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Phase relations in poly(vinyl chloride)/ethylene‐‐vinyl acetate copolymer blends with low contents of the EVA polymer
Author(s) -
Svanson S. E.,
Elmqvist C.,
Shur Young J.,
Rånby B.
Publication year - 1977
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1977.070210407
Subject(s) - vinyl chloride , materials science , ethylene vinyl acetate , copolymer , vinyl acetate , polyvinyl chloride , phase (matter) , polymer chemistry , polymer , polymer blend , composite material , chemical engineering , chemistry , organic chemistry , engineering
A series of polymer blends of commercial poly(vinyl chloride) (suspension‐polymerized powder) and an ethylene–vinyl acetate copolymer (EVA with 45 wt % VA) containing 2–10 wt % EVA were prepared by mixing at room temperature (0) and by milling at 160°C for 15 min (I) and then heat treated at 170°C for 20 min (II) and 40 min (III). Wide‐line NMR measurements for protons at room temperature show a broad band (assigned to PVC phase) and a superimposed narrow band (assigned to mobile EVA phase). The 0‐samples had a narrow band intensity corresponding to the total EVA content; the I‐samples had a less intense narrow band than expected, indicating that 2–3% EVA was included in the rigid PVC phase. Heat treatment for 20 min (II) and 40 min (III) increased the narrow band intensity toward the 0‐samples showing phase separation except for milled blends containing 2 wt % EVA, which had no separable narrow band and remained so. These results indicate that about 2 wt % EVA is compatible with the PVC phase and in equilibrium, while milled blends with more than 2 wt % EVA are metastable.