Preparation Of Polyacrylate/nano SiO₂ Composites And Study On Superhydrophobic Finishing Of Cotton Fabrics

Superhydrophobic textiles due to their unique properties such as self-cleaning,anti fouling and so on,were widely used in sports fabrics,kitchen cloth,tents,protective clothing and other fields.Learning from the lotus effect,superhydrophobic surface could be realized by the cooperation of micro-nano rough structure and low surface energy material.Nano SiO₂ was widely used for construction of rough structure of super hydrophobic textile surface.But the connection between nano SiO₂ and textiles is insufficient.Nano SiO₂ is difficult to fix on the surface of the fiber.Therefore after washing several times,the rough structure on the surface of the fiber would gradually lose,eventually leading to disappearance of superhydrophobic properties of superhydrophobic textiles.And the polymer with low surface energy/nano SiO₂ organic-inorganic composite material with rough structure due to nanoparticles and low surface energy caused by polymer can be used for preparation of superhydrophobic textiles.The polymer with low surface energy/nano SiO₂ with excellent cohesiveness can improve the combination fastness of inorganic nano material and textiles,and increase washing resistance of superhydrophobic textiles.Polyacrylate due to its wide source,low cost,no pollution,good adhesion,film,color retention,gloss and other excellent properties,is widely used in many fields.But it has the poor water resistance,poor solvent resistance and poor permeability,and it is hot sticky and cold crisp,restricting its application.In this paper,polyacrylate/nano SiO₂organic-inorganic nanocomposite materials with high hardness,strong adhesion and excellent superhydrophobic properties were prepared by solution polymerization,and their structures,properties and application in fabric finishing agent were studied.The specific research are as follows:(1)Preparation of modified nano SiO₂ sol and its application in superhydrophobic finishing of cotton fabrics.The modified nano-silica was prepared by sol-gel method using tetraethyl orthosilicate(TEOS)as the precursor,methacryloxypropyltrimethoxysilane(KH-570)and hexadecyltrimethoxysilane(HDTMS)as modifiers and ammonia as the catalyst.The influence of reaction conditions on the modified nano-silica was discussed.The results showed that when the concentration of TEOS was 3%,the concentration of KH-570 was 4%,and the amount of ammonia was 2mL,the prepared modified nano-silica had narrow size distribution with an average particle diameter of 53.38nm and polydispersity index(PDI)of 0.078.Modified nano-silica sol was stable and transparent,and has blue light.And the particle size and PDI of modified nano SiO₂ would be increased gradually with the increase of HDTMS.FT-IR spectra showed that KH-570 and HDTMS were successfully grafted onto the surface of nano SiO₂.The prepared modified silica was used for superhydrophobic finishing of cotton fabrics.The influence of experimental factors was discussed.The results showed that when the TEOS concentration was 3%and HDTMS concentration was 4%,the treated cotton fabric had the contact angle of 152.2°,and the rolling angle of 9°,showing superhydrophobic performance.From SEM,the cotton fiber surface was covered with granular materials.So the cotton fiber surface roughness increased,improving the hydrophobicity of cotton fabric.(2)Preparation and characterization of polyacrylate/nano Si O₂ composite and its superhydrophobicity on cotton fabrics.The polyacrylate/nano SiO₂ composite was synthesized by solution polymerization using octadecyl methacrylate(OM),methyl methacrylate(MMA),butyl acrylate(BA),and modified nano SiO₂ as raw materials.The influence of reaction time,reaction temperature and initiator concentration on the conversionrateofpolyacrylate/nanoSiO₂compositeswasdiscussed.The superhydrophobicity of polyacrylate/nano SiO₂ composites on cotton fabrics was investigated.The effects of modified nano SiO₂ sol dosage and OM dosage on the hydrophobic property of cotton fabric were discussed.The results showed that when the polymerization temperature was 70?,the reaction time was 5h,and the amount of initiator was 2%of the total monomer,the conversion rate of polyacrylate/nano SiO₂ composite materials was up to 96.6%;FT-IR showed that the polyacrylate/nano SiO₂ composites were prepared successfully;the SEM showed that the particle size of polyacrylate/nano SiO₂composite was about 300nm;TG analysis showed that the introduction of nano SiO₂ could effectively improve the thermal stability of polyacrylate/nano SiO₂ composite material.The polyacrylate/nano Si O₂ composite material was used for superhydrophobic finishing of cotton fabric.The experimental results showed that when the modified nano SiO₂ dosage was 12%and the dosage of OM was 4%,the treated cotton fabric had excellent superhydrophobic performance with the contact angle of 152.63°and the rolling angle was10°.(3)Studyonsuperhydrophobicfinishingprocessofcottonfabricusing polyacrylate/nano SiO₂ composite and durability of superhydrophobic cotton fabric.The prepared polyacrylate/nano SiO₂ composite was used for hydrophobic finishing of cotton fabric.The effects of the amount of finishing agent,baking temperature and baking time on the superhydrophobic property of cotton fabric were discussed.The experimental results showed that when the polyacrylate/nano SiO₂ composite material amount was 90g/L,the curing time was 5min and the baking temperature was 170?,that treated cotton fabric showed excellent superhydrophobicity and the contact angle was 153.14°,and the rolling angle was 9°.In order to further enhance the binding of polyacrylate/nano SiO₂ composite material and the treated fabric,the methacrylic acid was introduced into polyacrylate/nano SiO₂ composite during polymerization process,and durable polyacrylate/nano SiO₂composite finishing agent was successfully prepared.Covalent binding of-COOH with-OH on the surface of cotton fiber was achieved,further improving the binding of polyacrylate/nano SiO₂ composite material and fabric.The wearability of cotton fabrics before and after finishing was compared.The effect of washing cycles on the durability of superhydrophobic cotton fabrics was explored.The experimental results showed that the fabric treated by durable polyacrylate/nano SiO₂ composite had better washing fastness.