(233i) Synthesis of Pressure-Sensitive Adhesives with Polyester-Based Macromonomers and Their Rheological Properties

Use of pressure-sensitive adhesive (PSA) continues to expand due to its convenience, versatility, and relative low cost. Replacement of traditional monomers derived from fossil fuels with those from renewable resources increases the sustainability of PSA.  It also provides an alternative raw material for its production providing a hedge in times of shortages.  In this presentation, results from a study are reviewed on the rheological properties of biomass-containing, hot-melt PSA. Commercial acrylic PSAs with their hard monomer component, methyl acrylate (MA), replaced by polyester-based macromonomers (MMs) were synthesized. Generated adhesive polymers have lower glass transition temperatures (Tgs).  Measured molecular weights for MM-containing PSAs, via gel permeation chromatography, ranged from Mn = 105 to 157 kg/mol, significantly higher than that determined for the PSA polymer with MA, Mn = 74 kg/mol.  Rheological characterization of the developed PSA shows that it possesses dynamic moduli consistent with good PSA performance for tack and peel and identifies trends believed consistent with high shear strength.  Furthermore, this analysis indicates that the viscoelastic properties of the MM-containing adhesives are highly sensitive to changes in MM chain-length and content, which provides a sensitive means to manipulate and gauge performance.