Přehled od AI:
Natural rubber and gutta-percha are geometric isomers of polyisoprene
cca ((C_{5}H_{8})_{n}), but differ structurally in their stereochemistry:
natural rubber is a cis-1,4-polyisoprene (kinked, amorphous), while gutta-percha is a trans-1,4-polyisoprene (linear, crystalline).
The cis configuration allows high elasticity, while the trans configuration makes gutta-percha rigid and brittle at room temperature.
Structural Differences: Stereochemistry: Natural rubber’s chain configuration has hydrogen atoms on the same side of the double bond (cis), creating a coiled, flexible, amorphous structure. Gutta-percha has hydrogen atoms on opposite sides (trans), leading to a linear, crystalline polymer chain.
Crystallinity: Natural rubber is largely amorphous with low crystallinity, which enables elasticity. Gutta-percha is highly crystalline (~60%),
causing it to be hard, tough, and horn-like, rather than elastic!!§§§
Chain Mobility: The cis form allows for significant mobility between polymer chains, resulting in high elasticity and tackiness.
Conversely, the trans configuration of gutta-percha restricts chain movement, contributing to its rigidity and lack of elasticity. Molecular Form: Gutta-percha can exist in two distinct crystalline forms, (alpha ) and (beta ), resulting from different cooling rates, whereas natural rubber does not exhibit this behavior.
These structural differences cause natural rubber to be an elastomer (elastic) and gutta-percha to behave as a thermo-plastic (hard, but pliable when heated).
MAGA §§§ !!!!
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