Polymers containing fluorinated ketone groups. II. NMR studies of the reaction of methylbenzyl trifluoromethyl ketones with alcohols in carbon tetrachloride

Prior to the study of poly(o- and p-vinylbenzyl trifluoromethyl ketone) (PVTFK) polymers and their reaction with alcohols, the reactions of some simple model compounds with alcohols were investigated. The reaction of fluorinated ketones toward alcohols was determined by proton nuclear magnetic resonance (NMR) spectroscopy. Two fluorinated ketones–p-methylbenzyl trifluoromethyl ketone (p-MTFK) and o-methylbenzyl trifluoromethyl ketone (o-MTFK)–were prepared. Studies of the reaction of p-MTFK and o-MTFK to various alcohols based on NMR produced equilibrium constants (1M in CCl₄) at 31°C that ranged from 0.1 to 6.0. The equilibrium constants for p-MTFK with alcohols were larger than those for o-MTFK. In addition, the equilibrium constants for primary alcohols were larger than those for secondary and tertiary alcohols. Steric effects in this reaction could explain the lowered equilibrium constants for o-MTFK and the secondary and tertiary alcohols.     

Polymers containing fluorinated ketone groups. III. Synthesis of styrene/p-vinyltrifluoroacetophenone copolymers by modification of polystyrene and the copolymerization of monomers

Copolymers of styrene/p-vinyltrifluoroacetophenone were prepared by two different reaction routes: (1) modification of polystyrene with trifluoroacetyl chloride and (2) copolymerization of styrene and p-vinyltrifluoroacetophenone (VTFA). There appears to be a limit to the modification method because only a maximum content of 14.5 mole % trifluoroacetyl functionality could be attached to the polymer before the onset of crosslinking. Differential scanning calorimetry (DSC) was used to determine their T_g's. In addition, the reactivity ratios of styrene and VTFA were investigated. The reactivity ratios and Q and e values were r₁ = 0.30 ± 0.09 (styrene) and r₂ = 1.3 ± 0.3 (VTFA); Q₁ = 1.0 and e₁ = ?0.8 (styrene); Q₂ = 0.44 and e₂ = 1.93 (VTFA).     

Polymer containing fluorinated ketone groups. I. DSC and NMR studies of poly(p-vinyltrifluoroacetophenone) and polymers of similar structure

The unexpected crystallinity of free radically polymerized poly(p-vinyltrifluoroacetophenone) (PVTFA) due to lateral order was previously found in this laboratory. To further the understanding of the relationship between chemical structure and crystalline order in polymers of the PVTFA type, polymers of similar structure were synthesized and characterized by differential scanning calorimetry (DSC). These polymers were poly(p-vinyldifluoroacetophenone) (PVDFA), poly(p-vinylphenylheptafluoropropyl ketone) (PVHFK), poly(p-vinylacetophenone) (PVA), and poly(p-vinylphenyltrifluoromethyl carbinol) (PVPTC). Only PVTFA had a crystalline melting temperature (188°C); 220-MHz nuclear magnetic resonance (NMR) measurements on the microstructure of PVTFA and PVDFA revealed broad peaks for the chain protons. The PVTFA was therefore assumed to be predominantly atactic. The results suggested that the unusual crystallinity of PVTFA was related to the unique size and interaction of the trifluoroacetyl moiety on the polymeric side chain.     

Synthesis and characterization of fluorinated poly(aryl ether ketone)s containing 1,4-naphthalene moieties

