阅读说明：本技术 一种聚合物发泡微球及其制备方法和用途 (Polymer foaming microsphere and preparation method and application thereof ) 是由 刘祥 刘刚 汪舟鹭 邢祎琳 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种聚合物发泡微球及其制备方法和用途。所述的聚合物发泡微球是由可塑性聚合物外壳以及封在外壳内部的惰性烃类发泡剂构成；通过加热使发泡剂汽化,汽化压力使壳层聚合物膨胀,发泡形成热膨胀聚合物中空微球；所述可塑性聚合物外壳是丙烯腈和/或甲基丙烯腈单体、甲基丙烯酸单体和自由基聚合可能的其它单体,在经偶联剂处理过的二氧化硅胶体分散剂及阳离子稳定助剂构成的水相复合分散液的存在下,通过自由基微悬浮聚合形成的。本发明还公开了所述聚合物发泡微球在制备聚硫密封剂中的应用。本发明的优点在于密度低,易于作为复聚硫橡胶的轻量化添加剂,能大幅降低聚硫密封剂重量。(The invention discloses a polymer foaming microsphere and a preparation method and application thereof. The polymer foaming microspheres are composed of a plastic polymer shell and an inert hydrocarbon foaming agent sealed in the shell; heating to vaporize the foaming agent, expanding the shell polymer by vaporization pressure, and foaming to form the thermal expansion polymer hollow microspheres; the plastic polymer shell is formed by free radical micro-suspension polymerization of acrylonitrile and/or methacrylonitrile monomer, methacrylic acid monomer and other possible monomers for free radical polymerization in the presence of aqueous composite dispersion liquid formed by silica colloid dispersant treated by coupling agent and cation stabilizing auxiliary agent. The invention also discloses application of the polymer foaming microsphere in preparation of a polysulfide sealant. The invention has the advantages of low density, easy use as light additive of polysulfide rubber and capability of greatly reducing the weight of polysulfide sealant.)

1. a polymer foaming microsphere is characterized by comprising a plastic polymer shell and an inert hydrocarbon foaming agent sealed in the shell; heating to vaporize the foaming agent, expanding the shell polymer by vaporization pressure, and foaming to form the thermal expansion polymer hollow microspheres; the plastic polymer shell is formed by free radical micro-suspension polymerization of acrylonitrile and/or methacrylonitrile monomer, methacrylic acid monomer and other monomers possibly polymerized by free radicals in the presence of aqueous composite dispersion liquid consisting of silica colloid dispersant treated by coupling agent and cation stabilizing auxiliary agent; based on the total weight of the unsaturated monomers being 100 wt%, the acrylonitrile and/or methacrylonitrile monomer accounts for 30-60 wt%, the methacrylic acid monomer accounts for 50-30 wt%, and the other monomers possible for free radical polymerization account for 20-10 wt%; silica solids account for 5-20 wt% based on 100 wt% total unsaturated monomer weight; the amount of the coupling agent used is 0.1 to 10% by weight based on 100% by weight of the solid content of silica.

2. The polymer expanded microspheres of claim 1, wherein the other monomers for radical polymerization are one or a mixture of two of N, N-dimethylacrylamide, N-diethylacrylamide, diacetone acrylamide, methacrylamide, acrylamide, N-methylolacrylamide, N-methylenebisacrylamide in any ratio; the inert hydrocarbon foaming agent is one of isobutane, n-butane, isopentane, n-pentane and cyclopentane or a mixture of two of the isobutane, the n-butane, the isopentane, the n-pentane and the cyclopentane in any proportion.

3. The polymer foam microsphere of claim 1, wherein the cationic stabilizing auxiliary agent is one of coconut diethanol amine condensate, diethanol amine-adipic acid condensate, polyethyleneimine-carboxymethyl cellulose, and a mixture of two of the above in any proportion.

