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A kind of polyvinyl alcohol with high degree of polymerization and high syndiotacticity and preparation method thereof

A technology of high degree of polymerization and polyvinyl alcohol, applied in the field of high degree of polymerization and high syndiotactic polyvinyl alcohol and its preparation, can solve the problems of difficult to obtain fibers, small steric hindrance of side group groups, low melting point, etc., and achieve High conversion rate, simple process and easy control

Active Publication Date: 2021-07-30
DONGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the small molecular weight of VAc, active reactivity, and small steric hindrance of side groups, the degree of polymerization and syndiotacticity of the synthesized PVA is not high. The degree of polymerization is generally 1700-3500, and the syndiotacticity is generally 48-48 51%
[0003] Due to the low degree of polymerization and syndiotacticity of PVA produced by the prior art, this will not only limit the orientation and crystallization of macromolecules during fiber formation, thereby affecting the strength and modulus of PVA fibers, as well as the acid and alkali corrosion resistance and weather resistance of the fibers. Etc performance
Moreover, because the melting point of PVA with low degree of polymerization and low syndiotacticity is not high, it is difficult to obtain a higher melting point for the prepared fiber.

Method used

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  • A kind of polyvinyl alcohol with high degree of polymerization and high syndiotacticity and preparation method thereof
  • A kind of polyvinyl alcohol with high degree of polymerization and high syndiotacticity and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0032] A kind of preparation method of high degree of polymerization high syndiotacticity polyvinyl alcohol, adopts emulsion polymerization method, comprises the steps:

[0033] (1) VBz, VAc and VPi monomers with a molar ratio of 20:39:41, initiator (i.e. a mixture of KPS and DMEA with a molar ratio of 5.0:2.0), the molar ratio of the total amount of monomer to the initiator 100:0.6, emulsifier (that is, the mixture of SDS and OP-10 with a molar ratio of 5.0:1.0), the molar ratio of the total amount of monomers to the emulsifier is 100:1.5, add it to a three-necked flask, and nitrogen at 25 ° C The reaction was carried out under the atmosphere (the time was 6.5h); then excess n-hexane was used to remove the remaining monomers in the reaction product, and the temperature was 75°C and dried for 16h to obtain PVBz-co-PVAc-co-PVPi prepolymer ;

[0034] (2) PVBz-co-PVAc-co-PVPi prepolymer is dissolved in methanol to obtain a mass concentration of 9.8wt% PVBz-co-PVAc-co-PVPi / methan...

Embodiment 2

[0041] A kind of preparation method of high degree of polymerization high syndiotacticity polyvinyl alcohol, adopts emulsion polymerization method, comprises the steps:

[0042] (1) VBz, VAc and VPi monomers with a molar ratio of 20:45:35, initiator (i.e. a mixture of KPS and DMEA with a molar ratio of 5.0:2.5), the molar ratio of the total amount of monomer to the initiator 100:0.5, the emulsifier (that is, the molar ratio of 5.0:1.0 is a mixture of SDS and OP-10), the molar ratio of the total amount of monomers to the emulsifier is 100:1.5, add it to a three-necked flask, and nitrogen at 30 ° C Carry out the reaction under the atmosphere (time is 6.5h); then use excess n-hexane to remove the remaining monomer in the reaction product, and dry at 80°C for 19h to obtain PVBz-co-PVAc-co-PVPi prepolymer ;

[0043] (2) PVBz-co-PVAc-co-PVPi prepolymer is dissolved in methanol to obtain a mass concentration of 9.0wt% PVBz-co-PVAc-co-PVPi / methanol solution;

[0044] (3) Slowly add ...

Embodiment 3

[0046] A kind of preparation method of high degree of polymerization high syndiotacticity polyvinyl alcohol, adopts emulsion polymerization method, comprises the steps:

[0047] (1) VBz, VAc and VPi monomers with a molar ratio of 20:30:50, initiator (i.e. a mixture of KPS and DMEA with a molar ratio of 5:3), the molar ratio of the total amount of monomer to the initiator 100:0.4, the emulsifier (that is, the mixture of SDS and OP-10 with a molar ratio of 5.0:2.0), the molar ratio of the total amount of monomer to the emulsifier is 100:1.0, add it to the three-necked flask, and put it in a carbon dioxide atmosphere at 20 ° C Reaction under low temperature (time is 8h); then use excess n-hexane to remove the remaining monomer in the reaction product, and dry at 68°C for 12h to obtain PVBz-co-PVAc-co-PVPi prepolymer;

[0048] (2) PVBz-co-PVAc-co-PVPi prepolymer is dissolved in methanol to obtain a mass concentration of 9.7wt% PVBz-co-PVAc-co-PVPi / methanol solution;

[0049] (3) ...

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Abstract

The present invention relates to a kind of polyvinyl alcohol with high degree of polymerization and high syndiotacticity and its preparation method, comprising the following steps: (1) carrying out emulsion polymerization of three monomers VBz, VAc and VPi and an initiator under certain conditions to obtain prepolymerization material PVBz-co-PVAc-co-PVPi; the initiator is a mixture of potassium persulfate and N,N-dimethylethanolamine, and the emulsifier in the emulsion polymerization is sodium lauryl sulfate and polyoxyethylene A mixed solution of octylphenol ether-10; (2) PVBz-co-PVAc-co-PVPi is dissolved in methanol to obtain PVBz-co-PVAc-co-PVPi / methanol solution; (3) a certain concentration of NaOH / The methanol solution is slowly added to the PVBz-co-PVAc-co-PVPi / methanol solution, stirred while adding until the product appears, and then left to react to obtain polyvinyl alcohol with a high degree of polymerization and high syndiotacticity. The degree of polymerization of the prepared polyvinyl alcohol is 9000-21000, the degree of syndiotacticity is 54-65%, and the melting point is 237°C-256°C; the proportion of monomers can be selectively changed to synthesize the required high degree of polymerization and high syndiotacticity The method has the characteristics of simple process, easy control, environmental protection and high conversion rate.

Description

technical field [0001] The invention belongs to the technical field of synthesis of polyvinyl alcohol (PVA), and relates to a high degree of polymerization and high syndiotactic polyvinyl alcohol and a preparation method thereof. Background technique [0002] The currently prepared high-strength and high-modulus polyvinyl alcohol (PVA) fibers mainly use ordinary PVA polymers as raw materials. When this polymer is synthesized, it mainly uses cheap and easy-to-obtain vinyl acetate (VAc) as a monomer. Because of the small molecular weight of VAc monomers, The reaction property is relatively active, and the PVA prepolymer PVAc can be prepared by various polymerization methods, and then the PVA polymer can be prepared by using NaOH / methanol solution as a catalyst for alcoholysis. However, due to the small molecular weight of VAc, active reactivity, and small steric hindrance of side groups, the degree of polymerization and syndiotacticity of the synthesized PVA is not high. The d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F218/10C08F218/08C08F8/00
CPCC08F8/00C08F218/08C08F218/10
Inventor 邹黎明王华君李文刚吴迪王艳丽孙晨凯王超何钧炜
Owner DONGHUA UNIV