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공업화학과 / 정보통신소재연구실 / 석사 2 기 이인재 2000.10.16

Fluorinated Polymers. 공업화학과 / 정보통신소재연구실 / 석사 2 기 이인재 2000.10.16. Introduction Definition Properties of fluorinated polymers Classification Application. General properties of fluorine Fluoropolymers Fluorinated polymers. Properties of fluorinated polymers High thermal stability

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공업화학과 / 정보통신소재연구실 / 석사 2 기 이인재 2000.10.16

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  1. Fluorinated Polymers 공업화학과/정보통신소재연구실/석사2기 이인재 2000.10.16 • Introduction • Definition • Properties of fluorinated polymers • Classification • Application • General properties of fluorine • Fluoropolymers • Fluorinated polymers

  2. Properties of fluorinated polymers • High thermal stability • Low moisture absorption • Low flammability • Good resistance to most chemicals • Good resistance to oxidation and ageing Low dielectric constant Excellent weatherability Low surface energy Introduction • Definition • Polymer made from monomers containing one or more atoms of fluorine, or copolymers of such monomers with other monomers

  3. Classification • Application • 1. Military use. • seals for super sonic aircraft, • submarine coating, • perfluoropolyether liquids as • lubricant for bearing in satellites, • canopies for supersonic fighter aircraft, • heat-resistant shields for satellite • and spacecrft coatings. • 2. Daily use. • Gortex, Scotchard coatings • liquid perfluoropolyether, • fluoropolymer coatings of • skyscrapers • 3. As a specialty polymer. • cable insulation • low flame-spreading • low smoke-generating • crosslinked fluoropolymer • Organic Fluoropolymer • 1)Fluorocarbonpolymer • Perfluoropolymer • Partially fluoropolymer • 2) Fluorinated polymer • Inorganic Fluoropolymer

  4. General properties of fluorine • B.E. Smart in “Chemistry of organic Fluorine Compounds II A Critical Review”, Ed. by Milos Hulicky , p.979, (1995) • Fluorine atom (F) • High ionization potential and low polarizability • ;very weak inter- and intramolecular interactions • Storng inductive electron withdrawal and polarized +C-F- • ;C-F bonds are more ionic and stronger than other C-X bonds • Physical properties • 1)Saturated fluorocarbon(PFC) (perfluorinated carbon) ;lowest dielectric constant, surface tension, refractive indexes of any liquid at r.t. (nonpolar, extremely low polarizability) ;greater densities, viscosities, critical temp, and compressibilities 2)Partially fluorocarbon(HFC) • ;properties fall between fluorocarbon and • hydrocarbons

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

  6. 1.Why is the dielectric constant lowered by the fluorination? • Molar polarization • (Lorentz and Lorentz equation) • Dielectric constant • M : molar weight • : molar density NA : Avogadro’s number -1 M +2  1 3 0 = = NA P • The relative dielectric constant of insulatiog materials is the ratio of the capcities of a parallel plate condenser measured with and without material placed between the plates. • Due to the polarization of the dielectric. • Dimensionless quantity • The presence of bulky group between imide linkages may reduce inter-chain electronic interaction. • The presence of fluorine substituents may cause steric changes, resulting in less dfficient chain packing and an increase in the free volume of the polymer, bringing the dielectric constant closer to the value of air, ‘1’. •  Fluorine may effect a decrease in the electronic • polarizability due to its strong electron • withdrawing inductive effect. Polarizabilityis the ability of an atom or molecule to become polarized in the presence of an electric field. P=EP:induced dipole moment(polarization) :polarizability E:electric filed = e+ i+ o e: electronic polarizability i: Ionic polarizability o: orientational polarizability

  7. G. Hougham et al, Macromolecules, 27, 5964, (1994) • Polarization effects of Fluorine on the Relative Permittivity • Change in the electronic mode → Change in the dielectric constant • Change in the atomic mode → Negligible • Change in the dipole orientation mode → Nonsymmetric substitution is always positive

  8. Gareth Hougham et.al., Macromolecules 29,3453, (1996) • The relation between free volume and dielectric constant Density and fractional free volume Percent of change in Dielectric constant due to change in FFV. From the previous tables, we can notice that the the dielectric constant is decreased by the fluorination whereas the free volume of polymer is increased

  9. 2.Why is the heat-resistance improved by • the fluorination? • 지방족 탄화수소와 고분자에서 C-H, C-F의 해리에너지를 비교해 보면, • methane에서 C-H, C-F의 비교 • 1)CH4, CF4 • C-H (104kcal/mol) < C-F (130.5kcal/mol) • 2)CH3F, CF4 • C-F (CH3F,108.3kcal/mol) < C-F(CF4,130.5kcal/mol) • 즉, 같은 구조에서는 C-H보다 C-F의 결합이 더 강하고, fluorination의 정도가 클수록 강한 결합이다. • Ethane에서 C-H, C-F의 비교 CH3-CF3에서 보면, C-H (106.7kcal/mol) < C-F (124.8kcal/mol) • Polymer의 경우 ( C-C 비교 ) PTFE의 C-C 결합이 PE의 C-C 결합보다 8kcal/mol 더 강하다. 이상에서 fluorination에 의해 C-C및 C-F의 강한 결합이 유도되므로 고분자의 내열성이 증가한다고 볼 수 있다.

