Study on Preparation and Properties of Hydrophilic Copolyester of PET- co -PEA/Nano SiO 2

Polyethylene terephthalate (PET) is the most used fiber material, but its hydrophilic property is weak. Common hydrophilic treatment process on PET clothes has lots of defects such as poor washability and undurablity. In this paper, long-chain monomers were introduced into PET main chains to improve its elastic property to promote the diffusion of water molecules. In addition, modified nano-SiO2 particles were also added into PET matrix to improve its hydrophilicity. PET-co-PEA/SiO2 was synthesized by direct esterification with terephthalic acid (PTA), ethylene glycol (EG), polyethylene glycol adipate (PEA), and SiO2 modified by KH560 on the surface. Morphology, structure, thermal property, and hydrophilicity of PET-co-PEA/SiO2 were investigated. PET-co-PEA/SiO2 has a typical PET characteristic absorption peak in FTIR spectra, indicating that the addition of SiO2 has little effect on PET chemical structure. PET-co-PEA/SiO2 shows similar thermal stability as PET, which is weaker than PET/SiO2 but superior to PET-co-PEA. Both nano-SiO2 particles and the copolymerized long-chain PEA can improve the hydrophilicity of PET. Contact angle of PET-co-PEA/SiO2 is 69.56°, which is much lower than that of neat PET 108.5°.