Abstract: A method of encapsulating and sterilizing waste material is disclosed. Medical waste is deposited inside of a mold. When full, the mold is charged with plastic and one of several reactants. The mold is then heated while rotated biaxially. The heat simultaneously sterilizes the waste and causes the charging materials to expand and envelop the waste, encapsulating it. The mold is then cooled while spinning biaxially, forming a hollow brick of solidified, encapsulated material in the mold. The brick of material is removed and pulverized into granules. The pulverized material is separated and readied for recycling.

Abstract: A screw with replaceable threads is particularly useful to releasably join the spiders of rotational molding machines. The screw comprises a master bolt that passes through a first spider, and a tip that is removably assembled to the master bolt. The tip is threaded to selectively engage and disengage a receiver on the second spider. When the tip is assembled to the master bolt, the screw is captured in the first spider. When the tip has worn through use, it can be replaced without disturbing the master bolt. Similarly, when the tip seizes to the receiver, the tip and receiver are replaceable as a unit without disturbing the master bolt.

Abstract: Rotationally molded component parts for a skid steer loader are disclosed wherein the parts provide specialized operative functions heretofore unrealized. A fuel tank structure includes both a tank body and a separate filler tube formed from a rotational molding process. The filler tube is connected to the fuel tank body by a fastening mechanism and an O-ring to provide a liquid-tight connection. The coolant recovery bottle formed with the rotational molding process incorporates an inwardly directed vent tube formed as an integral part of the recovery bottle. The container for the operator's manual is formed with the rotational molding process to incorporate a live hinge connecting a lid closable against the body of the container to provide a substantially dirt-free environment. Double walled light housings mounting front and rear lights serve as bumpers protecting the frame of the skid steer loader from damage from impact.

Abstract: A method for producing zirconia fused cast refractories, which comprises casting zirconia fused cast refractories containing at least 33 wt % of a ZrO.sub.2 component utilizing a mold, wherein the mold is rotated on a rotation axis, so that at least a portion of a meltage of raw material poured into the mold, is cooled to solidify under a centrifugal force of at least 1.2 G.

Abstract: In a rotationally-molded thermoplastic refuse container of the type having a hollow handle integrally-molded with a refuse carrying compartment of the container, the improvement which includes a wall integrally-formed with the refuse container and sealingly enclosing the hollow handle from communication with the refuse-carrying compartment of the container for providing greater strength to the container and preventing refuse from lodging in the hollow handles.

Abstract: A process is described for the production of a curable multi-component reaction mixture (and, in particular, a polyurethane), containing filler in which the reaction components are premixed and then mixed with the dry filler in a friction mixer having a conically shaped screw rotatable in a conical mixing chamber. The friction mixer is preferably operated under a fractional load at a low rotational speed.

Abstract: The present invention provides a new and improved liquid color system for use in rotational molding. The liquid color system includes from about 10% to about 75% by weight carrier, from about 0% to about 15% by weight water, from about 0.01% to about 10% by weight dispersant and from about 10% to about 80% by weight colorant. The carrier comprises a material selected from the group consisting of propylene glycol, ethylene glycol, diethylene glycol, tri(ethylene glycol), glycerin and mixtures of such materials. The liquid color system displays an evaporation rate of from about 0.01 to about 0.36 pursuant to the test procedures of ASTM D3539-87. The invention also provides a method of using the liquid color system which includes the step of mixing the liquid color system with the polymeric resin powder using a distributive mixer prior to rotational molding.

Abstract: For the manufacture of breast prostheses from a shell-shaped body made from an addition-vulcanising two-component silicone rubber mass, which body is enclosed in a plastic sheet sheathing said body, a filler of fairly low density composed of hollow spheres or microspheres is added to the two-component silicone rubber mass. The mixture is filled into a sheath of plastic sheet and is cured in a mould under the effect of heat. To obtain the most uniform distribution possible of the filler in the prosthetic body, the mould filled and degassed in the customary way is turned continuously through one or two axes before and during the curing of the two-component silicone rubber mass until the silicone rubber is vulcanised to such an extent that any rising of the filler materials is prevented.

