Boosted Gasoline Transport Performance of Poly(vinyl alcohol) Tubes by Constructing Wear-Resistant and Hydrophobic Coatings on the Surface

Poly(vinyl alcohol) (PVA) is an environmentally friendly polymer that can be prepared from nonpetroleum routes, offering a promising alternative to save finite fossil resources and protect our environment. However, the multihydroxyl groups in PVA endow it with sensitivity to environmental humidity, deteriorating its mechanical and gasoline barrier properties in aqueous environments, limiting its long-term application in gasoline transportation. In order to improve the water resistance and achieve long-term use of PVA tubes prepared by melt extrusion, herein, hydrophobic polydimethylsiloxane (PDMS) was adopted to be grafted onto the surface of PVA tubes with the assistance of ethyl orthosilicate (TEOS), and an organic silicon hydrophobic coating with an approximate thickness of 5 μm was established. Ascribing to this rough hydrophobic coating, the water resistance of the PVA tube was greatly improved, which was reflected by its contact angle increasing from 30.6° to 110.2°. Simultaneously, the mechanical properties and gasoline barrier property of the PVA tube in high ambient humidity (95%) were, respectively, increased by 6.4 MPa and 1.8 times, compared with the original one. This PDMS hydrophobic coating also exhibited good friction and tear resistance to adhesive tape, largely promoting the potential applications of PVA tubes in the field of gasoline transportation.