Hydrophilicity Improvement of <scp>LDPE</scp> Films With an Amphiphilic Copolymer

ABSTRACT An amphiphilic copolymer (SAP‐37) was synthesized from stearyl acrylate (SA) and poly(ethylene glycol) methacrylate (PEGMA) via free‐radical copolymerization and incorporated into low‐density polyethylene (LDPE) through melt blending to prepare LDPE/SAP‐37 blend films with regulated surface characteristics and water‐interaction behavior. Structural, thermal, morphological, molecular‐weight, mechanical, and surface‐property characterizations were conducted to evaluate the incorporation of SAP‐37 into the LDPE matrix and its effect on film properties. The results showed that SAP‐37 was successfully synthesized and remained stable under the blending conditions. Compared with neat LDPE, the blend films exhibited improved surface wettability, higher surface energy, enhanced water uptake and moisture absorption, increased tensile strength, and good durability of hydrophilic performance. Among the investigated compositions, the 6 wt% SAP‐37 film showed the best overall performance, combining relatively high tensile strength, the lowest water contact angle, and the strongest water‐interaction behavior. This study provides a simple and effective melt‐blending strategy for the surface functionalization of nonpolar polyolefin films, and the resulting materials show potential in packaging films and polymer films with tunable moisture absorption.