CN113607877A - Method for testing acid value of water-soluble resin - Google Patents
Method for testing acid value of water-soluble resin Download PDFInfo
- Publication number
- CN113607877A CN113607877A CN202110853972.5A CN202110853972A CN113607877A CN 113607877 A CN113607877 A CN 113607877A CN 202110853972 A CN202110853972 A CN 202110853972A CN 113607877 A CN113607877 A CN 113607877A
- Authority
- CN
- China
- Prior art keywords
- sample
- titrated
- experimental group
- water
- potassium hydroxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229920005989 resin Polymers 0.000 title claims abstract description 97
- 239000011347 resin Substances 0.000 title claims abstract description 97
- 239000002253 acid Substances 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000012360 testing method Methods 0.000 title claims abstract description 19
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims abstract description 183
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 90
- 239000012086 standard solution Substances 0.000 claims abstract description 59
- 239000011259 mixed solution Substances 0.000 claims abstract description 35
- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 claims abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000004448 titration Methods 0.000 claims abstract description 18
- 238000005303 weighing Methods 0.000 claims abstract description 7
- 239000007788 liquid Substances 0.000 claims description 11
- 238000004090 dissolution Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 230000014759 maintenance of location Effects 0.000 claims description 2
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 238000003912 environmental pollution Methods 0.000 abstract description 3
- 239000002904 solvent Substances 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 22
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 125000000524 functional group Chemical group 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004737 colorimetric analysis Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 238000005562 fading Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000003918 potentiometric titration Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Molecular Biology (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention discloses a method for testing the acid value of water-soluble resin, which comprises the following steps: respectively adding equal amounts of mixed solution of ethanol and water into the two conical flasks to respectively obtain an experimental group and a blank group; weighing a resin sample, and adding the resin sample into an erlenmeyer flask of an experimental group; after the resin sample is completely dissolved in the experimental group, adding phenolphthalein indicator into the experimental group and the blank group to obtain a sample to be titrated in the experimental group and a sample to be titrated in the blank group; respectively carrying out titration reaction on the experimental group to-be-titrated sample and the blank group to-be-titrated sample by using a potassium hydroxide standard solution, and recording the consumption volumes of the potassium hydroxide standard solutions of the experimental group to-be-titrated sample and the blank group to-be-titrated sample; and calculating the acid value of the resin sample according to the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the experimental group and the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the blank group. The solvent used in the testing method has the advantages of economy, environmental protection, high safety and small environmental pollution.
Description
Technical Field
The invention relates to a detection technology in the field of chemical analysis, in particular to a method for testing the acid value of water-soluble resin.
Background
The water-soluble resin is a novel resin system using water as a dispersion medium instead of an organic solvent. The resin has the advantages of environmental protection, flame retardance, small film forming shrinkage, high hardness, good wear resistance and the like, is wide in application and high in added value, and is always the key point for the development of the chemical industry.
The acid number of the resin is the number of milligrams of potassium hydroxide consumed by neutralizing 1g of sample, to characterize the total amount of free acid in the sample. Functional group determination has become a conventional method in organic quantitative analysis, and many methods can be directly used for determination of a high molecular material, with the advantage of determining the content of a certain functional group in a mixture without previously separating and purifying a sample. The analysis method of the high polymer material is not only convenient, but also suitable for the rapid control of the production process.
The determination of the acid value of the water-soluble resin is significant for representing the structural performance of the resin according to the determined amount. Although corresponding testing methods exist in national standards, the testing operation is relatively complex, and various chemical reagents used in the testing process belong to dangerous chemicals, so that the dangerousness is high, and the harmfulness to the human body is also high.
Therefore, it is necessary to provide a method for measuring the acid value of a water-soluble resin to solve the above problems.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
The invention aims to provide a method for testing the acid value of a water-soluble resin, which has the advantage of little environmental pollution caused by reagents used for testing.
In order to achieve the above object, an embodiment of the present invention provides a method for measuring an acid value of a water-soluble resin, including the steps of:
respectively adding equal amounts of mixed solution of ethanol and water into the two conical flasks to respectively obtain an experimental group and a blank group;
weighing a resin sample, and adding the resin sample into an erlenmeyer flask of an experimental group;
after the resin sample is completely dissolved in the experimental group, adding phenolphthalein indicator into the experimental group and the blank group to obtain a sample to be titrated in the experimental group and a sample to be titrated in the blank group;
respectively carrying out titration reaction on the experimental group to-be-titrated sample and the blank group to-be-titrated sample by using a potassium hydroxide standard solution, and recording the consumption volumes of the potassium hydroxide standard solutions of the experimental group to-be-titrated sample and the blank group to-be-titrated sample; and
and calculating the acid value of the resin sample according to the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the experimental group and the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the blank group.
