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Determination of the crosslinking agent for epoxy coatings
2017-7-13 19:23:12
Determination of the crosslinking agent for epoxy coatings
In this paper, the preparation of standard solution of perchloric acid non - water titration method was introduced, and the determination of epoxy crosslinking agent was determined to improve the accuracy and scientificity of the determination of amine value.
The crosslinking reaction of epoxy resin is achieved by adding crosslinking agent. Crosslinking agent is mostly directly take part in the reaction and combination in the paint film structure, when using polyamide resin as the crosslinking agent, its molecular structure contains active amino, can be at room temperature with the epoxy groups of epoxy resin reaction, crosslinking network structure.
To determine the ratio of polyamide resin to epoxy resin, the amine value must be considered. The content of amino content in polyamide resin is often expressed as an amine value, which is the acid required to neutralize each l g sample, which is expressed in terms of the number of potassium hydroxide (mgKOH/g). Previous determination of amine value using c (HCl) = 0.1 mol/L (0.1 N) hydrochloric acid - ethanol droplet, this method is only applicable to fatty amine, low amine value when used to determination of polyamide resin, the finish is not obvious.
At present abroad mainly using perchloric acid nonaqueous titration method (non aqueous titration), based on the analysis of the method through a large number of experimental comparison, the test results show that it has accurate, convenient, fast and other characteristics, the following brief introduction with perchloric acid nonaqueous titration in the determination process.
Laboratory instruments and reagents. Oven, analytical balance (one in 10,000), measuring cylinder (100 mL, 10 mL), conical bottle (250 mL), acid burette and dryer. 70% perchloric acid (analytical pure), glacial acetic acid (analytical pure), pure benzene (analysis of pure), acetic anhydride (analysis of pure), phthalic acid potassium (reference), methyl violet (indicator).
Chinese name: Diethyl toluene diamine(DETDA)
In this paper, the preparation of standard solution of perchloric acid non - water titration method was introduced, and the determination of epoxy crosslinking agent was determined to improve the accuracy and scientificity of the determination of amine value.
The crosslinking reaction of epoxy resin is achieved by adding crosslinking agent. Crosslinking agent is mostly directly take part in the reaction and combination in the paint film structure, when using polyamide resin as the crosslinking agent, its molecular structure contains active amino, can be at room temperature with the epoxy groups of epoxy resin reaction, crosslinking network structure.
To determine the ratio of polyamide resin to epoxy resin, the amine value must be considered. The content of amino content in polyamide resin is often expressed as an amine value, which is the acid required to neutralize each l g sample, which is expressed in terms of the number of potassium hydroxide (mgKOH/g). Previous determination of amine value using c (HCl) = 0.1 mol/L (0.1 N) hydrochloric acid - ethanol droplet, this method is only applicable to fatty amine, low amine value when used to determination of polyamide resin, the finish is not obvious.
At present abroad mainly using perchloric acid nonaqueous titration method (non aqueous titration), based on the analysis of the method through a large number of experimental comparison, the test results show that it has accurate, convenient, fast and other characteristics, the following brief introduction with perchloric acid nonaqueous titration in the determination process.
Laboratory instruments and reagents. Oven, analytical balance (one in 10,000), measuring cylinder (100 mL, 10 mL), conical bottle (250 mL), acid burette and dryer. 70% perchloric acid (analytical pure), glacial acetic acid (analytical pure), pure benzene (analysis of pure), acetic anhydride (analysis of pure), phthalic acid potassium (reference), methyl violet (indicator).
Chinese name: Diethyl toluene diamine(DETDA)Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).
Make the solution. Indicator: 0.1% methyl violet glacial acetic acid solution. Solvent: ice acetic acid: pure benzene = 2:1.3 l standard solution preparation, measuring 4.3 mL, 70% perchlorate solution dissolved in 500 mL analysis pure ice acetic acid, and then take the analysis of pure acetic anhydride 7.5 mL, fractional join, shake to mix evenly and place for the night, with perchloric acid contained in water reaction, into acetic acid, as [c (HCl04) = 0.1 mol/l (0.1 N)] perchloric acid standard solution.
