Poly(diphenyl-dimethyl siloxane) with terminals sealed by alkyloxy groups, and preparation method thereof

Abstract

The invention relates to a poly(diphenyl-dimethyl siloxane) with terminals sealed by alkyloxy groups, and a preparation method thereof. The preparation method comprises that octaphenylcyclotetrasiloxane and octamethylcyclotetrasiloxane as monomers for a polymerization reaction, low viscosity polydimethylsiloxane with terminals sealed by alkyloxy groups as a terminal sealing agent, and potassium silanolate as a catalyst are adopted; the monomers, the terminal sealing agent, the catalyst and accelerating agents are added into a reaction system; the reaction system is sealed up and then the mixture in the reaction system is stirred and heated to a temperature of 120 to 180 DEG C to undergo a polymerization reaction for 1 to 16 hours; and processes of neutralization, filtering and removal of low molecules on the reaction system are carried out. The preparation method has the advantages of high purity of raw materials, simple process, no need of a mass of organic solvents, and environmentally friendly characters. Products prepared by the preparation method has the advantages of high refractive index and good radiation resistance, high-low temperature resistance and climate resistance, and is especially suitable for base polymers of a dealcoholization type room temperature vulcanized silicone rubber, and surface treatment agents of filling materials such as white carbon black and the like utilized in various silicone rubber and other rubber processing.

Description

technical field [0001] The invention relates to a preparation method of linear polyorganosiloxane containing phenyl, belonging to the field of organosilicon materials. technical background [0002] The phenyl-containing polymethylphenylsiloxane can be considered as a product in which some of the methyl groups in the polydimethylsiloxane structure are replaced by phenyl groups. In addition to the common performance characteristics of polymethylsiloxane, It also has outstanding advantages such as excellent low temperature resistance, high temperature resistance, radiation resistance and high refractive index, and is widely used in the fields of electronic appliances, green energy, aerospace and life sciences. [0003] According to the structure of the siloxane chain where the phenyl group is located, it can usually be divided into polydiphenyldimethylsiloxane and polyphenylmethylsiloxane. The structural formula is as follows: [0004] [0005] Change the functional group o...

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Problems solved by technology

However, due to the large steric hindrance of octaphenylcyclotetrasiloxane, high melting point (about 200 ° C), and poor solubility in the ring body, resulting in low ring-opening reactivity, it is commonly used in the production of polydimethylsiloxane Acidic catalysts such as concentrated sulfuric acid, acid clay, ion exchange resins, lithium hydroxide, sodium hydroxide and silicon alkoxides of these alkalis usually cannot cause ring-opening polymerization.

CN101016446A reported the use of octaphenylcyclotetrasiloxane and dimethylsiloxane rings to prepare vinyl-terminated polydiphenyldimethylsiloxane under the catalysis of silicon alkoxide of potassium hydroxide, and then Preparation of addition-type silicone rubber for LED device packaging, but the polymerization temperature of this patented method is high and the time is long. Excessive silicon-based phosphate and neutralization product potassium phosphate will affect the transparency of the product and lead to product loss. Storage stability and heat resistance decline, and the product with a refractive index of 1.51 cannot be obtained according to the charging amount in Example 1 of this patent

In particular, under the catalysis of potassium silanolate and the action of accelerator, the process of preparing alkoxy-terminated polydiphenyldimethylsilane from octaphenylcyclotetrasiloxane according to the present invention has not been reported yet.

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