Fabrication of Anisotropic Poly(vinyl alcohol) Scaffolds with Controllable Mechanical Properties and Structural Recoverability under Compression via a Freeze-Casting Technique

Abstract

In this study, poly­(vinyl alcohol) (PVA) scaffolds are fabricated by an advanced polymer-based freeze-casting method. The sintering process for ceramic-based scaffolds is replaced by cross-linking. It is essential that the selected polymer is water-soluble and cross-linkable. The cross-linking temperature for PVA is 180 °C and it does not require sintering at high temperature as in the typical freeze-casting method. The ultimate compressive strength of PVA scaffolds is measured to be 11 MPa at 75% RH. In the axial direction, the stress–strain curve shows ductility and exhibits a series of jagged breaks after the yield strength. In the radial direction, the scaffold shows compressibility that nature recovery percentage at least exceeded 90% below the strain of 50% and shows complete recoverability via the swelling/deswelling process below the strain of 60%. In summary, the PVA scaffold possesses anisotropic mechanical strength, structural recoverability, and humidity regulating properties, which can be applied as multifunctional materials.

Ice-templated additive-free porous starches with tuned morphology and properties

“…The curves exhibit three regions, in particular well defined for the compression in the longitudinal direction, and typical for porous materials: an elastic region up to few strains per cent, a plastic deformation plateau and a final densification region. The stresses in the longitudinal direction are much higher than in the transverse direction, as expected, and as reported for other anisotropic porous materials, bio-based [27][28][29][30][31] or not [32,33],…”

Fabrication of Anisotropic Silk Fibroin-Cellulose Nanocrystals Cryogels with Tunable Mechanical Properties, Rapid Swelling, and Structural Recoverability via a Directional-Freezing Strategy

“…Natural materials have always exhibited well-defined anisotropic structures ranging from molecular to meso and macro for addressing challenges during millions of years of evolution. , The highly orientated structure plays a critical role in their biological and mechanical functions. Wood, as a typical example, is light but shows strong mechanical property due to its distinctive hierarchical structure .…”

Effect of Plasticization on Stretching Stability of Poly(Vinyl Alcohol) Films: A Case Study Using Glycerol and Water

“…For the neat PVA, the absorption peak in at 1414 cm –1 is assigned to the bending vibrations of hydroxyl (OH), and two bands at 2939 and 2906 cm –1 correspond to the asymmetric and symmetric stretching vibrations of methylene (CH 2 ), respectively. [ 32 ] It is worth noting that the wide and strong absorption band of 3254 cm –1 refers to OH stretching vibration, coupling of several hydrogen bond associations. By increasing the GLY or H 2 O content, the shifts of the OH stretching vibration band are appreciable.…”