Abstract: A process for the purification of a tetraol PFPE derivative [tetraol (T)] of formula (I): HO—CH2—CH(OH)—CH2—O—CH2—CF2—O—Rf—CF2—CH2O—CH2—CH(OH)—CH2OH, wherein Rf represents a fluoropolyoxyalkene chain (chain Rf), from a mixture (M) of hydroxyl (per)fluoropolyether derivatives, said mixture comprising said tetraol (T) and at least one hydroxyl (per)fluoropolyether [PFPE (OH)] comprising a chain Rf terminated with at least one end group of formula: —CF2CH2OH; —CF2CH2O—CH(OH)—CH2—O—CH2—CH(OH)—CH2OH; said process comprising: step 1: reacting the mixture (M) with ketones and/or aldehydes so as to selectively protect couples of hydroxyl groups on vicinal carbon atoms by forming corresponding cyclic ketal/acetal derivatives, so as to yield a protected mixture (P); step 2: reacting residual hydroxyl groups of the mixture (P) with suitable functionalizing agents enabling substantial volatility modification, so as to obtain a functionalized protected mixture (Pf); step 3: fractional distillation of the mixture (Pf) so a

Abstract: This invention pertains to sealing articles of vulcanized (per)fluoroelastomer compositions incorporating particles of a vinylidene fluoride (VDF) polymers having a Shore A hardness of at least 85 when determined according to ASTM D 2240 Type A Durometer method, and a compression set of less than 30%, when determined according to ASTM D395 at 200° C. for 70 h on O-ring according to ASTM D1414, and to a process for their manufacture by vulcanizing-molding and thermal post-treating at a temperature above the melting point of the VDF polymer.

Abstract: Extrudable (per)fluoroelastomer compositions comprising crosslinkable (per)fluoroelastomers having: at least two glass transition temperatures Tg on DSC analysis, at least one melting peak on DSC analysis with a ?H of second melting of between 0.3 and 5.5 J/g, and a bimodal molecular weight distribution such that the ratio Mn1/Mn2 is between 10 and 30, wherein Mn1 represents the number-average molecular weight of the distribution of the high molecular weight fluoroelastomer and Mn2 represents the number-average molecular weight of the distribution of the low molecular weight fluoroelastomer.