Polyether modified silicone oil is one of the most widely used and produced modified silicone oils. it is a kind of oily polymer connected by polyether segment and chemical bond in the main chain or side chain of linear dimethyl silicone oil. In the molecule of polyether modified silicone oil, the polyether chain contains strong polar oxygen atoms and is connected with carbon, so it can form hydrogen bond with water, so it is hydrophilic and soluble in water; the silicone group in polysiloxane chain segment has relatively high bond energy, and the hydrocarbon group on it is not hydrophilic, so the polysiloxane chain segment is not hydrophilic or hydrophilic; the connection of these two segments can reduce the surface tension of water, so it is a kind of surfactant with good performance. Polyether modified silicone oil is widely used in industry and daily chemicals, for example, it can be used as fabric softener to make fabric soft, smooth, improve water absorption and anti-static; it can be used as cosmetic diffuser to increase the diffusivity of cosmetics in human skin; in addition, it can also be used as defoamer, glass antifogging agent, water-soluble lubricant and so on.
The synthesis of polyether modified silicone oil generally includes two steps: one is to synthesize the intermediate of hydrophobic group containing silicon, and the other is to introduce polyether group. The introduction of polyether groups is a more important step in the synthesis of polyether modified silicone oil. The way of introduction varies with different types of polyether, so polyether modified silicone oil has many varieties with different functions and has a wide range of applications.
1. Synthetic raw materials of polyether modified silicone oil.
1.1 solvent for synthesis of polyether modified silicone oil.
The solvent is added because polyether and silicone oil have larger molecular weight and will form higher molecular weight products. Allyl polyether includes capped polyether and uncapped polyether, the end of uncapped polyether is hydroxyl, the capped polyether is generally terminated by methyl, ethyl, butyl, etc., and the capped polyether is allyl double bond at the other end. in the case of loss of active hydrogen, the main reaction of graft addition can be carried out smoothly, which improves the effective content of polyether modified silicone oil and the quality of the product. Although the performance of allyl polyether modified silicone oil is better than that of unterminated silicone oil (defoamer product), the use of end-capping process leads to higher price. The addition of inert solvents such as toluene and isopropanol can also reduce the side reaction and cross-linking in the synthesis process. The addition of these solvents can increase the contact area between different substances and aggravate the reaction between allyl polyether and low hydrogen silicone oil. However, the amount of solvent should be appropriate, because the addition of too little solvent is not conducive to accelerate the interaction between products, and too much solvent will also cause catalyst dilution.
1.2 the catalyst for the synthesis of polyether modified silicone oil.
Chloroplatinic acid hydrate (H2Pt C16) is the most widely used catalyst in the synthesis of polyether modified silicone oil. In the catalytic process of silicon-hydrogen bond and carbon-carbon double bond addition reaction of tetravalent platinum, platinum goes through the process from reduction to zero valence, to bivalent, and then to tetravalent, in which the transition state of bivalent platinum has strong catalytic ability. The use of the catalyst reduces the activation energy of the reaction, so that the hydrosilylation reaction can take place under wider conditions. It is worth noting that in the process of synthesizing polyether modified silicone oil, the application of catalyst not only accelerates the main reaction, but also increases the occurrence of side reaction. Among them, the main reaction is hydrosilylation, and accelerating the main reaction rate can increase the content of effective components, while the side reaction includes hydrogen-containing silicone oil self-polymerization and modified group double-bond thermal polymerization, and accelerating the side reaction rate will increase the impurity content. and affect the performance of the product. Therefore, the amount of catalyst is also one of the important factors in the synthesis of polyether modified silicone oil.
1.3 Synthesis of functional silicone oil with polyether modified silicone oil.
The polysiloxane of polyether modified silicone oil is functional silicone oil, such as hydrogen silicone oil, alkoxy silicone oil, amino silicone oil, carbon functional silicone oil containing epoxy group and carboxylic acid group, etc.
1.4 Polyether modified silicone oil polyether was synthesized.
The synthesis of polyether modified silicone oil generally uses the copolymer of ethylene oxide and propylene oxide: RO (C2H4O) x (C3H6O) yR'. R'is usually H, or CH3 and Et, in which the preparation of hydrolyzed polyether modified silicone oil R is usually H, CH3, Et, C3H7 or C4H9, etc.; the preparation of non-hydrolyzed polyether modified silicone oil R is usually unsaturated group such as CH2CHCH2,CH2CH. When R is H2=CH3CH2, the polyether whose R'is CH3 is more stable than the polyether with R'H and Et. The ratio and content of ethylene oxide and propylene oxide will affect the performance of the product. The different ratio of polyoxyethylene to polypropylene in the polyether chain has great differences in product properties, such as some products can be used as emulsifiers, some products can be used as defoamers, some products can be used as defoamers, and some products can be used as foam stabilizers; increasing the content of ethylene oxide can improve the water solubility of polyether modified silicone oil, while increasing the content of propylene oxide will reduce the water solubility of polyether modified silicone oil.
2. Preparation method of polyether modified silicone oil.
2.1 there are two methods for the preparation of hydrolyzed polyether modified silicone oil
(1) displacement reaction:
(2) condensation reaction:
2.2 preparation of non-hydrolyzed polyether modified silicone oil:
Non-hydrolytic polyether modified silicone oil has been widely used because of its good hydrolysis resistance and stability. According to the different kinds of functional silicone oil and polyether, the synthesis method can be divided into the following three kinds.
(1) Si-H addition:
(2) esterification reaction:
(2) ring-opening addition reaction:
In addition, polyether modified silicone oil can also be prepared by graft polymerization of methyl silicone oil and unsaturated polyether under the catalysis of peroxide.
Hangzhou Danwei Technology Co., Ltd. specializes in customizing allyl polyether with different EO/PO ratio and molecular weight. Welcome to consult: 0571-82890506 13567543015.
