Preparation method of high-thermal-conductivity graphene/polyimide-based composite graphite fiber

A high thermal conductivity graphite, polyimide-based technology, applied in the chemical characteristics of fibers, rayon manufacturing, textiles and papermaking, etc., can solve weak interaction forces, insignificant effects, and unsatisfactory fiber axial orientation. and other problems, to achieve the effect of increasing steric hindrance, changing types, and improving size and order.

Pending Publication Date: 2022-08-02
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But this method relies on the π-π conjugation between PAA and GO, which has weak intermolecular interactions, so the effect is not significant.
Patent CN110644075A discloses a method for preparing carbon fibers by doping PI with planar aromatic macromolecules. The planar aromatic macromolecules have high planarity, and the orientation of PI molecular chains is induced by π-π conjugation, but the axial orientation of the fibers still cannot reach expected

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  • Preparation method of high-thermal-conductivity graphene/polyimide-based composite graphite fiber
  • Preparation method of high-thermal-conductivity graphene/polyimide-based composite graphite fiber

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0033] 1 wt% GO was added to DMF solvent to be fully dissolved by ultrasound, and equimolar amounts of PMDA and ODA were weighed and polymerized in a nitrogen atmosphere at a temperature of 5 °C. ODA was firstly added to DMF, and after complete dissolution, PMDA was added in batches for polymerization, and the reaction was continued for 2 h after all the additions to obtain a GO / PAA solution with a solid content of 10%. A certain amount of acetic anhydride (30 mol% of PAA) and pyridine (the molar ratio of acetic anhydride and pyridine is 4:1) was mixed uniformly, and slowly added dropwise to the above PAA solution for chemical imidization, stirring while adding. After the dropwise addition, the reaction was continued to be stirred for 1 hour, and then left to stand for 24 hours to remove foam.

[0034] The above-mentioned GO / PAA-PI spinning solution was subjected to wet spinning. The coagulation bath ratio is V 水 : V 乙醇=9:1, the temperature is 20°C. The spinning solution e...

Embodiment 2

[0038] The amount of GO added was changed to 0.5 wt%, and other conditions were the same as in Example 1, and the average diameter was 10 μm and the thermal conductivity was 730 W m -1 ·K -1 , a high-performance graphite fiber with a tensile strength of 2500 MPa.

Embodiment 3

[0040] The addition amount of acetic anhydride was changed to 10 mol%, and other conditions were the same as in Example 1, to obtain an average diameter of 10 μm and a thermal conductivity of 710 W m -1 ·K -1 , a high-performance graphite fiber with a tensile strength of 2450MPa.

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Abstract

The invention discloses a preparation method of high-thermal-conductivity graphene / polyimide-based composite graphite fibers, and belongs to the technical field of carbon fibers. Under the combined action of a dehydrating agent and a catalyst in a chemical imidization reagent, on one hand, a part of polyamide acid (PAA) is converted into polyimide (PI), and a planar pyrophthalic anhydride type PI fiber with high axial orientation is prepared to serve as a carbon precursor; on the other hand, nitrogen for catalyzing diamine is used as a nucleophilic reagent to be subjected to nucleophilic substitution reaction with carbonyl carbon on graphene oxide (GO), so that a PAA-PI molecular chain is connected with the GO through a chemical bond, and the induced orientation effect of the GO is fully exerted. Finally, great drafting tension is applied in the heat treatment process, damage to an original ordered structure caused by thermal motion of molecular chains and escape of small molecules at high temperature is reduced, and hexagonal carbon net sheet layers are tightly stacked in the axial direction of the fibers. Finally, the high-thermal-conductivity graphene / polyimide-based composite graphite fiber is prepared.

Description

technical field [0001] The invention relates to a preparation method of a composite graphite fiber using polyimide (PI) as a precursor, in particular to a preparation method of a graphite fiber with high thermal conductivity, and belongs to the technical field of carbon fibers. Background technique [0002] Graphite fiber refers to a fiber with a carbon content higher than 99%, which is formed by graphite crystals arranged along the fiber axis. Graphite fiber has high strength and high modulus, low density, low thermal expansion coefficient and extremely high thermal conductivity, and is often used in cutting-edge fields such as aerospace, defense and military industries. At present, high thermal conductivity graphite fibers are mainly made from mesophase pitch. However, the refining of the precursor mesophase pitch is difficult, the spinning equipment is required to be precise, and the mechanical properties of the primary fibers are very low, which makes the subsequent hea...

Claims

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Application Information

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IPC IPC(8): D01F9/24D01F1/10
CPCD01F9/24D01F1/10Y02E60/10
Inventor 马兆昆孟泰生
Owner BEIJING UNIV OF CHEM TECH
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