CN113549219A

CN113549219A - Preparation method of polydimethylsiloxane

Info

Publication number: CN113549219A
Application number: CN202110934574.6A
Authority: CN
Inventors: 吕斌; 张鹤年; 高党鸽; 马建中
Original assignee: Shaanxi University of Science and Technology
Current assignee: Shaanxi University of Science and Technology
Priority date: 2021-08-16
Filing date: 2021-08-16
Publication date: 2021-10-26

Abstract

The invention relates to a preparation method of polydimethylsiloxane. The methoxy-terminated polysiloxane has two preparation methods, one is prepared by adopting the condensation polymerization reaction of the hydroxyl-terminated polysiloxane and methoxy silane, and the other is prepared by adopting the hydrosilylation reaction of vinyl-terminated polysiloxane and hydrogen-containing methoxy silane. Both the two preparation methods need to modify and prepare specific polysiloxane, and the preparation process needs air isolation and high-temperature heating, so that the process is complex and tedious, and the preparation cost is increased. The invention takes dimethyl dimethoxy silane with lower cost as a main raw material, prepares polydimethylsiloxane through acid catalysis polycondensation reaction at room temperature, and then adopts a method of reduced pressure distillation and liquid separation for purification treatment. The method has low cost and energy consumption, and is simple, convenient and rapid.

Description

Preparation method of polydimethylsiloxane

Technical Field

The invention relates to a preparation method of polydimethylsiloxane, in particular to a method for synthesizing polydimethylsiloxane by acid-catalyzed polycondensation of an organic silicon monomer.

Background

The polydimethylsiloxane contains siloxane repeating groups (-Si-O-Si-) which dynamically rotate at room temperature, and the molecular chain has high flexibility, so that the polydimethylsiloxane can promote liquid slippage of a film-liquid interface, and the surface cleaning effect is achieved, and therefore the polydimethylsiloxane has various applications such as antifouling, anticorrosion, anti-icing and the like in daily life.

The methoxy-terminated polysiloxane has two preparation methods, one is prepared by adopting the condensation polymerization reaction of the hydroxyl-terminated polysiloxane and methoxy silane, and the other is prepared by adopting the hydrosilylation reaction of vinyl-terminated polysiloxane and hydrogen-containing methoxy silane. Both the two preparation methods need to modify and prepare specific polysiloxane, and the preparation process needs air isolation and high-temperature heating, so that the process is complex and tedious, and the preparation cost is increased.

Disclosure of Invention

The invention aims to provide a simple and quick preparation method of polydimethylsiloxane with low cost and low energy consumption, which takes dimethyldimethoxysilane as a raw material and forms-Si-O-Si-group through the rapid hydrolytic condensation of alkoxy under the acid catalysis condition so as to form the polydimethylsiloxane.

The method is realized by the following steps:

mixing 25-35 parts by weight of isopropanol, 6-10 parts by weight of dimethyl dimethoxysilane, 0.3-0.5 part by weight of deionized water and 0.1-0.2 part by weight of concentrated sulfuric acid catalyst in a three-necked bottle; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 1-3 hours at room temperature to form a homogeneous product; and separating and purifying the obtained reaction product, and removing the solvent isopropanol and unreacted dimethyl dimethoxysilane by reduced pressure distillation to obtain a phase separation product. And separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

The invention has the following advantages:

the invention takes dimethyl dimethoxy silane with lower cost as a main raw material, prepares polydimethylsiloxane through acid catalysis polycondensation reaction at room temperature, and then adopts a method of reduced pressure distillation and liquid separation for purification treatment. The method has the advantages of low cost, low energy consumption, simplicity, convenience and rapidness. The invention provides a new raw material source for the preparation of low surface energy materials.

Detailed Description

The present invention will be described in detail with reference to specific embodiments.

The alkoxy groups on the Si atoms have active chemical properties and can generate-Si-O-Si-bonds through polycondensation reaction, thereby further forming the long-chain structure of the polysiloxane. The patent proposes that polydimethylsiloxane is synthesized by the polycondensation reaction of low-cost dimethyldimethoxysilane at room temperature, and provides a new preparation idea for the industrial production of polydimethylsiloxane.