Abstract: The supporting structure coverable with a plurality of concentric layers of elastic silicone-based material to produce rollers having a mirror-finished flexible outer surface has a hollow cylindrical body and a surface that is affected by a plurality of openings which are variously distributed and sized to allow the passage, produced by centrifugal force, of the material in the fluid/semifluid state from the inside towards the outer surface and to provide subsequent engagement.

Abstract: An elastic blade for press contacting a developing roller to regulate a thickness of a layer of developing agent conveyed by the developing roller to a developing area includes a springlike supporting plate, and a centrifugally molded rubber elastic layer coated on the supporting plate.

Abstract: A method to reduce cross link vapors trapped in hollow cross link polyethylene products produced by rotomolding is disclosed. Ozone is introduced into the hollow product after the polymer has cross linked. Compressed air is delivered with the ozone to circulate the ozone effectively. Use of the ozone oxidizes the cross link vapors and permits reduction in stored inventory of units awaiting dissipation of the cross link polyethylene vapors. A system for batch treatment of the products is also disclosed.

Abstract: A high impact resistant rotationally molded door and process for molding the door is disclosed in which a hinge member is integrally molded to the door along one edge only. This hinge member forms to the hollow door edge without door warpage during curing and shrinking of rotationally molded plastic door body. Door warpage is avoided by delaying full integral attachment of the hinge member to the door until curing of the injected foam interior which both bonds to the interior of the door and the hinge member. An improved seal and hinge seal is disclosed together with a placed window construction that can include both placement and shaping to meet the special order needs. Further improvements including the expedient of venting a rotationally molded door during the rotational molding process through an integrally molded hinge edge reinforcing member. This same venting scheme is utilized for enabling improved cooling of the door once molding of the hollow door shell has occurred.

Abstract: A blade for a fan is formed by rotomolding around a pre-positioned support member, part of which extends out of the mold, the support member being shaped, or being provided with one or more projections, which are partly embedded in the plastic material forming a skin of the fan blade. The fan blade is made hollow by this method, but is preferably filled either during molding or subsequently with a hard foam material. A hub is also provided for mounting any fan blades, but in particular those made by the method, in which a hub includes a body portion having a first radial face associated therewith, a plate having a second radial face parallel to the first radial face and spaced therefrom, and a plurality of circumferentially equally spaced depressions facing one another on the first and second radial faces to accommodate the fan blade support members, means being provided to secure the plate to the body portion effective to clamp the fan blade and support members firmly.

Abstract: A method and apparatus for fabricating columns, wherein the apparatus includes a column fabricating assembly and a column extractor. The column fabricating assembly includes a unitary column mold and a mold support assembly. The unitary column mold is reusable and is fabricated specially for the task of fabricating a column therein. Uncured column materials are placed into the unitary column mold and the unitary column mold is enclosed in the mold support assembly. The uncured column materials cure, and thus the column is formed, while the unitary column mold is encased in and spun by the mold support assembly. The unitary column mold is removed from the mold support assembly with the column therein. The column extractor is used to extract the column from the unitary column mold; the unitary column mold is secured by the column extractor and the column extractor pulls the column out of the unitary column mold.

Abstract: An automobile chassis and a one-piece body integrated into a unitary structure, and a method for fabricating, assembling and integrating the chassis and body. The body includes interior panels, a cockpit, an engine enclosure module, and an underbody. The chassis/body structure, comprised of a single type of aluminum alloy and a single type of thermoplastic, is resistant to high-stress loads and is substantially recyclable into industrial-quality constituents. A first preferred embodiment includes a body rotomolded from a reinforced polycarbonate, polycarbonate/ABS blend, or polyimide thermoplastic, seven aluminum alloy bulkheads, and stacks of thin-wall aluminum honeycomb-cell panels embedded in an unreinforced foam of the thermoplastic. A second preferred embodiment includes a body rotomolded from a reinforced liquid crystal polymer thermoplastic, seven aluminum alloy bulkheads, and stacks of thin-wall aluminum honeycomb panels.

