Apparatus and method for spinning hollow polymeric fibres
AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
InventorJames Ferguson
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Abstract
A method of manufacture of solid-walled hollow polymeric fibres comprises the steps of dissolving polymeric material in a suitable solvent liquid to form a dope solution (44), extruding the dope solution through an aperture in a spinneret (41) to form a narrow jet of liquid injecting a coagulant (46) through an aperture (53) in the centre of the liquid dope jet as it leaves the spinneret, directing the jet through an air gap into a coagulant bath containing a further coagulant; and directing the fibre through a drawing bath to reduce the diameter, each coagulant solution being a mixture of a coagulant liquid capable of causing gelation and solidification of the liquid dope jet and between 20% and 80% of the solvent liquid.
Claims6
A hollow polyacrylonitrile fiber precursor for hollow carbon fiber, the precursor polyacrylonitrile fiber comprising a central lumen and a wall having a highly oriented interior surface facing the central lumen, a highly oriented exterior surface facing away from the central lumen and a homogenous, dense gel structure between the interior surface and the exterior surface, wherein the entire hollow polyacrylonitrile fiber is free of macrovoids.
A hollow polyacrylonitrile fiber precursor for hollow carbon fiber, the precursor polyacrylonitrite fiber comprising a central lumen and a wall having a highly oriented interior surface facing the central lumen, a highly oriented exterior surface facing away from the central lumen and a homogenous, dense gel structure between the interior surface and the exterior surface, wherein the entire hollow polyacrylonitrile fiber is free of macrovoids, said hollow fiber produced by the method of:
- (a) dissolving acrylic polymer in a solvent to form a dope;
- (b) extruding the dope through an aperture in a spinneret to form a jet of liquid;
- (c) injecting a first coagulant into the center of the liquid jet as it leaves the spinneret;
- (d) directing the jet through an air gap into a coagulant bath containing a second coagulant to form a fiber;
- and
- (e) directing the thus-formed fiber through a drawing bath to reduce the fiber's diameter;
- wherein each coagulant comprises a mixture of a coagulant liquid capable of causing gelation and eventual solidification of the dope jet and between 20% and 80% of the solvent liquid.
Dependencies are inferred from the claim text.