According to take 0.2 ~ 0.3 g f in the 105 ~ llO ℃ drying to constant quality benchmark of potassium hydrogen phthalate, accurate to 0.0001 g, put in dry conical flask, add 50 mL ice acetic acid, tepid dissolved, add 3 ~ 4 drops of methyl violet indicator, with good perchloric acid standard solution that has made [c (HCl04) = 0.1 mol/L] titration to solution from purple to a pure blue, is the end.
C (HCl04) = m/(V * 0.2042)
In the formula: c (HCl04) -- concentration of high chloric acid standard solution, mol/L; M -- the mass of potassium hydrogen phthalate, g; V -- the volume of high chloric acid standard solution consumed, mL; 0.2042 - the quality of potassium hydrogen phthalate, which is equivalent to 1.00 mL high chloric acid standard solution [c (HCl04) = 0.1 mol/L].
Note: this solution is calibrated before use. The temperature of the standard solution of high chloric acid should be the same as that of the standard solution when titration is used.
The method of determination of epoxy crosslinking agent amine value. Accurate to call the proper amount of sample (polyamide resin), put in 250 mL conical flask, joining about 25 mL ice acetic acid and pure benzene solvent, after shaking until completely dissolved, (such as it is not easy to dissolve sample, a little heat and let it cool to room temperature), to join the methyl violet indicator 3 ~ 4, with [c (HCl04) = 0.1 mol/L] perchloric acid standard solution titration to solution by purple into pure blue, is the end.
Determination of epoxy crosslinking agent amine value calculation: AN (mgKOH/g) = (cV x 56.1)/m
C - the concentration of a standard solution of perchloric acid, mol/L; V - the volume of perchloric acid standard solution volume, mL: M - the mass of the sample, g; 56.1 - quality of potassium hydroxide per mole.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Make the solution. Indicator: 0.1% methyl violet glacial acetic acid solution. Solvent: ice acetic acid: pure benzene = 2:1.3 l standard solution preparation, measuring 4.3 mL, 70% perchlorate solution dissolved in 500 mL analysis pure ice acetic acid, and then take the analysis of pure acetic anhydride 7.5 mL, fractional join, shake to mix evenly and place for the night, with perchloric acid contained in water reaction, into acetic acid, as [c (HCl04) = 0.1 mol/l (0.1 N)] perchloric acid standard solution.
According to take 0.2 ~ 0.3 g f in the 105 ~ llO ℃ drying to constant quality benchmark of potassium hydrogen phthalate, accurate to 0.0001 g, put in dry conical flask, add 50 mL ice acetic acid, tepid dissolved, add 3 ~ 4 drops of methyl violet indicator, with good perchloric acid standard solution that has made [c (HCl04) = 0.1 mol/L] titration to solution from purple to a pure blue, is the end.
C (HCl04) = m/(V * 0.2042)
In the formula: c (HCl04) -- concentration of high chloric acid standard solution, mol/L; M -- the mass of potassium hydrogen phthalate, g; V -- the volume of high chloric acid standard solution consumed, mL; 0.2042 - the quality of potassium hydrogen phthalate, which is equivalent to 1.00 mL high chloric acid standard solution [c (HCl04) = 0.1 mol/L].
Note: this solution is calibrated before use. The temperature of the standard solution of high chloric acid should be the same as that of the standard solution when titration is used.
The method of determination of epoxy crosslinking agent amine value. Accurate to call the proper amount of sample (polyamide resin), put in 250 mL conical flask, joining about 25 mL ice acetic acid and pure benzene solvent, after shaking until completely dissolved, (such as it is not easy to dissolve sample, a little heat and let it cool to room temperature), to join the methyl violet indicator 3 ~ 4, with [c (HCl04) = 0.1 mol/L] perchloric acid standard solution titration to solution by purple into pure blue, is the end.
Determination of epoxy crosslinking agent amine value calculation: AN (mgKOH/g) = (cV x 56.1)/m
C - the concentration of a standard solution of perchloric acid, mol/L; V - the volume of perchloric acid standard solution volume, mL: M - the mass of the sample, g; 56.1 - quality of potassium hydroxide per mole.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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