Study on porous silk fibroin materials: 3. Influence of repeated freeze–thawing on the structure and properties of porous silk fibroin materials

Abstract

The influence of repeated freeze–thawing on pore structural characteristics and physical properties of porous silk fibroin materials prepared by freeze drying were studied. It showed that when quick‐frozen silk fibroin solution was repeatedly thawed and frozen before being vacuum dried, thus pore size of prepared porous silk fibroin materials increased from 67 µm to about 120 µm, and pore density decreased from 80 per square millimeter to about 28 per square millimeter; at the same time compression ratio and moisture permeability increased from 22.7% and 230 g/m2 hr to about 33.7% and 308 g/m2 hr, respectively, tensile strength and dissolvability in hot water decreased from 20.2 N/cm2 and 42.7% to about 12.5 N/cm2 and 26.1%, respectively. Both the times of repeated thawing and the thawing temperature had a certain influence on the above‐mentioned pore characteristic parameters and physical properties. Copyright © 2001 John Wiley & Sons, Ltd.

A Biomimetic Silk Fibroin/Sodium Alginate Composite Scaffold for Soft Tissue Engineering

“…2b, the 50Fc scaffolds showed thin-layer structure with many long and narrow pores inside under −20 °C freezing environment, the pore diameter became smaller with reduction of freezing temperature. With the lower freezing temperature, the pore diameter of 50 Fc decreased dramatically from 532 to 54 μm, which attributed to the size of ice crystals acted as porogens in the freezing process38. At the same time, the scaffolds showed more regular and uniform pore morphology under lower temperature.…”

“…The specimens were gold coated before analysis. In order to calculate pore diameter in cross-section, the border of each pore in the top layer was defined according to the gradient method38. Each pore area (x 1 , x 2 , … x n ) and the area S (mm 2 ) of the porous scaffold were calculated according to the limits of each pore in bitmap and the number of picture points in the whole picture.…”

Biomedical applications of polymers 2001 - 2002

“…When the pore density decreased from 80 to 28 pores per mm 2 , an increase in pore size from 67 -120 nm and in moisture permeability from 230 g/(m 2 ·h) to 308 g/(m 2 ·h) has been observed. At the same time, their compressibility increased from 22.7 to 33.7% [150]. been fabricated by air-drying and freeze drying, respectively.…”

Study the effect of different dyeing conditions of extracted natural dye from leaves of neem on silk fabrics

“…Similar trends with more variations after exposing to artificial day light for 160 h were detected and the R% values reached their minimum values for dye bath temperature of 80 o C (Figure 3b). Figure 4 illustrates the R% spectra for unexposed undyed and neem dyed (a) as well as exposed (b) silk fabrics dyed in a medium of pH = 6 and at temperature of 60 o C in a dye bath for different times (15,30,45, and 60 minutes). It was clear from the figure that the behaviors of the unexposed and exposed dyed silk fabrics completely change in comparison with the undyed fabric.…”