The new monomer 2,2-bis[4-(4-{4-fluorobenzoyl}-1-naphthoxy)phenyl]hexafluoropropane ( 2 ) was synthesized in a two-step reaction sequence. 2,2-his[4-(1-naphthoxy)phenyl]-hexafluoropropane ( 1 ) was prepared using the Ullmann ether synthesis reaction of 4,4-(hex-afluoroisopropylidiene)diphenol with 1-bromonaphthalene. Friedel-Crafts acylation of 1 with 4-fluorobenzoyl chloride in methylene chloride containing dimethylsulfone selectively afforded 2 in 82% yield. The polycondensation of 2 with various bisphenols in DMAc in the presence of an excess of potassium carbonate as a condensation reagent was carried out at 165°C to quantitatively afford the corresponding fluorinated poly(aryl ether ketone)s containing 1,4-naphthalene moieties. Thermal analysis of the polymers showed them to have T_gs ranging from 194 to 230°C and to be thermally stable in air up with initial weight losses at about 500°C. In addition, these novel polymers exhibited excellent solubility in organic solvents including NMP, DMAc, and chloroform. © 1997 John Wiley & Sons, Inc.     

Syntheses and degradations of fluorinated heterocyclics. IV. Imidoylamidoximes, 1,2,4-oxadiazole precursors

Perfluoroalkylether amidoximes free from amide-contamination were prepared from imidate esters. The amidoximes were stable at 110°C; at ～170°C partial decomposition to 1,2,4-oxadiazoles, admixed with other compounds, took place. Interactions between nitriles and amidoximes at 50°C resulted in the formation of imidoylamidoximes; these dissociated readily into their constituents when subjected to higher temperatures. At 70°C and above, in the presence of excess nitrile or other ammonia acceptors, the imidoylamidoximes afforded high yields of the corresponding 1,2,4- oxadiazoles.     

Biocompatible polystyrenes containing pendant tetra(ethylene glycol) and phosphorylcholine groups

The synthesis and characterization of styrene‐based polymers and copolymers containing pendant tetra(ethylene glycol) and phosphorylcholine groups is reported. These polymers are obtained via radical polymerization reactions using α,α′‐azobis(isobutyronitrile) as the initiator, and are developed as protective biocompatible coatings for implantable biosensors. Cell morphology studies show that none of the synthesized polymers and copolymers are toxic, and that the rate of cell growth can be tuned by changing the monomer composition. The presence of tetra(ethylene glycol) groups in the coatings lowers the protein adsorption, thereby influencing the rate of cell growth. An equally profound effect is observed when a low percentage of phosphorylcholine groups is present in the polymers. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 468–474, 2001     

Photochemistry of fiber-forming polymers. I. Acrylonitrile copolymers and fibers containing ketone groups

The inclusion of minor amounts of methyl isopropenyl ketone in polyacrylonitrile and its copolymers with methyl acrylate and vinyl acetate causes the polymer to become sensitive to ultraviolet light in the 290–320 nm region. Both films and fibers show decreases in molecular weight on irradiation which are attributable to C? C bond scission by the Norrish type II reaction. In addition to bond cleavage, decarbonylation occurs, presumably by a type I radical process which also leads to the formation of ketonitrile groups. Fibers spun from such polymers lose most of their tensile strength and elongation after a few months outdoor exposure to natural sunlight, whereas control samples not containing carbonyl groups will retain their strength for much longer periods. Quantum yields both for chain scission and for carbonyl loss in these systems are estimated to be of the order of 0.005.     

Synthesis and characterization of chiral liquid‐crystalline polysiloxanes containing fluorinated units and sulfonic acid groups

Chiral side‐chain liquid‐crystalline polysiloxanes ( PS‐1 , PS‐2 , PS‐3 , PS‐4 , PS‐5 , PS‐6 ) bearing fluorinated units and sulfonic acid groups were synthesized with poly(methylhydrogeno)siloxane, cholest‐5‐en‐3‐ol(3β)‐4‐(2‐propenyloxy)benzoate, and 3‐trifluoromethyl‐phenyl 3‐sulfo‐4‐undec‐10‐ enoyloxy‐benzoate. The effects of fluorinated units and sulfonic acid groups on characteristic of liquid‐crystalline properties were studied. PS‐1 , PS‐2 , and PS‐3 exhibited both smectic and cholesteric mesophases, while PS‐4 , PS‐5 , and PS‐6 exhibited only cholesteric mesophase. As the polymers contained more fluorinated units and sulfonic acid groups, segregation of the fluorinated segment to the surface and aggregation of hydrogen bonding should occur. Therefore, the highly ordered lamellar mesogen–siloxane matrix systems should be disturbed severely, suggesting that PS‐4 , PS‐5 , and PS‐6 show no smectic phase. The maximum reflection bands become broad and shifted slightly to long wavelength from PS‐1 to PS‐6 . Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and characterization of new aromatic polyesters containing cardo decahydronaphthalene groups