4. A method for preparing the polymer foamed microspheres of claim 1, wherein the polymer foamed microspheres are prepared by mixing one or two of oil-soluble peroxide and azo initiator with acrylonitrile and/or methacrylonitrile monomer, methacrylic acid monomer, other monomer capable of free radical polymerization and foaming agent to form an oil phase, mixing with an aqueous composite dispersion liquid containing electrolyte, silica colloid dispersant treated by coupling agent and cationic stabilizing assistant, performing high-speed shearing emulsion dispersion, transferring the obtained emulsion dispersion liquid to a high-pressure reactor for micro-suspension polymerization to obtain a polymer microsphere emulsion containing foaming agent inside, and performing centrifugal separation, water washing, drying, crushing, foaming and the like.

5. The method of claim 4, wherein the steps comprise:

(1) coupling agent treatment of silica colloidal dispersant: adding a silica colloid dispersant into a three-neck flask with a stirring and separating funnel, slowly adding ethanol into the three-neck flask while stirring to ensure that the proportion of the ethanol to the water in the silica colloid dispersant is 50:50, then slowly adding 0.1-1.5 wt% of ammonia water of the solid component of the silica colloid dispersant into the three-neck flask to be used as a hydrolysis catalyst, and slowly dropping 0.5-10 wt% of a silane coupling agent into the three-neck flask by taking the solid component of the silica as 100 wt% as a calculation reference to obtain the silica colloid dispersant treated by the coupling agent;

(2) preparation of an aqueous phase composite dispersion phase: slowly adding soluble electrolyte into the silica colloid dispersant treated by the coupling agent while stirring, and then adding a small amount of cation stabilizing auxiliary agent to prepare aqueous phase composite dispersion;

(3) preparation of polymer foamed microspheres:

(a) respectively weighing acrylonitrile and/or methacrylonitrile monomers, methacrylic acid monomers and other monomers possibly subjected to free radical polymerization, taking 100 wt% of the total weight of unsaturated monomers as a calculation reference, dissolving 0.5-8.0 wt% of an oil-soluble initiator in 100 wt% of the unsaturated monomers, and mixing with 10-40 wt% of an inert hydrocarbon foaming agent to form an oil phase; (b) adding the oil phase into the water phase composite dispersion phase, mixing and stirring to form pre-emulsified dispersion liquid, and then adding a cationic stabilizing additive aqueous solution with the concentration of 10 percent and the weight of 0.05 to 1.5 percent of the total weight of the unsaturated monomer; (c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine; (d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 0.45-7.0MPa by using inert gas, and micro-suspending the polymer microsphere emulsion of the foaming agent at the temperature of 40-75 ℃; (e) and finally preparing the polymer foaming microspheres through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like.

6. The method for preparing polymer foamed microspheres according to claim 5, wherein in the step (1) of treating the silica colloidal dispersant with the coupling agent, the concentration of the silica colloidal dispersant is 20% of the acidic oxide; the coupling agent is a silane coupling agent and has a general formula of XSi (OR)3, wherein X represents one of amino, sulfydryl and epoxy.

7. The method for preparing polymer foamed microspheres according to claim 5, wherein the soluble electrolyte in step (2) is one or a mixture of two of sodium chloride, sodium carbonate, sodium nitrate, potassium carbonate and potassium chloride in any proportion; in the preparation of the aqueous phase composite dispersion liquid phase in the step (2), the concentration of the soluble electrolyte in deionized water is 15-40 wt%.

8. The method for preparing polymer expanded beads according to claim 5, wherein in the step (3), the oil-soluble initiator is one of dibenzoyl peroxide, tert-butyl peroxy (2-ethylhexanoate), tert-hexyl peroxypivalate, cumene hydroperoxide, dicumyl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile, azobisisoheptonitrile, and azobisisovaleronitrile, or a mixture of two of them in any proportion; in the preparation of the polymer foaming microspheres in the step (3), the shearing speed of the high-speed shearing emulsifying dispersion machine is 5000-15000 rpm, and the shearing time is 5-60 min.