Abstract: A method of bonding various materials, such as foam materials, to thermoplastic resins using a silane composition is provided. The thermoplastic resin is doped with a silane by washing the thermoplastic resin in a silane solution and then evaporating the solution from the resin. The silane-doped thermoplastic resin is then melted and formed into a polymeric article. In one embodiment, a polyurethane foam can then be sprayed onto the polymeric article. As the foam forms on the surface of the article, it bonds with silane trapped within the thermoplastic resin. In one embodiment, the polymeric article can be formed through a rotational molding technique. Through the process of the present invention, many useful articles can be formed such as polymeric pallets, water craft devices, thermocoolers and the like.

Abstract: A self-inflating structure consists essentially of a block of open-cell, resiliently compressible, foam material which has been shaped to a desired form and covered with an airtight envelope having a sealable aperture. The structure can be pressed to expel any air or other fluid out of the foam material and any internal void through the aperture. The structure is kept pressed or the aperture is sealed in order to keep it in its collapsed state. Upon release of the pressing form or the opening of the aperture, the block of foam bounces back to its original state sucking in ambient air and restoring the structure to its full size. The method for shaping the foam block includes extruding, machining, and carving with patterned sets of blades or burning wires.

Abstract: The invention is in the field of three-dimensional hollow novelty items and their manufacture, particularly items such as artificial pumpkins that the consumer desires to carve or alter after purchase. Disclosed is a carvable novelty article, such as an artificial Halloween pumpkin, comprising a polyurethane shell substantially surrounding an interior volume and having a thin, elastomeric coating, such as an acrylic, on the exterior surface of the shell. The carvable article can be formed by an inventive process in which polyurethane foam material, such as material having a nominal density of about 2.5-3.0 pounds per cubic foot, is sprayed from a nozzle rotating with respect to the inside of a mold. After the polyurethane foam article and the mold are separated, the article is coated with an elastomeric coating, such as an acrylic material that is applied as a liquid.

Abstract: Containers, which are impervious to hydrocarbon vapors, in particular to fuel vapors, and comprise an outer shell of plastic material, which is coated with a polyamide layer at least on the surface in contact with the fuel.Said containers are used in the sector of the fuel industry, in particular in the automotive industry, as tanks for automobiles and motor vehicles.

Abstract: A tunnel liner used for a shield tunneling method for a tunnel having a diameter of 1.5 to 7 m is fabricated by dividing a ring-shaped liner into a plurality of parts in the circumferential direction. The tunnel liner is required to be excellent in the dimensional accuracy with respect to the outer peripheral surface, to be tight, to be high in strength, and to be high in water tightness at the abutment between the adjacent liners. The tunnel liner is fabricated by a method of filling each arcuate enclosed hollow form with concrete, vibro-compacting concrete, molding the end surfaces of the tunnel liner, mounting the forms within a centrifugal molding drum, and tightly molding the outer peripheral surface of the forms by applying of a centrifugal force. According to this fabrication method, it is possible to effectively fabricate an excellent tunnel liner at a low cost.

Abstract: In a rotationally-molded thermoplastic refuse container of the type having a hollow handle integrally-molded with a refuse-carrying compartment of the container, the improvement which includes a wall integrally-formed with the refuse container and sealingly enclosing the hollow handle from communication with the refuse-carrying compartment of the container for providing greater strength to the container and preventing refuse from lodging in the hollow handles.

Abstract: In a rotationally-molded thermoplastic refuse container of the type having a hollow handle integrally-molded with a refuse-carrying compartment of the container, the improvement which includes a wall integrally-formed with the refuse container and sealingly enclosing the hollow handle from communication with the refuse-carrying compartment of the container for providing greater strength to the container and preventing refuse from lodging in the hollow handles.

