Toward a Sustainable
Approach for Durably Hydrophilic
and UV Protective PET Fabric through Surface Activation and Immobilization
Integrating Epigallocatechin Gallate and Citric Acid
Enhancing the hydrophilicity and UV protective property
of poly(ethylene
terephthalate) (PET) fabric are two significant ways to upgrade its
quality and enlarge the applicable area. Biobased finishes are greatly
welcomed for the fabrication of sustainable textiles; however, their
application on PET fabric is still challenging compared with the case
of natural fabric. This study presents a strategy that immobilizes
epigallocatechin gallate (EGCG) onto PET fabric using citric acid
(CA) for durably hydrophilic and UV-proof properties with negligible
color change. A controllable surface-activating method integrating
alkaline and deep eutectic solvent (DES) is customized for the PET
fabric to promote the reactions among PET, CA, and EGCG. The hydrophilic,
antistatic, and UV protective properties of functionalized PET fabric
were explored. Results show that the hydrophilicity of the PET fabric
after direct EGCG treatment increases but drops sharply after first-round
washing due to weak interactions. The combined alkaline/DES pretreatment
increases the number of hydrophilic groups and the roughness of PET
fibers. After EGCG modification, the moisture regain (MR) of PET fabric
increases from 0.41 to 0.64%. The contact angle and electrostatic
charge half-life (T1/2) decreases from
>120 to 23°, and from >60 to 0.13 s, respectively. The
MR and T1/2 are well retained after a
10-cycle washing.
In addition, the UV protective factor of the PET fabric increases
from 18 to 36. A very slight yellowing phenomenon occurs on the PET
fabric after the treatment. In all, this research attempts to integrate
a biobased finishing agent and an eco-friendly cross-linker on synthetic
fiber for durable functions, which is transferrable to the sustainable
fabrication of other polymeric materials such as fibers or films.