9. The method for preparing the polymer expanded microspheres according to any one of claims 5 to 10, wherein the average particle diameter of the prepared polymer expanded microspheres is 15 to 100 μm, and the true density is less than or equal to 0.10g/cm³。

10. Use of the polymeric foamed microspheres of claim 1 for the preparation of a polysulfide sealant.

Technical Field

The invention relates to the technical field of preparation methods of polymer microspheres, in particular to a preparation method of polymer foaming microspheres and application of the polymer foaming microspheres in preparation of a polysulfide sealant.

Background

The polymer foaming microsphere is composed of a plastic polymer shell and an inert hydrocarbon foaming agent sealed in the microsphere, and is foamed to form a polymer hollow structure after being heated. Due to the large cavity structure, the polymer foaming microspheres have the characteristics of heat insulation, shock absorption, sound insulation, light weight and the like, and are widely applied to the fields of weight reduction of automobile roofs, automobile fuel tanks, leather, sealing materials and the like.

Conventionally, as disclosed in patent document 1(JP 2016-. When the thermal expansion foaming microsphere is prepared by adopting the method, the silicon dioxide colloid is used as a dispersion stabilizer. However, silica adsorbed on the surface of the microsphere after polymerization easily absorbs water and is poorly compatible with liquid sulfur rubber.

For example, document 2 (materials engineering, vol. 44, No. 4, pp.14-19) discloses the title "preparation of hollow microspheres and their use in polysulfide sealants". In the document, methacrylic acid and methacrylate monomers are taken as a core and a styrene monomer is taken as a shell, and a polymer microsphere with a core-shell structure is synthesized by a seed emulsion polymerization method, wherein the particle size of the microsphere is 551nm at most. And (3) blending the polymer hollow microspheres and the polysulfide rubber to prepare the corresponding polysulfide sealant. The results show that: the density of the sealant can be reduced by adding the polymer hollow microspheres, but the effect of reducing weight and reducing density is not very obvious because the particle size of the microspheres is smaller.

Disclosure of Invention

The invention provides a preparation method of polymer foaming microspheres consisting of a shell of thermoplastic resin and a foaming agent encapsulated in the shell, and the polymer foaming microspheres are dispersed in liquid polysulfide rubber according to a certain proportion and are heated and vulcanized to form the low-density polysulfide rubber.

The polymer foaming microsphere is composed of a plastic polymer shell and an inert hydrocarbon foaming agent sealed in the shell; the foaming agent is vaporized by heating, the shell polymer is expanded by vaporization pressure, and the hollow microsphere of the thermal expansion polymer is formed by foaming. The plastic polymer shell is formed by free radical micro-suspension polymerization of acrylonitrile and/or methacrylonitrile monomer, methacrylic acid monomer and other monomers possibly polymerized by free radicals in the presence of aqueous composite dispersion liquid consisting of silica colloid dispersant treated by coupling agent and cation stabilizing auxiliary agent; based on the total weight of the unsaturated monomers being 100 wt%, the acrylonitrile and/or methacrylonitrile monomer accounts for 30-60 wt%, the methacrylic acid monomer accounts for 50-30 wt%, and the other monomers possible for free radical polymerization account for 20-10 wt%; silica solids account for 5-20 wt% based on 100 wt% total unsaturated monomer weight; the amount of the coupling agent is 0.5-10 wt% based on 100 wt% of the solid silica

In the invention, the other monomer capable of free radical polymerization is one or a mixture of two of N, N-dimethylacrylamide, N-diethylacrylamide, diacetone acrylamide, methacrylamide, acrylamide, N-methylolacrylamide and N, N-methylene bisacrylamide in any proportion; the inert hydrocarbon foaming agent is one of isobutane, n-butane, isopentane, n-pentane and cyclopentane or a mixture of two of the isobutane, the n-butane, the isopentane, the n-pentane and the cyclopentane in any proportion.

In the invention, the cationic stabilizing additive is one of coconut diethanol amine condensate, diethanol amine-adipic acid condensate and polyethyleneimine-carboxymethyl cellulose or a mixture of two of the coconut diethanol amine condensate, the diethanol amine-adipic acid condensate and the polyethyleneimine-carboxymethyl cellulose in any proportion.

