Pollen: A Novel, Biorenewable Filler for Polymer Composites

Abstract

Pollen has an exine shell with remarkable chemical stability, high‐strength, and unique microstructures that suggest use as a biorenewable polymer filler. Pollen‐filled polymers may offer potential for light‐weight, high‐strength materials that can displace some petroleum‐derived content with a sustainable plant‐based alternative. We report the first demonstration of the incorporation of pollen grains (short ragweed) on the mechanical, interfacial, and thermal properties of two polymers, poly(ε‐caprolactone) (PCL) and polystyrene (PS). Under certain solvent and annealing conditions, PS mechanical properties were improved synergistically upon addition of pollen, while those of PCL were always degraded, in strong agreement with wetting behavior of the polymer–pollen interface.

Pollen fillers for reinforcing and strengthening of epoxy composites

“…These results correspond well with FTIR peaks of higher intensity on BA pollen recovered from epoxy solution than D pollen and improved mechanical properties of E-BA films. Again, these results indicate that pollen-filled epoxies show improved compatibility versus previous thermoplastics [6,7]. Previously, T g of polyvinyl acetate was not altered significantly with increased pollen loading, even after surface treatment and functionalization.…”

“…Crosslinking between surface -OH groups, the epoxide, and the epoxy matrix eliminates the need for an additional functionalization step. These results indicate that pollen is more compatible with epoxy than with previous thermoplastics that were studied [6,7].…”

“…Improvements in mechanical properties in BA pollen versus D pollen likely result due to crosslinks with the epoxy matrix due to the presence of protic functional groups (hydroxyls or carboxyls) on the BA surface. BA pollen displayed higher compatibility with epoxy than with the thermoplastics previously studied (polystyrene, polycaprolactone, and polyvinyl acetate) [6,7], and with no additional surface functionalization step. Finally, BA pollen was found to lower slightly the composite density relative to neat epoxy.…”

“…Pollen exine has the potential to be an effective biorenewable filler due to its high strength, chemical stability, low density (when hollow) and unique architecture [5][6][7][8].…”

“…Only two studies have explored pollen grains as reinforcing filler, in the thermoplastics polystyrene, polycaprolactone, and polyvinyl acetate [6,7]. These studies showed that surface treatment and surface functionalization of pollen was critical in tuning interfacial adhesion and mechanical properties of pollen-polymer composites, in order to make pollen an effective load-bearing filler.…”