Fabrication of Silk Resin with High Bending Properties by Hot-Pressing and Subsequent Hot-Rolling

Abstract

This research reports the processability and mechanical properties of silk resins prepared by hot-pressing followed by hot-rolling and then analyzes their thermal and structural properties. The results show that regenerated silk (RS) resins are better suited for hot-rolling than Eri and Bombyx mori silk resins (untreated silk). When hot-rolling at 160 °C with a 50% of reduction ratio, maximum bending strength and Young’s modulus of RS resin reaches 192 MPa and 10.2 GPa, respectively, after pretreatment by immersion in 40 vol% ethanol, and 229 MPa and 12.5 GPa, respectively, after pretreatment by immersion in boiling water. Increased strength of the material is attributed to the increased content of aggregated strands and intramolecular linking of β sheets (attenuated total reflectance Fourier-transform infrared spectroscopy) and higher crystallinity (X-ray diffraction analysis). After hot-pressing and hot-rolling, RS resins have a stable decomposition temperature (297 °C).

Emerging Silk Material Trends: Repurposing, Phase Separation and Solution-Based Designs

“…Work conducted around the same time by Tuan and co-workers used milled raw sericin-containing silk and hot pressing (150–180 °C 31 MPa) to create monolithic silk resins [ 66 ]. These authors have since applied their technology to regenerated silk powders [ 67 ]. Overall, thermoplastic molding of silk adds a novel and useful processing strategy to the current manufacturing toolbox.…”

Porous Thermoplastic Molded Regenerated Silk Crosslinked by the Addition of Citric Acid

“…From the microstructural point of view while all previously developed protocols could not generate a porosity [ 24 , 25 , 26 , 27 , 28 , 29 , 32 ], the addition of CA was effective in generating pores which mean diameter was related to the amount of CA added. The higher the amount of CA the higher the mean diameter and the higher the number of pores generated.…”

“…The only fibroin structures developed for BTE reported to have high mechanical performances are resins [ 24 , 25 , 26 , 27 , 28 , 29 ]. These resins have a compact non-porous structure suitable for structural applications but mainly intended for osteofixation due to the lack of a biomimetic architecture.…”