Rheological and Mechanical Behavior of Silk Fibroin Reinforced Waterborne Polyurethane

Abstract

Waterborne polyurethane (WPU) is a versatile and environment-friendly material with growing applications in both industry and academia. Silk fibroin (SF) is an attractive material known for its structural, biological and hemocompatible properties. The SF reinforced waterborne polyurethane (WPU) is a promising scaffold material for tissue engineering applications. In this work, we report synthesis and characterization of a novel nanocomposite using SF reinforced WPU. The rheological behaviors of WPU and WPU-SF dispersions with different solid contents were investigated with steady shear and dynamic oscillatory tests to evaluate the formation of the cross-linked gel structure. The average particle size and the zeta potential of WPU-SF dispersions with different SF content were examined at 25˝C to investigate the interaction between SF and WPU. FTIR, SEM, TEM and tensile testing were performed to study the effects of SF content on the structural morphology and mechanical properties of the resultant composite films. Experimental results revealed formation of gel network in the WPU dispersions at solid contents more than 17 wt %. The conjugate reaction between the WPU and SF as well as the hydrogen bond between them helped in dispersing the SF powder into the WPU matrix as small aggregates. Addition of SF to the WPU also improved the Young's modulus from 0.30 to 3.91 MPa, tensile strength from 0.56 to 8.94 MPa, and elongation at break from 1067% to 2480%, as SF was increased up to 5 wt %. Thus, significant strengthening and toughening can be achieved by introducing SF powder into the WPU formulations.

Bioinspired Fabrication of Polyurethane/Regenerated Silk Fibroin Composite Fibres with Tubuliform Silk-Like Flat Stress–Strain Behaviour

“…The absorption band at 1720–1730 cm −1 (C=O stretching vibration) and 1591 cm −1 (benzene ring stretching) are characteristic peaks of polyurethane. Any specific interactions such as strong hydrogen bonding between PU and silk fibroin will result in peak shift or new peak [ 25 , 26 ]. However, the spectra obtained for the 100% PU and PU/RSF blends do not show any peak shift or presence of new peak in this region and suggests that no specific interactions between PU and RSF content.…”

“…In the literature, there are several examples on PU and silk fibroin composite films [ 22 , 25 , 26 , 27 , 28 ], fibre [ 29 ] and hydrogels [ 30 ] based on physical blending and chemical modification methods. However, rare study is reported on the preparation of biomimetic Polyurethane/Regenerated silk fibroin (PU/RSF) composite fibres possessing egg case-silk-like mechanical properties.…”

A Novel Application of Phosphorene as a Flame Retardant

“…In this paper, we report a novel application of black phosphorene as a flame retardant for polymers. We choose waterborne polyurethanes (WPU) as the matrix polymer since WPU have been widely used in the films, adhesives, paints, varnishes, and coatings, but they are inflammable, leading to an non-negligible disadvantages that threatens people’s safety [ 28 , 29 , 30 ].…”

Silk fibroin hydrogels for potential applications in photodynamic therapy

“…With an increase in the porphyrin concentration, the storage modulus also increased, resulting in a higher value of S (Table ). Low values of n indicate a purely elastic gel behavior …”