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Materiali Fluorurati IV° Approfondimento. Raggio Atomico Diminuisce Aumenta.

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Presentazione sul tema: "Materiali Fluorurati IV° Approfondimento. Raggio Atomico Diminuisce Aumenta."— Transcript della presentazione:

1 Materiali Fluorurati IV° Approfondimento

2

3 Raggio Atomico Diminuisce Aumenta

4 Elettronegatività Aumenta Diminuisce

5 Affinità elettronica Aumenta Diminuisce

6 Energia di ionizzazione Aumenta Diminuisce

7 Fluoro 9 F NomeNome: fluoro SimboloSimbolo: F Numero atomicoNumero atomico: 9 Peso Atomico Peso Atomico : CAS Registry IDCAS Registry ID: Gruppo Gruppo : 7 Gruppo Gruppo : Halogen Periodo Periodo : 2 BlockBlock: p-block 1s 2 2(s 2 p 5 )

8 Description Standard state: gas at 298 K (m.p o C, b.p o C) Standard state Colour: pale yellow Colour Classification: Non-metallic Classification Availability Availability : 0.08% by mass of Earth's crust.

9 Cloro 17 Cl NameName: chlorine SymbolSymbol: Cl Atomic numberAtomic number: 17 Atomic weightAtomic weight: CAS Registry IDCAS Registry ID: Group numberGroup number: 7 Group nameGroup name: Halogen Period numberPeriod number: 3 BlockBlock: p-block 1s 2 2(s 2 p 6 ) 3(s 2 p 5 )

10 Description Standard stateStandard state: gas at 298 K (m.p o C, b.p o C) ColourColour: yellowish green ClassificationClassification: Non-metallic Availability Availability : 0.05% by mass of Earth's crust.

11 Configurazione elettronica esterna n(s 2 p 5 ) Obbediscono alla regola dellottetto acquistando un elettrone o per trasferimento da elementi a carattere metallico (es. Na+C-l) o per formazione di un legame covalente con elementi a carattere non metallico (es. CCl 4 ). Forti Ossidanti Stati di ossidazione -1,0,+1,+3, +5,+7. Notevole gamma di reazioni di ossidoriduzione in ambiente acquoso. Formano facilmente anioni, ma non cationi ( ad eccezione dello iodio es. I + ClO 4 - )

12 HBCNOF PSCl SeBr TeI (Electron Affinities) Table of Electron Gain Enthalpies (kJ mol-l) X -n (g) + e- X -(n+1) (g)

13 Raggi atomici degli alogeni e dei relativi anioni

14 F + Na F - + Na +

15 Homopolar Single Bonds Table of X-X bond energies (kJ mol -1 ) H-H436 B-B308C-C347N-N158O-O144F-F Si-Si226P-P198S-S266Cl-Cl243 Ga-Ga113Ge-Ge188As-As178Se-Se192Br-Br193 In-In100Sn-Sn146Sb-Sb141Te-Te126I-I151 H-H strongest; no core electron repulsion Down group IV(14), bond strength goes down overlap and core repulsion goes up C-C > N-N > O-O, F-F F-F << Cl-Cl non-bonded electron replusion important

16 Table of bond energies (kJ mol -1 ) Element-Hydrogen Bonds B-H-389C-H411N-H386O-H456F-H565 Si-H318P-H321S-H364Cl-H432 Ge-H285As-H297Se-H313Br-H366 Sb-H257Te-H-270I-H298 Across period, B(E-H) increases, no core electron repulsion, so overlap can increase as covalent radius can be small Down group, B(E-H) decreases, as overlap decreases, as energy match condition is worse

17 Materiali fluorurati

18 Integration of Fluorine Chemistry HF F2F2 Organic Intermediates Fluorocarbons Base Monomers Melts Elastomers Fluids Fluorspar Chloro-feedstocks Special Gases PTFE Special Monomers