Three cardo bisphenols containing decahydronaphthalene group viz., 4,4′-(octahydro-2(1H)-naphthylidene)bisphenol, 4,4′-(octahydro-2(1H)-naphthylidene)bis-3-methylphenol and 4,4′-(octahydro-2(1H)-naphthylidene)bis-3,5-dimethylphenol were synthesized starting from commercially available 2-naphthol and were utilized for synthesis of new aromatic polyesters by phase transfer-catalyzed interfacial polycondensation with isophthaloyl chloride, terephthaloyl chloride and a mixture of isophthaloyl chloride and terephthaloyl chloride (50:50 mol %). Inherent viscosities and number average molecular weights (M_n) of polyesters were in the range 0.35-0.84 dL/g and 13,300-48,500 (Gel Permeation Chromatography, polystyrene standard), respectively. Polyesters were readily soluble in organic solvents such as dichloromethane, chloroform, tetrahydrofuran, meta-cresol, pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, and 1-methyl-2-pyrrolidinone at room temperature and could be cast into tough, transparent and flexible films from their chloroform solutions. Wide-angle X-ray diffraction measurements revealed the amorphous nature of polyesters. The glass transition temperature of polyesters was in the range 207-287 °C. The temperature at 10% weight loss (T₁₀), determined from thermogravimetric analysis of polyesters, was in the range 425-460 °C indicating their good thermal stability.     

Cyclosiloxane-based liquid-crystalline elastomers containing fluorinated mesogens and chiral crosslinking groups

A series of chiral fluorinated liquid-crystalline elastomers (LCEs) IP-VIP are prepared by 4-cyano-3-fluorophenyl 4′-(undec-10-enoyloxy)biphenyl-4-carboxylate, isosorbide bis(4-allyloxybenzoate) and 2,4,6,8-tetramethylcyclotetrasiloxane via Pt-catalyzed hydrosilylation. The chiral crosslinking moieties increase from IP to IVP. The elastomers IP, IIP, and IIIP containing low content of chiral crosslinking moieties display S_C ^* liquid-crystalline phase, but IVP, VP, and VIP do not show S_C ^* phase except for N^* mesophase. The mesophase is testified according to typical diffractogram measured by X-ray diffraction (XRD) analysis. The layer spacings of the LCEs decrease from IP (d-spacing of 34.2 Å) to VIP (d-spacing of 31.6 Å) with increase of chiral crosslinking groups in the polymers systems. Moreover, the optical properties are performed by ultraviolet–visible–near-infrared spectrophotometry. VP and VIP containing the most chiral crosslinking moieties display maximum reflection in near infrared spectra in the measurement of optical properties, while IP, IIP, IIIP, and IVP do not show obvious maximum reflection. It is interesting that a specific reflection of circularly polarized light appears along with a changing mesophase due to high enough concentration of chiral crosslinking dopants for VP and VIP. All these results suggest that the chiral crosslinking moieties exert influence on the structures of these kinds of LCEs.     

