New fluorinated thermoplastic elastomers

Tonelli, Claudio; Trombetta, Tania; Scicchitano, Massimo; Simeone, Giovanni; Ajroldi, Giuseppe

doi:10.1002/(sici)1097-4628(19960110)59:2<311::aid-app16>3.0.co;2-z

Cited by 86 publications

(19 citation statements)

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“…Generally, within each PTMEG series, T m increased, as expected, with the nominal concentration of MDI units in the hard phase up to a given polymerization degree and then leveled off to a nearly constant value. Similar behavior was described in a previous work 35. This trend was attributed to an artifact induced by annealing after casting carried out at a constant temperature, instead of a constant temperature difference becomes, with respect to the expected T m ; this point will be clearer after the discussion on the second melting.…”

Section: Resultssupporting

confidence: 84%

“…Earlier studies,34, 35 focused on both crosslinked and linear PUs obtained by a full replacement of the hydrogenated soft macromer by a PFPE segment, have confirmed the previously mentioned results. They have shown that PFPE‐containing PUs offer a larger service temperature range than conventional PUs, combined with superior chemical resistance and surface characteristics.…”

Section: Introductionsupporting

confidence: 74%

“…These data indicate that a slight modification of the bulk composition dramatically reduced the surface energy of the material to a minimum value that is that typically expected for perfluorinated PFPE‐based polymers (ca. 15 mN/m) 34, 35…”

Section: Resultsmentioning

confidence: 99%

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New fluoro‐modified thermoplastic polyurethanes

Tonelli¹,

Ajroldi²

2003

J of Applied Polymer Sci

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New fluoro-modified thermoplastic polyurethanes containing perfluoropolyether (PFPE) blocks were synthesized by the reaction of a fluorinated macrodiol with a hydrogenated prepolymer based on poly(tetramethylene glycol) and 4,4Ј-methylene-bis-phenylisocyanate, followed by subsequent chain extension with 1,4-n-butanediol. This multistep bulk process opened the way for a new family of polymeric materials whose tensile properties appear to be excellent and unchanged in comparison with the corresponding unmodified hydrogenated polymers. Dynamic mechanical analysis and differential scanning calorimetry revealed peculiar characteristics. These polymers showed an unusual multiphase structure in which not only the hard and the hydrogenated soft segments were self-organized, but also a second soft phase, constituted by the PFPE segments, was present. Moreover, an easier hard-phase segregation and self-organization were observed, as was evidenced by the higher melting temperatures of the semicrystalline phase. This unique characteristic combined with a selective enrichment of PFPE segments to the surface, as indicated by the unusually low coefficient of friction data and superior chemical resistance.

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Section: Resultssupporting

confidence: 84%

Section: Introductionsupporting

confidence: 74%

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New fluoro‐modified thermoplastic polyurethanes

Tonelli¹,

Ajroldi²

2003

J of Applied Polymer Sci

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“…The parameters were calculated using the MSI amorphous cell package with the PCFF2 force field. a From Tonelli et al16 …”

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confidence: 99%

Effect of polydimethylsiloxane macrodiol molecular weight on properties and morphology of polyurethane and polyurethaneurea

Adhikari

Gunatillake

Bown

2003

J of Applied Polymer Sci

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Two series of polyurethanes and polyurethaneureas were prepared using a two-step bulk-solution polymerization procedure. Each series consisted of three polymers based on three molecular weights of ␣,-bis(6-hydroxyethoxypropyl) polydimethylsiloxane (PDMS): 940, 1913, and 2955. The soft segment in all cases was an 80:20 mixture of PDMS and poly(hexamethylene oxide) (MW 700), and the hard segment was based on 4,4Ј-methylenediphenyl diisocyanate and mixed chain extenders (40 wt %). In the polyurethane (PU) series the chain extender was a 60:40 (mol) mixture of BDO and 1,3-bis(4-hydroxybutyl)1,1,3,3-tetramethyldisiloxane (BHTD), whereas in the polyurethaneurea (PUU) series it was a 60:40 (mol) mixture of BHTD and 1,2-ethylenediamine. The polymerization was carried out by preparing a prepolymer using a bulk polymerization procedure followed by chain extension in a solution of N,Ndimethylacetamide. Polymers were characterized by sizeexclusion chromatography, tensile testing, differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). The number-average molecular weights of the polymers in the PU series were in the range of 114,300 -124,500, whereas they were in the 78,400 -103,300 range for the PUU series. Polymers with good clarity and mechanical properties were obtained with PDMS-940 and PDMS-1913, but those obtained from PDMS-2955, despite having good tensile strength, had a low percentage of elongation, high modulus, and poor clarity. DSC and DMTA results indicated that regardless of the PDMS molecular weight, the siloxane segments existed as a highly phaseseparated state. This poor compatibility was consistent with the low solubility of PDMS compared to that of the hardsegment-forming components. The polymers in the polyurethane series exhibited multiple melting endotherms, attributed to the melting of ordered domains from different hard segments. The combined heats of fusion were similar for the materials in the PU series. In contrast, the polymers in the PUU series showed a hard-segment order that was significantly less defined, with the heat of fusion approximately a third to a half that of the materials in the polyurethane series.

