A composition comprising a polymeric crystalline structure having lamellae and/or multilamellar structures and that is devoid of any amount of amorphous material that is detectable by Scanning Electron Microscopy (SEM) with a magnification of ?2,300 at working distance of 10 mm and acceleration voltage of 15 kV. A novel method or preparation of the composition is also disclosed.

A particle-dispersed polyimide precursor solution contains a polyimide precursor having a unit represented by the following formula (I), particles, and a solvent, in which the particle-dispersed polyimide precursor solution satisfies both the following conditions (1) and (2), ##STR00001## (in the formula (I), A represents a tetravalent organic group, and B represents a divalent organic group represented by any of the following formulas (B1) to (B4)), ##STR00002## (in the formulas (B1) to (B4), Ar.sup.1, Ar.sup.10, and Ar.sup.11 each independently represent a trivalent aromatic group which may have a substituent, Ar.sup.2, Ar.sup.4, Ar.sup.5, Ar.sup.7 and Ar.sup.8 each independently represent a divalent aromatic group which may have a substituent, Ar.sup.3 and Ar.sup.6 each independently represent a tetravalent aromatic group which may have a substituent or a group represented by the following formula (II), Ar.sup.9 represents a divalent aromatic group which may have a substituent or a group represented by the following formula (III), X.sup.1 to X.sup.7 each independently represent NRa, O, or S, Ra represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group, and * represents a bonding site with an adjacent linking group), and ##STR00003## (in the formulas (II) and (III), Ar.sup.12 and Ar.sup.13 each independently represent a trivalent aromatic group which may have a substituent, Ar.sup.14 and Ar.sup.15 each independently represent a divalent aromatic group which may have a substituent, Y and Z each independently represent O, S, S(?O).sub.2, or CRbRc, Rb and Rc each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an aryl group, and * represents a bonding site with an adjacent linking group), Condition (1): a total content of the groups represented by the formulas (B1) to (B4) is 1% by mass or more and 40% by mass or less with respect to a total amount of the polyimide precursor, and Condition (2): a content of the particles is 5% by mass or more and 90% by mass or less with respect to a total content of the polyimide precursor and the particles.

A particle-dispersed polyimide precursor solution contains a polyimide precursor having a unit represented by the following formula (I), particles, and a solvent, in which the particle-dispersed polyimide precursor solution satisfies both the following conditions (1) and (2), ##STR00001## (in the formula (I), A represents a tetravalent organic group, and B represents a divalent organic group represented by any of the following formulas (B1) to (B4)), ##STR00002## (in the formulas (B1) to (B4), Ar.sup.1, Ar.sup.10, and Ar.sup.11 each independently represent a trivalent aromatic group which may have a substituent, Ar.sup.2, Ar.sup.4, Ar.sup.5, Ar.sup.7 and Ar.sup.8 each independently represent a divalent aromatic group which may have a substituent, Ar.sup.3 and Ar.sup.6 each independently represent a tetravalent aromatic group which may have a substituent or a group represented by the following formula (II), Ar.sup.9 represents a divalent aromatic group which may have a substituent or a group represented by the following formula (III), X.sup.1 to X.sup.7 each independently represent NRa, O, or S, Ra represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group, and * represents a bonding site with an adjacent linking group), and ##STR00003## (in the formulas (II) and (III), Ar.sup.12 and Ar.sup.13 each independently represent a trivalent aromatic group which may have a substituent, Ar.sup.14 and Ar.sup.15 each independently represent a divalent aromatic group which may have a substituent, Y and Z each independently represent O, S, S(?O).sub.2, or CRbRc, Rb and Rc each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an aryl group, and * represents a bonding site with an adjacent linking group), Condition (1): a total content of the groups represented by the formulas (B1) to (B4) is 1% by mass or more and 40% by mass or less with respect to a total amount of the polyimide precursor, and Condition (2): a content of the particles is 5% by mass or more and 90% by mass or less with respect to a total content of the polyimide precursor and the particles.

