Preparation method of polyacrylonitrile resin with controllable particle size and uniform distribution
A polyacrylonitrile resin, uniform distribution technology, applied in the field of polyacrylonitrile resin, can solve the problems of limited controllability of polyacrylonitrile resin particle size, poor shape of copolymerized unit particles, wide molecular weight distribution, etc., to achieve favorable The control of molecular weight and its distribution, the effect of high relative molecular mass of the product and less defects in molecular structure
Pending Publication Date: 2021-04-20
CHINA PETROLEUM & CHEM CORP +1
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Problems solved by technology
However, under this pH condition, the reactivity ratio of acrylonitrile and comonomer is quite different (for example, r AN = 0.25, r IA =1.57), it shows that the comonomers with higher activity in the system have a tendency to preferentially self-polymerize, resulting in uneven distribution of copolymerized units on the macromolecular chain, and the existence of a large number of "ineffective" functional group units, which not only cannot improve the thermo-oxidative stabilization Due to the effect of reactivity, excess hydrophilic groups will also lead to excessive hydrophilicity of particles, loose particles, and poor fluidity of polymerization reaction slurry, resulting in difficulty in dehydration and drying in the later stage
In addition, the inhomogeneous distribution of copolymerized units on this chain segment will also cause poor particle shape, poor circular regularity, and easy agglomeration into large particle size particles (>20um), and the amount of monomer adsorption on the particle surface in the reaction system Different, the reaction system is uneven, the molecular weight controllability is poor, and the molecular weight distribution is wide
[0005] Although by improving the polymerization equipment and optimizing process conditions (CN109721678A and CN109721679A), the uniformity and fluidity of the reaction slurry in the reactor can be improved by stirring and mixing, or adding pure water in different polymerization stages to adjust the reaction time and The solid content of the material and the growth of the polymer particle structure are improved, but the reactivity gap between the comonomers is not fundamentally resolved, so the hydrophilic groups on the polyacrylonitrile macromolecular chain are still unevenly distributed, resulting in the polyacrylonitrile resin. Limited particle size controllability and poor particle size uniformity
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[0022] Acrylonitrile is used as the main monomer, and the comonomer is selected from one of monomethyl itaconate, monoethyl itaconate, monopropyl itaconate, and monoamide itaconate. The types of comonomers are shown in the table 1. See Table 1 for the feed weight ratio of the two monomers. Based on the weight of the entire polymerization system, the total dosage of monomers is shown in Table 1. The initiator is a water-soluble azo initiator, the types are shown in Table 2, and the dosage of the initiator is shown in Table 1 based on the total monomer weight. Put all the monomers, initiators and pure water into the continuous stirring polymerization tank, carry out the polymerization reaction at a temperature of 60-80°C, and control the reaction residence time of 60-100 minutes. The reaction temperature and time are shown in Table 2. After the reaction is finished, the unreacted monomers are removed in a vacuum state, and the obtained polymer is sequentially washed with water,...
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Abstract
The invention discloses a preparation method of polyacrylonitrile resin with controllable particle size and uniform distribution. According to the invention, through an aqueous phase precipitation polymerization process, acrylonitrile is used as a main monomer, a comonomer is combined, water-soluble azo is used as an initiator, a continuous polymerization reaction is carried out at 60-80 DEG C, and the reaction residence time is 60-100 minutes. And after the reaction is finished, removing of the unreacted monomer in a vacuum state, and sequentially water washing, suction filtration and drying treatment on the obtained polymer are carried out to obtain the polyacrylonitrile resin. The polyacrylonitrile resin obtained by the method is good in particle size controllability and narrow in particle size distribution, and can be uniformly dispersed and dissolved in an organic or inorganic solvent, so that a stable polyacrylonitrile spinning solution with good spinnability is obtained, and is suitable for preparing carbon fiber precursors.
Description
technical field [0001] The invention relates to the technical fields of textile chemicals and high-performance fibers, in particular to a method for preparing a polyacrylonitrile resin with controllable particle size and uniform distribution by using aqueous phase precipitation polymerization. Background technique [0002] Due to its high specific strength and specific modulus, good chemical stability, and low thermal expansion coefficient, carbon fiber is widely used in different fields such as aerospace, satellite rockets, automobile industry, wind power, sports and leisure products, and the global demand is increasing year by year . Among the three organic fiber precursors, polyacrylonitrile is the one with the highest usage ratio and the best product quality. According to the continuity of the polymerization and spinning process, the preparation of polyacrylonitrile precursor can be divided into one-step method and two-step method. Due to the low temperature of the two...
Claims
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IPC IPC(8): C08F220/44C08F222/16C08F4/04C08F2/16
Inventor 宋文迪辛美音吴嵩义袁玉红季春晓
Owner CHINA PETROLEUM & CHEM CORP