Chemistry engineering

Question

What can I use as a plasticizer at home? I want to use it to create my own bioplastic for a school project

Answer 1

Hi Alyssa R.,

You don't specify a number of details that would make a difference in what you could answer.

If "bioplastic" just means, made from natural materials, and it's not going to be used internally, that's one thing; but if it's necessary to use it internally (i.e. as a resorbable bone cement, for example), that's quite another!

The easiest, and cheapest, plasticizer for use as a demo (e.g. for a science project?) is a hydrophilic material like a starch (cornstarch is cheap, you just have to slurry it up with cool water then cook gently until it loses the white appearance!) (besides water, which will dry out on you gradually) would be another hydrophilic, hygroscopic polymer such as pectin (get it at the supermarket, under canning supplies), with some sugar and citric acid (supermarket, or drugstore) thrown in to help make the gel set. Essentially, you're making a jelly. You could also use gelatin (jello or equivalent), made as per package directions or preferably with less water, and a dab of glycerin (drugstrore) or propylene glycol (you have some lying around, don't you??) thrown in to prevent excessive drying out to a crusty solid. What I don't know is, could you end up with a kneadable mass, if that's what you need? Most jellies fall apart if you manipulate them --.

There is also a possibility of just crosslinking a starch directly with citric acid; you'd need to add the glycerin before you cast the mixture out onto a greased baking sheet and oven-cook it gently to dry and dross-link it. You could then peel from the baking sheet, and use for your demo, whatever. The glycerin will attract and hold some moisture in as a plasticizer. You'd have to experiment a bit to get what you want.

For internal use, now you'd need it to be stable in whatever form you desire (solid, semisolid,??), without the plasticizer leaking out into the body, and without triggering immune responses. That's a tough go for any material or composite. I know that polymers from small hydroxycarboxylicacids are used for replacement bone matrix (polyglycolic acid/polylactic acid, and others), but these don't need to be plasticized, rather they need strength and toughness. For sheet materials that do not need especial tensile strength, a crosslinked poly(vinyl-pyrrolidone) would work, since it inherently keeps itself hydrated from tissue fluids. These are all specialty materials, though, not something you could easily cook up at home.

If you need additional pointers, comment back and I'll see it eventually.

-- Cheers, -- Mr. d.