Additives for processing rigid PVDC copolymers

Autor: David L. Dunkelberger, Michael C. Patterson
Rok vydání: 1994
Předmět:
Zdroj: Journal of Vinyl and Additive Technology. 16:46-51
ISSN: 1548-0585
0193-7197
DOI: 10.1002/vnl.730160112
Popis: Polyvinylidene chloride (PVDC) copolymers are highly crystalline materials used in packaging applications because of their strength and excellent barrier properties. The crystalline moiety (∼40 to 50%) generally melts from 160 to 170°C and the amorphous phase Tg is between 0 and 35°C depending on the comonomer type and level. PVDC is much less thermally stable than PVC and degrades very rapidly in the same temperature range (i.e. above the Tm) required to process the material. Added plasticizers are utilized to reduce processing temperatures but at the expense of barrier properties. There is a need to process PVDC sans plasticizer to achieve maximum possible barrier properties in multilayer composite sheet and films. Additives will be discussed that have been shown (in laboratory tests) to delay the fusion of the amorphous phase of unplasticized PVDC until the material temperature nears the crystalline melting point, thus reducing the overall heat history with a minimal effect on other important properties.
Databáze: OpenAIRE