  10. Fluoropolymers • Eunsil Han and Bumjae Lee, Prospectives of industrial chemistry, 2, 23, (1999) • Historical Background • 1938 PTFE를 DuPont사의 R.P.Plunkett에 • 의해 발견 • 1943 원자폭탄에 사용되는 우라늄 동위원소 • 를 분리하는 장치로 처음 사용 • 독일(I.G.Farben)에서 개발된 PCTFE • 가 별도로 연구 • 1944-1947 상업적 용도로 영국 I.C.I에서 • pilot규모로 생산 • 1954 Kel-F(VDF/CTFE) Categories of Fluoropolymers. Monomers used in fluoroplastics ETFE=E/TFE, THV=TFE/HFP/VDF, ECFE=E/CTFE/other, PFEVE=CTFE/PPVE, FKM=Vinylidenefluoride fluorocarbon elastomer, PFA=TFE/PPVE, FBE=TFE/HFP/PPVE, FEP=TFE/HFP, MFA=TFE/PMVE, CYTOP=poly[perfluoro-butenyl vinylether(BE)], Teflon AF=TFE/2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole, AFLAS=TFE/PP alternating elastomer, KALREZ=TFE/PMVE perfluoroelastomer

  11. “Fluorine Chemistry : A comprehensive Treatment”, Ed. by Mary Howe-Grant, p.381, (1995) • J.S.Forsythe and D.J.T.Hill, Prog.Polym.Sci., 25, 101, (2000) Polytetrafluoroethylene(PTFE) Polyvinylidene fluoride(PVDF) • PTFE 수지의 장점 • 우수한 화학적 저항성 • 넓은 사용온도 범위에서의 열적 안정성 • 비접착성 표면 특성 • 높은 dielectric strength를 지니면서 낮은 dielectric loss • 초순수한 고분자 • PTFE 수지의 단점 • 낮은 creep 저항성(cold flow) • 어려운 weldability • 어려운 용융가공성 • PVDF 수지의 장점 • 우수한 기계적 강도, 강인성 및 내마모성 • 낮은 가스 및 액체 투과성 • 우수한 열안정성 • 저연소 및 저발연 특성,고온에서의 creep 저항성 • 우수한 용융가공성,내화학적 저항성(단 Ketone, amine, amide에는 용해) • 우수한 UV 및 방사선 저항성, 내후성 • 초순수한 고분자 • PVDF 수지의 단점 • 낮은 충격강도 및 파단신율 • 화학적 응력 균열, 불투명성, 유연성 부족

  12. Meltprocessible perfluoromolymer

  13. Fluorinated polymers • Sang Youl Kim, Polymer Science and Technology, 3, 36, (1992) • Shigekuni Sasaki and Shiro Nishi in “Polyimide”, Ed. by GHOSH and MITTAL, p.71, (1996) • Polyimide Purpose 1)improve solubility 2)reduce of dielectric conatnt • 1. Requirement of properties • 가공성 • 공정상의 열적, 화학적 및 기계적 성질 우수 • 제조 후 제품의 형상유지에 필요한 충분한 • 기계적 성질 • 절연성(유전상수가 낮을 것) 1) • Fluorine, 주로 –CF3 group을 고분자의주쇄나 측쇄에 함유 • 내열성의 현저한 감소없이 고분자의 용해도를 증가 • 유전상수의 감소 및 흡수율의 저하효과 Du Pont에 의해 microelectronics용으로 제조 유전상수 2.9 흡수율 2% 열팽창계수 60ppm/℃ Tg 290℃ 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride(6FDA)와 oxydianiline(ODA)의 중합

  14. 2) Ethyl (Eymyd) 유전상수 2.92 Tg 331℃ 열팽창계수 55ppm/℃ 2,2-bis(4-aminophenoxyphenyl)hexafluoropropane (4BDAF)와 6FDA의 중합 3) Hoechst Cellanese (Sixef polyimide) 유전상수 2.65 Tg 322℃ 흡수율 1.1% 2,2’-bis(4-aminophenyl)hexafluoropropane (4,4’-6FDA)와 6FDA 의 중합

  15. Journal of polymer science:Part A:Polymer Chemistry, 38, 1991-2003, (2000) • Fluorinated Benzoxazole Polymer • Results • Fluorinated polymer system • Low dielectric constant, high thermal stability • Low moisture absorption • Benzoxazole polymer system • High Tg(>400℃)

  16. Journal of Polymer Science:Part A:Polymer Chemistry, 31, 3465, (1993) Macromolecules, 29, 852, (1996) Mat. Res. Soc. Symp. Proc, 443 ,21, (1997) • Perfluorocyclobutane Aromatic Ether Polymer • Parylene AF-4 Synthesis of monomer Synthesis of polymer • Dielectric constant : 2.2~2.3 • Dissociation : 530 ℃ in N2 • Thickness vs Annealing Temp : no change to 500℃ in N2 • Structure As Deposited : Crystalline/Amorphous Poly(1,1,1-triphenylethane perfluorocyclobutyl ether

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