stretch film 1

[eldadshirley]

hello
i am doing a research in the field of stretch film.unfortunattly ,i can't find in the web the specific information and answers to my questions,so if someone can help me on this one i will be gratefull:
1. why do i need to make rapid cool in the stretch film process?
2.what is going on in the prestretch process in the molecular point of view(strian hardening?)?
3.if some has good paperwork or good articles i will be more then happy to recieve some.
thank you all.
eldad eilam

 

[Demon3]

I have a friend working on that topic. You are stretching the polymer, and hence the polymer chains and then cooling them fast so that they are trapped in their stretched condition. They want to shrink back to their original, equilibrium shape but they can't because they are below their glass transition temperature and the chains cannot move. Then, when you heat them they go back to their original shape and the film shrinks. If I find an article on it I will tell you.

 

[eldadshirley]

TNX demon3 4 answreing me.
you talk about shrink film that shrink by heat, this is other type of films.what i meen is stretch film which can be stretch at room tem to high elongation and do not recover by heat or any thing else.

 

[Demon3]

Aha, sorry about that. I also have a friend working on stretch films. Google gave this link to presentations on the stretch film process

http://polymers.sabic-europe.com/publications/_en/index.htm

 

[eldadshirley]

TNX a lott about the link.