9.0^o),but also possesses Ultraviolet(UV)protection property with high Ultraviolet Protection Factor(UPF)value(126.7).(2)Preparation of multifunctional microcapsules with self-healing superhydropbocity,anti-by Pickering emulsion and their applicationThermosensitive TiO₂ nano capsules(FTCs)containing hydrophobic substance(FAS)were prepared by co-hydrolyzing polycondensation of isopropyl titanate and temperature-sensitive monomer N-isopropyl acrylamide at the oil-water interface,and Pickering emulsions were formed by emulsifying the oil phase values containing phase change materials and monomers.By heating,styrene monomer in the oil phase is polymerized to form shell material to obtain two-compartment microcapsules.The two-compartment microcapsule is loaded with phase change materials,while the Pickering particles in the outermost layer of the microcapsule are loaded with FAS.The core-shell structure of the two-compartment microcapsules was confirmed by SEM and TEM.The multifunctional fabric coating with double self-healing,energy storage and reflective heat insulation can be obtained by mixing the prepared two-compartment microcapsules with self-healing polyurethane and coating the fabric surface.The multifunctional fabric coating not only has the function of storing energy and regulating temperature of phase change material,but also has the effect of reflecting heat insulation due to the existence of TiO₂.Compared to the blank model,the two-compartment microcapsule showed a 39.28%infrared reflectivity for 780-2500 nm wavelength and a temperature difference of 6.3 ^oC in reflective insulation applications,demonstrating excellent thermal insulation performance.When the two-compartment microcapsule content is 40 wt%,the surface of the superhydrophobic fabric coating is still superhydrophobic under the conditions of press,brush friction,adhesive tape pasting and strong acid and alkali solvent,showing excellent durability.In addition,the surface chemical composition of the coating was damaged and the superhydrophobicity was lost after external wear.The surface chemical composition was restored after heating at 60 ^oC for 10 min and the superhydrophobicity was restored.When the coating is seriously damaged by external damage,the structure of the coating is damaged and the superhydrophobicity is lost.After heating at 60 ^oC for 2 h,the surface rough structure of the polyurethane and the microcapsule is restored through the exchange of multiple hydrogen bonds and disulfide bonds,and the superhydrophobicity is restored.This proves that the multi-functional fabric coating has double self-healing properties.(3)Preparation of multifunctional microcapsules with by Pickering emulsion and their applicationSiO₂ nanocapsuls encapsulating thermohromic materials were prepared by hydrolytic polycondensation of TEOS at the oil-water interface and modified by hydrophobic material(FAS),which were employed as Picering emulsifier to stabilize oil phase containing photochromic materials and polymerizable monomers for forming a stable emulsion.Multifunctiional microcapsules encapsulated photocromic dyes were prepared by thermal-curing the emusion,with loading thermochmic materials in the shell of microcapsules.SEM and TEM images illustrated that multifunctional microcapsules had a obviours strawberry-type morphology and core-shell structure.The thermal stability of multifunctional microcapsules was analysized by TGA.The microcapsule coating was applied to the fabric surface to prepare multi-functional textiles with double stimulation,discoloration,energy storage and super double-phobicity.To explore the effect of microcapsule content on hydrophobic performance.After the coating,the functional fabric was tested.It has the double stimulation of light and heat,and has a variety of colors.