Preparation method of high-purity grafted functionalized copolymer

Abstract

The invention relates to a preparation method of a high-purity grafted functionalized copolymer. The preparation method comprises the following steps: mixing and adding matrix resin, an antioxidant, an ultraviolet absorbent, other auxiliaries, an initiator and a grafted monomer into a double-screw extruder, grafting and copolymerizing at the melting temperature of the matrix resin, to obtain a crude grafted copolymer; adding the crude grafted copolymer into an autoclave, heating, keeping constant temperature, injecting carbon dioxide until the carbon dioxide is at supercritical state, maintaining for 5-120min, performing pressure relief to obtain the high-purity grafted functionalized copolymer. The high-purity grafted copolymer is prepared by firstly performing melt-grafting reaction through the double-screw extruder and purifying supercritical carbon dioxide, so that the preparation method is unique and novel and simple in preparation technology.

Description

technical field [0001] The invention belongs to the field of preparation of high-purity copolymers, in particular to a preparation method of high-purity graft functionalized copolymers. Background technique [0002] As an important means of polymer modification, graft copolymerization has been widely used in industry. The graft copolymer prepared by the graft copolymerization method can be used as a compatibilizer in the polymer alloy to effectively fuse two or more incompatible materials together to obtain high performance and high function Chemicalized polymer alloy materials. In addition, graft copolymers are also widely used in adhesive resins. For example, food packaging materials are co-extruded from a variety of materials with different polarities. In order to effectively achieve effective bonding between polymer materials with different polarities, graft copolymers must be used. [0003] However, during the graft copolymerization reaction, the grafted monomers can...

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Problems solved by technology

However, at present, traditional grafted polymers are usually simply extracted by installing a vacuum device on the reactor for low-molecular-weight volatiles. Due to the short extraction time and low vacuum degree of the equipment, the low-molecular-weight volatiles in the product cannot be completely removed. Therefore, in order to obtain pure grafted polymers, some enterprises still need to post-process the products, mainly as follows: 1. Put the grafted polymers in a drying box, and continuously take away the particles migrated to the surface of the grafted polymer particles through hot air circulation Low-molecular volatiles, because low-molecular volatiles migrate very slowly in the polymer, this method takes a long time, consumes a lot of energy, and cannot guarantee the complete removal of low-molecular volatiles; 2. Use various solvents to soak the graft Copolymerization products, solvent extraction of unreacted monomers

Such a treatment method is costly, pollutes the environment, and is very inefficient.

Moreover, the graft copolymerization product purified by this method cannot be used in products with high hygienic requirements such as food packaging and pharmaceutical packaging.

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