摘要:
An ionomeric membrane formed of a sulphonic (per)fluorinated ionomer wherein the sulphonic groups are at the end of short side chains (SSC), said ionomer having:
equivalent weight between 700 and 1600 g/eq; side chains of formula: -O-CF 2 -CF 2 -SO 3 - M + , wherein M is hydrogen or an alkaline metal;
said membrane having the following combination of properties:
size variations, for both the orthogonal directions xy of the plane, lower than 15%, measured after dipping of the ionomeric membrane, dried at 105°C under vacuum for one hour, in demineralized water at 100°C for 30 minutes; the membrane, dipped at the temperature of 50°C for 22 hours in a water/ethanol mixture containing 40% by weight of alcohol, remains integral.
摘要:
A composite ionomeric membrane comprising a layer or film of a porous inert material on which a (per)fluorinated sulphonic ionomer is deposited wherein the sulphonic groups are at the end of short side chains (SSC), said ionomer having:
equivalent weight comprised between 280 and 1,700 g/eq; side chains of formula: -O-CF 2 -CF 2 -SO 3- M + , wherein M is hydrogen or an alkaline metal;
said membrane having in each of the two orthogonal directions xy of the plane, after dipping in demineralized water at 100°C for 30 minutes and preliminary drying at 105°C under vacuum for one hour, the following size variations:
in one direction, size variation lower than 25%; in the other direction, size variation lower than 20%.
摘要:
The invention pertains to a process for stabilizing a semi-crystalline fluoropolymer comprising ion exchange groups, said process comprising: - suspending at least one semi-crystalline fluoropolymer having ion exchange groups [polymer (I)] in at least one fluorinated organic dispersing medium [medium (M)] so as to obtain a dispersion (D) of polymer (I) in a dispersing medium (M); - contacting said dispersion (D) with fluorine under irradiation with U.V. radiation so as to obtain a stabilized polymer. Still objects of the invention are a stable semi-crystalline fluoropolymer as above defined having a low amount of unstable ends groups of -COF type, the use of the stabilized fluoropolymer obtained by the process or of the stable fluoropolymer in fuel cells devices, a membrane and a membrane-electrode assembly comprising said fluoropolymers.
摘要:
The invention pertains to a fluoropolymer composition (C) comprising: - at least one functional fluoropolymer [polymer (I)], said polymer comprising : - recurring units derived from at least one ethylenically unsaturated monomer comprising at least one fluorine atom (fluorinated monomer, hereinafter); and - a substantial amount of recurring units derived from at least one ethylenically unsaturated monomer comprising at least one cation exchange group (functional monomer, hereinafter); and - at least one cerium compound [compound (O)]. Still objects of the invention are a process for the manufacture of said composition and the use of the same as catalyst.
摘要:
The invention pertains to a liquid composition comprising: - at least one fluoroionomer (I) [fluoroionomer (I-1)], said fluoroionomer (I-1) having a heat of fusion comprised between 4 and 20 J/g; - at least one fluoroionomer (I) [fluoroionomer (I-2)], said fluoroionomer (I-2) being substantially amorphous, that is to say having a heat of fusion of less than 4 J/g, and wherein the water extractable fraction of fluorionomer (I-2) is less than 40 % wt, said liquid composition comprising fluoroionomer (I-1) and fluoroionomer (I-2) in a weight ratio (I-1)/(I-2) of at least 2:1.
摘要:
A continuous process for applying subgaskets to both the flat surfaces of CCM assemblies, comprising the following steps: a) preparation of a roll (A) formed of a composite (20) consisting in one central layer (1), formed of an ionomeric membrane sheet, wherein on each of the two surfaces, electrocatalytic layers (2) longitudinally distributed at regular intervals are applied, said layers being on each of the two surfaces in symmetric position among each other with respect to the membrane plane; b) preparation of two subgasket rolls (B) wherein, on a subgasket sheet (21), in correspondence to the position of the electrocatalytic layers (2) in the roll (A), openings (3) are made; the per cent ratio (subgasket opening area (3))/(electrocatalytic layer area (2)) being between 90% and 99%; c) hot lamination of two rolls (B) with the roll (A), carried out by feeding the roll (A) between the two rolls (B), with the two drums (8) for the lamination; the step being carried out so that the perimeter of the openings (3) of the two rolls (B) falls inside the area of the electrocatalytic layers (2), and obtaining of a roll (C), wherein on each of the two surfaces of the sheet formed of a CCM sequence (roll (A)) a subgasket sheet (5) (roll (B)) is applied.