Information About Chemicals
Safety First – Know Your Chemicals
Making aerogels involves a number of chemicals you may not be familiar with.
Every commercially-produced chemical has what’s called a materials safety data sheet, or MSDS for short. This document (which is usually several pages long) contains information about toxicity, flammability, and what to do if you get the chemical on you.
Things you should know about your chemicals:
- What is its chemical formula?
- What is its toxicity?
- What happens if you get it in your eyes? Inhale it? Swallow it? Get it on your skin?
- Is it flammable?
- Is it especially hazardous to pregnant women?
- Does the chemical react violently with water? Air? Other chemicals?
- Does it react with or dissolve the materials your beakers, bottles, and tools are made of?
Where to Find MSDS’s
A good place to start is Sigma-Aldrich, a large chemical manufacturer.
Go to http://www.sigmaaldrich.com/united-states.html and type in the name of the chemical for which you want the MSDS in the search box. A results page with possibly a bunch of sublists with chemical names for headings will appear, each sublist with possibly several different products. Find the sublist with the chemical name you want, keeping in mind the search engine may find your chemical with a synonym name. Click on one of the products in the sublist. When that product entry loads, look for the link on the left side of the page marked “MSDS”–click on that and a pop-up window with the MSDS will appear.
Make sure you pick the chemical you want from the list and not just any chemical that pops up. For example, if you type in “ethanol”, pick from the sublist of “Ethanol” that pops up (there will be many products under that sublist) but be careful not to just blindly pick from another list, for example, “2-(2-Chloroethoxy)ethanol”, which also pops up.
MSDS Words to Know
- Lachrymator (say “lack-ra-may-tor”) – irritates the eyes and makes you cry
- Teratogen (say “ter-at-o-jin”) – especially toxic to the unborn fetus
- Carcinogen (say “car-sin-o-jin”) – known to cause cancer
- Mutagen (say “myoo-ta-jin”) – known to mutate DNA
Ever wonder if it’s safe to use a solvent on something? One thing an MSDS won’t tell you is whether ot not a chemical is compatible with a certain material. It’s important to know what the beakers, bottles, and measuring tools you use are made of and whether or not they will react with or be dissolved by the chemicals you are using. For example, polypropylene has excellent chemical compatibility with tetramethoxysilane, but dissolves in hexane. Polycarbonate is great for water and ethanol but reacts with ammonium hydroxide and acetone.
In general glass, stainless steel, and Teflon® (polytetrafluoroethylene or PTFE) are safe for pretty much all of the chemicals you will use in making aerogels, and polypropylene plastic is safe for most except for waterproofing procedures that use pentane, hexane, or toluene.
Steps you should take to verify materials compatability:
- Identify the chemicals you need to use.
- Identify what the stuff that will be contacted by those chemicals is made of
- Is the stuff that will be contacted made of glass, plastic, or metal?
- If plastic, what kind of plastic? Polypropylene? Polyethylene? Check on the object for a recycling symbol that can help you identify what it is (for example, #5 is polypropylene) or other embossed marking indicating what it is.
- If metal, what kind of metal? Aluminum? Stainless steel? Brass? Not all metals are created equal. For example, aluminum is corroded by aluminum chloride whereas stainless steel is not.
- For the most part, glass is pretty safe for most chemicals.
- Check to see if any caps, seals, o-rings, or other wetted parts (parts that will be in contact with the chemical) are compatible.
Cole-Parmer Materials Compatibility Database
Cole-Parmer hosts an excellent database of compatibility for a wide range of materials (rubbers, plastics, metals, etc.) with a wide range of chemicals (organic solvents, acids, bases, etc.). Always check before you pour!
Path: Cole-Parmer.com > Technical Library > Chemical Compatibility Database