19 Fluoropolymers Market Size (tons) Turnover ($ billion) EVA Polyethylene Fluoropolymers PE/Fluoropol. 100:1 10:1 1:1 Fluoropolymers are specialty polymers: small volumes – high revenues – high technological content

20 About Bn USD (year 2005) WORLD FLUOROPOLYMERS MARKET PTFE 55% Others (MFA/PFA, …) 15% FEP 15% PVDF 15%

21

22 Effetti chimici introdotti dal fluoro

23 Effects induced by Fluorine Atom P I.P. (Kcal/mol) V Å 3 ) r VdW (Å) Atomic Physical Properties B.Smart Organofluorine Chemistry: Principles and Commercial Applications, ed. Banks et al., Plenum Press, NY, C F p : Paulings electronegativity; I.P.: first ionization potential v : atomic polarizability r vdW : van der Waals radius

24 C-F Bond Dipoles in Partially Fluorinated Materials C-F Bond Dipoles in Partially Fluorinated Materials (Isomeric Polymer Structures) PVDF: piezoelectric FFFFFF FF FF F F F F ETFE: no piezoelectricity

25 Bond Dissociation Energies of Methanes CH 3 -X CH 2 F-X CHF 2 -X CF 3 -X B. E. Smart, "Molecular Structure and Energetics", J. F. Liebman, A. Greenberg, Eds., Vol. 3, Ch. 4, VCH Publishers, Deerfield Beach, FL (1986). Kcal/mol

26 Two-electron/Two-orbital Interaction Diagram for Alkyl Halides Bonds ( and * ) F Cl Br I I Cl F * C-X C-X 2p 3p 4p sp n

27 C-C Bond Strength in Fluoroethanes CH 3 -CH 3 CH 3 -CH 2 F CH 3 -CHF 2 CH 3 -CF 3 CF 3 -CF 3 Kcal/mol

28 Forza del legame negli etileni fluorurati

29 Benson's Definition of B.D.E. for C=C M. R. Zachariah et al., J. Phys. Chem., 1996, 100, CH 2 =CH 2 CH 2 =CHF CH 2 =CF 2 CHF=CF 2 CF 2 =CF 2 D °(C=C) (Kcal/mol) N° of F Atoms CF 2 =CF 2 + XCF 2 CF 2 X 2XF 2 C CF 2 ·

30 Key Effects of F Atomic Properties on Organic Molecules and Polymers Ê High I.P. and low V : weak intermolecular interactions, low surfaces energies, low refraction indexes. Ë Outstanding electronegativity: bond polarity index is very high C F Relatively high ionic character of C-F vs. C-H bonds Strong dipole moments in partially fluorinated molecules Ì Moderate small size (F = 1.47 Å): Í Excellent match between (2s,2p) F orbitals with (2s,2p) of C. Î Three tightly bound lone pairs.

31 Materiali perfluorurati caratteristiche generali

32 PER-fluoromaterials Effects induced by Fluorine >Strong Intra-molecular bonds: >High thermal resistance >High chemical resistance >Weak Inter-molecular interactions: >Low solvent swelling >High chemical resistance

33 Fluoropolymers: general properties General Advantages (All Fluoropolymers) High Temperature Endurance Outstanding Chemical Resistance Low Leach-out Outstanding Fire Propagation Resistance Excellent Weathering Behaviour Superior Dielectric Properties Main Drawbacks Low Tensile (Modulus, Yield Strength) Low Affinity with Fillers THE BEST POLYMER CLASS AVAILABLE AS A COMBINATION OF TEMPERATURE, CHEMICAL RESISTANCE, ELECTRICAL AND ANTI-STICK PROPERTIES

