CN111024583B - Simple method for testing porosity of porous material - Google Patents

Abstract

The invention discloses a simple method for testing the porosity of porous materials. The method comprises the following steps: cutting out a thin sheet sample of an appropriate size, measuring the thickness of the sample as δ, and affixing a waterproof transparent tape on one side of the sample , place the sample on a horizontal table with the side with the tape facing down, and drop a drop of pure water with a mass of m and a volume of V (=m/ρ, ρ is the density of water) in the test On the side of the sample without the waterproof tape, the seepage process of water on the surface of the sample was observed with a microscope-CCD-computer system. Photo of a circular seepage area with radius R in . The seepage time is long enough that the water of volume V fills the pores of the entire seepage area, according to the formula:

Calculate the porosity η of the sample. The porosity test method provided by the invention has simple, easy and convenient test process. In addition, the consumption of instruments and materials used in the testing process is low in cost, cost-effective, and practical.

Description

A Simple Method to Test the Porosity of Porous Materials

technical field

The invention relates to the field of material technology detection, and more particularly, to a simple method for measuring porosity.

Background technique

Porosity is the ratio of the volume of all voids in a porous medium to the total volume of the porous medium (all porosity referred to in this application refers to effective porosity). Porosity characterizes the porosity or compactness of porous media, and has an important influence on the thermal conductivity and electrical conductivity, strength and toughness, air permeability and water absorption of materials.

At present, traditional and novel methods for measuring the porosity of porous materials include density determination drainage method, gas adsorption method (BET method), mercury intrusion method, scanning electron microscope SEM method, transmission electron microscope TEM method, micro-computed tomography scanning technology Micro-CT, etc. . There are many methods of measuring porosity, but each method has its scope of application and shortcomings. For example, the density measurement drainage method is very suitable for water as a non-wetting solvent and easily penetrates into the material voids without causing the material to swell or swell. Determination of the total porosity of shrunken scaffolds, while for hydrophilic materials such as bacterial cellulose, which are easily swelled by water, the densitometry drainage method is inaccurate to measure the porosity of the material; the gas adsorption method (BET method) is often used for catalyst porosity However, this method only measures open pores, the effective range is 0.4-100 nm and takes a long time; the mercury intrusion method is generally used for the determination of pore size and pore size distribution. Mercury pollution; scanning electron microscope SEM method, transmission electron microscope TEM method and micro-computed tomography scanning technology Micro-CT method, the determination method is simple and fast, but the equipment investment is large, and the measurement of porosity is too expensive.

Because the hydrophilic porous material is easy to absorb water and expand, the porosity of the hydrophilic porous material cannot be accurately measured by conventional methods, and the existing new technology method requires a large investment in instruments. Therefore, it is an urgent problem for those skilled in the art to invent a simple and accurate method for measuring the porosity of hydrophilic materials.

SUMMARY OF THE INVENTION

It is under the above background that the present invention provides a method for measuring porosity, which can solve the shortcomings of the existing methods, especially the existing methods. In fact, it solves the actual problem of more cumbersome and expensive testing instruments and consumables. This method is especially useful for measuring the porosity of hydrophilic porous materials.

To achieve the above object, the present invention provides the following technical solutions:

A simple method for testing the porosity of porous materials, the method includes:

Cut out a thin sheet sample with an appropriate size and uniform thickness, and measure the thickness δ of the sample; stick a waterproof transparent tape on one side of the sample, and place the sample on a horizontal table with the side with the tape facing down;

Drop a drop of pure water with a mass of m on the side of the sample without the waterproof tape with a plastic-head dropper, and use a microscope-CCD-computer system to observe the seepage process of water on the surface of the sample. After a long enough time, the water droplets completely penetrate. When entering the thin porous material sample, take a picture of the circular seepage area with the radius R of water in the sample;

The mass m of the water droplet is weighed by a precision electronic weighing, and the volume V of the water droplet is calculated by the formula V=m/ρ, where ρ is the droplet density, which is the density of water during the experiment;

计算所述多孔材料的孔隙率η。According to the formula:

The porosity η of the porous material is calculated.

Wherein, the porous material is a hydrophilic porous material.

Wherein, the weighing of the water droplets with the mass m, the operation steps are: use a precision electronic weighing to weigh the weight m ₁ of the dropper that absorbs a certain amount of water, and then drop a drop of water onto the surface of the sample, and then weigh it again The total weight of the water and the drip tube is m ₂ , then the mass of the water droplet can be calculated by m=m ₁ -m ₂ .

计算所述试样的孔隙率η。本发明所提供的孔隙率测试方法，测试过程简单、易行、方便。测试过程中所用仪器及材料的消耗方面成本低，性价比高，实用性强。It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method for testing the porosity of porous materials. , when the water droplets completely penetrate into the thin porous material sample, take a picture of the circular seepage area with a radius R of water in the sample. The seepage time is long enough that the water of volume V fills the pores of the entire seepage area, according to the formula:

Calculate the porosity η of the sample. The porosity test method provided by the invention has simple, easy and convenient test process. The consumption of the instruments and materials used in the test process is low in cost, high in cost performance and strong in practicability.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. It is obvious to those skilled in the art that the accompanying drawings in the following description are only embodiments of the present invention. For those skilled in the art, without creative work , other drawings can also be obtained according to the drawings provided.

FIG. 1 is a flow chart of a method for testing porosity disclosed by the present invention.

