How to get artificial fiber

In recent decades, man-made fibers have literally taken over the world. And although cotton and flax are still sown, sheep and goats are raised, artificial fiber is added to traditional natural fibers to give strength, elegance, and other useful properties. How to get artificial fiber in conditions close to home?..

How to get artificial fiber in conditions close to home?..

It will be, perhaps, difficult to prepare the most common artificial fibers nowadays - polyamide (nylon type) and polyester (lavsan type). Let's opt for copper-ammonia fiber. It is one of the very first man-made fibers, and cellulose, for example, from sawdust and other waste from the forest industry, serves as a raw material for it. Copper-ammonia artificial fiber is still used now - in carpet weaving, in knitwear factories, but much less often than before. However, for an independent experiment it is probably not more convenient to find an object.

Artificial fiber is formed from viscous spinning solutions, forcing them through narrow holes - spinnerets. In this case, the dissolved fiber is released in the form of threads. In our case, the solution is based on a copper-ammonia compound having the general formula (Cu(NH3)n)(OH)2. To prepare such a solution, first of all, stock up on basic copper carbonate Cu(OH)2CO3. If there is no ready-made salt, prepare it in the simplest way - drain the aqueous solutions of copper sulfate and soda ash (washing) soda, filter the precipitate and dry it.

Pour 20 ml of 25% ammonia solution into a bottle with a narrow neck (it is better to do this under draft or in the fresh air) and add 2 g of basic copper carbonate. After closing the bottle with a rubber stopper, shake the mixture to form a dark blue homogeneous liquid. It is a copper-ammonia solution. It has a very important property: it is able to dissolve cellulose (fiber).

Pick up the rubber stoppers for two small flasks and pour the dark blue solution into these flasks. In one, throw small pieces of pharmacy cotton wool; throwing the next portion of cotton wool, close the bottle with a stopper and shake the contents. In a second bottle, in the same way, in small pieces, dissolve white absorbent or filter paper. And in fact, and in another case, viscous solutions should be obtained, resembling syrup in density. Of these, fiber can be distinguished, which is the basis of the fiber. To verify this, pour diluted vinegar into a glass and add any of the spinning solutions drop by drop. Fiber flakes will precipitate.

However, yarn cannot be made from flakes. How to get a thread from a solution? Just like at a factory - pushing a solution through a narrow hole, moreover, into a solution of sulfuric acid - the shape of the thread is fixed in it.

To see how this happens, put the following experiment: into a glass with a 10% sulfuric acid solution, drip a copper-ammonia solution of cotton wool or blotting paper from a pipette. Some of the solution will sink to the bottom, leaving behind a shiny thread. Try to grab this thread with tweezers and gently pull it out of the glass. This is real man-made fiber. True, the thread is not very straight. But this is fixable. Only two people need to set up the experiment: one will form the thread, and the other will remove it from the solution.

Insert the needle from the medical syringe as tightly as possible into the thick-walled rubber tube. Pour spinning solution into the tube, close it with a stopper and immerse the needle in a bath or cuvette with sulfuric acid solution. Your friend should stand with tweezers at the ready: you will gradually squeeze the tube, and he will pick up the formed thread with tweezers and pull it through the solution poured into the bath.

This experience usually works well after a little practice. For convenience, try winding the resulting thread onto a spool. Instead of a rubber tube, you can use a large syringe or an old bicycle pump.

Probably, even a handkerchief cannot be weaved from the thread you received. But, you saw with your own eyes how to get a beautiful artificial fiber from a nondescript paper dissolved in a dark blue liquid.