Abstract: This invention provides the method of centrifugal casting consisting of the steps of: adding a polymeric material to a centrifugal apparatus; centrifuging said polymeric material until said polymeric material is cast; removing said cast polymeric material from said centrifugal apparatus; and mounting said cast polymeric material to an outside surface of a support, whereby the air interface side of said cast polymeric material is furthest from the outside surface of the support.

Abstract: A concrete pipe liner is formed from a difficult-to-compact hydraulic cement slurry applied to a pipe interior. The slurry contains inorganic non-compactible hydraulic cement particles, a concrete superplasticizer component, water, and optionally and preferably filler particles. The pipe is then spun to centrifugally cast a stronger, denser pipe liner than a comparable liner containing no superplasticizer.

Abstract: Spherical particles having a diameter between 0.007" and 0.040" are formed from melt extruded thermoplastic material suitable for casting on a heated mold surface and melting thereon to form a thin layer of material that is cooled and removed from the mold surface as a part having a porosity less than a visually observable threshold. The process includes the steps of providing microspheres formed of blended and melt extruded thermoplastic, plasticizers (if necessary) and pigment additives that constitute less than 5% by weight of the blend and shaped as a smooth round spherical particle. The microspheres may then be distributed as a predetermined charge of such microspheres against the heated casting surface to melt the microspheres as a layer of thermoplastic material having a porosity less than 0.003 inches and thereafter cooling and removing the non-porous layer from the casting surface.

Abstract: A method of manufacturing hollow molded articles having a beautiful surface at a low cost and by a simple and efficient process includes providing a hollow elastic molding die made of an elastic film and having an opening port, feeding a material to be molded of an amount smaller than the internal volume of the elastic molding die into the elastic molding die through the opening port, closing the opening port, solidifying the material to be molded while the elastic molding die is rotated to all directions, and parting the solidified hollow molded article from the elastic molding die. Arrangement for preventing the elastic molding die from being deformed while it is rotated to all directions includes holding it firm by a solid holding member conforming to the external shape thereof or by positioning it in a fluid or powdery material holding member.

Abstract: Methods have been invented for molding parts and for embedding a decorative, instructional or identifying pattern into the surface of molded products during a molding process. In certain embodiments of this method, the pattern is formed as a pattern structure consisting of one or more shaped film elements or of many complementary shaped elements of various opaque, translucent, and/or transparent films. Inks, paints, overlays and inlays may be used on one or more of the films to further embellish the pattern structure. The pattern structure is then applied to the inner surface of a molding mold. In a rotomolding process according this invention, the mold is charged with casting resin, heated and rotated. The pattern structure is molded into and becomes an integral part of the product.

Abstract: A molding process and apparatus produces molded parts from cellulosic fibers. A dry process molds cellulosic fibers including the steps of mixing the cellulosic fibers and a binder to form a substantially homogeneous mixture; distributing the mixture to a desired pre-form, preferably having a non-uniform cross-section; and molding the pre-form, under a predetermined pressure and heat, to form a molded part having a substantially uniform density. A distribution assembly distributes the mixture to a desired pre-form by rotational and/or vibrational motion. The rotor on the upper surface of the telescoping portion of the distribution assembly cylindrically rotates to mechanically move the mixture in a desired pre-form shape. The rotor may be unevenly weighted such that as it rotates, the distribution assembly vibrates thereby mechanically distributing the mixture by causing it to settle in the cartridge in the desired pre-form shape.

Abstract: A development apparatus includes a housing defining a chamber holding a supply of two-component developer material including toner, and magnetizable carrier beads. The development apparatus also includes an increased reliability roller assembly within the housing for repeatably transporting a desired quantity of attracted developer material through a development zone. The roller assembly includes a first and a second preformed end cap sections each having a stub shaft portion and a cylindrical capping portion connected to the stub shaft portion and having an outer surface and assembly recesses formed into the outer surface. The roller assembly also includes a sleeve section connecting the first and the second preformed end cap sections, the sleeve section being spincast as a layer over each of the cylindrical capping portions, and into the assembly recesses of the end cap sections, so as to precisely and reliably assemble each capping portion, to the sleeve section.

