Abstract:
Absorbent polymeric macrostructures that are porous and comprise an interparticle crosslinked aggregate having a circumscribed dry volume greater than about 10.0 mm.sup.3. The interparticle crosslinked aggregate comprises a multiplicity of precursor particles of substantially water-insoluble, absorbent, hydrogel-forming, polymer material; and an interparticle crosslinking agent reacted with the polymer material of the precursor particles to form crosslink bonds between the precursor particles. Because of the particulate nature of the precursor particles, the macrostructure has pores between adjacent precursor particles. The pores are interconnected by intercommunicating channels such that the macrostructure is liquid permeable.
Abstract:
A porous polymeric material has cell sizes within the range 100 to 0.5 .mu.m and total pore volume with respect to the overall volume of the material in the range 75 to 98% and includes cross-linked polycondensation polymeric material. The material can be made from a high internal phase emulsion in which the cross-linked polycondensation polymer is formed in the continuous phase. The materials are preferably open interconnected cellular structures. They can be made of a wide range of polycondensation materials. The materials are thus highly porous and light weight and have a range of properties depending primarily on their constituent polycondensation materials.
Abstract:
A membrane of defined pore structure and controlled pore diameter and a method of preparing the membrane which comprises dispersing in a water soluble polymer solution (A) an organic polymer solution (B), the water-soluble polymer solution (A) being a non-solvent for the polymer solution (B), to form micro-spherical droplets of the polymer solution (A) which are enveloped by a solid phase consisting of a coagulated or cross-linked polymer solution (B); evenly casting the dispersion on a flat surface; and evaporating the solvent for the polymer solution (B) to form a microporous membrane comprised of the polymer (B), the porosity, pore size, and void volume of the microporous membrane being a function of the polymer (A) concentration, the microsphere dimensions and the temperature and evaporation rate. The water-soluble polymer (A) is selected from polyethyleneimine, gelatin, polyvinyl-pyrrolidone, polyvinyl pyridinium halide, polyacrylic acid, polyhydroxyethylmethacrylate (HEMA), dextran, or polyvinyl acetate. The continuous phase polymer (B) is selected from a brominated polyphenylene oxide, polyphenylene oxide, polyacetic acid, polystyrene, polyglycol acrylate (PGA), polymethylmethacrylate, cellulose acetate, polyvinyl acetate, polycarbonate and polyvinylidene fluoride.
Abstract:
An anisotropic membrane is provided having excellent mechanical properties combined with good permeation characteristics which comprises a vinyltriorganosilane polymer or copolymer consisting of a dense layer, of average thickness between 0.01 and 10 Mu , and a porous layer with open pores, of thickness up to 500 Mu in which the volume of the interstitial spaces in the porous layer represents 20 to 80 percent of the total volume of the membrane.
Abstract:
1,135,649. Coating compositions. UNITED SHOE MACHINERY CORP. 15 Dec., 1965 [18 Dec., 1964], No. 53160/65. Headings C3C, C3P and C3R. [Also in Division B2] Coating compositions suitable for depositing porous films comprise an aqueous dispersion of a film-forming polymeric material and fine droplets, of which from 30-60% have dimensions in the range of 0À001-0À003 mm. and substantially the remainder of said droplets have dimensions in the range of 0À003-0À010 mm., of a water-immiscible volatile organic liquid in which the polymeric material is insoluble or substantially insoluble, said liquid being suspended in the aqueous phase of said dispersion and being present in an amount of 25-300% based on the weight of said polymeric material. Preferred organic liquids are petroleum hydrocarbon fractions, e.g. mineral spirits, petroleum naphtha and kerosene; others mentioned are halogenated hydrocarbons and nitroparaffins. The polymeric material may be, for example, a latex of a butadiene-acrylonitrile copolymer which may be carboxylated, an acrylic ester polymer or copolymer emulsion, a latex of polyvinyl chloride or copolymer of vinyl chloride with e.g. vinyl acetate, or a latex of an elastomeric polyurethane, formed by reacting a polyester or polyether polyol with excess of a polyisocyanate and then chain extending the -NCO terminated condensate by reaction with a compound such as a polyol, polyamine or amino-alcohol. The composition may include a modifier to improve gel strength of the coatings, e.g. casein rendered water-soluble by treatment with an alkaline material, polyvinyl alcohol, methyl cellulose, and the insoluble resinous residue obtained from the distillation of pine tar resin. Other components which may be added include waxes or wax-like substances, gums, colouring agents, e.g. carbon black or zinc oxide, and mineral fillers. After a coating has been deposited on a surface, it is coalesced by evaporating water whereby the polymer particles gel; and when the solvent droplets are evaporated a porous coating is obtained.
