A versatile route to the synthesis of pressure-sensitive adhesives and polyHIPE-like microparticles: an experimental study on glycerol valorization

This present work focuses on the synthesis of styrene / n-acylglycerol (n-ACG) (a macromonomer formed by glycerol esterification with acrylic acid catalyzed by methane sulfonic acid) copolymers through suspension polymerization process. The final properties of poly(styrene-co-n-acylglycerol) was strongly dependent on the n-ACG fraction into the polymer chains. The effect of n-ACG on the copolymer properties was evaluated and a huge reduction in both the thermal stability and the T-g values (from 93 degrees C for polystyrene homopolymer to -22 degrees C for styrene / n-ACG copolymers synthesized with 20 wt% of n-ACG) was observed when the n-ACG fraction was increased. The variations in the thermal properties were accompanied by drastic morphological changes of the materials, depending essentially on the n-ACG composition as for instance: i) porous spherical particles with polyHIPE-like structures (copolymers containing from 5 to 15 wt% of n-ACG), which indicates that these porous microparticles may be used as support/carries in heterogeneous catalysis, ion exchange resins, and controlled drug delivery, among others; ii) adhesive films containing n-ACG fractions higher than 15 wt%, conferring "tack" features similar to the one observed in for pressure-sensitive adhesives (PSA) evaluated by using a rolling ball test. Mechanical tests also showed that the polymer adhesives have an enormous potential to be used as PSA materials in the adhesive industry.