The present disclosure provides a foamable composition containing (A) a high density polyethylene (HDPE); (B) a low density polyethylene (LDPE); (C) a peroxide-modified HDPE; and (D) a nucleator. The present disclosure also provides a process for making a foam composition. Additionally, the present disclosure provides a foam formed from a foamable composition, and a cable with an insulation layer containing the foam.

A foamable composition includes a base polymer, talc blended with the base polymer, and a citrate compound blended with the base polymer. The foamable composition is usable as an insulator, a separator and a jacket for cables, such as communications cable. The foamable composition can include conductive inclusions in the foamable composition.

Thermoplastic polymers, for example fluoropolymers, are foamed by use of a solid formulation comprising thermoplastic polymer and manganese oxalate.

A melt blended composition comprising, in weight percent (wt %) based upon the weight of the composition: (A) 55 to 94.98 wt % of a thermoplastic polymer, (B) 5 to 44.98 wt % of a moisture curable polymer, (C) 0.01 to 5 wt % of a moisture condensation catalyst, and (D) 0.01 to 5 wt % of a foaming agent, exhibits enhanced foaming, rheological and mechanical properties as compared to a composition alike in all aspects save for the presence of a moisture curable polymer.

The invention relates to low density fluoropolymer foam, and preferably polyvinylidene fluoride (PVDF) foam, such as that made with KYNAR PVDF resins, and articles made of the foam. The foam is produced by adding microspheres containing blowing agents to the polymer and processing it through an extruder. The microspheres consist of a hard shell containing a physical blowing agent. The shell softens at elevated temperatures and allows the expansion of the blowing agent, and microsphere to create larger voids within the polymer matrix. By proper control of the polymer composition, viscosity, processing temperature, blowing agent selection, loading ratio, and finishing conditions, useful articles such as foamed PVDF pipe, tube, profiles, film, wire jacketing and other articles can be produced. The microspheres may be added to the fluoropolymer matrix by several means, including as part of a masterbatch with a compatible polymer carrier.

Described herein are solid and foamable fluoropolymer alloy compositions and foamed articles using said foamable fluoropolymer alloy compositions. The foamable fluoropolymer alloy compositions can comprise a fluoropolymer, and a plastic polymer mixed with said fluoropolymer, wherein said plastic polymer is miscible with said fluoropolymer. The fluoropolymer alloy composition may further comprise a foaming agent. By way of example, the foaming agent can be talc or a talc derivative, or a mixture of talc (or talc derivative) with a citrate compound, such as a citrate salt. One or more additives are added to render the compositions flame retardant and/or smoke suppressant.

The process of foaming a polyolefin composition using as a nucleator a combination of a fluororesin and a boron nitride at a fluororesin-to-boron nitride weight ratio of less than 4:1. The synergistic effect between these two nucleating agents results in a higher nuclei density and a foamed product with a smaller average cell size as compared to processes using and products produced by the use of neat PTFE or neat boron nitride alone as the nucleating agent.

An insulated electric wire includes a linear conductor and one or a plurality of insulating layers formed on an outer peripheral surface of the conductor. At least one of the one or plurality of insulating layers contains a plurality of pores, outer shells are disposed on peripheries of the pores, and the outer shells are derived from shells of hollow-forming particles having a core-shell structure. A varnish for forming an insulating layer contains a resin composition forming a matrix and hollow-forming particles having a core-shell structure and dispersed in the resin composition. In the varnish, cores of the hollow-forming particles contain a thermally decomposable resin as a main component, and shells of the hollow-forming particles contain a main component having a higher thermal decomposition temperature than the thermally decomposable resin.

The invention relates to a foamable ethylene polymer composition comprising at least one antioxidant, at least one process aid and at least 80 wt % of a peroxide-treated ethylene polymer composition. The foamable ethylene polymer composition has melt strength of at least 2 cN, a density of 940 to 970 kg/m3, and dissipation factor measured at 1.9 GHz of 50-8010.sup.6. The invention further relates to a process for making such a foamable ethylene polymer composition, and use of the foamable ethylene polymer composition in a foamed cable insulation.

A polymer matrix composite comprising a porous polymeric network; and a plurality of dielectric particles distributed within the polymeric network structure; wherein the dielectric particles are present in a range from 5 to 98 weight percent, based on the total weight of the dielectric particles and the polymer (excluding the solvent); and wherein the polymer matrix composite has a dielectric constant in a range from 1.05 to 80; and methods for making the same. Polymer matrix composites comprising dielectric particles are useful, for example, as electric field insulators.