Specific implementation method

For reference and clarity, descriptions, abbreviations or abbreviations of technical terms used hereinafter are summarized as follows:

Porosity: The ratio of the volume of measurable pores and pores in an amount of solid (pore volume) to the total volume it occupies.

Hydrophilic: "hydrophilic" English definition: hydrophilic property; hydrophilicity, refers to a molecule with a polar group, has a greater affinity for water, can attract water molecules, or easily dissolve in water.

Seepage: Seepage refers to the flow of fluids in a porous medium.

The technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

计算所述试样的孔隙率η。本发明所提供的孔隙率测试方法，测试过程简单、易行、方便。测试过程中所用仪器及材料的消耗方面成本低，性价比高，实用性强。The invention discloses a method for testing the porosity of porous materials. By observing the seepage process of water on the surface of the sample with a microscope-CCD-computer system, after a long enough time, the water droplets completely penetrate into the thin porous material sample, and then take a picture. A photograph of a circular seepage area with a radius R of water in the sample is obtained. The seepage time is long enough that the water of volume V fills the pores of the entire seepage area, according to the formula:

Calculate the porosity η of the sample. The porosity test method provided by the invention has simple, easy and convenient test process. The consumption of the instruments and materials used in the test process is low in cost, high in cost performance and strong in practicability.

Instruments and solutions used in the method of the present invention: microscope-CCD-computer system, precision balance (±0.1 mg); precision thickness gauge (±0.1 μm); distilled water.

Please refer to FIG. 1 , which is a flowchart of a method for testing the porosity of porous materials disclosed in the present invention;

Step 101: Cut out a thin sheet sample with an appropriate size and a uniform thickness, and measure the thickness δ of the sample; paste a waterproof transparent tape on one side of the sample, and place the side with the tape down and place the sample horizontally on the desktop;

Step 102: Use a glue tip dropper to drop a drop of pure water with a mass of m on the side of the sample without the waterproof tape, and use a microscope-CCD-computer system to observe the seepage process of water on the surface of the sample. After a long enough time, When the water droplets completely penetrate into the thin porous material sample, a picture of a circular seepage area with a radius R of water in the sample is taken.

Step 103: use a precision electronic weighing scale to weigh the mass m of the water droplet, and calculate the volume V of the water droplet by the formula V=m/ρ, where ρ is the droplet density, which is the density of water during the experiment;

计算所述多孔材料的孔隙率η。Step 104: According to the formula:

The porosity η of the porous material is calculated.

Wherein, the porous material is a hydrophilic porous material.

Wherein, the weighing of water droplets with a mass of m is specifically: using a precision electronic weighing machine to weigh the weight m ₁ of a dropper that absorbs a certain amount of water, and then weigh a drop of water on the surface of the sample, and then weigh the water. and the total weight of the dropper m ₂ , then m=m ₁ -m ₂ .

Among them, V is the volume of water droplets, which can be calculated by the formula V=m/ρ, where ρ is the density of water.

计算所述试样的孔隙率η。本发明所提供的孔隙率测试方法，测试过程简单、易行、方便。测试过程中所用仪器及材料的消耗方面成本低，性价比高，实用性强。To sum up: the present invention discloses a method for testing the porosity of porous materials. By observing the seepage process of water on the surface of the sample with a microscope-CCD-computer system, after a long enough time, the water droplets completely penetrate into the thin porous material. When the water is in the sample, take a picture of the circular seepage area with the radius R of water in the sample. The seepage time is long enough, and the water volume V fills the pores of the entire seepage area, according to the formula:

Calculate the porosity η of the sample. The porosity test method provided by the invention has simple, easy and convenient test process. The consumption of the instruments and materials used in the test process is low in cost, high in cost performance and strong in practicability.

The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Accordingly, the applicability of the present invention is accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (3)

1. A simple method for testing the porosity of a porous material, characterized in that the porosity of the porous material is determined by the phenomenon of water seepage, the method comprising:

step 1: cutting a sheet sample with proper size and uniform thickness, and measuring the thickness delta of the sample; sticking a waterproof transparent adhesive tape on one side of the sample, and placing the sample on a horizontal table top with the side, on which the adhesive tape is stuck, facing downwards;

step 2: dropping a drop of purified water with mass m by using a rubber head dropper on one surface of the sample which is not pasted with the waterproof adhesive tape, simultaneously observing the seepage process of the water on the surface of the sample by using a microscope-CCD-computer system, and shooting to obtain a circular seepage area photo of the water with radius R in the sample when the water drops completely penetrate into the thin porous material sample after a sufficient long time;

and step 3: weighing the mass m of the water drop by using a precise electronic scale, and calculating the volume V of the water drop according to a formula V = m/rho, wherein rho is the density of the water drop, namely the density of water in the experimental process;

and 4, step 4: according to the formula:

calculating the porosity eta of the porous material.

2. The easy method for testing porosity of porous material according to claim 1, wherein the porous material is hydrophilic porous material.

3. The simple method for testing the porosity of the porous material according to claim 1, wherein the operation of weighing the mass m of the water drops comprises the following steps: weighing the weight m of a dropper having a certain amount of water absorbed therein by a precision electronic scale ₁ Then dropping a drop of water to the surface of the sample by a dropper, and weighing the total weight m of the water and the dropper ₂ Then the mass of the water droplet is represented by m = m ₁ –m ₂ And (5) calculating.

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