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Why are semicrystalline polymers often tougher and more opaque than amorphous polymers?
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polymer
Industrial polymers are synthesized from simple compounds joined together to form long chains. For example, polyvinyl chloride is an industrial homopolymer synthesized from repeating units of vinyl chloride.
Semicrystalline polymers are often tougher and more opaque than amorphous polymers due to their unique internal structure, which consists of ordered regions known as crystallites embedded within an amorphous matrix.12
- Toughness: The toughness of these materials arises from the strong intermolecular forces created by the close packing of polymer chains within the crystallites. When these polymers are in a rubbery state (above their glass transition temperature), the combination of these rigid crystalline regions and the flexible amorphous matrix allows the material to absorb significant energy and undergo substantial elongation without failing.13
- Opacity: Semicrystalline polymers appear more opaque because the crystallites are large enough to scatter light as it passes through the material. In contrast, amorphous polymers have a randomly intertwined molecular structure that lacks these light-scattering regions, resulting in a transparent, glasslike appearance.1