The invention also provides a preparation method of the polymer foaming microsphere, which comprises the steps of firstly mixing one or two combinations of oil-soluble peroxide and azo initiator with acrylonitrile and/or methacrylonitrile monomer, methacrylic acid monomer, other monomers possibly polymerized by free radicals and foaming agent to form an oil phase, then mixing the oil phase with water phase composite dispersion liquid which comprises electrolyte, silica colloid dispersing agent treated by coupling agent and cation stabilizing auxiliary agent, carrying out high-speed shearing emulsification dispersion, transferring the obtained emulsification dispersion liquid to a high-pressure reactor for micro-suspension polymerization, finally obtaining polymer microsphere emulsion internally coated with the foaming agent, and then carrying out processes of centrifugal separation, water washing, drying, crushing, foaming and the like to obtain the polymer foaming microsphere.

The preparation method comprises the following specific steps:

(1) coupling agent treatment of silica colloidal dispersant: adding a silica colloid dispersant into a three-neck flask with a stirring and separating funnel, slowly adding ethanol into the three-neck flask while stirring to ensure that the proportion of the ethanol to the water in the silica colloid dispersant is 50:50, then slowly adding 0.1-1.5 wt% of ammonia water (the concentration of the ammonia water is 28%) of solid components of the silica colloid dispersant into the three-neck flask as a hydrolysis catalyst, and slowly dropping 0.5-10 wt% of a silane coupling agent into the three-neck flask by taking 100 wt% of the solid components of the silica as a calculation reference to obtain the silica colloid dispersant treated by the coupling agent;

(2) preparation of an aqueous phase composite dispersion phase: slowly adding soluble electrolyte into the silica colloid dispersant treated by the coupling agent while stirring, and then adding a small amount of cation stabilizing auxiliary agent to prepare aqueous phase composite dispersion;

(3) preparation of polymer foamed microspheres:

(a) respectively weighing acrylonitrile and/or methacrylonitrile monomers, methacrylic acid monomers and other monomers possibly subjected to free radical polymerization, taking 100 wt% of the total weight of unsaturated monomers as a calculation reference, dissolving 0.5-8.0 wt% of an oil-soluble initiator in 100 wt% of the unsaturated monomers, and mixing with 10-40 wt% of an inert hydrocarbon foaming agent to form an oil phase; (b) adding the oil phase into the water phase composite dispersion phase, mixing and stirring to form pre-emulsified dispersion liquid, and then adding a cationic stabilizing additive aqueous solution with the concentration of 10 percent and the weight of 0.05 to 1.5 percent of the total weight of the unsaturated monomer; (c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine; (d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 0.45-7.0MPa by using inert gas, and micro-suspending the polymer microsphere emulsion of the foaming agent at the temperature of 40-75 ℃; (e) and finally preparing the polymer foaming microspheres through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like.

In the step (1), the coupling agent is used for treating the silica colloidal dispersant, wherein the concentration of the silica colloidal dispersant is 20% of acid oxide; the coupling agent is a silane coupling agent with a general formula of XSi (OR)₃Wherein X represents one of amino, mercapto and epoxy.

The soluble electrolyte in the step (2) is one of sodium chloride, sodium carbonate, sodium nitrate, potassium carbonate and potassium chloride or a mixture of two of the sodium chloride, the sodium carbonate, the sodium nitrate, the potassium carbonate and the potassium chloride in any proportion.

In the step (2) of preparing the aqueous composite dispersion phase, the concentration of the soluble electrolyte in the deionized water is 15-40 wt%.

In the step (3) of preparing the polymer foaming microspheres, the oil-soluble initiator is one of dibenzoyl peroxide, tert-butyl peroxy (2-ethylhexanoate), tert-hexyl peroxypivalate, cumene hydroperoxide, dicumyl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile, azobisisoheptonitrile and azobisisovaleronitrile or a mixture of two of the two in any proportion.

In the step (3) of preparing the polymer foaming microspheres, the shearing speed of the high-speed shearing emulsifying dispersion machine is 5000-15000 rpm, and the shearing time is 5-60 min.

