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Method for determining azodiisobutyronitrile free radical initiation efficiency

A technology of azobisisobutyronitrile and initiation efficiency, which is applied in the direction of chemical reaction of materials and material analysis by observing the influence of chemical indicators. It can solve problems such as detection of adverse effects and meet equipment requirements. Low, easy-to-use effects

Active Publication Date: 2020-05-08
WUHAN WUYAO SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the commonly used method for detecting the free radical initiation efficiency of azobisisobutyronitrile is the expansion agent method (specific volume), but this method is easily affected by the nitrogen gas generated by the decomposition of azobisisobutyronitrile, which has an adverse effect on the detection.

Method used

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  • Method for determining azodiisobutyronitrile free radical initiation efficiency
  • Method for determining azodiisobutyronitrile free radical initiation efficiency
  • Method for determining azodiisobutyronitrile free radical initiation efficiency

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] Liquid C: VA;

[0059] Solution A: Dissolve 0.50177g AIBN with VA and dilute to 50ml, shake well.

[0060] Liquid B: Dissolve 9.16mg DPPH with VA and dilute to 25ml, shake well.

[0061] Take 5ml of each of the above A solution and add them to 5 10ml measuring flasks, then take 1, 1.5, 2, 2.5, 3ml of B solution and add them to the above 5 measuring flasks, add C solution to dilute to the mark, and shake well. Transfer the above reactants into a 20ml headspace bottle, seal it, put it in a 65±0.5°C constant temperature water bath, and start timing. When the color of the reactant changes from purple to yellow, it is determined that the induction period is over, and the time t is recorded. The results of the induction period t corresponding to different concentrations of DPPH are shown in Table 1. Taking the DPPH concentration and the induction period t as a linear equation, figure 1 As shown, the slope is R i .

[0062] Table 1 Results of 65±0.5℃ constant temperature water bath ...

Embodiment 2

[0069] Liquid C: VA;

[0070] Solution A: Dissolve 0.50402g AIBN with VA and dilute to 50ml, shake well.

[0071] Liquid B: Dissolve 8.86mg DPPH with VA and dilute to 25ml, shake well.

[0072] Take the above A, B, and C liquids into 4 10ml round-bottomed flasks according to Table 2 respectively, put them into a magnetic stirrer (rotating speed of 200 rpm), connect the glass tee, vacuum, and replace with nitrogen three times. Nitrogen ball protection. Put the device into 69.5±0.5℃, 65±0.5℃, 60.5±0.5℃ and 50±0.5℃ constant temperature water bath, and start timing. When the color of the reactant changes from purple to yellow, it is determined that the induction period is over, and the time t is recorded. The results of the induction period t corresponding to different concentrations of DPPH are shown in Tables 3 to 6. The linear equations of the DPPH concentration and the induction period t are as follows: Figure 2-5 As shown, the slope is R i .

[0073] Table 2 Mixing ratio

[0074] ...

Embodiment 3

[0102] Liquid C: VA;

[0103] Solution A: Dissolve 0.50142g AIBN with VA and dilute to 50ml, shake well.

[0104] Liquid B: Dissolve 8.55mg DPPH with VA and dilute to 25ml, shake well.

[0105] Take the above-mentioned A, B, and C liquids into 4 10ml round-bottomed flasks respectively in Table 7 below, put in a magnetic stirrer (rotational speed of 200 rpm), and connect the condenser. Put the devices into a 65±0.5°C constant temperature water bath and start timing. When the color of the reactant changes from purple to yellow, it is determined that the induction period is over, and the time t is recorded. The results of the induction period t corresponding to different concentrations of DPPH are shown in Table 8. The linear equation of the DPPH concentration and the induction period t is as follows: Image 6 As shown, the slope is R i .

[0106] Table 7 Mixing ratio

[0107] Round bottom flask number Liquid A Liquid B Liquid C 1514 251.53.5 3523 452.52.5

[0108] Table 8 Results ...

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Abstract

The invention relates to a method for determining azodiisobutyronitrile free radical initiation efficiency, and belongs to the technical field of analytical test methods. The method comprises the following steps of: mixing azobisisobutyronitrile, 2, 2-diphenyl-1-bitter hydrazide and vinyl acetate to carry out polymerization reaction, judging that an induction period is ended when the color of thepolymerization reactants is changed from purple to yellow, determining the polymerization induction periods of free radical trapping agents with different concentrations, drawing a linear regression equation according to the polymerization induction periods and the concentrations of the free radical trapping agents, and marking a straight slope of a linear regression equation as Ri. Specifically,the azodiisobutyronitrile free radical initiation efficiency f is equal to Ri / (2kd[I]), Ri is an initiation rate, kd is a decomposition rate constant of azodiisobutyronitrile, and [I] is the concentration of azodiisobutyronitrile. The determination method has the advantages of high sensitivity and high detection efficiency, and can accurately determine the azodiisobutyronitrile free radical initiation efficiency.

Description

Technical field [0001] The invention belongs to the technical field of analytical testing methods, and particularly relates to a method for determining the initiation efficiency of azobisisobutyronitrile free radicals. Background technique [0002] Azobisisobutyronitrile (AIBN) is the most commonly used azo initiator, and its thermal decomposition reaction formula is as follows: [0003] [0004] AIBN is mostly used at 45-80°C. The decomposition reaction is characterized by a first-order reaction. There is no induced decomposition, only one kind of free radical is generated, which is relatively easy to control, so it is mostly used for polymerization kinetics research. Another advantage is that it is relatively stable and safe to store, but it will decompose violently at 80-90°C. Azo initiators have stable reaction and are widely used in the research and production of polymers. For example, they are used as initiators for the polymerization of chlorine monomers, and can also be us...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78
CPCG01N21/78
Inventor 沈婕乔春莲易钊郭亚兵杨波
Owner WUHAN WUYAO SCI & TECH