34 Fluoropolymers: Operating Temperature

35 Fluoropolymers: Tensile Properties vs. T

36 C.E.D. of Homologous Fluorinated and Hydrogenated Compounds ParaffinsPolyethers

37 1) PFCs The b.ps of PFCs are similar with those of HCs Unlike HCs, negligible branching effect on the b.ps of PFCs This trend of b.ps is due to extremely low intermolecular interactions in PFCs 2) HFCs different b.p. patterns b.ps // dipole moment Boiling pointSurface tension 1) PFCs due to the weak intermoleclar interactions, PFCs have the lowest surface tension of any organic liquids and can completely wet almost any surface 2) HFCs always greater than PFCs greater, smaller, or equal to those of HCs: depending upon fluorine content

38 MONOMERI E POLIMERI SPECIFICI

39 Key Monomers in Fluoropolymers Crystalline Amorphous CF 2 =CF 2 TFE CF 2 =CFCl CTFE CH 2 =CF 2 VDF CH 2 =CHF VF CF 2 =CF-CF 3 HFP CF 2 =CF-O-CF 3 FMVE CF 2 =CF-O-C 3 F 7 FPVE CF 2 =CF-O-CF 2 OC 2 F 5 MOVE Special Fluorinated Monomers: Cyclic Dioxolenes, Ionomers

40 Major uses Semiconductor Telecommunications AerospaceAutomotive Construction Mechanical/electromechanical Chemical/PharmaceuticalOil/gas industry Major properties high temperature endurance outstanding chemical resistance purityfire resistance weathering protection... FLUOROPOLYMERS

41 FLUOROELASTOMERS Major uses : Sealing applications in aggressive chemical and high heat environments : AerospaceAutomotive Chemical processesWire and cables... Major properties : A particularity of this special class of fluoropolymers is their ability to resume their original shape when a deforming force is removed

42 Major uses lubricants and surfactants in heat transferelectronic semiconductorspecial surface treatment polymer modification Major properties Impressive range of physicochemical properties : chemical stability, non-toxicity, non-flammability, high and low temperature tolerance FLUOROFLUIDS

43 Oxygen Diffusion of Fluoropolymers Oxygen Diffusion of Fluoropolymers (100 μ Films)

44 PTFE

45

46 TETRAFLUOROETILENE CF 2 =CF 2 Peso Molecolare:100 Punto di ebollizione: -76,3°C Punto di solidificazione: -142,5°C Temperatura critica: 33,3°C

47 CaF 2 + H 2 SO 4 CaSO 4 + 2HF CHCl 3 + HFCHClF HCl 2 CHClF 2 CF 2 =CF HCl Sintesi del CF 2 =CF 2 SbF 3 C [CF 2 : ]

48 PolyEthylene and PolyTFE C-C B.D.E. PolyEthylene and PolyTFE C-C B.D.E. H P gg (TFE) = D ° (CF 2 =CF 2 ) - DH° [ CF 3 CF 2 -(CF 2 CF 2 ) n - ] DH° [ CF 3 CF 2 -(CF 2 CF 2 ) n - ] = 89.4 Kcal/mol DH° [ CH 3 CH 2 -(CH 2 CH 2 ) n - ] = 86,5 Kcal/mol H P gg (TFE) = - 37,05 Kcal/mol H P gg (E) = - 22,35 Kcal/mol TFE is a highly reactive monomer ( H p = -41,1 Kcal/mol). The monomer is thermodynamically unstable. Explosive decomposition might occur during polymerization reaction. CF 2 =CF 2 C g + CF 4 H ° r = -85,5 Kcal/mol

49 T m (II) =327°C T m (I) = 343°C 1st Fusion 2nd Fusion PTFE Melting Behaviour PTFE Melting Behaviour Fine Powder - Scan Rate 10 °C/min DSC =.80

50 Fluorinated Plastics: Algoflon PTFE (CF 2 -CF 2 ) n Impregnation Rod, sheet, tubes films Cookware Expanded PTFE: Textile, Filtration, seals Laminates W & C