The average particle diameter of the polymer foaming microsphere prepared by the method is 15-100 mu m, and the true density is less than or equal to 0.10g/cm³。

The invention also discloses application of the polymer foaming microsphere in preparation of a polysulfide sealant. Dispersing polymer foaming microspheres in a certain proportion in liquid polysulfide rubber, and heating and vulcanizing to form the low-density polysulfide rubber. The addition amount of the polymer foaming microspheres is 1-10 wt% of the total weight of the liquid polysulfide rubber, and the invention has the advantages of low density, easy use as a light additive of the polysulfide rubber and capability of greatly reducing the weight of the polysulfide sealant.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are only for the purpose of the present invention and are not intended to limit the scope of the present invention. It should be understood that various changes and modifications can be made by those skilled in the art after reading the disclosure of the present invention, and equivalents fall within the scope of the appended claims.

Example 1

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 0.03g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 0.05g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents amino) is slowly dropped into a three-neck flask to obtain a silica colloid dispersant treated by a coupling agent;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 15g of sodium chloride into the silica colloid dispersing agent treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 30g of acrylonitrile, 50g of methacrylic acid and 20g of N, N-dimethylacrylamide are respectively weighed, 0.5g of dibenzoyl peroxide is dissolved in a monomer mixture, and then the monomer mixture is mixed with 10g of isobutane to form an oil phase;

(b) adding the oil phase into 53.77g of the water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 0.05g of a 10% cocodiethanolamine cocoate condensate aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 5000rpm, and the shearing time is 5 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 0.45MPa by using inert gas, and micro-suspending the polymer microsphere emulsion of the foaming agent at 40 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 100 mu m, and the true density of the polymer foaming microspheres is 0.03g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 2

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 2.0g of a silane coupling agent (the general formula is XSi (OR))₃Wherein X represents mercapto) is slowly dropped into the three-necked flask to obtain the silica colloid dispersant treated by the coupling agent;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 40g of sodium carbonate into the silica colloid dispersing agent treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 60g of acrylonitrile, 30g of methacrylic acid and 10g of N, N-diethylacrylamide were weighed out, respectively, and 8.0g of tert-butyl peroxy (2-ethylhexanoate) was dissolved in the monomer mixture and mixed with 40g of N-butane to form an oil phase;

(b) adding the oil phase into 242.3g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 1.5g of 10% diethanolamine-adipic acid condensate aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 15000rpm, and the shearing time is 60 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 7.0MPa by using inert gas, and micro-suspending the polymer microsphere emulsion of the foaming agent at the temperature of 75 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microsphere is finally preparedThe average particle diameter is 15 μm, and the true density is 0.10g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 3

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, then 0.15g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 1.0g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents an epoxy group) is slowly dropped into a three-necked flask to obtain a coupling agent-treated silica colloidal dispersant;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 30g of sodium nitrate into the silica colloid dispersing agent treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) respectively weighing 50g of methacrylonitrile, 40g of methacrylic acid and 10g of diacetone acrylamide, dissolving 5.0g of tert-hexyl peroxypivalate in the monomer mixture, and mixing with 20g of isopentane to form an oil phase;

(b) adding the oil phase into 92.46g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 0.5g of 10% polyethyleneimine-carboxymethyl cellulose aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 6000rpm, and the shearing time is 6 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 0.50MPa by using inert gas, and carrying out polymer microsphere emulsion of a micro-suspension foaming agent at 42 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 35 mu m, and the true density of the polymer foaming microspheres is 0.085g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 4

(1) Coupling agent treatment of silica colloidal dispersant:

100g of the mixture is concentratedThe acidic silica colloidal dispersant having a degree of 20% was added to a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added to the three-necked flask while stirring, and then 0.22g of aqueous ammonia (having an aqueous ammonia concentration of 28%) as a hydrolysis catalyst, 0.18g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents amino) is slowly dropped into a three-neck flask to obtain a silica colloid dispersant treated by a coupling agent;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 20g of potassium nitrate into the silica colloid dispersant treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 45g of methacrylonitrile, 35g of methacrylic acid and 20g of methacrylamide were weighed out separately, 2.0g of cumene hydroperoxide was dissolved in the monomer mixture and mixed with 30g of n-pentane to form an oil phase;