Abstract: A radar reflector buoy is disclosed comprising a unitary molded inflatable hollow body with an enlarged or thickened portion which is used to attach the buoy to an anchor. The thickened portion includes a mount for an internal staff and corner radar reflector. Also disclosed is a process for producing the radar reflective buoy. The process involved open molding of the attachment area from a liquid unpolymerized polymer, partially curing it with a mount for a radar reflector staff in place, transferring the attachment area to a rotational molding apparatus, inserting a radar corner reflector and rotational molding the buoy body from a compatible powdered polymer.

Abstract: Methods and apparatus for molding a solid article incorporating one or more vulnerable inserts are disclosed. Centrifugal casting methods for producing a finished article composed of single or multiple curable fluid compounds utilize a self-releasing securing device for holding an insert stably and insulatedly protected within a mold.

Abstract: A concrete article having a mixture layer comprising concrete and a polysulfide-modified epoxy resin as an intermediate layer between a concrete body and a cured layer of a polysulfide-modified epoxy resin, which concrete article is excellent in corrosion resistance, durability and workability, and shows good adhesion to the concrete body and to the cured layer of the polysulfide-modified epoxy resin. This concrete article can be produced by applying a coating composition containing the polysulfide-modified epoxy resin to the concrete body in an uncured state.

Abstract: An apparatus is disclosed for enhancing the concentration of a second material within a first material, by liquefying the first material and introducing the second material within the first material. The first and second materials are introduced into a container and the container is rotated to generate a centrifugal force for facilitating the migration of the second material through the first material to enhance the concentration of the second material within the first material.

Abstract: A module for crossflow filtration, a method of making same, and a filtration device that accommodates at least one such module, which includes at least two multilayer filter units which are stacked on top of one another and are separated from one another by a respective spacer, with the module having at least one channel for unfiltered material and at least one filtrate channel that connects the filter units. The module further includes a sealing material ring for sealingly interconnecting peripheral portions of the filter units, with at least one edge section of the filter units being spaced from the sealing material ring to form the channels for unfiltered material. The layers of each individual filter unit are fused together at least at edge sections that are not embedded in the sealing material ring which, at edge sections of the filter units that are embedded therein, has a width that is sufficient to completely accommodate the filtrate channels.

Abstract: A rotationally symmetrical molded part of a high-temperature superconductor achieves a critical current density of j.sub.c .gtoreq.800 A/cm.sup.2 at a temperature of 77K, by using a powder mixture (8) having the stoichiometric composition of Bi.sub.2+x EA.sub.3 Cu.sub.2 O.sub.y, where -0.15<x<0.4; EA=an alkaline earth metal or a mixture of alkaline earth metals, in particular a mixture of Sr and Ca in the ratio of Sr:Ca=(2+z):(1-z), where 0<x<0.2; 8.ltoreq.y.ltoreq.8.3. With the aid of a conveying chute (9), the powder mixture (8) is brought uniformly at room temperature with a grain size of <50 .mu.m into a silver mold (5) which is arranged inside a rotating fusion mold (4), open at one side, in a furnace (3). Subsequently, the fusion mold (4) is accelerated, heated to 500.degree. C. and held for approximately 30 min at 500.degree. C. After subsequent partial melting at a temperature of T.sub.m K to T.sub.m +6K, where T.sub.

Abstract: Structural parts are produced from fiber composite preforms which are placed into a mold conforming to the shape of the desired part. A resin is then injected into the mold so as to fill the mold and encapsulate the fiber preform. The mold is evacuated prior to the injection step, and is rotated about a vertical axis during the injection step. The resin is maintained under pressure during the injection step, and the resin is hardened in the mold whereby net molded parts are formed.

