Dense fluoropolymer film

A process for the manufacture of a dense film, said process comprising:

• processing, in a molten phase, a solid composition (C), said composition (C) comprising:
• at least one polymer (F), wherein polymer (F) is a fluoropolymer comprising recurring units derived from vinylidene fluoride (VDF), recurring units derived from at least one (meth)acrylic monomer (MA) of formula (II):
• wherein:
• R1, R2 and R3, equal to or different from each other, are independently selected from a hydrogen atom and a C1-C3 hydrocarbon group, and
• Rx is a hydrogen atom or a C1-C5 hydrocarbon group and, optionally, from one or more fluorinated monomers different from VDF;
• and one or more carboxylic acid functional end groups,
• at least one poly(alkylene oxide) (PAO) of formula (I):
• HO—(CH2CHRAO)n—RB (I)
• wherein RA is a hydrogen atom or a C1-C5 alkyl group, RB is a hydrogen atom or a —CH3 alkyl group and n is an integer comprised between 2000 and 40000, and
• optionally, at least one inorganic filler [filler (I)];
• thereby providing a dense film having a thickness of from 5 μm to 30 μm formed of at least one grafted fluoropolymer [polymer (Fg)] comprising:
• at least one fluorinated backbone comprising recurring units derived from vinylidene fluoride (VDF) and from one or more hydrogenated monomers, and
• at least one pendant side chain linked to one or more fluorinated backbones of the polymer (Fg) through one or more ester functional groups, said pendant side chain comprising alkylene oxide recurring units of formula:
• —(CH2CHRAO)n—.