Permeability and Phase Structure of PVC/EVA Systems
1971; American Chemical Society; Linguagem: Inglês
10.1021/ba-1971-0099.ch008
ISSN0065-2393
Autores Tópico(s)Polymer Foaming and Composites
ResumoThin films of poly(vinyl chloride) (PVC) containing various amounts of an ethylene vinyl acetate (EVA) copolymer (55% ethylene by weight) were prepared from mechanical blends and graft copolymerized blends. The film properties were studied by gas permeability measurements with helium, argon, and carbon dioxide as penetrants and by light transmission measurements. Addition of small amounts of EVA (≤ 5% by weight) give negligible changes in permeability and opacity. With larger amounts of EVA added, both permeability and opacity of the films increased sharply. The data indicate that addition of more than 5 wt % EVA increases the heterogeneity of the system, probably because of the development of a continuous EVA phase, thus enclosing (embedding) the PVC particles. This phase structure model is supported by published electron micrographs of thin sections of polymer blends. Permeability measurements have proved valuable in studies of multicomponent polymer systems.
Referência(s)