In one or more embodiments of the present invention, the volume of the mixed solution of ethanol and water in the experimental group and the blank group is 40 to 60 ml.
In one or more embodiments of the present invention, the specific step of weighing the resin sample comprises: weighing 2-3 g of resin sample by using a ten-thousandth precision electronic balance.
In one or more embodiments of the present invention, the dissolution process of the resin sample in the experimental group comprises: and (3) completely dissolving the resin samples in the experimental group by adopting a heating, stirring or ultrasonic mode.
In one or more embodiments of the present invention, the phenolphthalein indicator is added in an amount of 5 to 6 drops.
In one or more embodiments of the present invention, in the mixed solution of ethanol and water, the mass fraction of ethanol is 1% to 99%.
In one or more embodiments of the present invention, in the mixed solution of ethanol and water, the mass fraction of ethanol is 40% to 60%
In one or more embodiments of the present invention, the specific steps of the titration reaction include: and (3) dripping the potassium hydroxide standard solution into the to-be-titrated sample of the experimental group or the to-be-titrated sample of the blank group, and continuously shaking the conical flask until the liquid in the conical flask is pink, wherein the pink retention time is 20-30s, and the consumed volume of the consumed potassium hydroxide standard solution is recorded at the moment.
Compared with the prior art, the testing method provided by the embodiment of the invention uses the mixed solution of ethanol and water as the solvent for dissolving the resin sample, and has the advantages of economy, environmental protection, high safety and small environmental pollution compared with the solvent of the testing method in the national standard.
Drawings
FIG. 1 is a graph illustrating the effect of a resin sample after it has been completely dissolved in a conical flask, according to an embodiment of the present invention;
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
As shown in fig. 1 to 1, a method for measuring an acid value of a water-soluble resin according to a preferred embodiment of the present invention specifically includes the steps of:
step S1: the two erlenmeyer flasks were filled with the same amount of mixed solution of ethanol and water to obtain an experimental group and a blank group.
In step S1, the volume of the mixed solution of ethanol and water is 40 to 60mL, and the mass fraction of ethanol in the mixed solution of ethanol and water is 1 to 99%. When the mass fraction of the ethanol in the mixed solution is 40-60%, the acid value of the resin sample is measured more quickly and accurately.
It should be noted that, when the ethanol content is high, the dissolution rate of the sample is high, the color at the end point of titration is light, and after the color changes, the color disappears after shaking for a long time (no more than 20s), and the titration is continued and shaking is repeated for many times, so that the color is kept from fading for 20-30 s. When the water content is high, the dissolution rate of the sample is slow, the color of the titration end point is dark, after the color changes, the sample is slightly shaken, and after the color disappears, 1-2 drops of standard titration solution are dripped, so that the color can be kept stable and not faded. When the mass fraction of the ethanol is 40-60%, the sample dissolution rate is high, the color change at the titration end point is obvious, the color change appears, and the color can be stabilized to be fadeless within 20-30s only by 1-2 drops. Therefore, tests show that when the mass fraction of the ethanol is 40-60%, the sample dissolution rate is high, the color of the titration end point is dark, and the method has the advantages of narrow color-changing region, instantaneity and the like, and the result judgment is accurate.
Step S2: resin samples were weighed and added to the erlenmeyer flasks of the experimental group.
In step S2, a ten-thousandth precision electronic balance is used to weigh 2-3 g of resin sample. In the step S1, the volume of the mixed solution of ethanol and water is 40-60 mL, so that 2-3 g of the resin sample in the step 2 is selected and weighed, and the resin sample is conveniently and fully dissolved.
It should be noted that step S1 may be interchanged with step S2, wherein the resin sample in the erlenmeyer flask is the experimental group.
Step S3: and after the resin sample is completely dissolved in the experimental group, adding phenolphthalein indicator into the experimental group and the blank group to obtain a sample to be titrated in the experimental group and a sample to be titrated in the blank group.
In step S3, in order to accelerate the dissolution rate of the resin sample in the mixed solution of the experimental group, the resin sample in the experimental group can be completely dissolved by heating, stirring or ultrasound.
In step S3, the phenolphthalein indicator is added to the experimental group and the blank group in an amount of 5 to 6 drops per erlenmeyer flask, so as to ensure the accuracy of the titration process.