The invention relates to a preparation method of polydimethylsiloxane, which comprises the steps of taking dimethyl dimethoxysilane and concentrated sulfuric acid as catalysts, forming polydimethylsiloxane through hydrolysis and condensation of methoxyl, finally removing a solvent through reduced pressure distillation, and separating liquid to obtain an upper layer product. The method is realized by the following steps:

Example 1:

the method comprises the following steps: and (3) polycondensation reaction:

mixing 27 parts by weight of isopropanol, 7 parts by weight of dimethyldimethoxysilane, 0.4 part by weight of deionized water and 0.1 part by weight of concentrated sulfuric acid catalyst in a three-necked flask; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 1 hour at room temperature to form a homogeneous product; and separating and purifying the obtained reaction product, and removing the solvent isopropanol and unreacted dimethyl dimethoxysilane by reduced pressure distillation to obtain a phase separation product. And separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

Example 2:

mixing 35 parts by weight of isopropanol, 10 parts by weight of dimethyldimethoxysilane, 0.5 part by weight of deionized water and 0.2 part by weight of concentrated sulfuric acid catalyst in a three-necked flask; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 3 hours at room temperature to form a homogeneous product; and separating and purifying the obtained reaction product, and removing the solvent isopropanol and unreacted dimethyl dimethoxysilane by reduced pressure distillation to obtain a phase separation product. And separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

Example 3:

mixing 25 parts by weight of isopropanol, 6 parts by weight of dimethyldimethoxysilane, 0.3 part by weight of deionized water and 0.1 part by weight of concentrated sulfuric acid catalyst in a three-necked flask; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 1 hour at room temperature to form a homogeneous product; and separating and purifying the obtained reaction product, and removing the solvent isopropanol and unreacted dimethyl dimethoxysilane by reduced pressure distillation to obtain a phase separation product. And separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

Example 4:

mixing 32 parts by weight of isopropanol, 8 parts by weight of dimethyldimethoxysilane, 0.4 part by weight of deionized water and 0.1 part by weight of concentrated sulfuric acid catalyst in a three-necked flask; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 2 hours at room temperature to form a homogeneous product; and separating and purifying the obtained reaction product, and removing the solvent isopropanol and unreacted dimethyl dimethoxysilane by reduced pressure distillation to obtain a phase separation product. And separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

The polydimethylsiloxane can be obtained by the method. The method can avoid complex and fussy preparation process, simultaneously save the cost and energy consumption, and the product can be used for preparing low-surface-energy materials.

The invention is not limited to the examples, and any equivalent changes to the technical solution of the invention by a person skilled in the art after reading the description of the invention are covered by the claims of the invention.

Claims

1. A method for preparing polydimethylsiloxane is characterized by comprising the following steps:

the method is realized by the following steps:

mixing 25-35 parts by weight of isopropanol, 6-10 parts by weight of dimethyl dimethoxysilane, 0.3-0.5 part by weight of deionized water and 0.1-0.2 part by weight of concentrated sulfuric acid catalyst in a three-necked bottle; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 1-3 hours at room temperature to form a homogeneous product; separating and purifying the obtained reaction product, and removing isopropanol and unreacted dimethyl dimethoxysilane serving as solvents by reduced pressure distillation to obtain a phase separation product; and separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

2. The method according to claim 1, wherein:

mixing 35 parts by weight of isopropanol, 10 parts by weight of dimethyldimethoxysilane, 0.5 part by weight of deionized water and 0.2 part by weight of concentrated sulfuric acid catalyst in a three-necked flask; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 3 hours at room temperature to form a homogeneous product; separating and purifying the obtained reaction product, and removing isopropanol and unreacted dimethyl dimethoxysilane serving as solvents by reduced pressure distillation to obtain a phase separation product; and separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.

3. The method according to claim 1, wherein:

mixing 25 parts by weight of isopropanol, 6 parts by weight of dimethyldimethoxysilane, 0.3 part by weight of deionized water and 0.1 part by weight of concentrated sulfuric acid catalyst in a three-necked flask; adjusting the mechanical stirring speed to 200r/min, and mechanically stirring for 1 hour at room temperature to form a homogeneous product; separating and purifying the obtained reaction product, and removing isopropanol and unreacted dimethyl dimethoxysilane serving as solvents by reduced pressure distillation to obtain a phase separation product; and separating the upper layer of transparent colorless organic phase liquid to obtain the upper layer of organic phase liquid which is the polydimethylsiloxane product.