Partial Pressure

EXAMPLE 1

In an AISI 316 steel vertical autoclave, equipped with baffles and a stirrer working at 570 rpm, 3.5 liter of demineralized water were introduced. The temperature was then brought to reaction temperature of 80° C. and the selected amount of 34% w/w aqueous solution of cyclic surfactant of formula (VI) as defined above, with X_a=NH₄, was added. VDF and ethane were introduced to the selected pressure variation reported in Table 1. A gaseous mixture of TFE-VDF in the molar nominal ratio reported in Table 1 was subsequently added via a compressor until reaching a pressure of 20 bar. Then, the selected amount of a 3% by weight water solution of sodium persulfate (NaPS) as initiator was fed. The polymerization pressure was maintained constant by feeding the above mentioned TFE-VDF while adding the PPVE monomer at regular intervals until reaching the total amount indicated in the table 1.

When 1000 g of the mixture were fed, the reactor was cooled at room temperature, the latex was discharged, frozen for 48 hours and, once unfrozen, the coagulated polymer was washed with demineralized water and dried at 160° C. for 24 hours.

The composition of the obtained polymer F-1, as measured by NMR, was Polymer (F-1)(693/99): TFE (69.6% mol)—VDF (27.3% mol)—PPVE (2.1% mol), having melting point T_m=218° C. and MFI=5 g/10′.

The procedure of example 1 was repeated, by introducing the amount of ingredients indicated in the third column of Table 1.

The composition of the obtained polymer P-1, as measured by NMR, was Polymer (C-1)(693/67): TFE (71% mol)—VDF (28.5% mol)—PPVE (0.5% mol), having melting point T_m=249° C. and MFI=5 g/10′.

EXAMPLE 2

The procedure of example 1 was repeated, by introducing the amount of ingredients indicated in the second column of Table 1.

The composition of the obtained polymer F-2, as measured by NMR, was Polymer (F-1)(693/100): TFE (68% mol)—VDF (29.8% mol)—PPVE (2.2% mol), having melting point T_m=219° C. and MFI=1.5 g/10′.

In an AISI 316 steel horizontal reactor, equipped with a stirrer working at 42 rpm, 56 liter of demineralized water were introduced. The temperature was then brought to reaction temperature of 65° C. and the selected amount of 40% w/w aqueous solution of cyclic surfactant of formula (VI) as defined above, with X₁=NH₄, was added. VDF and ethane were introduced to the selected pressure variation reported in Table 1.

A gaseous mixture of TFE-VDF in the molar nominal ratio reported in Table 1 was subsequently added via a compressor until reaching a pressure of 20 bar.

Then, the selected amount of a 0.25% by weight water solution of sodium persulfate (NaPS) as initiator was fed. The polymerization pressure was maintained constant by feeding the above mentioned TFE-VDF while adding the PPVE monomer at regular intervals until reaching the total amount indicated in the table 1.

When 16000 g of the mixture were fed, the reactor was cooled at room temperature, the latex was discharged, frozen for 48 hours and, once unfrozen, the coagulated polymer was washed with demineralized water and dried at 160° C. for 24 hours. The composition of the obtained polymer C-2, as measured by NMR, was Polymer (C-2)(SA1100): TFE (70.4% mol)—VDF (29.2% mol)—PPVE (0.4% mol), having melting point T_m=232° C. and MFI=8 g/10′.

EXAMPLE 3

The procedure of Comparative Example 2 was repeated, by introducing the following changes:

• • demineralized water introduced into the reactor: 66 litres;
  • polymerization temperature of 80° C.
  • polymerization pressure: 12 abs bar
  • Initiator solution concentration of 6% by weight
  • MVE introduced in the amount indicated in table 1
  • Overall amount of monomers mixture fed in the reactor: 10 000 g, with molar ratio TFE/VDF as indicated in Table 1.

All the amount of ingredients are indicated in the fifth column of Table 1.

The composition of the obtained polymer (C-3), as measured by NMR, was Polymer (C-3)(693/22): TFE (72.1% mol)—VDF (26% mol)—PMVE (1.9% mol), having melting point T_m=226° C. and MFI=8 g/10′.

The results regarding polymers (F-1), (F-2) of the invention, and comparative (C-1), (C-2) and (C-3) are set forth in Table 2 here below

In particular, the polymer (F) of the present invention as notably represented by the polymers (F-1), (F-2), surprisingly exhibits a higher elongation at break at 200° C. as compared to the polymers (C-1) and (C-2) of the prior art.

Also, the polymer (F) of the present invention as notably represented by the polymers (F-1), (F-2), despite its lower tensile modulus, which remains nevertheless in a range perfectly acceptable for various fields of use, surprisingly exhibits a higher strain hardening rate by plastic deformation as compared to the polymers (C-1) and (C-2) of the prior art.

Finally, the polymer (F) of the present invention as notably represented by the polymers (F-1) and (F-2) surprisingly exhibits higher environmental stress resistance when immersed in fuels as compared to the polymers (C-1) and (C-2) of the prior art.

Yet, comparison of polymer (F) according to the present invention with performances of polymer (C-3) comprising perfluoromethylvinylether (FMVE) as modifying monomer shows the criticality of selecting perfluoropropylvinylether: indeed, FMVE is shown producing at similar monomer amounts, copolymer possessing too high stiffness, and hence low elongation at break, unsuitable for being used e.g. in O&G applications.

Example 13

Different thin-film electrodes were tested using the Type 1 Cyclic Voltammetry Test. In more detail, thin-film electrodes formed with a stainless steel 304 (SS304) conductive layer and capped with a carbon containing layer sputtered in an atmosphere of N2 that ranged from 0, 5, 10, 15, 20, 40, and 50% N2 by partial pressure, respectively. The electrodes were all produced in a roll-to-roll sputter coater.

Cyclic voltammograms in PBS, with 2 mM [RuIII(NH3)6]Cl3 mediator added, at 25 mV/s using a saturated calomel (SCE) reference electrode and each of the SS304 electrodes as the working electrode. The results are illustrated graphically in FIG. 12. A review of FIG. 12 reveals that the electron transfer kinetics between the mediator and electrode are not affected by the introduction of N2 into the sputtering chamber when [RuIII(NH3)6]Cl3 is used as the redox mediator. This is unexpected because the electron transfer kinetics with a K₄[Fe^II(CN)₆] redox mediator are slightly negatively affected by the introduction of N2 into the sputtering chamber during carbon deposition.

Example 9

Thin film electrodes having a conductive layer sputtered from a SS304 source and carbon-containing layers sputtered in an Ar and N₂ gas mixture atmosphere having various concentrations of N₂ were analyzed by XPS analysis to investigate the formation of a C—N species in the carbon-containing film layer as a function of nitrogen concentration in the sputtering atmosphere. All samples were sputtered on a SS304 conductive layer generated in a roll-to-roll production machine. The results are shown in FIG. 6. A review of FIG. 6 reveals that there is a rapid increase in carbon-nitride species present in the carbon-containing film, as determined by XPS analysis, and the C—N species reaches a saturation of about 35% after the nitrogen content (in the chamber) reaches about 5% by partial pressure. It was unexpected that the C—N species concentration within the sputtered film would reach saturation at such a low N₂ concentration. In addition, it was unexpected that these films would have similar stoichiometry because the films made with different nitrogen concentrations did have slightly different electrochemical performance and the deposition rates of carbon under these atmospheres was different, as shown in FIGS. 4 and 9-11 below.