The word polyethylenes is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 25
Highest Scoring Words With Friends™ Play In The Letters polyethylenes
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Seven Letter Word Alert: (33 words)
enstyle, eophyte, ethenes, ethynes, ethynyl, eyehole, eyelets, eyeshot, eyespot, heptene, heptose, heptyne, honesty, leptons, neotype, onestep, openest, pellets, pentose, phenols, phenyls, phoneys, pollens, polyyne, poteens, potheen, pythons, spyhole, steepen, steeple, steeply, stollen, tensely