PLA polymers that can be expanded into microporous articles having a node and fibril microstructure are provided. The fibrils contain PLA polymer chains oriented with the fibril axis. Additionally, the PLA polymers have an inherent viscosity greater than about 3.8 dL/g and a calculated molecular weight greater than about 150,000 g/mol. The PLA polymer article may be formed by bulk polymerization where the PLA bulk polymer is made into a preform that is subsequently expanded at temperatures above the glass transition temperature and below the melting point of the PLA polymer. In an alternate embodiment, a PLA polymer powder is lubricated, the lubricated polymer is subjected to pressure and compression to form a preform, and the preform is expanded to form a microporous article. Both the preform and the microporous article are formed at temperatures above the glass transition temperature and below the melting point of the PLA polymer.

PLA polymers that can be expanded into microporous articles having a node and fibril microstructure are provided. The fibrils contain PLA polymer chains oriented with the fibril axis. Additionally, the PLA polymers have an inherent viscosity greater than about 3.8 dL/g and a calculated molecular weight greater than about 150,000 g/mol. The PLA polymer article may be formed by bulk polymerization where the PLA bulk polymer is made into a preform that is subsequently expanded at temperatures above the glass transition temperature and below the melting point of the PLA polymer. In an alternate embodiment, a PLA polymer powder is lubricated, the lubricated polymer is subjected to pressure and compression to form a preform, and the preform is expanded to form a microporous article. Both the preform and the microporous article are formed at temperatures above the glass transition temperature and below the melting point of the PLA polymer.

A method of synthesizing aerogels and cross-linked aerogels in a single step and in a single pot without requiring any solvent exchange is described. Porous matrices are synthesized through a modification of hydrolysis condensation of alkoxides in which addition of water is minimized. The reaction occurs in an ethanol-water azeotrope mixture; the water in the azeotrope slowly hydrolyzes the alkoxide. Additionally, after gelation, the porous matrix is dried in supercritical ethanol rather than liquid CO.sub.2, which allows for elimination of solvent exchange steps. These modifications allow for the preparation of aerogel monoliths in any size in one step and in one pot and much faster than conventional procedures. In addition, the method provides for custom aerogel parts with large dimensions, as well as high volume fabrication of aerogels. The custom aerogel parts may be used in a variety of thermal insulation applications.

A method of synthesizing aerogels and cross-linked aerogels in a single step and in a single pot without requiring any solvent exchange is described. Porous matrices are synthesized through a modification of hydrolysis condensation of alkoxides in which addition of water is minimized. The reaction occurs in an ethanol-water azeotrope mixture; the water in the azeotrope slowly hydrolyzes the alkoxide. Additionally, after gelation, the porous matrix is dried in supercritical ethanol rather than liquid CO.sub.2, which allows for elimination of solvent exchange steps. These modifications allow for the preparation of aerogel monoliths in any size in one step and in one pot and much faster than conventional procedures. In addition, the method provides for custom aerogel parts with large dimensions, as well as high volume fabrication of aerogels. The custom aerogel parts may be used in a variety of thermal insulation applications.

A filtration material including a silica base material having a group represented by the following general formula (a0-1) [in formula (a0-1), Ya.sup.01 represents a divalent linking group; Ra.sup.01 represents a hydrocarbon group which may have a substituent; Ra.sup.02 represents a hydroxyl group or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent; n.sup.01 represents an integer of 0 to 5; and the symbol “*” represents a valence bond with respect to the silica base material].

##STR00001##

A filtration material including a silica base material having a group represented by the following general formula (a0-1) [in formula (a0-1), Ya.sup.01 represents a divalent linking group; Ra.sup.01 represents a hydrocarbon group which may have a substituent; Ra.sup.02 represents a hydroxyl group or a hydrocarbon group having 1 to 6 carbon atoms which may have a substituent; n.sup.01 represents an integer of 0 to 5; and the symbol “*” represents a valence bond with respect to the silica base material].

##STR00001##

Foam-formed collagen strands and methods for forming strands involve depositing a dispersed solution of an isolated cleaned, de-fatted, enzymatically-treated (or non-enzyme treated) human-derived collagen product having a preserved amount of its natural constituents into grooves of a grooved plate, and processing the dispersed collagen product to provide a foam-formed collagen strand. Foam-formed collagen strands may be processed into threads having a matrix of reticulated pores to conduct biological materials in and through the strand, the collagen of the collagen strand comprising isolated, enzymatically-treated human derived collagen having a preserved amount of its natural collagen constituents.

Foam-formed collagen strands and methods for forming strands involve depositing a dispersed solution of an isolated cleaned, de-fatted, enzymatically-treated (or non-enzyme treated) human-derived collagen product having a preserved amount of its natural constituents into grooves of a grooved plate, and processing the dispersed collagen product to provide a foam-formed collagen strand. Foam-formed collagen strands may be processed into threads having a matrix of reticulated pores to conduct biological materials in and through the strand, the collagen of the collagen strand comprising isolated, enzymatically-treated human derived collagen having a preserved amount of its natural collagen constituents.

Methods and materials are described for preparing organic-inorganic hybrid gel compositions where a sulfur-containing cross-linking agent covalently links the organic and inorganic components. The gel compositions are further dried to provide porous gel compositions and aerogels. The mechanical and thermal properties of the dried gel compositions are also disclosed.

Methods and materials are described for preparing organic-inorganic hybrid gel compositions where a sulfur-containing cross-linking agent covalently links the organic and inorganic components. The gel compositions are further dried to provide porous gel compositions and aerogels. The mechanical and thermal properties of the dried gel compositions are also disclosed.