51 Key Monomers in Fluoropolymers Crystalline Amorphous CF 2 =CF 2 TFE CF 2 =CFCl CTFE CH 2 =CF 2 VDF CH 2 =CHF VF CF 2 =CF-CF 3 HFP CF 2 =CF-O-CF 3 FMVE CF 2 =CF-O-C 3 F 7 FPVE CF 2 =CF-O-CF 2 OC 2 F 5 MOVE Special Fluorinated Monomers: Cyclic Dioxolenes, Ionomers

52 Thermochemistry of F-olefins Polymerization - H P gg = DH° [ (-C-C-) n - ] - DH °(C=C) f P (CH 2 =CF 2 ) = DH°(CH 3 -CF 3 ) -DH ° (CH 2 =CF 2 ) E PVF 2 PTFE f P (Kcal/mol) H P gc' (Kcal/mol) H P gc' = 7,34 + 0,76*f p ; R 2 = 0,982 Values Calculated from the Regression

53 CF 2 =CF 2 CF 2 =CF-CF 3 Sintesi del CF 2 =CF-CF 3 C [CF 2 :] CF 2 -CF 2 CF 2 [CF 2 :] CF 2 =C(CF 3 ) 2

54 Surface properties Surface properties

55 The surface tension of the perfluoroalkyl group [Rf group : -(CF 2 CF 2 ) n CF 3 ] is the lowest of all solids on the earth SURFACE TENSION n-Perfluoroheptane PFC-HC co-polymers

56 TENSIONE SUPERFICIALE

57 FLUOROPOLYMER S SURFACE TENSION (10MN/M) IS LOWER THAN THAT OF OIL (20MN/M), ENABLING IT TO REPELL OIL

58 LABILE COATING Via PFOS F SO 2 NH 2 F F F F F H2O Legame fisico debole Tessuto da trattare Idrorepellenza temporanea

59 PFOS PERFLUOROOCTANE SULFONATE Sale di potassio Acido o ammide

60 USI DEI DERIVATI DEL PFOS Individuare nuovi prodotti e nuove metodologie

61 PFOS AS ENVARIONMENTAL RISK Data extracted from the Swedish Chemical Inspectorate (Keml) and EPA Dossier August 2004

62 Trattamenti superficiali a base di prodotti fluorurati: Nuove opportunità

63 Desired Characteristics of the Treatment Cost-effective - Effective at low concentration Safety - Non-flammable material - Long lasting. - Easy use with other finishing agents. Wide application -Applicable for fabrics made from natural or -synthetic fibers Environmental friendly

64 Advantages and Characteristics... High Performance Excellent water and oil repellency. Soft to the touch. Durable washing and dry cleaning. Excellent color fastness.

65 Perfluoroalkyl chains give water and oil repellency and soil release ability Alkyl acrylate chains give the ability to form a film and maintain softness Vinyl chloride and crosslinking monomer gives durability. FLUORINATED COPOLYMER AS FABRIC COMPONENTS

66 Treatment with Fluoropolymers: perfluoroalkyl groups [R f group: -(CF 2 CF 2 ) n CF 3 ] cover the surface of the fiber FLUORINATION OF FIBERS SURFACE

67 BOTH OF TREATMENTS WITH SILICONE AND FLUOROPOLYMERS CAN REPELLE WATER AND SAUCE, BUT ONLY TREATMENT WITH FLUOROPOLYMERS CAN COMPLETELY REPELLE OIL

68 COSTRUIRE UN TESSUTO CARATTERIZZATO DA MIGLIORATE PROPRIETÀ BARRIERA

69 COATED / LAMINATED FABRIC COATED / LAMINATED FABRIC H 2 O liq. H2O vap.

70 MICROFIBER FABRIC

71 TRATTAMENTI SUPERFICIALI DI FINITURA

72 VALUTARE IL POTERE BARIERA

73 FFFFFF COATING IDROLITICAMENTE STABILE H2O Legame Chimico Stabile Tessuto da trattare Idrorepellenza permanente


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