[gloinddark]

Hello

Not sure if this post should be in the Materials section, but in any case...

I am carrying out a cryopreservation protocol, which suggests the use of a slow freezing container, such as this: http://www.nalgenelabware.com/products/productDetail.asp?product_id=405

Basically it is a polycarbonate box stuffed with foam. The foam is saturated with isopropanol. The cryovials are placed within the foam and then refrigerated at -80^oC. It enables the vials to freeze at a slow rate.

I don't have such a box, and my department is apparently broke so I'm trying to make one myself.

Do you know if any common household plastic box can withstand -80^oC?
From what I read, polypropylene crumbles at low temperatures. HDPE does not withstand it either.

I would appreciate any of your suggestions.

[typhoon2028]

Maybe LDPE or a rubber material, if the box must be polymer.

You probably need a material with a low glass transition temperature

[Wastrel]

Caveat:- I have no experience with biological preservation, well, apart from living in a house with a fridge freezer.

You could probably experiment with a cookie tin and rockwool.  If you need to make the container liquid tight you could try using a freezer bag.  You could also try buying plastic containers that are designed to be deep frozen at the supermarket and see how they hold up.  Getting the cooling rate right and repeatable sounds more of a problem than finding the materials.  You could fill a polythene bag with a known quantity of water and find out how long it takes to freeze inside the container.  That would tell you the heat flow close to freezing point and let you estimate the cooling rate you would get.

[AWK]

I used an upper part of PET bottle as a funnel for liquid nitrogen for a few years

[vmelkon]

Why not use a large styrofoam box instead of a polycarbonate box? It might resist any dry ice you throw in there.

[gloinddark]

I think I'll use HDPE, since it has a  glass transition temperatures lower than -80^oC, and I found various HDPE containers. Unfortunately I couldn't find any LDPE containers.

The tin box sounds convenient, but I read something about 'tin plague' occurring at very low temperatures. OK, tin boxes are not made out of pure tin, but somehow I don't think it will survive. But I may try it out if time permits. And I'll keep the polystyrene in mind too.

Thanks a lot to all of you