A low-dielectric board material includes a metal layer and a porous resin layer disposed on a one-side surface of the metal layer in the thickness direction. The porous resin layer includes a first region, a second region, a third region, and a fourth region that are located in sequence toward a direction away from the metal layer when the porous resin layer is equally divided into four in the thickness direction. The first region has a plurality of closed cells that are separate from each other in a resin matrix. The average of the aspect ratios AR of the plurality of closed cells in the first region is 0.80 or more and 1.20 or less. The average of the aspect ratios AR is a ratio (L1/L2) of a length L1 of a closed cell in a direction orthogonal to the thickness direction to a length L2 of the closed cell in the thickness direction in a cross-sectional view.

A method for forming a thermoplastic body having regions with varied material composition and/or porosity. Powder blends comprising a thermoplastic polymer, a sacrificial porogen and an inorganic reinforcement or filler are molded to form complementary parts with closely toleranced mating surfaces. The parts are formed discretely, assembled and compression molded to provide a unitary article that is free from discernible boundaries between the assembled parts. Each part in the assembly has differences in composition and/or porosity, and the assembly has accurate physical features throughout the sections of the formed article, without distortion and nonuniformities caused by variable compaction and densification rates in methods that involve compression molding powder blends in a single step.

In an aspect, provided herein are low density materials, including shell-based materials, with three-dimensional architectures formed, in part, via self-assembly processes. Shell-based materials of some embodiments exhibit a combination of ultralow density (e.g., ?100 mg cm.sup.?3 and optionally ?10 100 mg cm.sup.?3) and non-periodic architectures characterized by low defect densities and geometries avoiding stress concentrations. Low density shell based materials of some embodiments have architectures characterized by small curvatures and lack of straight edges providing enhance mechanical response. In some embodiments, for example, the present low density materials, including shell-based materials, providing a combination target mechanical properties including high stiffness-to-density ratios, mechanical resilience and tolerance for deformation.

In an aspect, provided herein are low density materials, including shell-based materials, with three-dimensional architectures formed, in part, via self-assembly processes. Shell-based materials of some embodiments exhibit a combination of ultralow density (e.g., ?100 mg cm.sup.?3 and optionally ?10 100 mg cm.sup.?3) and non-periodic architectures characterized by low defect densities and geometries avoiding stress concentrations. Low density shell based materials of some embodiments have architectures characterized by small curvatures and lack of straight edges providing enhance mechanical response. In some embodiments, for example, the present low density materials, including shell-based materials, providing a combination target mechanical properties including high stiffness-to-density ratios, mechanical resilience and tolerance for deformation.

Embodiments of the present disclosure include organic polymeric particles, paper coating compositions, coated paper, and methods of forming coated paper with the paper coating compositions. The embodiments of the organic polymeric particle include an organic hydrophilic polymer with a unit for hydrogen bonding, and a hollow porous structure that comprises an organic polymer that at least partially surrounds the organic hydrophilic polymer, where the hollow porous structure has a pore surface area greater than 1 percent of a total theoretical exterior surface area of the hollow porous structure and the organic hydrophilic polymer and the hollow porous structure give the organic polymeric particle a void volume fraction of 40 percent to 85 percent.

Embodiments of the present disclosure include organic polymeric particles, paper coating compositions, coated paper, and methods of forming coated paper with the paper coating compositions. The embodiments of the organic polymeric particle include an organic hydrophilic polymer with a unit for hydrogen bonding, and a hollow porous structure that comprises an organic polymer that at least partially surrounds the organic hydrophilic polymer, where the hollow porous structure has a pore surface area greater than 1 percent of a total theoretical exterior surface area of the hollow porous structure and the organic hydrophilic polymer and the hollow porous structure give the organic polymeric particle a void volume fraction of 40 percent to 85 percent.

The present invention relates to a method of preparing a hierarchically porous polymer and a hierarchically porous polymer prepared thereby. The method comprises the steps of: (a) polymerizing an external oil phase of a high internal phase emulsion (HIPE) consisting aqueous droplets to produce a cross-linked block copolymer; (b) obtaining a macroporous polymer with interconnected macropores by removing the aqueous droplets; and (c) treating the obtained porous polymer with a base, thereby obtaining a hierarchically porous polymer having three-dimensional mesopores formed in the macroporous walls. According to the method, the macropore size and mesopore size of the hierarchically porous polymer can all be controlled. The hierarchically porous polymer prepared by the method can easily separate polymers having different sizes, and thus is highly useful in the polymer separation field.