Step S4: and respectively carrying out titration reaction on the experimental group to-be-titrated sample and the blank group to-be-titrated sample by using a potassium hydroxide standard solution, and recording the consumption volumes of the potassium hydroxide standard solutions of the experimental group to-be-titrated sample and the blank group to-be-titrated sample.
In step S4, the solution in the erlenmeyer flasks of the experimental group to-be-titrated sample and the blank group to-be-titrated sample are titrated respectively with the potassium hydroxide standard solution with the alkaline burette with c being 0.1mol/L, and are shaken continuously until the solution is pink, and the solution is kept for (20-30) S. Recording the volume V of the potassium hydroxide standard solution consumed by the titration sample of the experimental group, wherein c is 0.1mol/L, and recording the volume V of the potassium hydroxide consumed by the blank group of the titration sample0。
Step S5: and calculating the acid value of the resin sample according to the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the experimental group and the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the blank group.
Wherein, according to the formula:
the acid value of the resin sample can be calculated.
Note: and m is the mass of the resin sample.
In the case of the example 1, the following examples are given,
40mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 1%. A2.0 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The flask containing the resin sample was placed in a water heater and heated to completely dissolve the resin sample and return it to room temperature (as shown in FIG. 1). And then respectively adding 4 drops of phenolphthalein indicator into the two conical flasks by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, respectively titrating the liquid in the two conical flasks, simultaneously shaking until the solution turns red, keeping the pink of the shaking solution for 20-30s, and recording the volume of the used potassium hydroxide standard solution. Wherein is composed ofThe volume of the standard solution of potassium hydroxide used in the flask with the resin sample was V, and the volume of the standard solution of potassium hydroxide used in the other flask was V0。
In the case of the example 2, the following examples are given,
50mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 20%. A2.3 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 5 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
In the case of the example 3, the following examples are given,
50mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 30%. A2.8 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 6 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is VIs a V0。
In the case of the example 4, the following examples are given,
50mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 40%. A2.5 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 5 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
In the case of the example 5, the following examples were conducted,
50mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 44%. A2.6 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 5 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
In the case of the example 6, it is shown,
50mL of ethanol and 50mL of ethanol are respectively taken by using a measuring cylinderThe mixed solution of water was poured into two 250mL Erlenmeyer flasks, wherein the mass fraction of ethanol in the mixed solution was 50%. A2.1 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 5 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
In the case of the example 7, the following examples are given,
50mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 60%. A2.9 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 6 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
In the case of the example 8, the following examples are given,
60mL of mixed solution of ethanol and water is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 99%. Reuse one ten thousandth of precision electricityOn a sub-balance, a 3.0g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out and poured into an Erlenmeyer flask. The flask containing the resin sample was stirred until the resin sample was completely dissolved. Adding 6 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
Comparative example 1
50mL of mixed solution of toluene and ethanol is respectively poured into two 250mL conical flasks by using a measuring cylinder, wherein the mass fraction of the ethanol in the mixed solution is 50%. A2.5 g sample of the resin (known as having an acid number of 35.00mg/g) was weighed out using a ten-thousandth precision electronic balance and poured into a conical flask. The conical bottle containing the resin sample is placed in an ultrasonic processor, and the resin sample is completely dissolved by adopting an ultrasonic method. Adding 6 drops of phenolphthalein indicator into the two conical flasks respectively by using a rubber head dropper, filling a potassium hydroxide standard solution with the concentration of c being 0.1mol/L by using an alkaline burette, titrating the liquid in the two conical flasks respectively, shaking simultaneously until the solution turns red, keeping the pink of the solution for 20-30s by shaking, and recording the volume of the used potassium hydroxide standard solution. Wherein the volume of the potassium hydroxide standard solution used in the conical flask containing the resin sample is V, and the volume of the potassium hydroxide standard solution used in the other conical flask is V0。
In the above examples and comparative examples, the resin samples used were polyester resins.
The following table shows the acid values of the measured values of the examples and comparative examples after being substituted into the formula:
from the data in the table above, it can be seen that the acid values calculated in examples 4 to 7 are closer to the acid value of the actual resin sample than those calculated in other examples and comparative examples, and therefore, in the testing method of the present invention, the mass fraction of ethanol is controlled between 40% and 60%, and the testing effect is better.
In the titration process using the potassium hydroxide standard solution in comparative example 1, the color change at the titration end point is not obvious, so that the finally calculated acid value has slight deviation from the acid value of an actual resin sample, and meanwhile, toluene is toxic and causes pollution to the environment, and is also a drug preparation easily.
