Natural Rubber Latex-Reinforced Polyacrylamide Hydrogels With Enhanced Mechanical Performance.

Abstract

Polyacrylamide (PAM) hydrogels are attractive soft materials owing to their high-water content and tunable network structure. However, their limited strength and toughness restrict practical use. Here, prevulcanized natural rubber (NR) latex was incorporated into an acrylamide precursor before polymerization to prepare NR latex-reinforced PAM (PAM@NR) hydrogels. The PAM matrix served as a continuous hydrophilic network, while NR latex particles served as flexible biobased dispersed domains. NR incorporation produced a denser freeze-dried surface morphology with NR-rich domains and increased the storage and loss moduli, indicating enhanced network stiffness and a stronger dissipative response. At a PAM-to-dry-NR mass ratio of 5:5 (PAM@NR-5:5), the hydrogel achieved a tensile strength of 255.0 kPa, elongation at break of 401%, and toughness of 809.1 kJ m- 3, representing increases of 278.3%, 165.6%, and 1207.1% compared with PAM, respectively. NR incorporation also suppressed swelling and slowed water loss under ambient conditions. These results suggest that prevulcanized NR latex can serve as a biobased reinforcing phase to improve the mechanical performance of PAM hydrogels.