Synthesis and characterization of new polystyrenes containing tributyltin moieties linked to the aromatic ring through a methylenic spacer

Novel polymeric derivatives bearing tributyltin carboxylate moieties in the side chain were synthesized. The coordination at tin in solution and in the solid state was investigated by both Sn‐NMR and FT‐IR: the metal atom appears completely tetracoordinated in chloroform solution, while in the solid state all polymeric products exhibit both tetra‐ and pentacoordination at tin, the latter increasing with the amount of tin containing units. No evidence of tin leaching by hydrolysis of the organometallic ester was observed for these materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5372–5383, 2004     

Synthesis and surface properties of fluorinated block copolymers containing sulfonic groups

A series of fluorinated block copolymers with different fluorinated block lengths and compositions were synthesized by atom transfer radical polymerization (ATRP), and then the block copolymers containing sulfonic groups with various sulfonation levels were successfully prepared further via a sulfonation reaction. These well‐defined block copolymers were characterized by means of Fourier transform infrared (FTIR), ¹H‐nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The surface activities of the fluorinated block copolymers containing sulfonic groups in N‐methyl pyrrolidone solution and the surface properties of the films prepared from such a solution were examined, and the experimental results showed that the fluorinated block copolymers exhibited a high surface activity in solution and quite a low solid surface energy of films, even though they contain hydrophilic sulfonic groups. The critical surface tensions of these copolymers were estimated and were comparable to that of polytetrafluoroethylene. Even more interestingly, the surface activities of the block copolymers containing sulfonic groups or sodium sulfonate groups in aqueous solution were also measured. It was found that the surface activity in aqueous solution was weaker than that in N‐methyl pyrrolidone solution and depended on both the length of the fluorinated block and the sulfonation level of the block copolymers. The surface properties of the films prepared from the block copolymers in aqueous solution were tested, and most of these films exhibited a hydrophilic surface property. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4809–4819, 2004     

Synthesis and characterization of fluorinated polyurethane with fluorine-containing pendent groups

A novel fluorinated polyurethane （FPU） with fluorine-containing pendent groups was prepared by using fluorinated polyether glycol （PTMG-g-HFP） as a soft segment, 1,6-hexamethylene diisocyanate （HDI） or toluene diisocyanate （TD1） as a hard segment and 1,4-butanodiol （BDO） as a chain extender. FTIR, ^1H NMR, ^13C NMR and GPC were used to characterize the structure of the fluorinated polyurethane. Thermal stabilities of the fluorinated polyurethane and the corresponding hydrogenated polyurethane were studied by TGA. XPS analysis at two different sampling depths for the fluorinated polyurethane was used to investigate the surface compositions of FPU. The results showed the fluorine enrichment on the surface of FPU.     

Synthesis and characterization of new cholesteric monomers and smectic polymers containing menthyl groups

New cholesteric monomers (M₂−M₅) and the corresponding smectic homopolymers (P₂−P₅) based on menthyl groups were synthesized. The chemical structures were characterized by Fourier transform infrared and ¹H NMR. The specific optical rotations were evaluated with a polarimeter. The structure–property relationships of the new compounds are discussed. The mesomorphism was investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X-ray diffraction. The selective reflection property of light was studied with UV/Visible/NIR. The monomers M₂−M₅ formed the cholesteric or blue phase when a flexible link chain was inserted between the mesogenic core and the terminal menthyl groups by reducing the steric effect. M₁ showed no mesomorphism, while M₂−M₅ revealed enantiotropic cholesteric phase. In addition, M₂ and M₃ also showed a cubic blue phase on cooling. The selective reflection of light for M₂−M₅ shifted to the short reciprocal wavelength region with increasing the temperature or intramolecular spacer length. P₂−P₅ exhibited the smectic A phase. The melting, clearing, and glass transition temperatures increased when increasing the aryl number in the mesogenic core or decreasing the intramolecular spacer length.     

