Boiling Your New Kitchenware
July 31, 2009
My mother always boils new glasses and plates. Says it made them stronger.
Just a couple of months ago I had a laboratory experiment in polymer making. The goal was to make urea-formaldehyde, which was mostly used as adhesives in plywood industries, for laminating, coating, molding, casting, lacquers, textile finishing, etc. Urea-formaldehyde is a thermosetting plastics or termosets, which is a class of polymers that are irreversibly cured (by heat, hence the name). After it is cured, it is resistant to acid and base, and cannot be melted nor re-shaped. It cannot, therefore, be recycled.
But the polymer used in kitchenware is not urea-formaldehyde, it is its brother, melamine-formaldehyde. Somehow, during the meetings with the module lecturer who is ever so obscure (although thankfully not annoying…he has the assistant who is already too annoying), we got into talking about kitchenware.
“What are kitchenwares made of?”
“No. Polymers. The ones you can put in a microwave.”
“That’s right. Now, what did you do before using them?”
“Um…” *contemplate on whether or not to answer “Clean them”, but then again, that sounds too stupid even for me*
“What would the elderlies do?”
Now he’s asking what my Grandma would do?
“Yes, that’s right. Do you know why?”
Apparently, it is to release the formaline in the kitchenware. In the process of making melamine-formaldehyde, melamine and formaldehyde are mixed, just like in the process of makin urea-formaldehyde, urea and formaldehyde are mixed.
And of course, there is always an excess of reagents. In this case, excess formaldehyde (a.k.a formalin, the chemical used to preserver biological specimen which includes dead people, will vaporized in heat. The formalin is trapped in the solid structure of the melamine-formaldehyde polymer, but will be release when the formalin turns into vapor and leaves the solid 3-D structure into the air.
This happens when heat is involved, say…when you put hot meal into your brand new melamine plate. The formalin released will then be absorbed by you. That will not do, will it?
That is why we boil new plate and glasses.