阅读说明：本技术 一种双连续相泡沫凝胶及其制备方法和应用 (Bicontinuous-phase foam gel and preparation method and application thereof ) 是由 燕永利 吕博 牛梦龙 尹丰丰 蔡雨秀 奚琪 张阳 宋兆洋 于 2019-10-31 设计创作，主要内容包括：本发明一种双连续相泡沫凝胶及其制备方法和应用,包括如下步骤：步骤1,配置聚合物溶液：按照质量百分比计,将0.3％～0.6％的起泡剂、0.05％～0.2％的交联剂和0.15％～0.35％的聚丙烯酰胺溶于水中；步骤2,向聚合物溶液中通入气体,形成湍流,至最大发泡量后,降低气体流量至0.5～2.5ml/50cm<Sup>3</Sup>·min,持续搅拌,然后静置熟化1～3小时,得到双连续相泡沫凝胶。本发明通过控制气泡成核速率和气泡聚并速率相等,制备出双连续相泡沫凝胶,具有高的孔隙率、较低的传热性、较高的比模量和比强度,可应用于超轻夹层材料隔热、减震和填充等功能材料方面。(The invention relates to a bicontinuous phase foam gel and a preparation method and application thereof, comprising the following steps: step 1, preparing a polymer solution: according to the mass percentage, 0.3 to 0.6 percent of foaming agent, 0.05 to 0.2 percent of cross-linking agent and 0.15 to 0.35 percent of polyacrylamide are dissolved in water; step 2, introducing gas into the polymer solution to form turbulent flow, and reducing the gas flow to 0.5-2.5 ml/50cm after the maximum foaming amount is reached 3 Min, stirring continuously, then standing for agingAnd (3) obtaining the bicontinuous phase foamed gel after 1-3 hours. The bicontinuous phase foam gel is prepared by controlling the bubble nucleation rate to be equal to the bubble coalescence rate, has high porosity, lower heat conductivity and higher specific modulus and specific strength, and can be applied to the aspects of functional materials such as heat insulation, shock absorption, filling and the like of ultralight sandwich materials.)

1. A preparation method of bicontinuous phase foam gel is characterized by comprising the following steps:

step 1, preparing a polymer solution: according to the mass percentage, 0.3 to 0.6 percent of foaming agent, 0.05 to 0.2 percent of cross-linking agent and 0.15 to 0.35 percent of polyacrylamide are dissolved in water;

step 2, introducing gas into the polymer solution to form turbulent flow, and reducing the gas flow to 0.5-2.5 ml/50cm after the maximum foaming amount is reached³And min, continuously stirring, standing and curing for 1-3 hours to obtain the bicontinuous phase foamed gel.

2. The method of claim 1, wherein the foaming agent is α -olefin sulfonate, sodium dodecylbenzene sulfonate, sodium fatty alcohol ether sulfate, or sodium secondary alkyl sulfonate.

3. The method of claim 1, wherein the crosslinking agent is a complex crosslinking agent comprising an organic phenolic crosslinking agent and a transition metal crosslinking agent.

4. The method of claim 3, wherein the transition metal crosslinker is an organochromium crosslinker or an organoaluminum crosslinker.

5. The preparation method of the bicontinuous phase foamed gel according to claim 3, characterized in that the mass ratio of the transition metal crosslinking agent to the phenolic resin crosslinking agent in the composite crosslinking agent is: 0.2: (0.086-0.8).

6. The method of claim 1, wherein the stirring speed in step 2 is 2000-4000 rpm.

7. The method of claim 1, wherein the stirring time in step 2 is 20-35 minutes.

8. Bicontinuous phase foamed gels obtainable by the process according to any one of claims 1 to 7.

9. Use of the bicontinuous phase foam gel according to claim 8 in sandwich materials, characterized in that it is used as a thermal insulation, shock absorbing or filling material.

10. Use of the bicontinuous phase foam gel of claim 8 in separation processes as a filtration membrane.

Technical Field

The invention relates to a bicontinuous phase structural material, in particular to a bicontinuous phase foam gel and a preparation method and application thereof.

