A filament comprising a polymer blend and specific articles comprising the filament are disclosed. The polymer blend includes an aliphatic nylon and a semiaromatic nylon. The aliphatic nylon is the major component of the blend and semiaromatic nylon is the minor component of the blend. The aliphatic nylon can be Nylon 6, Nylon 66, Nylon 610, Nylon 612, Nylon 12, and mixtures thereof. The semiaromatic nylon can be 6I/6T, 6T/6I, and mixtures thereof. The nylon blend filament provides enhanced mechanical properties such as modulus, ultimate strength, and yield strength with improved processability and reduced diameter variability at a reduced cost.

Provided herein are hexavalent, fully-functionalized benzene derivatives comprising two types of functional groups, wherein each functional group type alternates around the benzene ring, so no identical functional groups are positioned next to one another. In certain embodiments, the first functional group is selected from an aldehyde (CO), imine (CNH), or iminium, and the second functional group is selected from a primary amine (NH.sub.2) or ammonium (NH.sub.3.sup.+). The hexavalent, fully-functionalized benzene derivatives of the invention as useful as monomers in the formation of planar, two-dimensional polymer networks. Also provided are covalent organic frameworks comprising the hexavalent, fully-functionalized benzene derivatives of the invention. Also provided herein are synthetic fibers comprising such two-dimensional polymers. Further provided are methods of making the hexavalent, fully-functionalized benzene derivatives.

A resin sheet is provided that provide both light-weight properties and mechanical strength using a thermoplastic resin with high deflection temperature under load. The resin sheet is formed from a thermoplastic resin, including: a core layer being a foam resin layer; and skin layers located outward of the core layer as determined along the thickness direction, the core and skin layers forming a continuity. The core layer includes a region A1 and regions A2 each located between the region A1 and the associated skin layer. The regions A2 has a lower average porosity than the region A1, the average porosity being lower than 50%. The thermoplastic resin has a deflection temperature under load not lower than 90 C. The resin sheet has a thickness of 1 to 40 mm. Each skin layer has a thickness of 5 to 50% of the thickness of the resin sheet.

A continuous process for the recycling of aramid fiber comprising the following steps: combining aramid fibrous material including non-continuous aramid fibers with sulfuric acid to obtain a spin dope comprising aramid, and processing the spin dope including aramid into a continuous aramid fiber. The invention also pertains to a continuous aramid fiber, preferably obtainable by said process, and to a multifilament yarn including the continuous aramid fiber.