Abstract: In a process for producing a high-temperature superconductor from oxides of bismuth, strontium, calcium, copper and optionally of lead and including sulfates of strontium and/or barium, the oxides of bismuth, strontium, calcium, copper and optionally of lead in the desired molar ratio, and from 2 to 30% by weight of strontium sulfate and/or from 1 to 20% by weight of barium sulfate, each calculated according to the mixture of the oxides, are mixed intimately, the mixture is melted in a crucible of a platinum metal at temperatures from 870.degree. to 1600.degree. C., the melt is poured into permanent molds of desired form and size and is allowed to solidify slowly therein, and the moldings produced are freed from the permanent mold material and are annealed for from 6 to 200 hours at temperatures from 700.degree. to 900.degree. C. in an oxygen-containing atmosphere.

Abstract: An apparatus for making an endless, flat, flexible belt of pourable plastics include a core, especially a multiple core, as tension bearer, for example in a conveyor belt of polyurethane. The apparatus includes a drum-like frame adapted for use in a centrifugal casting mold utilized for casting an endless, flat, flexible belt of pourable plastic material having a multiple strand core as a tension bearer at the generally center plane of the belt.

Abstract: To produce tubular molded parts made of high-temperature superconductor oxide material based on bismuth, calcium, strontium and copper, a homogeneous melt of the oxide with a specified stoichiometry is allowed to run at temperatures of 900.degree. to 1100.degree. C. into a casting zone rotating about its horizontal axis. The solidified molded part is removed from the casting zone and it is annealed for 4 to 150 hours at 700.degree. to 900.degree. C. in an oxygen-containing atmosphere. A plant for producing tubular molded parts includes a rotatably arranged mold (4, 9) which is provided at least at one end face with a front plate 6 which reduces its free cross section, a runner 7 extending into the interior of the mold (4, 9) and a crucible 8 arranged above the runner 7 which is capable of feeding the runner 7 with melt (cf. FIG. 2 A).

Abstract: To eliminate the fluctuations in the precision of the material distribution which could not be avoided when manufacturing pipes in the centrifugal moulding process with the prior art installations, a new process and an installation for carrying out the process is proposed. This has at least two cylindrical centrifugal drums (1) serving as moulds and an injection carriage (12) which is displaceable in two directions perpendicular to each other, with a feed arm (11).

Abstract: A powder molding is manufactured from various powdery materials including an inorganic material, an organic material, a metallic material, etc., according to a wet forming process. A powdery material and a solvent are mixed into a mixture so that the mixture exhibits a dilatant flow. The mixture is molded into a molding of desired shape, and then the molding is dried.

Abstract: A dielectric multilayer filter applicable to optical communication systems is disclosed, as is a fabrication method therefor, and an optical element incorporating the same. The disclosed dielectric multilayer filter includes a fluorinated polyimide base layer with a dielectric multilayer formed thereover. According to the disclosed fabrication method, a fluorinated polyimide layer is formed by applying liquid fluorinated polyimide material over a smooth surface to a predetermined thickness followed by drying and hardening, after which a dielectric multilayer is formed over the fluorinated polyimide layer by an ion assist vapor deposition method, and then stripping the fluorinated polyimide layer away from the underlying smooth surface. The disclosed dielectric multilayer filter can be easily and economically produced at a suitably small thickness with no need for grinding, exhibits highly uniform physical and optical properties, and is exceedingly durable and resistant to curling and warping.

Abstract: A process for producing a plastic article having a decorative appearance which comprises multiplane rotational molding polymer and additives, including decorative metalflake in such a manner as will evenly distribute the metalflake.

Abstract: In a process known of per se for manufacturing plastic pipes, in which a liquid resin, a catalyst and sand and glass fibres are introduced into a centrifugal drum where the pipe is formed as the plastic sets, it was previously customary to start or stimulate the thermosetting process by blowing hot air into the centrifugal drum. The air escaping thereby from the inside of the drum contains solvent vapours which pollute the environment. The improved process consists in that the heat required to start the thermosetting process is no longer supplied from the inside by means of hot air, but by means of hot water which is sprayed onto the outside of the centrifugal drum and is fed through a hot water circuit and, after the exothermic thermosetting begins, heats up again in the latter to at least the original temperature, thereby drawing off heat released by the process. Further cooling is achieved by a cold water circuit, which can be switched on selectively to spray the centrifugal drum.