Background

For the bicontinuous phase structure, the thermodynamic stable structures such as microemulsion and liquid crystal formed in the surfactant aqueous solution system are common, and the cubic bicontinuous phase structure is more represented and can be explained by using a critical arrangement parameter theory.

Critical arrangement parameter theory: based on the data of the geometric shape of the surfactant molecules, a critical arrangement parameter P is combined, and the arrangement form of the surfactant molecules in space is predicted according to the value of the critical arrangement parameter P. The parameter expression is shown in formula (1):

P＝V/al (1)

in the formula, a is the sectional area of a polar group of a surfactant molecule; l is the hydrophobic chain length; v is the hydrophobic group volume. The critical arrangement parameter theory well explains that the surfactant aqueous solution system is easy to form disc-shaped micelles or bilayers with different degrees of bending and bicontinuous structures. However, not all surfactant systems follow this rule, which varies from case to case.

The critical alignment parameter theory can also be used to analyze the formation of microemulsions, when the volume ratio of oil phase to water phase in the system is equal, the critical alignment parameter value P in the bicontinuous phase system is very close to 1. All factors which can influence the volume V of the hydrophobic group, the sectional area a of the polar group of the surfactant molecule and the length l of the hydrophobic chain can influence the value P, and further influence the type of the microemulsion.

However, the current foam structures are closed cell structures, which have low porosity, high heat transfer, and low specific strength. Bicontinuous phase foam structures have not been reported to date, and no answer has been found to date as to how to control bubble coalescence to form a continuous phase rather than a closed cell bubble structure.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a bicontinuous phase foamed gel, a preparation method and application thereof, which can form the bicontinuous phase foamed gel instead of a closed cell bubble structure, have high porosity, lower heat conductivity, higher specific modulus and specific strength, and can be applied to interlayer materials and separation processes.

The invention is realized by the following technical scheme:

a method for preparing bicontinuous phase foam gel comprises the following steps:

step 1, preparing a polymer solution: according to the mass percentage, 0.3 to 0.6 percent of foaming agent, 0.05 to 0.2 percent of cross-linking agent and 0.15 to 0.35 percent of polyacrylamide are dissolved in water;

step 2, introducing gas into the polymer solution to form turbulent flow, and reducing the gas flow to 0.5-2.5 ml/50cm after the maximum foaming amount is reached³And min, continuously stirring, standing and curing for 1-3 hours to obtain the bicontinuous phase foamed gel.

Preferably, the foaming agent is α -olefin sulfonate, sodium dodecylbenzene sulfonate, sodium fatty alcohol ether sulfate or secondary alkyl sodium sulfonate.

Preferably, the crosslinking agent is a composite crosslinking agent, including an organic phenolic crosslinking agent and a transition metal crosslinking agent.

Further, the transition metal crosslinking agent is an organic chromium crosslinking agent and an organic aluminum crosslinking agent.

Further, the mass ratio of the transition metal cross-linking agent to the phenolic resin cross-linking agent in the composite cross-linking agent is as follows: 0.2: (0.086-0.8).

Preferably, in the step 2, the stirring speed is 2000-4000 rpm.

Preferably, in the step 2, the stirring time is 20-35 minutes.

The bicontinuous phase foamed gel prepared by the preparation method.

The bicontinuous phase foam gel is applied to sandwich materials and used as heat insulation materials, shock absorption materials or filling materials.

The bicontinuous phase foamed gel is applied in the separation process and used as a filter membrane.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention controls the bubble nucleation rate and the bubble coalescence rate by controlling the content of the foaming agent; the content of the cross-linking agent and the polyacrylamide is controlled so as to control the cross-linking rate and the gel nucleation rate, and meanwhile, the gas flow control is combined so that the bubble coalescence rate and the gel nucleation rate are equal. The method comprises the steps of enabling a polymer solution to be in a turbulent flow state by controlling the gas flow, then reducing the gas flow to enable the polymer solution to be in the turbulent flow state, so that bubble coalescence occurs, and successfully preparing the bicontinuous phase foamed gel by controlling the bubble coalescence rate to be equal to the gel nucleation rate. The bicontinuous phase foamed gel is a dispersion system with gas uniformly dispersed in gel, has special properties, has the foam property before being gelled, and has the gel property after being gelled.

