The Trial-manufacture And Performance Evaluation Of Fluorine-free Water Repellent Based On Long Chain Alkanes

Waterproof finishing of textiles is a common functional finishing of textiles.Due to organic fluorine chemicals commonly used in "three defenses" finishing contain perfluorooctanoic acid(PFOA),PFOS,FTOH,etc,which are difficult to degrade and highly bioaccumulative and highly toxic,the search for alternatives to fluorocarbon water repellents,that is non-fluorinated water repellents,has become a hot topic this year.The topic is based on the basic theory of water repellent,and through the selection of raw material components,the design of the structure,the improvement of the preparation process,and the introduction of functionalized monomers,five different structure kinds of fluorine-free water-repellent finishing agents which are polyurethane type Non-fluorine-containing water repellent ?polyurethane-modified acrylate type fluorine-free water repellent?modified nano-silicon water repellent?acrylate-modified silicone type water repellent and silicone water repellent were designed and synthesized and the synthetic water repellents were also evaluated for their stability and application performance.The results of the experimental study indicate that by initiating the polymerization of octadecyl acrylate(SA)and a functional double bond monomer,a long-chain alkyl group is introduced into the polyurethane structure to synthesize a polyurethane type fluorine-free water repellent agent,and the water repellent agent is treated to the cotton fabric On the cotton fabric,the contact angle is about 125°.However,SA can not be effectively connected to the polyurethane structure,so the treated cotton fabric is not only poorly wetted,and the synthesized sample cannot be stored stably;the polymerization of the double bond-containing polyurethane and octadecyl acrylate(SA)is initiated by the initiator.A polyurethane-modified acrylate-type fluorine-free water repellent was synthesized.Compared with cotton fabric treated with octadecyl acrylate self-polymer,the water repellency of the water repellent agent has been improved to some extent,indicating that the introduction of polyurethane can improve the water pressure resistance of the fluorine-free water repellent,but due to the hydrophilicity of polyurethane,the water repellent performance decreases with the increase of accessibility.The water repellent sample obtained by modifying the nano-silica with cetyltrimethoxysilane(KH310)has a poor storage stability due to the large sample particles,and The prepared water repellent sample not only has poor storage stability,but also lacks mutual cross-linking due to the low molecular weight of the product,thus failing to achieve the purpose of waterproofing;The acrylic esters modified by the silicone long-chain backbone modified by stearyl acrylate(SA)Silicone water repellent agent,its contact angle to cotton fabrics is about 105°;two kinds of structural branched silicone water repellents cross-linked with self-synthesizing silicone precursors through hydrolysis of siloxanes.The treated cotton fabrics have contact angles of 125° and 132°,respectively,and have a good water repellent effect.