In one instance a semicrystalline polyketone powder useful for additive manufacturing is comprised of a bimodal melt peak determined by an initial differential scanning calorimetry (DSC) scan at 20? C./min and a D.sub.90 particle size of at most 300 micrometers and average particle size of 1 micrometer to 150 micrometers equivalent spherical diameter. In another instance, A composition is comprised of a semicrystalline polyketone powder having a melt peak and a recrystallization peak, wherein the melt peak and recrystallization peak fail to overlap.

Disclosed is a polyimide film prepared from a liquid composition comprising a liquid composition comprising (a) a polyamic acid having a repeat unit structure of Formula I

##STR00001##

wherein R.sup.a is the same or different at each occurrence and represents one or more tetracarboxylic acid component residues and R.sup.b is the same or different at each occurrence and represents one or more diamine component residues, (b) one or more phosphorous-containing additivesm and (c) a high-boiling aprotic solvent. Also disclosed are processes for making the film and uses of the film in electronic devices.

A semicrystalline poly ketone powder useful for additive manufacturing may be made by dissolving a polyketone having differential scanning calorimetry (DSC) monomodal melt peak, at a temperature above 50? C. to below the melt temperature of the polyketone, precipitating the dissolved polyketone by cooling, addition of a nonsolvent or combination thereof. The method may be used to form polyketones having a DSC melt peak with an enthalpy greater than the starting polyketone.

Certain embodiments are directed to cyanate resin blends comprising, for example, a mixture of a cyanate monomer and a cyanate oligomer. The resin blends are effective to provide a dielectric constant of less than 2.7, a glass transition temperature of at least 150 C. and a moisture absorption of less than 1.5%. Radomes using the resin are also described.

An object of the present invention is to provide a resin composition that can attain cured products having high flame retardancy, high heat resistance, a small coefficient of thermal expansion, and high drilling processability, a prepreg having the resin composition, a laminate and a metal foil clad laminate having the prepreg, and a printed circuit board having the resin composition. A resin composition, having at least an epoxy silicone resin (A) prepared by reacting a linear polysiloxane (a) having a carboxyl group with a cyclic epoxy compound (b) having an epoxy group such that the epoxy group of the cyclic epoxy compound (b) is 2 to 10 equivalents based on the carboxyl group of the linear polysiloxane (a), a cyanic acid ester compound (B) and/or a phenol resin (C), and an inorganic filler (D).

Certain embodiments are directed to cyanate resin blends comprising, for example, a mixture of a cyanate monomer and a cyanate oligomer. The resin blends are effective to provide a dielectric constant of less than 2.7, a glass transition temperature of at least 150 C. and a moisture absorption of less than 1.5%. Radomes using the resin are also described.

Phenolic closed-cell foam comprises a hydrocarbon blowing agent and includes an alkali metal silicate in an amount of at least 1% by weight. The foam has an aged thermal conductivity as determined by the procedures of EN13166:2008 of less than 0.025 W/m.Math.K. The foam is formed from a phenolic resole resin mixture having a water content of greater than 15% by weight but less than 24% by weight.

A semicrystalline poly ketone powder useful for additive manufacturing may be made by dissolving a polyketone having differential scanning calorimetry (DSC) monomodal melt peak, at a temperature above 50 C. to below the melt temperature of the polyketone, precipitating the dissolved polyketone by cooling, addition of a nonsolvent or combination thereof. The method may be used to form polyketones having a DSC melt peak with an enthalpy greater than the starting polyketone.

Method of forming extruded thermoplastic foam comprising extruding a foamable composition comprising thermoplastic polymer and blowing agent, wherein said thermoplastic polymer consists essentially of ethylene furanoate moieties and optionally ethylene terephthalate moieties and wherein said extruding step comprises forcing said foamable composition from a relatively high pressure region through a die to a relatively low pressure region.

To provide a polyketone porous film having heat resistance and chemical resistance and useful as a filter for filtration having a high particle collection efficiency and as a battery or capacitor separator having a low permeation resistance to ion and the like. A polyketone porous film comprising from 10 to 100 mass % of a polyketone as a copolymer of carbon monoxide and one or more olefins, wherein the polyketone porous film has a pore formed only by a polyketone, the pore diameter uniformity parameter as a value obtained by dividing the standard deviation of the pore diameter in the pore by an average pore diameter is from 0 to 1.0, and the average through hole diameter of the polyketone porous film is from 0.01 to 50 m.