Provided are an imide-terminated prepolymer, a preparation method therefor, a curable resin composition, use thereof and a dual curing method. An end capped, imide-terminated prepolymer is mixed with at least one photopolymerizable ethylenic monomer, at least one photoinitiator and diamine, and optionally a pigment to form a curable resin composition, which, in a first step, is irradiated under conditions effective to polymerize the at least one ethylenic monomer. The irradiated composition is then heat-treated under conditions effective to cause a transimidation reaction between the prepolymer and the diamine to provide a solid polymer.

The present invention provides a composite film and a preparation method thereof. The composite film includes polyimide and a dense silica layer formed on a surface of the polyimide.

A dual-cure method for forming a solid polymeric structure is provided. An end-capped, imide-terminated prepolymer is combined with at least one photopolymerizable olefinic monomer, at least one photoinitiator, and a diamine, to form a curable resin composition, which, in a first step, is irradiated under conditions effective to polymerize the at least one olefinic monomer, thus forming a scaffold composed of the prepolymer and the polyolefin with the diamine trapped therein. The irradiated composition is then thermally treated at a temperature effective to cause a transimidization reaction to occur between the prepolymer and the diamine, thereby releasing the end caps of the prepolymer and providing the solid polymeric structure. A curable resin composition comprising an end-capped, imide-terminated prepolymer, at least one photopolymerizable olefinic monomer, at least one photoinitiator, and a diamine, is also provided, as are related methods of use.

A method for producing an aqueous polyimide precursor solution includes forming a polyamic acid by the reaction of a tetracarboxylic acid component and a diamine component in water without organic solvent together with an imidazole in an amount of 1.6 mole or more per mole of the tetracarboxylic acid component of the polyamic acid.

Low-density thermoplastic expandable microspheres are disclosed. Various low-density structures, in particular, sandwich panels, based on foam prepared from the low-density microspheres, are also disclosed. Process of preparing low-density polymeric microspheres, per se, and the corresponding low-density structures, based on the microsphere foam, are also disclosed.

A dual-cure method for forming a solid polymeric structure is provided. An end-capped, imide-terminated prepolymer is combined with at least one photopolymerisable olefinic monomer, at least one photoinitiator, and a diamine, to form a curable resin composition, which, in a first step, is irradiated under conditions effective to polymerize the at least one olefinic monomer, thus forming a scaffold composed of the prepolymer and the polyolefin with the diamine trapped therein. The irradiated composition is then thermally treated at a temperature effective to cause a transimidization reaction to occur between the prepolymer and the diamine, thereby releasing the end caps of the prepolymer and providing the solid polymeric structure. A curable resin composition comprising an end-capped, imide-terminated prepolymer, at least one photopolymerisable olefinic monomer, at least one photoinitiator, and a diamine, is also provided, as are related methods of use.

The present disclosure relates to a polyimide varnish composition for a flexible substrate and a polyimide film using the same, and a polyimide varnish composition for a flexible substrate according to the present disclosure may include an acid anhydride including 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA), and a diamine. The polyimide varnish composition according to the present disclosure has the advantage of being able to manufacture a polyimide film having heat resistance, high flexural properties, and high flexibility by increasing elongation while having a low coefficient of thermal expansion.

Examples are disclosed herein that relate to vehicles, composite parts, and methods for forming a composite part for a vehicle. In one example, a vehicle comprises a composite part comprising a skin comprising one or more material layers. The composite part further comprises a stiffener comprising one or more material layers, wherein the stiffener comprises a flange and a web. The composite part also includes an additively manufactured sub-structure positioned between at least a portion of the skin and at least a portion of the stiffener. The additively manufactured sub-structure comprises at least one flange portion, at least one radius, and at least one radius filler. A polymer matrix is co-infused within the skin, the stiffener, and the additively manufactured sub-structure.

The present invention relates to a method of controlling a step of a process carried out by a machine. The invention is characterized in that a sensor is used to measure a variable characteristic with an exponential course for a step, and with the aid of several consecutive measurements of the characteristic variable a time constant of the exponential change is determined, and the step is ended after it has been carried out for a period of time corresponding to a predetermined multiple of the time constant.

Methods for manufacturing articles of footwear are provided. In various aspects, the methods comprise utilizing additive manufacturing methods with foam particles. In some aspects, the additive manufacturing methods comprise increasing the temperature of a plurality of foam particles with actinic radiation under conditions effective to fuse a portion of the plurality of foam particles comprising one or more thermoplastic elastomers. Increasing the temperature of the foam particles can be carried out for one or multiple iterations. The disclosed methods can be used to manufacturer articles with sub-regions that exhibit differing degrees of fusion between the foam particles, thereby resulting in sub-regions with different properties such as density, resilience, and/or flexural modulus. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.