Controlling Sequence and Reactivity in Lactide-based Macromonomers for Hybrid Acrylic Design

This study investigated the influence of reaction conditions on monomer incorporation and sequence distribution in l-lactide-based macromonomers (MMs) for hybrid acrylic polymers. Hydroxyethyl methacrylate (HEMA)-initiated MMs composed of l-lactide and ε-caprolactone were synthesized via stannous octoate-catalyzed, Sn(Oct)2, ring-opening polymerization (ROP). l-lactide propagates more rapidly than ε-caprolactone, with the selectivity (S) decreasing from 12.9 to 3.9 as temperature increases from 100 to 130 °C. 13C nuclear magnetic resonance spectroscopy (NMR) confirmed that temperature and catalyst level promote transesterification, increasing the degree of randomness (R) from 0.51 to 0.76. When incorporated at 50 wt % into water-based pressure-sensitive adhesives (PSAs), these MMs showed strong microstructure-dependent performance. Low-R (blocky) MMs yielded higher tack and peel strength, whereas higher-R MMs provided substantially greater shear resistance. Water contact angle also increased with R. These results show that MM sequence can be tuned through synthesis conditions to tailor adhesive performance.