Therefore, in summary, the test method of the present invention has the following beneficial effects:
1. the characteristic that the water-soluble resin is dissolved in water is skillfully utilized, and a mixed solution of ethanol and water is selected to dissolve a resin sample. The organic solvent part, pyridine and methyl ethyl ketone in the national standard method are replaced by ethanol and water, so that the method is economical, environment-friendly and high in safety.
2. According to the characteristics of colorless and transparent samples after dissolution, a colorimetric titration method is selected. The colorimetric method is selected instead of the potentiometric titration method, so that the test cost and the test difficulty are greatly reduced.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (8)
1. A method for testing an acid value of a water-soluble resin, comprising the steps of:
respectively adding equal amounts of mixed solution of ethanol and water into the two conical flasks to respectively obtain an experimental group and a blank group;
weighing a resin sample, and adding the resin sample into an erlenmeyer flask of an experimental group;
after the resin sample is completely dissolved in the experimental group, adding phenolphthalein indicator into the experimental group and the blank group to obtain a sample to be titrated in the experimental group and a sample to be titrated in the blank group;
respectively carrying out titration reaction on the experimental group to-be-titrated sample and the blank group to-be-titrated sample by using a potassium hydroxide standard solution, and recording the consumption volumes of the potassium hydroxide standard solutions of the experimental group to-be-titrated sample and the blank group to-be-titrated sample; and
and calculating the acid value of the resin sample according to the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the experimental group and the consumption volume of the potassium hydroxide standard solution of the sample to be titrated in the blank group.
2. The method for measuring the acid value of a water-soluble resin according to claim 1, wherein the volume of the mixed solution of ethanol and water in the experimental group and the blank group is 40 to 60 ml.
3. The method for measuring the acid value of a water-soluble resin according to claim 1, wherein the step of weighing the resin sample comprises: weighing 2-3 g of resin sample by using a ten-thousandth precision electronic balance.
4. The method for measuring the acid value of a water-soluble resin according to claim 1, wherein the dissolution process of the resin sample in the experimental group comprises: and (3) completely dissolving the resin samples in the experimental group by adopting a heating, stirring or ultrasonic mode.
5. The method for testing the acid value of the water-soluble resin according to claim 1, wherein the phenolphthalein indicator is added in an amount of 5 to 6 drops.
6. The method for measuring the acid value of a water-soluble resin according to claim 1, wherein the mass fraction of ethanol in the mixed solution of ethanol and water is 1% to 99%.
7. The method for measuring the acid value of a water-soluble resin according to claim 6, wherein the mass fraction of ethanol in the mixed solution of ethanol and water is 40% to 60%.
8. The method for measuring the acid value of a water-soluble resin according to claim 1, wherein the specific step of the titration reaction comprises: and (3) dripping the potassium hydroxide standard solution into the to-be-titrated sample of the experimental group or the to-be-titrated sample of the blank group, and continuously shaking the conical flask until the liquid in the conical flask is pink, wherein the pink retention time is 20-30s, and the consumed volume of the consumed potassium hydroxide standard solution is recorded at the moment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110853972.5A CN113607877A (en) | 2021-07-27 | 2021-07-27 | Method for testing acid value of water-soluble resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110853972.5A CN113607877A (en) | 2021-07-27 | 2021-07-27 | Method for testing acid value of water-soluble resin |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113607877A true CN113607877A (en) | 2021-11-05 |
Family
ID=78305674
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110853972.5A Pending CN113607877A (en) | 2021-07-27 | 2021-07-27 | Method for testing acid value of water-soluble resin |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113607877A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102432831A (en) * | 2011-08-30 | 2012-05-02 | 华南理工大学 | Single-component aqueous epoxy resin emulsion capable of being self-cured at normal temperature, and preparation method thereof |