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“…In the last space group the adducts exist only at reduced temperatures, except for those containing squalene or aromatic guests (Clement, Jegoudez & Mazieres, 1974). In this type of classical inclusion compound the host structure is built of thiourea molecules in an extensively hydrogen-bonded lattice, which contains parallel channels or tunnels with a free diameter of ca 6.1/~, which can accommodate a variety of guest species, such as single-ring aromatics, cyclohexane and some of its derivatives (Schofield, Harris, Shannon & Rennie, 1993), ferrocene and other organometallics (Anderson, Calabrese, Tam & Williams, 1987), as well as fragments of polymers containing either phenyl groups or sugar tings (Tonelli, 1992).…”

Section: Introductionmentioning

confidence: 99%

Inclusion Compounds of Thiourea and Peralkylated Ammonium Salts. VI. Hydrogen-Bonded Host Lattices Constructed From Thiourea and Anions of Oxalic Acid and Fumaric Acid

Li¹,

Mak²

1997

Acta Crystallogr Sect B

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New inclusion complexes tetra-n-butylammonium hydrogen oxalate–thiourea (1/2), (n-C4H9)4N+.HC2O4 −.2[(NH2)2CS] (1), tetramethylammonium hydrogen fumarate–thiourea (1/1), (CH3)4N+.HC4H2O4 −.(NH2)2CS (2), di(tetraethylammonium) fumarate–thiourea (1/2), [(C2H5)4N+]2.C4H2O4 2−.2[(NH2)2CS] (3) and tetra-n-propylammonium hydrogen fumarate–thiourea–water (1/1/2), (n-C3H7)4N+.HC4H2 O4 −.(NH2)2CS.2H2O (4) have been prepared and characterized by X-ray crystallography. Crystal data, Mo Kα radiation: (1), space group P21/n, a = 8.854 (6), b = 9.992 (3), c = 32.04 (2) Å, β = 97.34 (3), Z = 4, R F = 0.055 for 2261 observed data; (2), space group P\overline 1, a = 6.269 (2), b = 8.118 (4), c = 14.562 (8) Å, α = 104.79 (4), β= 91.72 (4), γ = 101.30 (4)°, Z = 2, R F = 0.078 for 1543 observed data; (3), space group P21/n, a = 11.340 (2), b = 9.293 (6), c = 14.619 (2) Å, β = 102.41 (2)°, Z = 2, R F = 0.050 for 1856 observed data; (4), space group P2/n, a = 16.866 (4), b = 8.311 (1), c = 17.603 (2) Å, β = 104.94 (1)°, Z = 4, R F = 0.048 for 2785 observed data. In the crystal structure of (1) the tetra-n-butylammonium ions are sandwiched between puckered layers, which are constructed from thiourea-hydrogen oxalate ribbons. In the crystal structure of (2), zigzag O--H...O and C--H...O hydrogen-bonded hydrogen fumarate ribbons are linked by thiourea dimers to form a wide puckered ribbon and the crystal structure is built of a packing of these thiourea–anion composite ribbons and the cationic columns. In the layer-type crystal structure of (3) a series of thiourea–fumarate layers match the (002) planes and the (C2H5)4N+ cations occupy the intervening space. In the crystal structure of (4) the thiourea, hydrogen fumarate ions and water molecules are connected by hydrogen bonds to form wide puckered ribbons, which are crosslinked to generate a three-dimensional host framework containing open channels aligned parallel to the a axis, with the tetra-n-propylammonium cations accommodated in a single column within each channel.

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New fluorinated thermoplastic elastomers

Cited by 86 publications

References 1 publication

New fluoro‐modified thermoplastic polyurethanes

New fluoro‐modified thermoplastic polyurethanes

Effect of polydimethylsiloxane macrodiol molecular weight on properties and morphology of polyurethane and polyurethaneurea

Inclusion Compounds of Thiourea and Peralkylated Ammonium Salts. VI. Hydrogen-Bonded Host Lattices Constructed From Thiourea and Anions of Oxalic Acid and Fumaric Acid

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