The effect of silk fibroin nanoparticles on the morphology, rheology, dynamic mechanical properties, and toughness of poly(lactic acid)/poly(ε‐caprolactone) nanocomposite

Abstract

The silk fibroin nanoparticles (SFNPs) were extracted from silkworm cocoons and used as a nanofiller in poly(lactic acid) (PLA)/poly(ε‐caprolactone) (PCL) blend. The nanoparticle localization was studied theoretically and experimentally and the effects of SFNP on the morphology, rheology, toughness, and dynamic mechanical properties of the blend were investigated. According to the calculated wetting coefficient, SFNP should be thermodynamically located in the PLA matrix during the melting process. The results of SEM illustrated a common sea‐island structure for the PLA/PCL blend and the incorporation of SFNP reduced the PCL domain sizes from 1.170 ± 92 μm to 794 ± 46 nm. The atomic force microscopy results showed that the nanoparticles are mainly located in the PLA matrix and also, partially at the phase interface with a thickness of layers around 80 nm. The rheological tests displayed the network formation of SFNP in the prepared nanocomposites. The dynamic mechanical analysis revealed that by the addition of SFNP, the storage modulus of neat PLA and PLA/PCL blend were increased by around 57 and 50%, respectively and the glass transition temperatures (Tg) values of PLA and PCL shifted toward each other. Additionally, using SFNP caused a lower water uptake and higher impact strength (~64%) of the blend.

Three-Dimensional Printing of Customized Scaffolds with Polycaprolactone–Silk Fibroin Composites and Integration of Gingival Tissue-Derived Stem Cells for Personalized Bone Therapy

“…The practicality of understanding the viscoelastic behavior is foremost necessary for evaluating melt processing factors, dispersion, and the interfacial interaction of the fibers in the matrix, as well as the morphological aspects of various phases in the composites (filler and matrix), especially when working on 3D printing . A uniform dispersion of microfibers in the polymer matrix can impact the melt rheology of the composites . The viscoelastic behavior was reproducible despite repetitive melt–cooling cycles, suggesting even dispersion and stability of the silk fibroin microfibers in the PCL matrix with no signs of material degradation prompted by the temperature cycling as seen in other studies .…”

“…19 A uniform dispersion of microfibers in the polymer matrix can impact the melt rheology of the composites. 20 The viscoelastic behavior was reproducible despite repetitive melt−cooling cycles, suggesting even dispersion and stability of the silk fibroin microfibers in the PCL matrix with no signs of material degradation prompted by the temperature cycling as seen in other studies. 11 Our study demonstrated that with the increase in the silk content the storage and the loss moduli increased compared to those of PCL alone (Figure 1), and this has been shown in various PCL based composites with clay, 21 hydroxyapatite, and tricalcium phosphate.…”

Fabrication of an Antimicrobial Peptide-Loaded Silk Fibroin/Gelatin Bilayer Sponge to Apply as a Wound Dressing; An In Vitro Study

“…The scaffolds with an excellent arrangement of porous structure might have well mechanical attributes which have a direct impact on their clinical efficient (Xu et al 2015). The presence of fibroin in the present scaffold has improved the mechanical properties as mentioned in many studies (Chen et al 2019;Dadras Chomachayi et al 2020;Eivazzadeh-Keihan et al 2021). In addition, the opposite charge balance between silk fibroin and gelatin and the presence of the high content of hydrophilic amino acids of SF can affect the compression modulus (Lu et al 2010;Si et al 2011).…”

Effect of rigid nanoparticles and preparation techniques on the performances of poly(lactic acid) nanocomposites: A review

“…Indeed, cellulose nanofibers/whiskers (CNF) derived from renewable biomass are currently attracting research attention because they portray great potential in reinforcing PLA 121‐123 . However, a list of challenges prevents their usage.…”