| CN102495059A (en) * | 2011-12-09 | 2012-06-13 | 重庆国际复合材料有限公司 | Method for measuring acid value of unsaturated polyester resin |
| CN106324185A (en) * | 2016-08-26 | 2017-01-11 | 巨石集团有限公司 | Measuring method for acid value of unsaturated polyester resin emulsion |
| CN106383200A (en) * | 2016-08-30 | 2017-02-08 | 北京慧农生物科技有限公司 | Method for determination of fatty acid value of corn |
| CN107389669A (en) * | 2017-06-22 | 2017-11-24 | 湖北富邦科技股份有限公司 | A kind of dark oil anti-caking agent acid number content assaying method |
| WO2018079592A1 (en) * | 2016-10-27 | 2018-05-03 | リンテック株式会社 | Hydrophilic resin composition and laminated sheet |
| CN108107152A (en) * | 2017-12-29 | 2018-06-01 | 新津邦得科技有限公司 | A kind of method for measuring corn fatty acid value |
| CN108508010A (en) * | 2018-03-08 | 2018-09-07 | 江苏权正检验检测有限公司 | A kind of assay method of vegetable fat powder acid value |
-
2021
- 2021-07-27 CN CN202110853972.5A patent/CN113607877A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102432831A (en) * | 2011-08-30 | 2012-05-02 | 华南理工大学 | Single-component aqueous epoxy resin emulsion capable of being self-cured at normal temperature, and preparation method thereof |
| CN102495059A (en) * | 2011-12-09 | 2012-06-13 | 重庆国际复合材料有限公司 | Method for measuring acid value of unsaturated polyester resin |
| CN106324185A (en) * | 2016-08-26 | 2017-01-11 | 巨石集团有限公司 | Measuring method for acid value of unsaturated polyester resin emulsion |
| CN106383200A (en) * | 2016-08-30 | 2017-02-08 | 北京慧农生物科技有限公司 | Method for determination of fatty acid value of corn |
| WO2018079592A1 (en) * | 2016-10-27 | 2018-05-03 | リンテック株式会社 | Hydrophilic resin composition and laminated sheet |
| CN107389669A (en) * | 2017-06-22 | 2017-11-24 | 湖北富邦科技股份有限公司 | A kind of dark oil anti-caking agent acid number content assaying method |
| CN108107152A (en) * | 2017-12-29 | 2018-06-01 | 新津邦得科技有限公司 | A kind of method for measuring corn fatty acid value |
| CN108508010A (en) * | 2018-03-08 | 2018-09-07 | 江苏权正检验检测有限公司 | A kind of assay method of vegetable fat powder acid value |
Non-Patent Citations (1)
| Title |
|---|
| 中华人民共和国卫生部药典委员会: "《中华人民共和国药典 1995年版 二部》", 30 September 1995, 化学工业出版社 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sadullayeva et al. | Amperometric method of analysis and its advantages over other methods | |
| US9091674B2 (en) | Means and method for determining chemical oxygen demand | |
| Helm et al. | Micro-Winkler titration method for dissolved oxygen concentration measurement | |
| CN108152444A (en) | Method for detecting content of free nitric acid in bismuth nitrate solution | |
| CN106324185B (en) | A kind of assay method of Emulsion of UPR acid value | |
| Cunningham et al. | Sodium-selective membrane electrode based on p-tert-butylcalix [4] arene methoxyethylester | |
| WO2011007384A1 (en) | Sensitive membrane for ion selective electrode | |
| CN113607877A (en) | Method for testing acid value of water-soluble resin | |
| Zolotov et al. | Test methods for extra-laboratory analysis | |
| González et al. | A practical way to ISO. GUM measurement uncertainty for analytical assays including in-house validation data | |
| JP3623777B2 (en) | Quantitative determination method of environmental pollutants and quantitative kit used therefor | |
| JPS60194360A (en) | Ion test means having porous carrier matrix and manufacture thereof | |
| Capitán-Vallvey et al. | Irreversible optical test strip for mercury determination based on neutral ionophore | |
| Guinovart et al. | Sulphate-selective optical microsensors: overcoming the hydration energy penalty | |
| KA et al. | pH Indicators: A valuable gift for analytical chemistry | |
| Orriach-Fernández et al. | Hg 2+-selective sensing film based on the incorporation of a rhodamine 6G derivative into a novel hydrophilic water-insoluble copolymer | |
| CN113846142A (en) | Strong alkaline biochemical reagent, preparation method and application | |
| Rojanarata et al. | Microscale chemistry-based design of eco-friendly, reagent-saving and efficient pharmaceutical analysis: A miniaturized Volhard's titration for the assay of sodium chloride | |
| Mtewa et al. | Titrimetry | |
| Matharu et al. | A novel method for the determination of individual lanthanides using an inexpensive conductometric technique | |
| Isildak et al. | All-Solid-State PVC Membrane Fe (III) Selective Electrode based on 2-Hydroxymethyl-15-crown-5 | |
| Akash et al. | Introduction to pharmaceutical analysis | |
| CN110095564A (en) | A method of with titratable amine total in potentiometric determination 2-Propen-1-amine polymer with(chloromethyl)oxirane carbonate | |
| Kejla et al. | Gravimetric titrations in a modern analytical laboratory: evaluation of performance and practicality in everyday use | |
| Ruch et al. | Macro-and Semimicrodetermination of Aldehydes and Ketones by Reaction with Hydroxylammonium Formate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20211105 |