An object is to solve the problem that no reports have yet been made on a pure polyether nitrile that exhibits a semi-crystallization time of less than 120 seconds, which is considered to be a practical molding cycle, and provide a polyether nitrile from which a molded article can be produced with improved efficiency. As a solution, a polyether nitrile having a semi-crystallization time of 100 seconds or less at 275 C., the semi-crystallization time being determined by power-compensated differential scanning calorimetry when the polyether nitrile is cooled from a molten state at 370 C. to 275 C. at a cooling rate of 500 C. per minute, is provided.

An aromatic polyether including structural units represented by the following formulas (1A) to (4A): ##STR00001##

An aromatic polyether including structural units represented by the following formulas (1A) to (4A): ##STR00001##

A phosphorus-containing polymer includes a structural unit derived from a first monomer and a structural unit derived from a second monomer. A resin composition contains the phosphorus-containing polymer, and an article is made from the resin composition. The resin composition includes: 100 parts by weight of a free radical polymerizable resin, the free radical polymerizable resin including an unsaturated CC double bond-containing polyphenylene ether resin, a maleimide resin, a polyolefin or a combination thereof; and 12 parts by weight to 100 parts by weight of the phosphorus-containing polymer. The resin composition or the article made therefrom may achieve improvements in one or more properties including glass transition temperature, flame retardancy, dissipation factor, peeling strength, percent of thermal expansion in Z-axis, laminate appearance, heat resistance after moisture absorption and multi-layer board heat resistance.

##STR00001##

Thermoplastic compositions include from about 20 wt % to about 80 wt % of a polyphenylene ether (PPE), from about 1 wt % to about 30 wt % of a polystyrene resin that does not include a rubber component, and from about 0.01 wt % to about 10 wt % of a chemically reactive impact modifier. The combined weight percent value of all components does not exceed 100 wt %, and all weight percent values are based on the total weight of the composition. The compositions are resistant to bubbling upon processing.