(b) adding the oil phase into 110.2g of the aqueous phase composite dispersion, mixing and stirring to form pre-emulsified dispersion, and then adding 0.1g of 10% coco diethanol amine condensate aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 7000rpm, and the shearing time is 10 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 3.5MPa by using inert gas, and micro-suspending the polymer microsphere emulsion of the foaming agent at 50 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 80 mu m, and the true density of the polymer foaming microspheres is 0.04g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 5

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, then 0.25g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 1.8g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents mercapto) is slowly dropped into the three-necked flask to obtain the silica colloid dispersant treated by the coupling agent;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 23g of potassium carbonate into the silica colloid dispersing agent treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 50g of acrylonitrile, 35g of methacrylic acid and 15g of acrylamide are weighed respectively, 4.5g of dicumyl peroxide is dissolved in the monomer mixture, and then mixed with 33g of cyclopentane to form an oil phase;

(b) adding the oil phase into 123.78g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 0.2g of 10% diethanolamine-adipic acid condensate aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 7000rpm, and the shearing time is 15 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 5.5MPa by using inert gas, and micro-suspending the polymer microsphere emulsion of the foaming agent at 70 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 56 mu m, and the true density of the polymer foaming microspheres is 0.048g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 6

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 0.26g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 0.8g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents an epoxy group) is slowly dropped into a three-necked flask to obtain a coupling agent-treated silica colloidal dispersant;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 36g of potassium chloride into the silica colloid dispersant treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 56g of methacrylonitrile, 32g of methacrylic acid and 12g of N-methylolacrylamide are respectively weighed, 3.5g of tert-butyl hydroperoxide is dissolved in the monomer mixture, and then the mixture is mixed with 23g of isobutane to form an oil phase;

(b) adding the oil phase into 142.24g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 0.9g of 10% polyethyleneimine-carboxymethyl cellulose aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 9000rpm, and the shearing time is 20 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 6.0MPa by using inert gas, and carrying out polymer microsphere emulsion of a micro-suspension foaming agent at the temperature of 55 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 74 mu m, and the true density of the polymer foaming microspheres is 0.05g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 7

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 0.14g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 0.46g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents amino) is slowly dropped into a three-neck flask to obtain a silica colloid dispersant treated by a coupling agent;

(2) preparation of an aqueous phase composite dispersion phase:

adding 22g of sodium chloride slowly into the silica colloid dispersant treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion;

(3) preparation of polymer foamed microspheres:

(a) 22g of acrylonitrile and 20g of methacrylonitrile, 40g of methacrylic acid and 18g of N, N-methylenebisacrylamide were weighed, respectively, 3.8g of azobisisobutyronitrile was dissolved in the monomer mixture, and mixed with 19g of isobutane and 5g of N-butane to form an oil phase;

(b) adding the oil phase into 166.95g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 1.0g of 10% coconut acid diethanolamine condensation compound aqueous solution and 0.2g of diethanolamine-adipic acid condensation compound aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 11000rpm, and the shearing time is 30 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 0.55MPa by using inert gas, and carrying out polymer microsphere emulsion of a micro-suspension foaming agent at the temperature of 62 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 20 mu m, and the true density of the polymer foaming microspheres is 0.095g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 8

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 0.19g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 1.26g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents an epoxy group) is slowly dropped into a three-necked flask to obtain a coupling agent-treated silica colloidal dispersant;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 30g of sodium carbonate and 5g of potassium nitrate into the silica colloid dispersant treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 45g of methacrylonitrile, 40g of methacrylic acid and 5g N, N-dimethylacrylamide and 10g of N, N-diethylacrylamide were weighed out separately, 3g of dibenzoyl peroxide and 2g of tert-butyl peroxy (2-ethylhexanoate) were dissolved in the monomer mixture, and then mixed with 10g of isobutane and 20g of cyclopentane to form an oil phase;

