Some embodiments of the disclosure provides polyacrylonitrile (PAN) and a preparation method and use thereof. The method includes the following steps. Mixing raw materials for polymerization to obtain a suspension comprising the PAN. The raw materials include an acrylonitrile monomer, a first auxiliary monomer, a second auxiliary monomer, a polymerization medium, an initiator, a chain transfer agent, and a settling agent. Removing unreacted monomers and unreacted polymerization medium in the suspension to obtain the PAN. After subsequent removal of monomers, removal of a polymerization medium, washing, and drying, a PAN powder is obtained. In some embodiments, the preparation method of the PAN has a wide adjustable range of a PAN copolymerization composition, a low viscosity of a polymerization system, a high concentration of a polymerized monomer, and a strong anti-scaling ability.

Disclosed is a method for preparing an EVA copolymer with a high ethylene content by solution polymerization under a low to a medium pressure. The method comprises the following steps: initiating with a free radical initiator(s), a copolymerization reaction between ethylene and vinyl acetate in a solvent in a reactor under a low to a medium pressure to obtain the EVA copolymer; and continuing to add ethylene during the reaction to maintain the low to medium pressure, wherein the low to medium pressure is 1-101 MPa, and a ratio of a mass of the vinyl acetate to a mass of the initially added ethylene is (1:1) to (1:20). The amount of ethylene incorporated in the EVA copolymer prepared according to the method is ≥ 50 wt%, and the EVA copolymer has properties equivalent to those of an EVA copolymer obtained by bulk polymerization at high temperature under high pressure.

Disclosed is a method for preparing an EVA copolymer with a high ethylene content by solution polymerization under a low to a medium pressure. The method comprises the following steps: initiating with a free radical initiator(s), a copolymerization reaction between ethylene and vinyl acetate in a solvent in a reactor under a low to a medium pressure to obtain the EVA copolymer; and continuing to add ethylene during the reaction to maintain the low to medium pressure, wherein the low to medium pressure is 1-101 MPa, and a ratio of a mass of the vinyl acetate to a mass of the initially added ethylene is (1:1) to (1:20). The amount of ethylene incorporated in the EVA copolymer prepared according to the method is ≥ 50 wt%, and the EVA copolymer has properties equivalent to those of an EVA copolymer obtained by bulk polymerization at high temperature under high pressure.

Provided are hollow particles which have a high void ratio, hardly collapse, and have a reduced amount of volatile compounds. The hollow particles comprising a shell and a hollow portion surrounded by the shell, and having a void ratio of 50% or more and 90% or less, wherein the shell has a thickness of 0.2 μm or more and 0.9 μm or less, and the shell contains a polymer derived from a polymerizable monomer for shell, which is composed of 70% by mass or more and 100% by mass or less of a crosslinkable monomer and 0% by mass or more and 30% by mass or less of a non-crosslinkable monomer, and a polar resin selected from the group consisting of polymers containing a repeating unit which contains a hetero atom.

Disclosed is a compound having a chemical structure (X.sub.f.sup.− is a counter anion selected from the group consisting of Cl.sup.−, NO.sub.3.sup.−, Br.sup.−, I.sup.−, CH.sub.3SO.sub.3.sup.− and OH.sup.−) of the following general formula (I). By using this compound as a polymerization initiator, the amount of the aggregation formed in emulsion polymerization can be reduced.

##STR00001##

This invention provides a polymer, which is preferably a polyether polymer. The polymer may be uses in coating compositions. Containers and other articles comprising the polymer and methods of making such containers and other articles are also provided. The invention further provides compositions including the polymer (e.g., powder coatings), which have utility in a variety of coating end uses, including, for example, valve and pipe coatings.

This invention provides a polymer, which is preferably a polyether polymer. The polymer may be uses in coating compositions. Containers and other articles comprising the polymer and methods of making such containers and other articles are also provided. The invention further provides compositions including the polymer (e.g., powder coatings), which have utility in a variety of coating end uses, including, for example, valve and pipe coatings.

A flame-retardant antimicrobial agent is a polymer microsphere with the surface grafted thereof with a guanidine salt. The polymer microsphere has a cross-linked structure composed of a structural unit A derived from maleic anhydride, a structural unit B derived from a monomer M, and a structural unit C derived from a cross-linking agent. The monomer M is selected from a C.sub.4-C.sub.9 aliphatic olefin or a mixture thereof, and the guanidine salt comprises at least one guanidine salt having the property of flame resistance. The flame-retardant antimicrobial agent has both a good antimicrobial effect and a good flame-retardant effect. A flame-retardant antimicrobial thermoplastic resin composition containing the flame-retardant antimicrobial agent also has a good flame-retardant and antimicrobial performance and a good overall performance.

The method produces hollow particles which have a high void ratio, which can reduce the residual amount of a sparingly water-soluble solvent used in the production process, and which are less likely to collapse. The method for producing hollow particles which comprise a shell and a hollow portion and which have a void ratio of 50% or more and 90% or less, wherein a suspension treatment of a mixture liquid containing a polymerizable monomer for shell, a polar resin, a hydrocarbon solvent, a sparingly water-soluble inorganic metal salt as a dispersant, and an aqueous medium is carried out to prepare a suspension in which droplets of a monomer composition containing the polymerizable monomer for shell, the polar resin and the hydrocarbon solvent are dispersed in the aqueous medium; a polymerization reaction of the suspension is carried out; and the hydrocarbon solvent is removed from the obtained hollow particles.

An oligomer represented by the formula

##STR00001##

where R.sup.1 is hydrogen or methyl, R.sup.2 is an alkyl group having from 2 to 18 carbons, inclusive, R.sup.3 is hydrogen or hydroxyl, Y is hydrogen or an initiator residue, Z is a single bond or methylene, and n is an integer from 9 to 40, inclusive. Acrylate oligomer emulsions including the disclosed oligomer and fluorine-free treating compositions including the acrylate oligomer emulsion. Methods of making and using such compositions are also disclosed.