The bicontinuous phase foam gel structure model prepared by the invention is shown in figure 1, has high porosity, lower heat conductivity, higher specific modulus and specific strength, can generate larger deformation under low stress, has excellent buffering and energy absorbing characteristics when being pressed, and can be applied to functional materials such as ultralight sandwich material heat insulation, shock absorption, filling and the like; meanwhile, the bicontinuous phase foamed polymer material is an ultralight porous material with a novel structure, can be used as a filtering membrane, is suitable for a chemical separation process, and is suitable for the fields of buildings, traffic, energy and chemical industry.

Drawings

FIG. 1 is a model diagram of a bicontinuous phase foam gel structure.

FIG. 2 is a scanning electron micrograph of the bicontinuous phase foam gel of example 1.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

The bicontinuous phase foam gel comprises the following components in percentage by mass: 0.3 to 0.6 percent of foaming agent, 0.05 to 0.2 percent of cross-linking agent, 0.15 to 0.35 percent of polyacrylamide and the balance of water.

The foaming agent is anionic surfactant with content of 0.3-0.6%, 0.3%, 0.4%, 0.5%, 0.6%, and is suitable for bicontinuous phase foamed gel system, and the anionic surfactant is selected from α -olefin sodium sulfonate, sodium dodecyl benzene sulfonate, sodium fatty alcohol ether sulfate, secondary alkyl sodium sulfonate, and one or two of alcohol acyl carboxylate.

The crosslinking agent is a composite crosslinking agent and consists of a phenolic resin crosslinking agent and a transition metal crosslinking agent, and the mass ratio of the phenolic resin crosslinking agent to the transition metal crosslinking agent is 0.2: 0.8-0.7: 0.3; the total amount of the additive is adjustable between 0.05 percent and 0.2 percent, and can be 0.05 percent, 0.10 percent, 0.15 percent and 0.20 percent to control the crosslinking rate. Wherein the organic chromium is Cr³⁺E.g. chromium hydroxide, organo-aluminium being Al³⁺Such as alumina. The mass percentage of the polyacrylamide is 0.15-0.35% of polyacrylamide (HPAM), and can be 0.15%, 0.20%, 0.25%, 0.30% and 0.35%.

The gel forming rate of the gel is determined by the composition of the polymer aqueous solution, the molecular weight of the selected polyacrylamide is 800-1200 ten thousand, and the addition amount of the selected polyacrylamide is controlled to be 0.15% -0.35% so as to adjust the gel forming rate and the gel strength.

In order to more clearly express the purpose of the invention, the technical scheme of product design and the specific performance of the product, the following detailed description is combined with the related implementation case.

According to industry-related standards:

in the foam gel system, the porosity test method of the foam gel is as follows: during the preparation process, the foam gel is cut into cubic blocks of 1 × 1cm, the side length and the mass of the foam gel are measured after dehydration, the apparent density is obtained by using the mass to volume ratio, and the theoretical density of a sample can be consulted. The formula is shown as formula (2), so that the porosity of the sample is calculated.

In the foam gel system, the determination of the specific strength of the foam gel is tested by using the national standard GB/T28304-.

In the foam gel system, the heat conduction rate of the foam gel is tested by adopting the national standard GB/T10294. The standard heat transfer coefficient value is less than or equal to 0.053W/(m.k)

In the foam gel system, the measurement of the water absorption of the foam gel is tested by using the national standard GB/T8810-2005. The standard is that the water content is not less than 500cm³Three component samples were taken for parallel testing.

According to the formula

And calculating the water absorption of the foamed gel.

Wherein m is₁The sample mass; m is₂Is the apparent mass of the sample; m is₃The apparent mass of the sample after soaking;

V₁the volume of the sample soaked in water; v_cIs the apparent cell system of the sample; ρ is the density of water.