Re: help me

shahram.nematy@xxxxxxxxx wrote:
>
> Hi
> i am a siniour student of polymer engineering .
> i have a question : is there any relationship between structure and
> modulus & strenght in all material. a basic low that have used for all
> material.
>
> thank for aU.

Steric hindrance hard by a polymer backbone raises Tg and stiffness
and imparts strength - polyethylene, iso- or syndiotactic
polypropylene, then TPX. Poly(acrylate esters) are rubbery,
poly(methacrylate esters) are glassy. Sauflon,
poly(N-vinylpyrrolidinone-co-methyl methacrylate), is hardly more than
Jello when hydrated. Invulneron,
poly(N-vinylpyrrolidinone-co-N-vinylcarbazole), is still as strong as
silicone rubber at 60% hydration.

Now you can diddle crystalline vs. glassy phases, and controlled phase
separation for self-reinforcement (Kraton thermoplastic elastomers,
ABS resins) and crack termination (impact-resistant polystryene).

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.