Non cross-linked block polyetherester, preparation and uses

Non crosslinked block polymer having the general formula (I)

• [—Pa—(Pb—Pc)s—Pa′—Pd—Pe]z
• wherein:
• z=1 to 20,
• S=0 to 25,
• Pa represents:
• —[COA—COOB]t—
• where:
• t=1 to 150, and
• A represents CH═CH or CH2—CH2
• B represents (CH2)n—O— where n=1 to 7,
• Pb represents —[COO]—x where x=0 or 1,
• Pd represents:
• —[COO]y—
• where y=0 or 1
• provided that if s=0 or x=0 then y=1, and if y=0 then s≠0 and x=1;
• Pc and Pe, each independently of one another, represent:
• [RO]u
• where:
• u=4 to 150, and
• R represents an alkylidene,
• Pa′ represents —[COA—COOB′]—t
• where A has the same meaning as above
• B′ represents (CH2)n′O, where n′=1 to 7, and t′=0 to 150 the weight-average molecular mass of the polymer being in the range 2,000 daltons to 300,000 daltons.