Neat EVA examples of VST C versus VA content

For long-term heat ageing, property retention depends on the property and grades considered, notably the heat stabilizers used. Characteristics such as elongation at break and impact strength are especially heat sensitive. Heat resistance decreases as the VA content rises. These results relate to some grades only and cannot be generalized. 

In the visible light region, the transparency of neat EVAs increases as the VA content rises. The transparency in the near infrared region is weak and favours heat retention for greenhouse films. 

Refractive indices are intermediate between those of polyethylenes (ca. 1.52) and polyvinyl acetate (ca. 1.47) for example, 1.48 for an EVA with 40% VA. 

Example values of haze for films are 1.5 for one film and 6 for another. 

These results relate to some grades only and cannot be generalized. 

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