Abstract:
The invention provides a foam, comprising a cellular structure and having a density of at most 0.50 g/cm3, wherein the cellular structure is provided by a solid material that comprises humins. Such a foam is prepared in a process, which comprises: - providing a starting material containing humins; and - heating the starting material to a temperature in the range of 150 to 450 °C. The foam can be used in articles for a variety of applications such as substrate for plant growth, as adsorbent for treating waste water or waste gases, as support for solid catalysts, as insulation material, or packaging material.
Abstract:
The invention provides a foam, comprising a cellular structure and having a density of at most 0.50 g/cm3, wherein the cellular structure is provided by a solid material that comprises humins. Such a foam is prepared in a process, which comprises: - providing a starting material containing humins; and - heating the starting material to a temperature in the range of 150 to 450 °C. The foam can be used in articles for a variety of applications such as substrate for plant growth, as adsorbent for treating waste water or waste gases, as support for solid catalysts, as insulation material, or packaging material.
Abstract:
A composition comprising a gelling agent is provided. The gelling agent consists essentially of a cellulose ether based gelling polymer and the composition is a rigid foam at 20 degrees Celsius. The composition may also comprise an active ingredient. Also provided is a process of making the composition comprising drying a foamed liquid composition comprising the gelling agent at low temperatures. The foamed liquid composition may also comprise an active ingredient.
Abstract:
Gegenstand der Erfindung ist eine symmetrisch poröse Membran M aus mindestens zwei Amino NH-Gruppen pro Molekül aufweisendem thermoplastischen Siliconelastomer S1, das mittels Aldehyd vernetzt ist; zwei Verfahren zur Herstellung der mittels Aldehyd vernetzten symmetrisch porösen Membran M, bei dem in einem ersten Schritt eine Lösung oder Suspension aus einem thermoplastischen Siliconelastomer S1, das mindestens zwei Amino NH-Gruppen pro Molekül aufweist, in einem Gemisch aus Lösungsmittel L1 und Lösungsmittel L2 gebildet wird, in einem zweiten Schritt die Lösung oder Suspension in eine Form gebracht wird, in einem dritten Schritt Lösungsmittel L1 aus der Lösung oder Suspension entfernt wird bis die Löslichkeit des thermoplastischen Siliconelastomers S1 im Gemisch unterschritten wird, wobei sich eine an thermoplastischem Siliconelastomer S1 reiche Phase A und eine an thermoplastischen Siliconelastomer S1 arme Phase B ausbildet und damit die Strukturbildung durch die Phase A erfolgt, in einem vierten Schritt das Lösungsmittel L2 und Reste des Lösungsmittels L1 entfernt werden, wobei eine Membran entsteht und in einem fünften Schritt die Membran aus dem thermoplastischen Siliconelastomer S1 vernetzt wird, wobei die Membran M entsteht, wobei beim ersten Verfahren im ersten Schritt und beim zweiten Verfahren im fünften Schritt ein Aldehyd enthaltendes Aldehydreagenz (AR) zugesetzt wird; sowie Verwendungen der porösen Membran M.