Improving the hydrophobicity/oleophobicity of polyethylene terephthalate fibrous materials using electron beam‐induced graft polymerization with 2‐(perfluorohexyl)ethyl acrylate monomer and alkyl acrylate monomer

Abstract

Better hydrophobic/oleophobic properties and durability were added to polyethylene terephthalate (PET) fabrics using graft polymerization induced by pre-and simultaneous electron beam (EB) irradiation. 2-(Perfluorohexyl) ethyl acrylate (FEA), butyl acrylate (BA(C4)), dodecyl acrylate (DA(C12)), and stearyl acrylate (SA(C18)) with different alkyl chain lengths were used as vinyl monomers that can react with the radicals generated by EB irradiation. For the pre-irradiation method, the changes in weight gain were negligible. While irradiating the monomer solution and the PET fabric simultaneously, a weight gain of approximately 3%-5% was observed. Contact angle measurements confirmed, hydrophobicity/oleophobicity in the PET fabric graft polymerized with FEA and SA(C18) monomers using the simultaneous irradiation method. The addition of the alkyl acrylate monomer increased the dodecane contact angle in the order of FEA < FEA/BA(C4) < FEA/DA(C12) < FEA/SA(C18). XPS analysis showed that the surface fluorine concentrations of PET fabrics with FEA and FEA/SA(C18) monomers were 18.3% and 38.9%, respectively. The contact angle and surface fluorine concentration after rubbing decreased, but the change was small when SA(C18) monomer was added to the FEA monomer. These results indicate that the hydrophobic/oleophobic properties and durability can be improved by EB graft polymerization in combination with FEA and SA(C18) monomers.

Enhancing oil repellency of electron beam‐grafted polyethylene terephthalate fabric with 2‐(perfluorohexyl) ethyl acrylate monomer via pre‐irradiation

“…44,45 The reactive monomers used for EB graft polymerization were the same as those reported previously. 45 FEA (98.0%, 418.2 g/mol CH 2 =CHCOO(CH 2 ) 2 C 6 F 13 ) monomers (Apollo Scientific Ltd., Stockport, UK) and stearyl acrylate (stabilized with MEHQ) (n = 18, SA(C18), 97.0%, 324.5 g/mol, Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) were used without further purification. As a solvent for the monomer, ethyl alcohol (99.5%, Nacalai Tesque, Inc., Kyoto, Japan) was used.…”

“…Water (surface tension: 72.1 mN/m) and dodecane (surface tension: 25.3 mN/m) were used as liquid probes. 44,45 The contact angle was determined from the image 1 s after a 3-4 μL droplet was placed on the fabric in a room set to 23 C and 50% relative humidity (RH).…”

“…The rubbing method was performed under the same conditions as those described in the previous report. 45 The rubbing test was performed using a Gakushin II type friction tester in accordance with JIS L 0849 in a room set to 20 C and 65% RH. The EB-grafted PET fabric was cut into 50 mm  25 mm pieces.…”

“…The importance of the solvent in graft polymerization depends on the compatibility between the monomer and substrate polymer. 22,45 Graft uniformity and monomer diffusion improve under the presence of solvent. 50 Therefore, even at higher concentrations (0.5 M), the diffusivity of FEA monomer decreased and did not increase the amount of grafting.…”

“…44 We have found that EB graft polymerization using the simultaneous irradiation method with 2-(perfluorohexyl) ethyl acrylate (FEA) monomer and stearyl acrylate (SA(C18)) with long alkyl chains improved the hydrophobic/oleophobic properties and durability. 45 In this study, we investigate the effect of surface properties on the oil repellency of EB-grafted PET fabric fluorinated with monomers via pre-irradiation. First, the effects of FEA monomer concentration on surface properties are investigated.…”