Determination of bromine content in flame retardant of bromine

Determination of bromine content in flame retardant of bromine

The main factors that influence the full combustion of bromine flame retardant and the fully absorbed components of the flame retardant are studied in the process of oxygen flask combustion. The influence of the determination of potential titration, titration operation, electrode performance and other factors on the accuracy of bromine content determination of bromine flame retardants is discussed. The corresponding solutions are put forward for different influencing factors, and the accurate and reliable results are guaranteed.

Oxygen bottle combustion method is one of the most simple methods for the determination of bromine in flame retardants of bromine. It is a semi-micro and micro analysis method. Bromine content in the bromine flame retardants measurements, as well as other sample sample preparation process and their accuracy by potentiometric titration process parameters, the artificial operation, instrument, such as the electrode performance of the influence of factors and restriction.

The method of oxygen flask combustion is characterized by simple operation process, convenient equipment making, short treatment period, batch processing of samples and less interference of matrix. The determination of the bromine content in bromine flame retardant was determined by the process of the determination of the amount of iodine in the bottle. The accurate weighing samples are wrapped in a paperless filter, and the sample is wrapped in platinum wire. Add the absorbent liquid to the iodine gauge and fill it with oxygen. Light the tail filter of the sample bag and put it in the iodine gauge quickly to make it burn fully. try

The organic halogens in the sample form halogenated hydrogen and free halogen are absorbed by the dilute solution of sodium hydroxide, and the content of halogen is determined by the method of potentiometric titration. Potentiometric titration method generally has high accuracy and precision, the widely used in the automatic potentiometric titration apparatus, the titration end point is more rapid, accurate, improve the repeatability and accuracy of the measurement result, reduce the human error, make complex titration process automation. The following author focuses on the influence of pretreatment process, potential titration parameter, operation process, electrode performance and other factors on the measurement results.



Triphenyl Phosphate (TPP)

Retardants tpp quality standards:

Appearance: white flaky crystal

Content : ≥ 99%;

Acid value (mgKOH / g): ≤ 0.1;

Free phenol : ≤ 0.1%;

Freezing point : ≥ 47.0 ℃

Chromaticity (APHA): ≤ 60;

Moisture : ≤ 0.1%

Density (50 ℃, g/cm3) :1.185-1 .202

Retardants tpp Packing: NW 25KG / composite paper ( lined with black plastic bags ) , a small cabinet loaded 12.5 tons .

Flame retardant TPP has many advantages, such as excellent transparency, softness, bacterial resistance, and water proof, grease-proof, good electric insulation, as well as good compatibility. Flame retardant TPP is mainly used as the flame-retardant plasticizer for cellulose resin, vinyl resin, natural rubber and synthetic rubber. And it may also be used as the flame-retardant plasticizer for glyceryl triacetate thin ester and film, rigid polyurethane foam, phenolic aldehyde resin, and PPO, etc.

Flame retardant TPP is a kind of halogen-free environment-friendly flame retardant with phosphorus element. Most of the products in the market are self-colored flaky crystal, our product is self-colored crystalline powder, and is more soluble in organic solvents. TPP is not soluble in water, but soluble in benzene, chloroform, ether and acetone, and slightly soluble in Z alcohol. Flame retardant TPP is nonflammable with slight aromatic odor and slight deliquescence. The fusion point is about 50 ℃, and fast melts to hoop-shape when heated. The lubricate effect is excellent, and it is often used as the flame retardant plasticize lubricant. What is more, it is used as the flame retardant for many plastics and resins, such as phenolic aldehyde resin, epoxy resin and so on.


The aim of the sample pretreatment is to make the determination of bromine in flame retardant of bromine system simple and fast, and the results of the measured components can truly reflect the properties of the sample. Before the sample is processed, it is necessary to study whether the interference component of the test component is present in the pretreatment method of the sample to reduce the influence of the sample operation process. Using oxygen flask combustion - potentiometric titration to determine the bromine content of bromine flame retardants, the following four aspects need to be taken into consideration when the oxygen bottle combustion method is used to process the high bromine content samples.

(1) the sample size. Bromine flame retardants are difficult to burn because of the high bromine content in the sample, and the amount of oxygen in the iodine cylinder is largely unadjustable in the capacity of the combustion flask. Therefore, under the premise of ensuring the accuracy of measurement, the less the sample quantity, the less the sample quantity burns, the more the sample size is, the more the sample will be burned, the less thorough the decomposition will be. For 500 mL of iodine, sample size should be no more than 15 mg.

Because the sample size is small, it is easy to measure uncertainty of the result. So the balance is crucial to the performance of the precision of the scales is prerequisite to guarantee the accuracy of the measurement result or not, weighing the sample need to use more than one over one hundred thousand of the precision balance, it is best to use one over one million precision balance, and to reduce the weighing error.

(2) accelerant. The key of this method is whether the sample can be burnt and decomposed completely. The sample is fully burned and fully absorbed to ensure the accurate and reliable measurement results. Bromine content is higher in bromine flame retardants, using the general method of oxygen flask combustion processing samples, incomplete combustion, component under test is not sufficient in the sample decomposition, the determination results and actual values will have bigger difference.

The combustion state of the sample can be improved by adding the auxiliary fuel, and the combustion temperature of the sample can be improved to ensure the decomposition of the measured components. Specific operation is on the filter paper bag package sample to add some fuel can produce high fever, such as ethylene glycol containing a high percentage of hydrogen long-chain alcohol, together with samples when combustion to produce heat and the purpose of the hydrogenation, can ensure that the sample under test when burnt component complete decomposition. If the residue in the absorbent is found to fall in after combustion, the sample is not fully decomposed, and the sample must be reignited.

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