Project recquirement of endothermic reaction

[wajeeh]

Actually in a project i need such a reversible endothermic reaction which starts above the temperature 20-25 c spontaneously and proceeds as the temperature rises.Then it becomes reversible as the temperature of the environment decreases below 20-25 c .Also the reactants are mixed together but do not react below 20-25 c spontaneously.

[factor-fiction]

Hi thanks for adding extra info. I'm out of my depth here now but lets hope theprof or one of our other science experts sees this.
(For future reference you can add information like this simply by replying to your own question. That way it keeps everything together.)

[theprof]

I need more information here because you've decided to withhold information from the outset for purposes unknown. I tend not to provide answers in situations like this without knowing more about the OP and precisely what that person is studying academically and at what academic level.

Whilst I have no objection to providing a precise answer to your question, I won't provide you with an answer that will give you an unfair advantage over your peers. You really need to come clean here!

[jomifl]

The solution may be Glaubers salt.

[wajeeh]

OK theprof I am becoming polymer engineer . I want to make cool fiber . The idea is that the clothes made of cool fiber will not only be temperature resistant but also will keep the body cool in hot areas of the world like India. To make such fiber there are different possibilities. (1). The fiber which performs endothermic polymerization reaction itself above 25c (2). I mix such reactants with fibers so that they perform endothermic reaction when temperature rises. so that's it !

[jomifl]

Have you calculated how much heat your fibre could absorb under the most favourable conditions? The weight of cloth required to absorb a significant amout of heat might become an intolerable burden once it's heat absorbing capacity is saturated and it becomes an insulator.

[wajeeh]

well! jomifil i am not thinking of fiber which will absorb the heat .In fact that will only detect heat above 25 c and will activate its cooling process . It will be like ordinary fibers with the enhancement of cooling process.Its absorbance properties will be like ordinary fibers.

[jomifl]

Wajeeh, I appear to have misunderstood you. Are you saying that the polymerization of a chemical on the fibes will increase it's thermal conductivity thus reducing the insulation, or that the fibres will tighten up and reduce the size of the insulating air filled cavities?

[theprof]

Hmm. I'm afraid that if your intentions regarding your cool fibre were truly feasible, you would probably win a Nobel Prize for your discovery. Do you fully understand how revolutionary such a discovery would be? It would transform the textile industry overnight.

I know of no process in polymerisation chemistry that would meet your requirements. However having gained my applied organic chemistry degrees some years ago, I ran your idea past a couple of Oxbridge polymer professors and a senior university polymer engineer. They are of the opinion that your idea is simply not feasible on the basis of a number of issues. They advise that you present your idea to your mentors for them to explain the drawback in your theory.

R&D in this this area is constantly occurring and advancing and I really believe that it would be virtually impossible for you to circumvent the expenditure and research budgets of the major companies involved in this research. in essence, if you've thought of it, you can bet your bottom dollar that they've researched it with no budgetary restrictions.

[ChuckFickens]

If you can invent a fabric that does what you say I'd suggest you don't limit your marketing at only clothing... an active cooling system that requires no energy input would be worth billions at least.

[jomifl]

On a practical note, when the ambient temperature rises much above about 25C humans get rid of excess heat by the latent heat of evaporation ie. they sweat. Unless there is sufficient ventilation for water vapour to escape from underneath the fabric then a fabric which 'wicks' the liquid water to the outside where it can evaporate would be necessary. These are already fairly well developed in sports clothing.

[wajeeh]

OK I can understand all the complications and worth of project.But there is another possibility that I make a hollow fiber, then crush the (solid) reactants of endothermic reaction (to micro level) and fill them in that hollow fiber . Now due to heat, the fiber will expand. Due to expansion the filled reactants will be mixed and endothermic reaction will start. as temperature lowers down the fiber loses expansion and then it behaves like a normal fiber. Now what about this theory??

[theprof]

Ok wajeeh, here's some other issues you need to consider. Firstly, do you know how difficult it is to fill hollow tubular material with a powdered mixture in the manner you propose? To begin with, it would demand costly prototype machinery being built and this would be before you would have to find a way of ensuring that the mix remains consistent throughout every millimetre of the hollow fibre.

I'm afraid that your idea of crushing the endothermic reactants to "micro level" as you term it, only reinforces my opinion that you've not researched the likely optimum size of the mix particles. What is your idea of "micro level"?

The next point I want to make is that you appear to be unaware of the potential difficulties of marketing such a product. Let me put it to you like this. If you managed to convince a UK Size 8 woman that a jacket made of your material would enable her keep warm in Winter and cooler in summer, do you think she'd buy it without seeing it in action? Let's imagine the lady donning the jacket in her warm home and then going out for a walk in wintry conditions. I really don't think she'd thank you for appearing as a Size 8 one minute only to change to a Size 22 shortly afterwards! The fashion industry would bankrupt you.

In industrial situations, yes at face value there could be a demand but remember that the more bulky the clothing, the more restrictive it is to work.

All this is before we even begin to discuss what occurs when your fabric gets wet.

[wajeeh]

ok but i will keep on searching to produce cool fiber.