Synthesis and characterization of side-chain liquid-crystalline polysiloxanes containing fluorinated units

Several new chiral side-chain LC polysiloxanes (IP–VIIP) bearing fluorinated methyl groups were synthesized with a cholesteric LC monomer and a non-LC monomer containing fluorinated units. The chemical structures and LC properties of the monomers and polymers were characterized by use of various experimental techniques. The effect of copolymer composition on mesomorphic properties of the fluorine-containing polymers was studied as well. The obtained polymers were soluble in many solvents and the specific rotations showed negative values. The temperatures at which 5% weight loss occurred (T _d) were greater than 300 °C for all the polymers and the residue weight on heating to 600 °C increased slightly with increase of the monomer containing fluorinated units in the polymer systems. All the polymers displayed two-phase transitions when they were heated and cooled. The IP, IIP, and IIIP exhibited cholesteric textures when they were heated and cooled, while IVP, VP, VIP, and VIIP showed smectic fan-shaped textures. XRD curves of samples of IVP, VP, VIP, and VIIP displayed sharp and strong peaks at low angle, but no sharp peaks were shown at low angle for the samples IP, IIP, and IIIP.     

Syntheses and characterization of new palladium(II) complexes with functionally substituted cyclopentadienyl groups

Thallium [1-(p-tolylimino)-2-methylpropyl]cyclopentadienide, Tl[C₅H₄C(=NC₆H₄CH₃)CH(CH₃)₂], was prepared and treatment of the salt with [{PdCl₂(PREt₂)}₂] (R = Ph and Et) yielded mononuclear palladium(II) complexes, [Pd{η⁵-C₅H₄C(=NC₆H₄CH₃)CH(CH₃)₂}Cl(PREt₂)], with an imidoyl-substituted η⁵-cyclopentadienyl group. In addition, [Pd(η⁵-C₅H₄-COY)Cl(PPhEt₂)] (Y = CH₃ and OCH₃) complexes were obtained from the sodium salts of their substituted cyclopentadienyl groups. These new compounds were characterized by means of ¹H and ¹³C NMR and IR spectroscopy.     

Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials

A series of sulfonated poly(aryl ether ether ketone ketone)s statistical copolymers with high molecular weights were synthesized via an aromatic nucleophilic substitution polymerization. The sulfonation content (SC), defined as the number of sulfonic acid groups contained in an average repeat unit, could be controlled by the feed ratios of monomers. Flexible and strong membranes in sodium sulfonate form could be prepared by the solution casting method, and readily transformed to their proton forms by treating them in 2 N sulfuric acid. The polymers showed high T_gs, which increased with an increase in SC. Membranes prepared from the present sulfonated poly(ether ether ketone ketone) copolymers containing the hexafluoroisopropylidene moiety (SPEEKK‐6F) and copolymers containing the pendant 3,5‐ditrifluoromethylphenyl moiety (SPEEKK‐6FP) had lower water uptakes and lower swelling ratios in comparison with previously prepared copolymers containing 6F units. All of the polymers possessed proton conductivities higher than 1 × 10^?2 S/cm at room temperature, and proton conductivity values of several polymers were comparable to that of Nafion at high relative humidity. Their thermal stability, oxidative stability, and mechanical properties were also evaluated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2299–2310, 2006     

Langmuir monolayers and the transferred films of fluorinated amphiphiles containing vinyl groups

The monolayer behavior of long-chain esters of acrylic and methacrylic acids containing perfluoro or partially fluorinated carbon chains at the air/water interface was studied by surface pressure-area isotherm measurements and Brewster angle microscopy. It has been found that a minor change in the chemical structures of these fluorinated amphiphiles, such as a hydrogen substituted at the omega-position of the hydrophobic fluorocarbon tails instead of a fluorine as well as hydrophilic vinyl ester groups inserted between acrylates and methacrylates, induces a drastic change in the isotherms for the monolayers, suggesting different molecular orientation and packing in the films. The monolayers were transferred by horizontal lifting, Langmuir-Blodgett, and surface-lowering methods to give the X-, Y-, and Z-type films, respectively. These films were characterized by scanning probe microscopy, to clarify the mesoscopic surface structures of the molecular films exposed with the hydrophilic or hydrophobic moieties in air, depending upon the dipping methods. The Z-type films with the outermost surface of the fluorinated substituents were examined in relation to the frictional properties that strongly depend upon the fluorine and the hydrogen atoms at the end of the hydrophobic fluorocarbon chains, which is controllable at the atomic level.