GPC test method of pa10t, the hottest and most hea

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GPC test method of high temperature resistant polyamide pa10t

gel permeation chromatography (GPC) is one of the effective and commonly used methods to test the molecular weight and molecular weight distribution * of high molecular materials. In order to obtain accurate test results, the test sample must have good solubility in GPC mobile phase solvent. PA is one of the engineering plastics used in large quantities. However, due to intermolecular hydrogen bonding, the solvents that can dissolve PA are very limited. At room temperature, GPC commonly used mobile phase solvents, such as tetrahydrofuran (THF) and dichloromethane (CH2Cl2), cannot dissolve PA. However, previous research reports have some problems, such as high requirements for GPC equipment, strong toxicity of mobile phase solvents, and expensive chromatographic columns. Huttenberg et al. Proposed that PA can be N-acylated to solve the problem of solvent resistance of PA. This method is widely used in GPC testing of various aliphatic PA and its copolymer systems

Jinfa Technology Co., Ltd. took pa10t as a sample and studied the GPC test method of pa10t, which is generally suitable for all kinds of semi aromatic high temperature resistant PA

main raw materials

1, 10 - decanediamine: purity 99.5%, Wuxi Yinda nylon Co., Ltd

terephthalic acid: purity is 99.99%, British Petroleum Chemical Company

sodium hypophosphite, ether: analytically pure, Guangzhou Chemical Reagent Factory

dichloromethane: analytically pure, anhydrous treatment, Guangzhou Chemical Reagent Factory

hexafluoroisopropanol (HFIP): analytical pure, Shanghai Aladdin Biochemical Technology Co., Ltd

deuterated chloroform (CDCl3): analytically pure, sigma Aldrich company of the United States

thf: chromatographically pure, Beijing Merida Technology Co., Ltd.

pa10t polymerization reaction

at 20? L stainless steel reactor, add 2? 960? G terephthalic acid, 3? 200? G1, size of upper and lower pressing plates (mm): Φ 160 (alternative 204*204) 10 – decanediamine, 6.2? G catalyst sodium hypophosphite and 2? 550? G deionized water. After vacuumizing and filling nitrogen for replacement for three times, start heating up. When the material temperature reaches 1, the system will exit the detection state after confirmation. When 80 ℃, start mixing, 3? After h, the material temperature rises to 220 ℃. Stay at this temperature for 40? Minutes later, start draining. During the drainage process, the temperature of the material is controlled to be maintained at 220 ℃ by adjusting the temperature of the heat transfer oil. The total drainage is 1? 650? g。 Close the drain valve after drainage, and keep it constant for 25? Stirring rate of r/min 8? After h, open the bottom valve and spray the material into the stainless steel tank through the reaction pressure to obtain the reaction product

pa10t n-acylation reaction

will be 3? G pa10t at 250? Ml reaction bottle, replace the air in the reaction bottle with nitrogen, and use a syringe to write the durability according to the L screen: more than 100000 words (width r0.8mm, pressure 250g) times add 50? Ml of anhydrous dichloromethane

, stir 0.5? h。 Then add 10? Mltfaa, room temperature reaction 24? h。 The reaction product was evaporated and dried at 40 ℃. After removing the unreacted tfaa and solvent, 20? Dissolve in ml of anhydrous methylene chloride. Then add the solution drops into anhydrous ether to disperse and filter to obtain pure white solid powder. Dry in 50 ℃ vacuum oven for 5? After h, a dry and pure N-acylated pa10t sample was obtained, which was recorded as pa10t-tfaa

method accuracy and application range

(1) the n-acylation product of pa10t was characterized by FTIR, TG and 1H-NMR, which confirmed that the reaction was successful. By studying the influence of tfaa dosage and reaction time on the degree of n-acylation reaction, it was found that the ratio of tfaa to pa10t was 2.0 and the reaction time was 24? Under the condition of H, pa10t-tfaa with grafting rate can be obtained stably, and the limit grafting rate of the reaction is about 75%

(2) because the hydrodynamic volume of pa10t-tfaa is larger than that of PS standard, the molecular weight of GPC test with PS standard as calibration curve is much higher than the real molecular weight of the sample. A series of samples with different relative viscosities were used to calibrate the wide distribution of GPC. The error between the corrected molecular weight and the real molecular weight of the sample is less than 4%, and the accuracy is good

(3) combining the molecular weight and intrinsic viscosity of pa10t, the mark Houwink equation of pa10t was fitted. The molecular weight range of this equation covers all commercialized pa10t products, which has important guiding significance for production practice

quotation format: Yan Kun, Fu Wei, Xie Mingchen, etc. GPC test method for high temperature resistant polyamide pa10t [j] Engineering plastics applications, 2019, 47 (1): 108 – 114120

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