A method for determining the rate of desorption of free radicals from latex particles into the continuous phase in emulsion polymerization

A technology of emulsion polymerization and free radicals, applied in the field of emulsion polymerization, can solve problems such as limited promotion, doubtful applicability of macroscopic mass transfer theory, and extremely complicated modeling work

Active Publication Date: 2015-12-02
ZHEJIANG UNIV
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Problems solved by technology

Although this method is widely used, its accuracy directly depends on the reliability of the relevant theoretical model. At present, there is still a lot of debate on the theoretical model of aggregation, and there are still problems with the authenticity of the measurement results; on the other hand, the method’s The modeling work is extremely complicated, requires high theoretical literacy and research skills, and is difficult to implement; finally, this method is highly dependent on the accuracy of the aggregation implementation results. less reliable
[0004] The theoretical estimation method starts from a theoretical point of view and uses various mass transfer theories to measure the rate of free radicals desorbing from latex particles into the continuous phase. However, since the process of free radicals desorbing from latex particles into the continuous phase is a single molecular process, the macroscopic The applicability of mass transfer theory is still questionable; on the other hand, the parameters required in this method are very difficult to obtain, which limits the generalization of this method

Method used

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  • A method for determining the rate of desorption of free radicals from latex particles into the continuous phase in emulsion polymerization
  • A method for determining the rate of desorption of free radicals from latex particles into the continuous phase in emulsion polymerization
  • A method for determining the rate of desorption of free radicals from latex particles into the continuous phase in emulsion polymerization

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0086] Mix 850g of water, 30g of methanol, 20g of formamide, 96g of butyl acrylate, 1g of cetyltrimethylammonium bromide, 1g of n-hexadecene, 1g of potassium hydrogen phthalate and 1g of benzoyl peroxide, The emulsion is formed by mechanical stirring, and the emulsion is put into a calorimetric reactor, and nitrogen gas is introduced to exclude oxygen, and then the temperature is raised to start the reaction. The reaction temperature was 90°C, and the polymerization rate was monitored after the polymerization started. When the reaction was carried out for 20 minutes, 1 mL of 1.1 wt % potassium nitrosodisulfate aqueous solution was added to the system. The duration of the polymerization rate decline stage was determined to be 160s, and P was optimized according to formulas 1-3. d =0.87, and then calculated according to formula 4 to obtain the apparent rate R of primary free radical desorption from latex particles into the continuous phase da =7.03×10 -6 mol / (L s), the absolu...

Embodiment 2

[0088] 350g of water, 50g of α-methylstyrene, 199g of sodium lauryl sulfate, 1g of silica with an average size of 1nm, 230g of n-pentanol, 50g of suberic acid, 9g of n-octadecane, and 8g of n-hexadecanol , 1g of 8-hexadecane, 2g of borax, 50g of hydroxybutyl azobisisobutyrate (initiator 1) and 50g of methyl azobisisobutyrate (initiator 2) were mixed and stirred mechanically to form an emulsion. The emulsion was put into a 2000mL glass jacketed reactor, nitrogen gas was introduced to remove oxygen, and then the temperature was raised to start the reaction. The reaction temperature was 25°C. After the polymerization started, the polymerization rate and polymer molecular weight were monitored by gravimetric method and viscosity method, respectively. When the reaction was carried out for 10 minutes, 50 mL of a 30 wt % aqueous solution of sodium nitrosodisulfate was added to the system. The measured duration of the polymerization rate decline phase and the duration of the polymer ...

Embodiment 3

[0090] Mix 980g of water, 10g of ethanol, 9.98g of stearyl methacrylate, 0.01g of Tween 80 and 0.01g of azobisisobutyronitrile, disperse and form an emulsion through an ultrasonic cell pulverizer while mechanically stirring, and put the emulsion into 2000mL glass-jacketed reaction kettle, nitrogen-argon mixed gas is introduced to exclude oxygen, and then the temperature is raised to start the reaction. The reaction temperature was 60°C, and the polymerization rate was monitored by gas chromatography after the polymerization started. At the beginning of the reaction, 1mL of 0.1wt% ammonium nitrosodisulfate solution was added to the system. The duration of the polymerization rate decline stage was measured to be 3120s, and P d =0.91, and then calculated according to formula 4 to obtain the apparent rate R of primary free radical desorption from latex particles into the continuous phase da =7.03×10 -9 mol / (L s), the absolute rate R of primary free radicals desorbing from latex...

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Abstract

The invention discloses a method for measuring the continuous phase entering rate of free radicals desorbed from latex particles in emulsion polymerization. The method comprises the following steps: at the initial reaction stage or the monomer conversion rate rising stage of an emulsion polymerization system, adding water-soluble nitrosyl disulfate; monitoring the polymerization rate or polymer molecular weight, determining time deltat needed by full consumption of water-soluble nitrosyl disulfate; calculating to obtain the continuous phase entering apparent rate Rda and absolute rate Rd of free radicals desorbed from latex particles. The method for directly measuring the continuous phase entering rate of free radicals desorbed from latex particles is easy to operate, low in cost, accurate in test result, wide in application range and high in sensitivity.

Description

technical field [0001] The invention relates to the field of emulsion polymerization, in particular to a method for measuring the rate at which free radicals desorb from latex particles into continuous phases in emulsion polymerization. Background technique [0002] In emulsion polymerization, the desorption of free radicals from latex particles is an important factor that determines the polymerization rate and the morphology of latex particles. However, due to the high reactivity and short life of free radicals, it is very difficult to capture their traces. At present, the methods for determining the desorption of free radicals from latex particles in domestic and foreign reports mainly include indirect measurement and theoretical estimation. [0003] The indirect measurement method is a kind of polymerization theoretical model based on the basic principle of emulsion polymerization, which first establishes the polymerization rate, the average number of free radicals in lat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N33/00C08F120/18C08F112/12C08F212/08C08F230/08C08F220/14C08F2/28C08F2/26
Inventor 单国荣尚玥潘鹏举
Owner ZHEJIANG UNIV
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