Preparation method of polyacrylonitrile fiber

Abstract

The invention relates to a preparation method of polyacrylonitrile fibers with the aim of solving the technical problems in the prior art such as poor spinnability, high fiber breakage rate, low fiber strength and large coefficient of dispersion of spinning solution. The preparation method of polyacrylonitrile fibers comprises polyacrylonitrile / dimethyl sulfoxide solution with 80 thousand to 200 thousand in moceluar weight and from 60pa*s to 120Pa*s in viscosity and comprises following steps: adopting an embedded spinning assembly, filtering through a multi-layer combined filter net and matching with a matching board for carry out wet spinning in order to obtain polyacrylonitrile fibers. The preparation method is characterized in that nascent fibers do not have broken filaments when a first coagulating bath stretches from 50% to 95% with the fiber breakage rate of 4 per thousand to 15 per thousand and strength of 5cN / dtex to 8cN / dtex; and CV value of breakage strength ranges from 4% to 20%. The preparation method of polyacrylonitrile fibers better solves the problem and can be used for industrial production of original filaments ofpolyacrylonitrile fibers.

Description

technical field

[0001] The invention belongs to a method for preparing polyacrylonitrile precursors for carbon fibers, in particular to a method for wet spinning polyacrylonitrile / dimethyl sulfoxide spinning solution. Background technique

[0002] Since the 1950s, developed countries have urgently needed new structural materials and corrosion-resistant materials in order to develop large-scale rockets and artificial satellites and comprehensively improve aircraft performance, so that carbon fibers reappeared on the stage of new materials, and gradually formed PAN-based carbon fibers. The three major raw material systems of viscose-based carbon fiber and pitch-based carbon fiber. Because the production process of PAN-based carbon fiber is simpler than other methods, and the mechanical properties of the product are good, it has been developed rapidly and has become the mainstream of the current production of carbon fiber.

[0003] PAN-based carbon fiber has excellent properti...

Examples

Embodiment 1

[0047] (1) Preparation of stock solution: Add acrylonitrile, itaconic acid and methyl methacrylate to the polymerization kettle, then add initiator and dimethyl sulfoxide, react at a temperature of 40°C for 10 hours, and then remove Unreacted monomers and the bubbles generated by the reaction obtain the spinning dope, the initiator is azobisisoheptanonitrile, the mass ratio of acrylonitrile and comonomer is 98.5:1.5, and the mass percent of the initiator accounting for the total monomer is 0.08%, and the total monomer concentration is 15%. After filtration, high-performance polyacrylonitrile copolymer spinning stock solution is obtained. The spinning stock solution has a particle weight of 110,000, a molecular weight distribution of 2.0, and a viscosity of 90 Pa·S at 60°C. The spinning dope temperature was 60°C.

[0048] (2) Conveying, filtering and distributing of raw liquid: adopt embedded spinneret, the heat preservation temperature of pipeline, filter and spinning assembly...

Embodiment 2

[0055] (1) Preparation of stock solution: Add acrylonitrile, ammonium itaconate and methacrylic acid to the polymerization kettle, then add initiator and dimethyl sulfoxide, react at a temperature of 60°C for 24 hours, and then remove untreated The reacted monomer and the bubbles generated by the reaction are used to obtain the spinning dope, the initiator is azobisisobutyronitrile, the mass ratio of acrylonitrile and comonomer is 90:10, and the mass percentage of the initiator in the total monomer is 0.25 %, the total monomer concentration is 25%, and the high-performance polyacrylonitrile copolymer spinning dope is obtained through filtration. The temperature of silk stock solution is 60°C.

[0056] (2) Conveying, filtering and distributing of the raw liquid: the embedded spinneret is adopted, and the heat preservation temperature of the pipeline, filter and spinning assembly is 65°C; 10, the filter mesh of the first filter layer is 1600, and the filter mesh of the second f...

