Preparation method of modified polybenzobisoxazole resin polymer

Abstract

The invention discloses a preparation method of a modified polybenzobisoxazole resin polymer. According to the preparation method, 8-12% of polyphosphoric acid (mass ratio) and 12-18% of phosphorus pentoxide (mass ratio) are added; the molar ratio of the molar sum of the added terephthalic acid and other diacid except the terephthalic acid of the residual mass ratio to 4,6-diamidoresorcinol is 1:1, wherein the molar content of terephthalic acid at least accounts for 80% of the total molar content of diacid; at least one of terephthalic acid and isophthalic acid is used for sure; the non-formic acid diacid is used or not, and the molar content does not exceed 10% of the total molar content of diacid if the non-formic acid diacid is used; and a conventional polybenzobisoxazole resin method is adopted for polymerization. The preparation method disclosed by the invention has the advantages that the strength of the fiber obtained by spinning by use of the polymer provided by the invention can exceed 3GPa, the viscosity of the spinning solution is greatly reduced, the equipment requirements in the spinning process are lowered, and the operation rate and production efficiency of the equipment in a production process are improved.

Description

technical field [0001] The invention relates to a preparation method of a polymer, in particular to a preparation method of a modified polybenzobisoxazole resin polymer. Background technique [0002] Polyphenylene benzobisoxazole (referred to as PBO) resin has excellent heat resistance and chemical stability, and its fibers obtained by dry jet wet spinning have the characteristics of high strength and high modulus, and are known as the 21st century The super fiber has a wide range of applications. [0003] The molecular structure of PBO is as follows: [0004] [0005] PBO is formed by polycondensation of 4,6-diaminoresorcinol and terephthalic acid in polyphosphoric acid solvent, and the polymerization system is directly used as spinning solution. Extensive research has been done on the spinning process of PBO. In the spinning process, since the concentration of PBO needs to reach more than 10%, the viscosity of the spinning solution is very high. The resulting conseq...

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Problems solved by technology

The resulting consequence is that, from a technological point of view, the high viscosity of the spinning solution will cause difficulty in evenly distributing the spinning solution in the melt pipe, difficulty in filtering, and poor uniformity of spinning; from the perspective of equipment requirements Generally speaking, such a high viscosity requires very high pressure resistance of the entire post-polymerization and spinning system, requiring a metering pump to provide a pressure of up to 30-40 MPa, and the spinning pressure reaches 10-25 MPa

[0006] This pressure range has reached or exceeded the upper pressure limit considered in the design and manufacture of the current spinning equipment, so that in the actual production process of PBO fibers, tiny particles often cannot be completely filtered, Excessive pressure in the pipeline causes problems such as inaccurate measurement of the metering pump, liquid return and leakage, slurry leakage at the joint of the pipeline, and large diameter unevenness of the fiber, which makes the operation stability in large-scale production poor, and the equipment operation rate is low. Process repeatability is not good

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