Question

what's the relationship between polymer structures and relative physical properties?

Answer 1

Majorly the physical properties of polymers are decided by the secondary forces of interaction between the polymer chains which in turn depend on the structure.

If the polymer has less branches, stacking of layers of polymers is more compact and thus has more density. On the other hand more branchings, less density of poymer due to loose stacking.

If the inter molecular forces are weak vanderwaals' forces ( that is if the polymer chain does not have any polar groups) then they are rubbers/ elastomers with more elastic properties. Eg. natural and synthetic rubbers.

If the inter molecular forces are very strong , that is highly hydrogen bonded, they form fibres with very less elastic nature and less water retaining properties. Eg. nylons and terelynes

If the inter molecular forces are moderate , they are plastics ( thermosetting plastics and thermoplastics) .They can be hard substanceswith crosslinkings. The greater the degree of crosslinkings, the harder is the plastic. eg: polypropylenes, melamins,