Methods for cleaning glass instruments used in polymer processing
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Glassware used for polymer synthesis experiments, such as Sample Text, should be cleaned immediately after the experiment is completed. If it is not washed for a long time, dirt will adhere firmly to the glass surface, making it difficult to clean later on. Experimenters should develop the habit of cleaning and drying glass instruments promptly. The method for cleaning glass instruments should be determined based on the nature of the experiment being conducted, as well as the amount of dirt or degree of contamination. The most common method is to use a brush dipped in a little laundry detergent or cleaning powder to gently scrub the inside and outside of the glass instruments, followed by rinsing them clean with water. Pay attention to the top of the brush; if it has become bare and the wire is exposed, it needs to be replaced promptly. Because cleaning instruments with a bristled brush, puncturing flasks, beakers, test tubes and other equipment happens from time to time. For sticky or tar-like residues that are difficult to clean away using ordinary methods, they can be soaked in a small amount of organic solvent (either a single solvent or a mixture of solvents) for a period of time; the duration of soaking depends on how well the adhering substance dissolves. After the adhesive has dissolved, pour the solvent back into the covered solvent recovery bottle, and then rinse it thoroughly with clean water. Propanone, diethyl ether, ethanol, chloroform, dichloroethane, etc. are common organic solvents. The first three of these are flammable; therefore, they should be kept away from open flames when in use, and care must be taken to ensure safe handling. For difficult-to-remove acidic adherents or charred substances, they can be boiled in a dilute alkaline solution, with the amount of solution used being sufficient to cover the adherents. After the adhesive has dissolved, pour out the weak alkaline solution, and then rinse the glassware thoroughly with water. In the same way, the alkaline residues can be cleaned with a dilute sulfuric acid solution. Cleaning glassware with detergent can replace the chromic acid solution prepared from potassium dichromate and concentrated sulfuric acid, eliminating the hazards associated with its preparation and use
I often wash bottles using a strong alkaline solution, one made of sodium hydroxide and ethanol; it works very well, especially for bottles used in polymerization processes. Immersing them in this solution makes cleaning them much easier.
Yes! These are the bottles used for cleaning in ordinary laboratories! But if it can’t be removed, acid can work! The preparation of acid solutions is described in any organic chemistry laboratory book!
It is generally more convenient to use the appropriate acid or alkali solution for cleaning; if it cannot be cleaned thoroughly right away, it can be soaked overnight before being washed again.
What is the approximate ratio of sodium hydroxide to ethanol?
Typical laboratory manuals provide instructions for preparing common solutions; as for the specific proportions for strong alkaline solutions, these can be determined based on actual circumstances.
Personally, I think the alkali tank is more convenient – you just throw things in it and can take them out after a few days; for industrial 95% ethanol, solid sodium hydroxide can be added. Generally, 10–15% alkali is added. Over time, the alcohol evaporates, so just add more – it can be used for a long time
The washing process depends mainly on the properties of the synthetic polymer; for example, after synthesizing AM/DMC, it can be rinsed with hot water. Since DMC is a quaternary ammonium cationic monomer, using laundry detergent will cause it to clump and solidify, making it difficult to remove later.
:D: In the past, we used to clean things with toluene for experiments; toluene is cheap
The acid solution prepared using potassium dichromate works quite well, but safety must be taken into account
When I was in the factory laboratory, I simply used a stainless steel tank, filled it with a highly alkaline solution, and soaked the flasks in there for a week; even the toughest residues could be removed that way, haha. However, it is necessary to regularly remove the swollen substances using a mesh bag, and gloves must be worn when putting your hand inside