Neck Stretching (Necking Phenomenon)
Neck Stretching (Necking Phenomenon)
Refers to the phenomenon where, when stretching a plastic film without heating it excessively, a portion appears to soften and stretch, causing that area to elongate gradually. It eventually breaks at its limit.
This type of stretching is called neck stretching (necking phenomenon) or cold stretching.
It is used for stretching polyethylene and is also employed in dry stretching methods for ion exchange membranes.