(b) adding the oil phase into 189.16g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 1.25g of 10% polyethyleneimine-carboxymethyl cellulose aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 12000rpm, and the shearing time is 55 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 3.2MPa by using inert gas, and carrying out polymer microsphere emulsion of a micro-suspension foaming agent at the temperature of 55 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 26 mu m, and the true density of the polymer foaming microspheres is 0.082g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 9

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 0.11g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 1.05g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents amino, mercapto and epoxy) is slowly dropped into a three-necked flask to obtain a silica colloidal dispersant treated by a coupling agent;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 20g of sodium chloride and 2g of potassium nitrate into the silica colloid dispersant treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) weighing 40g of acrylonitrile and 6g of methacrylonitrile, 42g of methacrylic acid and 8g N-hydroxymethyl acrylamide and 4g of N, N-methylene bisacrylamide respectively, dissolving 3.9g of azobisisobutyronitrile in the monomer mixture, and mixing with 29g of isopentane to form an oil phase;

(b) adding the oil phase into 178.53g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 1.28g of 10% coconut diethanol amine condensate aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 13000rpm, and the shearing time is 22 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 6.8MPa by using inert gas, and carrying out polymer microsphere emulsion of a micro-suspension foaming agent at 52 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microsphere is finally preparedThe average particle diameter is 30 μm, and the true density is 0.075g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance:

example 10

(1) Coupling agent treatment of silica colloidal dispersant:

100g of 20% acidic silica colloidal dispersant was put into a three-necked flask equipped with a stirrer and a separatory funnel, 100g of ethanol was slowly added into the three-necked flask while stirring, and then 0.29g of aqueous ammonia (having an aqueous ammonia concentration of 28%) was slowly added into the three-necked flask as a hydrolysis catalyst, and 0.09g of a silane coupling agent (having a general formula of XSi (OR))₃Wherein X represents an epoxy group) is slowly dropped into a three-necked flask to obtain a coupling agent-treated silica colloidal dispersant;

(2) preparation of an aqueous phase composite dispersion phase:

slowly adding 37g of potassium carbonate into the silica colloid dispersing agent treated by the coupling agent while stirring to prepare an aqueous phase composite dispersion liquid;

(3) preparation of polymer foamed microspheres:

(a) 52g of methacrylonitrile, 37g of methacrylic acid and 11g N, N-methylenebisacrylamide were weighed out separately, 2.0g of azobisisoheptonitrile and 1g of azobisisovaleronitrile were dissolved in the monomer mixture, and mixed with 28g of N-pentane to form an oil phase;

(b) adding the oil phase into 213.64g of water phase composite dispersion liquid, mixing and stirring to form pre-emulsified dispersion liquid, and then adding 1.45g of 10% diethanolamine-adipic acid condensate aqueous solution;

(c) emulsifying and dispersing the pre-emulsified dispersion liquid by adopting a high-speed shearing emulsifying dispersion machine, wherein the shearing speed is 14000rpm, and the shearing time is 36 min;

(d) transferring the emulsified dispersion liquid into a high-pressure reaction kettle, adjusting the polymerization pressure to 5.2MPa by using inert gas, and carrying out polymer microsphere emulsion of a micro-suspension foaming agent at the temperature of 60 ℃;

(e) through the processes of centrifugal separation, water washing, drying, crushing, foaming and the like, the polymer foaming microspheres are finally prepared, the average particle diameter of the polymer foaming microspheres is 18 mu m, and the true density of the polymer foaming microspheres is 0.098g/cm³。

(4) Application in polysulfide sealant

A. Formulation composition

B. Preparation:

the base paste and the vulcanizing agent are prepared by mixing by using a three-roll grinder and then mixing according to the weight ratio of 100: 10, weighing, manually mixing for 5 minutes, sealing the part to be sealed within 3 hours, coating the part to be sealed to the thickness of about 8mm, and vulcanizing at room temperature for 7 days.

C. Performance: