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Method for rapidly determining molecular weight and hydroxyl value of polymer polyol

A rapid determination and polymer technology, applied in the direction of nuclear magnetic resonance analysis, etc., to achieve the effects of stable detection conditions and data, low instrument cost, and fast detection speed

Pending Publication Date: 2020-10-16
ZHENGZHOU ZHONGYUAN SPANDEX ENG TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is no report on molecular weight determination of polymer polyols using low-field NMR

Method used

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  • Method for rapidly determining molecular weight and hydroxyl value of polymer polyol
  • Method for rapidly determining molecular weight and hydroxyl value of polymer polyol
  • Method for rapidly determining molecular weight and hydroxyl value of polymer polyol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Utilize low-field nuclear magnetic resonance technology to quickly measure the method of polyester polymer polyol molecular weight / hydroxyl value:

[0038] Detection of molecular weight / hydroxyl value by low-field NMR method: turn on the low-field NMR detector and thermostat to preheat 2 hours in advance, and calibrate to stability. Then prepare the sample, take about 3g of the sample to be tested in the detection tube, put it in a 40°C thermostat for 30min, then measure its peak relaxation time in a low-field nuclear magnetic detector, and record the measured value, and then use the relational formula (2) Calculate the molecular weight of the sample, and further calculate its hydroxyl value.

[0039] Wherein, the working curve and relational expression of relaxation time and molecular weight are made according to the following steps:

[0040] Get a group of polyester polymer polyols containing N samples, measure its hydroxyl value (molecular weight) by acylation metho...

Embodiment 2

[0051] A method for quickly determining the molecular weight / hydroxyl value of polyether polymer polyols using low-field nuclear magnetic resonance technology:

[0052] Hydroxyl value detection by low-field NMR method: turn on the low-field NMR detector and thermostat to preheat 2 hours in advance, and calibrate until stable. Then prepare the sample, take about 3g of the sample to be tested in the detection tube, put it in a 40°C thermostat for 30min, then measure its peak relaxation time in a low-field nuclear magnetic detector, and record the measured value, and then use the relational formula (3) Calculate the molecular weight of the sample, and further calculate its hydroxyl value.

[0053] Wherein, the working curve and relational expression of relaxation time and molecular weight are made according to the following steps:

[0054] Take a group of polyether polymer polyols containing N samples, measure their hydroxyl value (molecular weight) by acylation method, and perf...

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Abstract

The invention provides a method for rapidly determining the molecular weight and the hydroxyl value of polymer polyol. The hydroxyl value / molecular weight of the polymer polyol is one of important indexes. The method provided by the invention utilizes a low-field nuclear magnetic resonance technology to detect the relaxation time of the polymer polyol. The relaxation time of a sample with a knownmolecular weight / hydroxyl value is compared, so the molecular weight / hydroxyl value of the sample and the relaxation time are obtained, and the corresponding relaxation time and the molecular weight / hydroxyl value of the polymer polyol are in a linear relationship within a certain range, so that the molecular weight of the polymer polyol can be determined according to the relaxation time, and thehydroxyl value of the polymer polyol can be calculated. Compared with a traditional acylation method for detecting the hydroxyl value, the method for detecting the molecular weight / hydroxyl value of the polymer polyol has the advantages that the relative deviation is within 1%, the detection result is accurate, the detection speed is high; a sample is not subjected to chemical treatment, chemicalreagents such as pyridine and imidazole are not used, and the method is more environmentally friendly and healthier.

Description

technical field [0001] The invention relates to the detection technology of polymer polyol molecular weight and hydroxyl value, in particular to an application method for detecting the relaxation time of polymer polyol by using low-field nuclear magnetic technology, and then detecting its molecular weight and hydroxyl value. Background technique [0002] The hydroxyl value (molecular weight) of polymer polyol is an important index in the process of polyurethane synthesis and application. At present, the main detection methods are acylation method and near-infrared spectroscopy to determine the hydroxyl value of polymer polyols. [0003] The main principle of the acylation method is: the hydroxyl group of the sample is acylated with the acylating agent (acetic anhydride or phthalic anhydride) of the pyridine solution (imidazole can be used as a catalyst). The excess acid anhydride is hydrolyzed with water, and the generated acetic acid (or phthalic acid) is titrated with pot...

Claims

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Application Information

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IPC IPC(8): G01N24/08
CPCG01N24/08
Inventor 李锐李元伟张运启王俊霞白富强贺昊阳闫倡霖周桦任志勇
Owner ZHENGZHOU ZHONGYUAN SPANDEX ENG TECH