Study On Hydrophilic And Oleophobic Modification Of Cotton And Polyester Fabrics Via UV-induced Grafting

Surface wettability of fabrics is one of the important properties of textiles materials.Now more works focus on superhydrophobic modification on the fabrics,while the moisture absorption and perspiration performance of the fabrics are usually reduced by the superhydrophobic treatment.In practical applications,water stains on the fabrics are easy to be washed away,while oily stains are hard to remove Therefore,it is urgent to develop hydrophilic-oleophobic fabrics with good moisture absorption and perspiration performance,as well as effective oil repellency.In this study,surface UV grafting method was used to endow the fabrics hydrophilic-oleophobic properties.Surface grafting polymerization of fluorine monomers or copolymerization with other comonomers were used for hydrophlilic-oleophobic treatment on hydrophilic cotton fabrics,while surface grafting polymerization of hydrophilic monomers was firstly used for hydrophilic finishing on hydrophobic polyester fabrics and then,the effects of surface grafting polymerization of fluorine monomers or copolymerization with other comonomers on hydrophilic-oleophobic properties of polyester fabrics were also evaluated.The details are as follows:(1)Study on the hydrophilic-oleophobic modification of cotton fabrics by surface UV grafting method:Surface UV grafting polymerization of fluorine monomers was used for hydrophilic-oleophobic finishing on cotton fabrics,when perfluorooctyl ethyl methacrylate(FOEMA)and benzophenone(BP)and were used as oleophobic fluorine monomer and photoinitiator,respectively.Results showed that surface UV grafting polymerization of fluorine monomer could achieve the hydrophilic-oleophobic properties on cotton fabrics,but the spreading time of water droplets was relatively long(more than 65 s).Then,three comonomers,including butyl methacrylate(BA),methyl methacrylate(MMA)and α-methylstyrene(AMS),were selected to copolymerize with FOEMA oleophobic fluorine monomer on the surface of cotton fabrics,respectively,aiming at spreading the water droplets quickly(around ten seconds)on the surface of cotton fabrics by reducing the density of FOEMA fluoropolymer chain segment to speed up the penetration of water into the hydrophilic layer of cellulose.The co-grafted fabrics still had good oil repellency(ranging from 96°to 118°).Besides,the fabrics also had better antistatic effect(Grade B),higher moisture regain(4.4%),and excellent wash durability.(2)Study on the hydrophilic-oleophobic modification of polyester fabrics by surface UV grafting method:Hydrophilic-oleophobic properties of polyester fabrics can be achieved in two steps.First,three hydrophilic monomers,including methyl methacrylate(MMA),Methacryloxyethyltrimethyl ammonium chloride(DMC)and 3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate(SBMA),were used for hydrophilic pretreatment.The spreading time of water droplets on the resulting polyester fabrics was only 300-500 ms.Besides,the fabrics also had good moisture regain and antistatic effect,and could keep good hydrophilicity after 5 times of AATCC standard washing.Then,surface UV grafting polymerization of fluorine monomer or copolymerization with other comonomers on the surface of resulting hydrophilic polyester fabrics were used for hydrophilic-oleophobic finishing.The results showed that surface grafting PFOEMA fluoropolymer could not achieve the hydrophilic-oleophobic properties,which is different from that of cotton fabrics.It is very likely that the weak hydrophilicity is not enough to make the water droplets penetrate the fluorine oleophobic layer and to spread it,as compared to hydrophilic cotton fabrics.However,surface UV grafting copolymerization of FOEMA oleophobic fluorine monomer and hydrophilic comonomers(BA,MMA or AMS)could achieve the hydrophilic-oleophobic properties on the resulting hydrophilic polyester fabrics.The introduction of comonomers can reduce the density of fluoropolymer chain segments,providing a path for water droplets to penetrate through the fluoropolymer reservoir and spread it.The fabrics had good oleophobicity(ranging from 95°to 100°),antistatic effect(Grade C)and moisture regain(around 1.2%),and the spreading time ranged from 80 s to 120 s.In addition,the fabrics also had good wash durability.It could maintain good hydrophilic-oleophobic properties after 5 times of AATCC standard washing.