Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: dgt20 on 09/08/2018 07:11:16

Title: What are the main properties of a polymer?
Post by: dgt20 on 09/08/2018 07:11:16

what are the main properties of a organic and inorganic polymer? how does the primary, secondary and tertiary affect a polymer's properties?

Title: Re: What are the main properties of a polymer?
Post by: chris on 10/08/2018 18:37:08

Ok, I'll start the ball rolling; then others can add one each!

1) High molecular weight

Title: Re: What are the main properties of a polymer?
Post by: chiralSPO on 10/08/2018 23:31:10

Polymers (both organic and inorganic) are made of one or more types of identical units (monomers), many of which are linked together in a 1D chain (can also be crosslinked). For instance, given generic monomers A, B, and C one could have polymers that look something like:
–A–A–A–A–A–A–A–A–A–A–A–A–A–A–A–A–A–A–
or
–A–A–A–A–A–A–A–A–A–A–B–B–B–B–B–B–B–B–
or
–A–B–A–B–A–B–A–B–A–B–A–B–A–B–A–B–A–B– (though one could argue that A–B is the monomeric unit, and call that A)
or
–A–B–A–C–A–A–A–B–C–B–C–A–A–C–B–B–A–B–
etc.

Beyond that, there are soooo many different kinds of polymers that it is difficult to generalize. Their properties will depend highly on how long the chains are (molecular weight, which can be 100s of Daltons up to 100s of MegaDaltons), how similarly long the chains are (dispersity, from monodisperse, when they are all the same length, all the way to very wide ranges), to what extent they are cross linked (more crosslinks = stronger and more rigid), how ordered the monomers are when there are more than one type (alternating, random, or blocks, as shown above), how similar all of the linkages are (polyporpylenes are all made entirely of identical monomers, but atactic, syndiotactic, and isotactic varieties have linkages with different types of symmetry involved; or starch and cellulose are both made of the same monomer, glucose, but in cellulose they are all connected in the α fashion, while in starches, they alternate between α and β)

Of course, the identity of the monomers also plays a HUGE role in the properties (physical, chemical, and biological).

Title: Re: What are the main properties of a polymer?
Post by: evan_au on 11/08/2018 02:40:15

Polymers often have other chemicals added for physical strength, UV resistance, ease of moulding, high-temperature stability, fire retarding properties and color.