Provided is a method for manufacturing fine polyarylene sulfide (PAS) powder, in which impurities such as alkali metal salts and/or PAS oligomers are reduced while the wettability of the fine PAS powder in a fine PAS powder-containing solid is retained after solid-liquid separation of a separation liquid obtained by subjecting a dispersion liquid containing granular PAS to separation into granular PAS and a separation liquid; and a fine PAS powder. The method for manufacturing a fine PAS powder of the present invention includes: (a) separating granular PAS and a separation liquid from a dispersion liquid containing granular PAS, by solid-liquid separation using at least one screen that has an opening diameter of 75 to 180 m; (b) performing solid-liquid separation of the separation liquid to obtain a fine PAS powder-containing solid; (c) heating the fine PAS powder-containing solid to reduce an amount of an organic solvent to obtain a wet cake; and (d) washing the wet cake using an aqueous solvent. The water content of the wet cake after heating is at least 30 wt. %.

Provided is a method for manufacturing fine polyarylene sulfide (PAS) powder, in which impurities such as alkali metal salts and/or PAS oligomers are reduced while the wettability of the fine PAS powder in a fine PAS powder-containing solid is retained after solid-liquid separation of a separation liquid obtained by subjecting a dispersion liquid containing granular PAS to separation into granular PAS and a separation liquid; and a fine PAS powder. The method for manufacturing a fine PAS powder of the present invention includes: (a) separating granular PAS and a separation liquid from a dispersion liquid containing granular PAS, by solid-liquid separation using at least one screen that has an opening diameter of 75 to 180 m; (b) performing solid-liquid separation of the separation liquid to obtain a fine PAS powder-containing solid; (c) heating the fine PAS powder-containing solid to reduce an amount of an organic solvent to obtain a wet cake; and (d) washing the wet cake using an aqueous solvent. The water content of the wet cake after heating is at least 30 wt. %.

A poly(phenylene sulfide) fiber contains 1-10% by weight of a poly(phenylene sulfide) oligomer having a weight-average molecular weight of 5,000 or less, has a difference between a cold crystallization heat quantity (Hc) and a crystal melting heat quantity (Hm) during temperature rising in DSC, HmHc, of 25 J/g or larger, and has an elongation of less than 40% and a strength of 3.0 cN/dtex or higher. The poly(phenylene sulfide) fiber has high heat resistance and chemical resistance and high strength and, despite this, has excellent suitability for high-order processing, e.g., thermal shapability, because the amorphous parts thereof have high molecular movability.

A poly(phenylene sulfide) fiber contains 1-10% by weight of a poly(phenylene sulfide) oligomer having a weight-average molecular weight of 5,000 or less, has a difference between a cold crystallization heat quantity (Hc) and a crystal melting heat quantity (Hm) during temperature rising in DSC, HmHc, of 25 J/g or larger, and has an elongation of less than 40% and a strength of 3.0 cN/dtex or higher. The poly(phenylene sulfide) fiber has high heat resistance and chemical resistance and high strength and, despite this, has excellent suitability for high-order processing, e.g., thermal shapability, because the amorphous parts thereof have high molecular movability.

It is provided a process for modifying an aromatic polyether backbone for obtaining a modified polyether comprising the steps of: a) providing the at least one aromatic polyether to be modified in dissolved state in an inert organic solvent, b) adding at least one modification reagent, c) adding at least one catalyst, d) carrying out the process until a desired degree of functionalization of said aromatic polyether backbone is reached, e) recovery of the modified aromatic polyether.

Provided is a method for manufacturing fine polyarylene sulfide (PAS) powder, in which impurities such as alkali metal salts and/or PAS oligomers are reduced while the wettability of the fine PAS powder in a fine PAS powder-containing solid is retained after solid-liquid separation of a separation liquid obtained by subjecting a dispersion liquid containing granular PAS to separation into granular PAS and a separation liquid; and a fine PAS powder.

The method for manufacturing a fine PAS powder of the present invention includes: (a) separating granular PAS and a separation liquid from a dispersion liquid containing granular PAS, by solid-liquid separation using at least one screen that has an opening diameter of 75 to 180 m; (b) performing solid-liquid separation of the separation liquid to obtain a fine PAS powder-containing solid; (c) heating the fine PAS powder-containing solid to reduce an amount of an organic solvent to obtain a wet cake; and (d) washing the wet cake using an aqueous solvent. The water content of the wet cake after heating is at least 30 wt. %.

A poly(phenylene sulfide) fiber contains 1-10% by weight of a poly(phenylene sulfide) oligomer having a weight-average molecular weight of 5,000 or less, has a difference between a cold crystallization heat quantity (Hc) and a crystal melting heat quantity (Hm) during temperature rising in DSC, HmHc, of 25 J/g or larger, and has an elongation of less than 40% and a strength of 3.0 cN/dtex or higher. The poly(phenylene sulfide) fiber has high heat resistance and chemical resistance and high strength and, despite this, has excellent suitability for high-order processing, e.g., thermal shapability, because the amorphous parts thereof have high molecular movability.

A poly(phenylene sulfide) fiber contains 1-10% by weight of a poly(phenylene sulfide) oligomer having a weight-average molecular weight of 5,000 or less, has a difference between a cold crystallization heat quantity (Hc) and a crystal melting heat quantity (Hm) during temperature rising in DSC, HmHc, of 25 J/g or larger, and has an elongation of less than 40% and a strength of 3.0 cN/dtex or higher. The poly(phenylene sulfide) fiber has high heat resistance and chemical resistance and high strength and, despite this, has excellent suitability for high-order processing, e.g., thermal shapability, because the amorphous parts thereof have high molecular movability.

A heat treated fine polyarylene sulfide powder. (i) The heat treated fine polyarylene sulfide powder is manufactured from separation liquid. (ii) The heat treated fine polyarylene sulfide powder is obtained by subjecting the separation liquid to solid-liquid separation to obtain a raw material fine powder polyarylene sulfide. Thereafter the raw material fine powder polyarylene sulfide is subjected to pre-heat treatment and heat treatment. (iii) The heat treated fine polyarylene sulfide powder has an average particle size of from 1 to 80 m. (iv) The heat treated fine polyarylene sulfide powder has a melt viscosity of 1 Pa.Math.s or greater. (v) A generated gas amount of the heat treated fine polyarylene sulfide is 10 ppm or less.

A heat treated fine polyarylene sulfide powder. (i) The heat treated fine polyarylene sulfide powder is manufactured from separation liquid. (ii) The heat treated fine polyarylene sulfide powder is obtained by subjecting the separation liquid to solid-liquid separation to obtain a raw material fine powder polyarylene sulfide. Thereafter the raw material fine powder polyarylene sulfide is subjected to pre-heat treatment and heat treatment. (iii) The heat treated fine polyarylene sulfide powder has an average particle size of from 1 to 80 m. (iv) The heat treated fine polyarylene sulfide powder has a melt viscosity of 1 Pa.Math.s or greater. (v) A generated gas amount of the heat treated fine polyarylene sulfide is 10 ppm or less.