[c0d3]

Is there a standard in defining a polymer is high molecular weight or low molecular weight?? For example, molecular weight need to higher than what value to consider it a high molecular weight of polymer?

[cliverlong]

I do not know if the following is the correct answer.

But ... is there any meaning to talk of the molecular weight of a polymer since the chains will be of varied, uncertain, length?

Is your original question about high-density polymers?

http://en.wikipedia.org/wiki/HDPE


Clive

[ARGOS++]

Dear c0d3;

In several cases only an average molecular weight of a polymer is wanted and that’s often done with viscosity model of standard solutions like polystyrene in toluol.
The result is then most given in Numbers of monomer.

If also the range and the distribution of the molecular weight are required, then often gel-permeation-chromatography is used:
               http://en.wikipedia.org/wiki/Gel_permeation_chromatography  

Good Luck!
                    ARGOS⁺⁺

[c0d3]

I do not know if the following is the correct answer.

But ... is there any meaning to talk of the molecular weight of a polymer since the chains will be of varied, uncertain, length?

Is your original question about high-density polymers?

http://en.wikipedia.org/wiki/HDPE


Clive

I found the high and low molecular weight word through here:
Molecular weight, for the purposes of this discussion, may be pictured as representing polymer chain length. The greater the M.W., the greater the chain length and the greater the flocculating ability. Longer chain length allows bridging, or attaching to, greater numbers of particles. However, coagulant polymers have relatively low molecular weights and flocculating ability when compared to the high molecular weight cationic, nonionic and anionic flocculant polymers. Therefore, polymeric coagulants have the ability to enhance flocculation only to a limited degree.
from this source:http://www.tramfloc.com/tf29.html

Thats why i am curios about the high and low molecular weight thing