Poly(acrylonitrile-co-methyl acrylate) compositions comprising a hindered amine light stabilizer are described herein. A poly(acrylonitrile-co-methyl acrylate) composition may be in the form of a fiber, thread, yarn, and/or fabric. Also described herein are methods of making and using the poly(acrylonitrile-co-methyl acrylate) compositions and articles comprising poly(acrylonitrile-co-methyl acrylate) compositions as described herein.

An acrylic fiber for artificial hair may include an acrylic copolymer. The acrylic fiber has a fiber cross section including 2 to 4 T-shaped protrusions that extend radially from a central portion. Each of the T-shaped protrusions has an arc-shaped upper side that bulges in a direction away from the central portion. A circumradius of the fiber cross section is 40.0 to 60.0 μm. A distance between adjacent end portions of the corresponding upper sides of the adjacent T-shaped protrusions is 3.0 to 60.0 μm. An axial width is 10.0 μm or more. Torsional rigidity of the acrylic fiber is 0.30 to 2.0 mg.Math.cm.sup.2. The acrylic fiber for artificial hair has high volume, good texture, and good twist processability, and a hair ornament may include the acrylic fiber for artificial hair.

An acrylic fiber for artificial hair may include an acrylic copolymer. The acrylic fiber has a fiber cross section including 2 to 4 T-shaped protrusions that extend radially from a central portion. Each of the T-shaped protrusions has an arc-shaped upper side that bulges in a direction away from the central portion. A circumradius of the fiber cross section is 40.0 to 60.0 μm. A distance between adjacent end portions of the corresponding upper sides of the adjacent T-shaped protrusions is 3.0 to 60.0 μm. An axial width is 10.0 μm or more. Torsional rigidity of the acrylic fiber is 0.30 to 2.0 mg.Math.cm.sup.2. The acrylic fiber for artificial hair has high volume, good texture, and good twist processability, and a hair ornament may include the acrylic fiber for artificial hair.

A drawing method is provided which enables a pressurized steam drawing of an acrylonitrile-based fiber bundle used as the precursor fiber of the carbon fiber bundle. In particular, a drawing method is provided which realizes a high processability when this treatment is conducted at a high draw ratio and high speed. This invention is a method for producing an acrylonitrile-based fiber bundle which includes the steps of spinning a spinning solution containing an acrylonitrile-based copolymer, and subjecting the fiber bundle to a pressurized steam drawing in a pressurized steam drawing apparatus (A) having at least two zones which are a preheating zone on the fiber bundle inlet side and a heating zone on the fiber bundle exit side, the two zones being separated by a seal member. The preheating zone is in a pressurized steam atmosphere at 0.05 to 0.35 MPa, the heating zone is in a pressurized steam atmosphere at 0.45 to 0.70 MPa, temperature difference ΔT1 in the preheating zone of the steam drawing apparatus in the fiber bundle-moving direction defined in the specification is up to 5° C., and temperature difference ΔT2 in the preheating zone of the steam drawing apparatus in the cross-sectional direction of the steam drawing apparatus defined in the specification is up to 5° C.

A drawing method is provided which enables a pressurized steam drawing of an acrylonitrile-based fiber bundle used as the precursor fiber of the carbon fiber bundle. In particular, a drawing method is provided which realizes a high processability when this treatment is conducted at a high draw ratio and high speed. This invention is a method for producing an acrylonitrile-based fiber bundle which includes the steps of spinning a spinning solution containing an acrylonitrile-based copolymer, and subjecting the fiber bundle to a pressurized steam drawing in a pressurized steam drawing apparatus (A) having at least two zones which are a preheating zone on the fiber bundle inlet side and a heating zone on the fiber bundle exit side, the two zones being separated by a seal member. The preheating zone is in a pressurized steam atmosphere at 0.05 to 0.35 MPa, the heating zone is in a pressurized steam atmosphere at 0.45 to 0.70 MPa, temperature difference ΔT1 in the preheating zone of the steam drawing apparatus in the fiber bundle-moving direction defined in the specification is up to 5° C., and temperature difference ΔT2 in the preheating zone of the steam drawing apparatus in the cross-sectional direction of the steam drawing apparatus defined in the specification is up to 5° C.

A carbon fiber having a strand elastic modulus of 360 GPa or more, a strand strength of 3.5 GPa or more, and a single-fiber diameter of 6.0 μm or more, and having a residual twist count of 2 turns/m or more in a test in which one end is fixed end and another end is free end which is capable of rotation about the axis of a fiber bundle.

Provided are carbon fiber bundles which have high knot strength even if the single fiber fineness is large, and which have excellent handling properties and processability. The carbon fiber bundles have a single fiber fineness of 0.8-2.5 dtex, knot strength of 298 N/mm.sup.2 or greater. This method of producing carbon fibers having knot strength of 298 N/mm.sup.2 or greater involves a heat treatment step for heat treating, for 50-150 minutes, specific polyacrylonitrile-based precursor fiber bundles described in the description in an oxidizing atmosphere rising in temperature in the temperature range of 220-300 C.

Provided are carbon fiber bundles which have high knot strength even if the single fiber fineness is large, and which have excellent handling properties and processability. The carbon fiber bundles have a single fiber fineness of 0.8-2.5 dtex, knot strength of 298 N/mm.sup.2 or greater. This method of producing carbon fibers having knot strength of 298 N/mm.sup.2 or greater involves a heat treatment step for heat treating, for 50-150 minutes, specific polyacrylonitrile-based precursor fiber bundles described in the description in an oxidizing atmosphere rising in temperature in the temperature range of 220-300 C.

An optimized process for the preparation of a spinning solution for the production of acrylic fiber precursors (PAN) of carbon fibers and an optimized process for the production of carbon fibers from said acrylic precursor (PAN), are described.

Neutron radiation can be attenuated by a material comprising acrylonitrile butadiene styrene (ABS) filament infused with gadolinium, boron, gold, and/or cadmium. The metal-infused filaments are 3D-printed to form a sleeve or cover for gamma and/or alpha radiation detectors to shield, absorb and allow detection of neutrons that are converted to gamma and or alpha radiation. The materials can also allow discrimination between neutron and gamma and/or alpha radiation in a mixed radiation field. Boron-infused filaments also provide neutron shielding and can be used in the manufacture of water equivalent phantoms.