Foamed polymers. cellular structure and properties

Shutov, F.

doi:10.1007/bfb0017587

Cited by 57 publications

(18 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The compressive modulus and strength of the silk scaffolds with 500–600 μm pore size were higher than those with 210–300 μm pore size; however, the results were not significantly different. The influence of porogen size on mechanical behavior has been described elsewhere 26, 56–58…”

Section: Resultsmentioning

confidence: 99%

“…The influence of porogen size on mechanical behavior has been described elsewhere. 26,[56][57][58] Mechanical stability of the implanted biomaterials should be considered for load-bearing bone tissue engineering applications. Although silk is a stiff and ductile polymer in natural fiber form, fabrication and processing ultimately determine scaffold mechanical behavior.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical improvements to reinforced porous silk scaffolds

Gil

Kluge

Rockwood

et al. 2011

J Biomedical Materials Res

View full text Add to dashboard Cite

Load bearing porous biodegradable scaffolds are required to engineer functional tissues such as bone. Mechanical improvements to porogen leached scaffolds prepared from silk proteins were systematically studied through the addition of silk particles in combination with silk solution concentration, exploiting interfacial compatibility between the two components. Solvent solutions of silk up to 32 w/v% were successfully prepared in hexafluoroisopropanaol (HFIP) for the study. The mechanical properties of the reinforced silk scaffolds correlated to the material density and matched by a power law relationship, independent of the ratio of silk particles to matrix. These results were similar to the relationships previously shown for cancellous bone. The mechanism behind the increased mechanical properties was a densification effect, and not the effect of including stiffer silk particles into the softer silk continuous matrix. A continuous interface between the silk matrix and the silk particles, as well as homogeneous distribution of the silk particles within the matrix were observed. Furthermore, we note that the roughness of the pore walls was controllable by varying the ratio of particles matrix, providing a route to control topography. The rate of proteolytic hydrolysis of the scaffolds decreased with increase in mass of silk used in the matrix and with increasing silk particle content.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Mechanical Propertiesmentioning

confidence: 99%

Mechanical improvements to reinforced porous silk scaffolds

Gil

Kluge

Rockwood

et al. 2011

J Biomedical Materials Res

View full text Add to dashboard Cite

show abstract

“…Scaffolds prepared from freezing at a higher temperature have larger pores after removal of the solvent crystals. 35 It has previously been observed 37 that an increase in pore size causes a rise of the modulus of both flexible and rigid foams. Furthermore, these pore sizes are closer to the average size of the pores obtained from leaching of the sugar particles.…”

Section: Preparation Of Porous Polymer Structures By Replication and mentioning

confidence: 97%

Preparation of interconnected highly porous polymeric structures by a replication and freeze‐drying process

2003

View full text Add to dashboard Cite

Three-dimensional degradable porous polymeric structures with high porosities (93-98%) and well-interconnected pore networks have been prepared by freeze-drying polymer solutions in the presence of a leachable template followed by leaching of the template. Templates of the pore network were prepared by fusing sugar or salt particles to form a well-connected structure. The interstices of the template were then filled with a polymer solution (5-15% w/v) in 1,4-dioxane, followed by freeze-drying of the solvent. Subsequent leaching of the sugar template ensures the connectivity of the pore network. The scaffold architecture consists of relatively large interconnected pores modeled after the template and smaller pores resulting from the freeze-drying process. The total porosity of the resultant porous structures is determined by the interstitial space of the leachable template and by the polymer concentration in the freeze-drying solution. The freezing temperature also has an effect on the final morphology of the porous structures. Compared with freeze-drying and combination of freeze-drying /particulate leaching techniques, this method facilitates higher interconnectivity of the scaffolds. Porous structures have been prepared from several relevant polymers in the biomedical and tissue-engineering field: poly(D,L-lactide) (PDLLA), 1000PEOT70PBT30, a segmented poly(ether ester) based on polyethylene oxide and polybutylene terephthalate, and poly(epsilon-caprolactone) (PCL). The mechanical properties of the porous structures prepared by this technique depend on the nature of the polymer, porosity, and the freezing temperature. With porosities in the range of 95-97%, the compression moduli of scaffolds prepared from the different polymers could be varied between 13.0 and 301.5 kPa.

show abstract

“…In two dimensions, the cellular solids resemble the lattice of a honeycomb; in 3D the cells are polyhedra packed to fill space. In recent years, several review articles have been published on the specific properties of cellular materials including a general overview [28,29], polymer materials [30,31], and metal foams [32]. The micro structures of most cellular solids are highly disordered due to variations in cell wall thickness, wavy distortions, and the non-uniform shape of the cells.…”

Section: Background On the Modeling Of Stretching Porous Materialsmentioning

confidence: 99%