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US 8,263,695 B2Granted
Polyvinylidene fluoride having an increased melting point
AssigneeArkema Inc.
InventorsLawrence H. Judovits, Nicholas J. Rodak, Saeid Zerafati, Ravi R. Gupta
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Abstract
The invention relates to compositions of polyvinylidene fluoride (PVDF) and its copolymers that have been modified with an onium salt. The PVDF compositions exhibit an increased melting point, a reduced heat distortion and piezo properties. The improved properties can be further enhanced through annealing, and/or the addition of nanoclays. Additionally, the combination of PVDF, nanoclays and annealing can also produce a PVDF with an increased melting point and piezoelectric properties.
Claims8
An annealed polyvinylidene fluoride (PVDF) composition in the form of a film comprising:
- a) a polyvinylidene fluoride homopolymer, copolymer or terpolymer, and
- b) from 0.1 to 20 weight percent of an organically-modified nanoclay based on the weight of the polyvinylidene fluoride polymer and organically-modified nanoclay, wherein said nanoclay platelet surfaces are modified with one or more onium salts, said onium salt having the formula:
- −X+Y—R1R2R3R4
- wherein X is an anionic center;
- Y is a cationic center formed from the addition of radicals that create four bonds to that center and may be either a heterocyclic imidazolium +N═R1(R2R3), a quaternary ammonium, +NR1R2R3R4, or a phosphonium +PR1R2R3R4;
- and R1, R2, R3, and R4 are each individually H or a C1-20 group selected from alkyl, aryl, alkylaryl, alkylaryl radicals;
- wherein said film is piezioelectric, wherein said film is poled and non-stretched, and wherein said composition is annealed at from 130° C. to 180° C. for at least 1 minute after formation of the film.
4 more elements
Dependencies are inferred from the claim text.