YBB00252003-2015

Glass particles in121℃Determination method and grading of water resistance

This method is applicable for the titration determination and grading of water resistance of various medicinal glass materials.

This method is a material testing method that takes a certain amount of glass particles of a specified size, places them in a specified container, adds a specified amount of water, and heats them under specified conditions. The degree of water erosion on the glass particles is measured and graded by titrating the extraction solution.

Experimental water The test water must not contain heavy metals (especially copper), and if necessary, the limit test method of disulfide trace can be used to test its conductivity25℃±1CAt the time, it shall not exceed0.1mS/m.The test water should be boiled in a beaker that has undergone aging treatment15More than minutes to remove gases such as carbon dioxide. The experimental water should be neutral to methyl red, that is, in50mlAdd methyl red indicator solution (sodium methyl red) to water0.025gDissolve in water and dilute to100ml）4Drip, the color of the water turns orange red（pH5.4～5.6）. This water can be used for conducting blank experiments. The experimental water can usually be stored in a flask with a ground glass stopper24Hour without changing itpHValue.

Instrument device Pressure steam sterilizer, conical flask, beaker (note: glass containers must have an average coefficient of thermal expansion of approximately)3.3×l0K1Made of borosilicate glass, new glass containers must undergo aging treatment, which involves adding an appropriate amount of water to the glass container and repeatedly processing it under the specified hot pressing conditions in the test steps until the water becomes neutral to methyl red before use. This includes an oven, hammer, grinding bowl and pestle made of quenched steel, and a set of stainless steel mesh screens (containingASieve: pore size425umTheBSieve: pore size300umTheOSieve: pore size600~1000um）.

Preparation of test samples Strike the test sample into small pieces, take an appropriate amount and place it in a grinding bowl. Insert the pestle and strike it with a hammer, only once. Transfer the glass in the grinding bowl to the upper layer of the sieveOScreen and repeat the above process. Use a vibrating screen machine to vibrate the sleeve screen (or manually shake the sleeve screen)5Minutes will passAScreen but stayBThe glass particles on the sieve are transferred to the weighing bottle, and the glass particles are more than10gTo be accurate. Co preparation of glass particles3Share.

Use a magnet to remove the iron filings from each glass particle and move them in250mlIn a conical flask, wash the glass particles by spinning with anhydrous ethanol or acetone at least6Every time, every time30mlUntil anhydrous ethanol or acetone becomes clear. Then place the conical flask containing glass particles on an electric heating plate to heat, remove residual acetone or anhydrous ethanol, and transfer it to an oven for drying. Remove it and cool it in a dryer. The storage time shall not exceed24Hour.

Measurement method Take the above glass particles separately10.00gPrecise weighing and positioning250mlCone shaped bottle, precisely added with water50mlInvert the beaker onto the conical flask, place the conical flask into the pressure steam sterilizer, open the exhaust valve, heat it at a constant speed, and continuously spray steam from the exhaust valve10Minutes, close the exhaust valve, continue heating, and19~33Within minutes, raise the temperature to121CStart timing when the temperature is reached. In121℃maintain30Minute soillAfter minutes, slowly cool and reduce pressure, then38~46Reduce the temperature to within minutes100℃(To prevent the formation of a vacuum). Remove from the pressure steam sterilizer and cool to room temperature. Prepare blank solution using the same method. In1Complete titration within hours.

Add methyl red indicator solution (sodium methyl red) to each conical flask0.025gDissolve in water and dilute to100ml）4Drip, use hydrochloric acid titrant（0.02mol/L）Titrate to a slight red color and calibrate with blank solution.

The results indicate Calculate the average value of titration results for each1gGlass particles consume hydrochloric acid titrant（0.02mol/L）The volume（ml）Expressed.

grading The water resistance of glass particles should be based on hydrochloric acid titrant（0.02mol/L）The consumption amount（ml）Classify according to the table below.

table1Classification of water resistance in glass particle test