Abstract: A method of preparing a hydrophilic plastic cartridge by centrifugally cang polymerizable hydrophilic material in a rotating polymerization tube whose longitudinal axis is maintained parallel to the ground. The speed of rotation causes radial outward displacement of the polymerizable material which upon assuming a predetermined shape within the rotating tube is then polymerized to the predetermined solid configuration. The resulting plastic cartridge is characterized by smooth, unscored internal and external cylindrical surfaces. The cartridges are used as a rate-limiting membrane in drug delivery devices. Sterilized kits containing a disposable needle/syringe or trocar-like instrument and the drug delivery device are used for subcutaneous implantation of the device in an animal body.

Abstract: A centrifugally cast plastic pipe comprised of a polymer derived from monomers polymerized in bulk is provided. A pressurized cylindrical mold provides smooth inner and outer surfaces. Pipes with a wall thickness of from 1/8 inch to 3 inches and an outer diameter of 1 inch to 12 feet are provided.

Abstract: A method is provided for the preparation of homogeneous copolymers having a redetermined equilibrium water content (EWC) value formed by the addition polymerization of a mixture of ethylenically unsaturated monomer A and ethylenically unsaturated monomer B, for example, 2-hydroxyethyl methacrylate and hydroxypropyl methacrylate. The method requires determining the EWC values of the hydrogel homopolymer of hydrophilic monomer A (homopolymer A) and the hydrogel homopolymer of hydrophilic monomer B (homopolymer B); determining the relationship of the EWC values of the homogeneous copolymers AB versus the chemical composition of said copolymers AB; selecting the targeted EWC value and determining the chemical composition of copolymer AB having the targeted EWC value; forming a polymerizable mixture of monomer A and monomer B in amounts sufficient to yield copolymer AB having the targeted EWC value; and effect the polymerization reaction to yield copolymer AB characterized by the targeted EWC value.

Abstract: A ceramic compact having excellent high temperature strength, toughness and reliability, which comprises a matrix preferably composed predominantly of silicon nitride and ceramic fibers uniformly dispersed in the matrix and orientated in a desired direction, said matrix and fibers being closely bonded by sintering. This compact is produced, for example, by preparing a shaped body of silicon, for example, in which ceramic fibers are uniformly dispersed by centrifugal casting and then heating and nitriding the shaped body in a nitrogen atmosphere to form a fiber-reinforced silicon nitride sintered compact. The ceramic fibers may include such fibers as aluminum oxide or silicon carbide fibers. Sintering assistants, such as silicon nitride, may be used to prepare the sintered compact.

Abstract: A method of fabricating free-standing thin films of polyimide by casting a polyamic acid solution onto a substrate that is free of parting agents and release agents is disclosed. The polyamic acid film is imidized on the substrate. The thickness of the polyimide film can range from about 200 .ANG. to about five microns. A frame is adhered to the polyimide film while the film still attached to the substrate, and the frame, film, and substrate assembly is immersed in an aqueous based liquid bath for several hours wherein the liquid bath is free of reactive chemical agents. The liquid bath is heated, preferably, to a temperature within the range 30.degree. to 100.degree. C. The liquid is prevented from contacting the polyimide film within the interior region of the frame. Next, the assembly is removed from the water bath. The film is scored around the outside edge of the frame with a cutting tool; this cutting step may be performed either prior to, during, or after the immersion step.

Abstract: An apparatus and process is disclosed for the preparation by molding of composite materials formed of a metallic or organic matrix and at least one reinforcing element which includes a mold having an axis of revolution, the mold being equipped with a rotator allowing it to rotate about its axis, with a device for feeding liquid matrix material and with a device for feeding a reinforcing element. The reinforcing element feeding device opens into the feed device of the matrix material-feeding device which causes turbulence. The feed device can be a shoot, a casting channel, a feed pipe, a funnel or another equivalent device.