Designing styrene-acrylate interpenetrating polymer networks with tunable damping and acoustic properties using waterborne core-shell nanoparticles

Although styrene-acrylate systems exhibit significant sound damping properties, less attention has been paid to the relationship between their damping and acoustic behavior. In this study, styrene-acrylate latex particles with a core-shell structure were synthesized and the effect of the shell feeding method, crosslinker ratio, core monomer type and methyl methacrylate ratio in the shell on the mechanical properties of the latex was studied. The FTIR results confirmed the formation of a network within the core. DLS analysis revealed uniform latex particle size distribution (150–185 nm) and zeta potential measurements (−56 to −30 mV) indicated particle stability. Addition of 1 wt% crosslinker to the core, reduced the particle size and increased stability, but raising it to 3, 5 wt% reversed the effect, leading to decreased stability in the system. SEM and TEM results confirmed the spherical morphology and complete coverage of the core by the shell. The tensile test results showed that increasing MMA monomer content in the shell from 0 to 42 wt% raised tensile strength from 0.2 to 4.6 MPa. Moreover, adding 5 wt% crosslinking agent in the core increased the tensile strength from 3.3 to 7.3 MPa. Damping and acoustic properties were investigated using DMTA analysis and impedance tube, respectively. Comparison of the acoustic test results with theoretical calculations showed a strong correlation at 2000 Hz. In order to compare the damping and acoustic properties, a simple linear equation between TA effect and NRC was proposed which showed a strong correlation (R 2 = 0.97) between mechanical and acoustic damping results. • Styrene-acrylate LIPNs were synthesized using multi-stage emulsion polymerization. • The effect of shell feeding method and hard monomer type on mechanical and damping properties were studied. • The damping-acoustic relation in the system was explored. • A linear model was developed to link damping properties (TA effect ) and sound absorption (NRC).