Embodiment 3

[0063] (1) Stock solution preparation: add acrylonitrile and itaconic acid to the polymerization kettle, then add initiator and dimethyl sulfoxide, react at a temperature of 65°C for 30 hours, and then remove unreacted monomers and Bubbles generated by the reaction were used to obtain the spinning dope, the initiator was azobisisobutyronitrile, the mass ratio of acrylonitrile and comonomer was 95:5, the mass percentage of the initiator accounting for the total monomer was 0.2%, and the total monomer The concentration of the polyacrylonitrile copolymer is 20%, and the high-performance polyacrylonitrile copolymer spinning stock solution is obtained through filtration. The spinning stock solution has a particle weight of 80,000, a molecular weight distribution of 15, a viscosity of 60 Pa·S at 60°C, and a spinning stock solution temperature of 60°C. ℃.

[0064] (2) Conveying, filtering and distributing of the stock solution: the embedded spinneret is adopted, and the heat preserva...

technical field

[0001] The invention belongs to a method for preparing polyacrylonitrile precursors for carbon fibers, in particular to a method for wet spinning polyacrylonitrile / dimethyl sulfoxide spinning solution. Background technique

[0002] Since the 1950s, developed countries have urgently needed new structural materials and corrosion-resistant materials in order to develop large-scale rockets and artificial satellites and comprehensively improve aircraft performance, so that carbon fibers reappeared on the stage of new materials, and gradually formed PAN-based carbon fibers. The three major raw material systems of viscose-based carbon fiber and pitch-based carbon fiber. Because the production process of PAN-based carbon fiber is simpler than other methods, and the mechanical properties of the product are good, it has been developed rapidly and has become the mainstream of the current production of carbon fiber.

[0003] PAN-based carbon fiber has excellent properti...

Examples

Embodiment 1

[0047] (1) Preparation of stock solution: Add acrylonitrile, itaconic acid and methyl methacrylate to the polymerization kettle, then add initiator and dimethyl sulfoxide, react at a temperature of 40°C for 10 hours, and then remove Unreacted monomers and the bubbles generated by the reaction obtain the spinning dope, the initiator is azobisisoheptanonitrile, the mass ratio of acrylonitrile and comonomer is 98.5:1.5, and the mass percent of the initiator accounting for the total monomer is 0.08%, and the total monomer concentration is 15%. After filtration, high-performance polyacrylonitrile copolymer spinning stock solution is obtained. The spinning stock solution has a particle weight of 110,000, a molecular weight distribution of 2.0, and a viscosity of 90 Pa·S at 60°C. The spinning dope temperature was 60°C.

[0048] (2) Conveying, filtering and distributing of raw liquid: adopt embedded spinneret, the heat preservation temperature of pipeline, filter and spinning assembly...

Embodiment 2

[0055] (1) Preparation of stock solution: Add acrylonitrile, ammonium itaconate and methacrylic acid to the polymerization kettle, then add initiator and dimethyl sulfoxide, react at a temperature of 60°C for 24 hours, and then remove untreated The reacted monomer and the bubbles generated by the reaction are used to obtain the spinning dope, the initiator is azobisisobutyronitrile, the mass ratio of acrylonitrile and comonomer is 90:10, and the mass percentage of the initiator in the total monomer is 0.25 %, the total monomer concentration is 25%, and the high-performance polyacrylonitrile copolymer spinning dope is obtained through filtration. The temperature of silk stock solution is 60°C.

[0056] (2) Conveying, filtering and distributing of the raw liquid: the embedded spinneret is adopted, and the heat preservation temperature of the pipeline, filter and spinning assembly is 65°C; 10, the filter mesh of the first filter layer is 1600, and the filter mesh of the second f...

Embodiment 3

[0063] (1) Stock solution preparation: add acrylonitrile and itaconic acid to the polymerization kettle, then add initiator and dimethyl sulfoxide, react at a temperature of 65°C for 30 hours, and then remove unreacted monomers and Bubbles generated by the reaction were used to obtain the spinning dope, the initiator was azobisisobutyronitrile, the mass ratio of acrylonitrile and comonomer was 95:5, the mass percentage of the initiator accounting for the total monomer was 0.2%, and the total monomer The concentration of the polyacrylonitrile copolymer is 20%, and the high-performance polyacrylonitrile copolymer spinning stock solution is obtained through filtration. The spinning stock solution has a particle weight of 80,000, a molecular weight distribution of 15, a viscosity of 60 Pa·S at 60°C, and a spinning stock solution temperature of 60°C. ℃.

[0064] (2) Conveying, filtering and distributing of the stock solution: the embedded spinneret is adopted, and the heat preserva...

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