Phase behavior and some calorimetric and physical properties of diurethanes from perfluoropolyether macromonomers

Tonelli, Claudio; Bassi, Mattia; Ajroldi, Giuseppe

doi:10.1002/(sici)1099-0488(19990715)37:14<1609::aid-polb6>3.0.co;2-8

Cited by 10 publications

(18 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, coatings containing only ZDOL 500 (BC‐5–HDI‐5 and MC‐5–HDI) show no apparent T g F and behave as monophasic materials. As a matter of fact, the miscibility of low molecular weight PFPE oligomers with urethanes, indicated by a marked decrease of the segregation ratio R of the fluorinated phase, was already observed in linear systems 13. Glass transition temperature of the urethane phase ( T g H ) values strictly depend on the coating composition; in particular, the crosslinking density of the MC products, higher than that of the BC products, causes higher T g H values.…”

Section: Resultsmentioning

confidence: 91%

“…From an examination of the data in Table III, it appears that all the coatings are amorphous and that most of them are biphasic because of the segregation of a soft PFPE rich phase and a hard polar (urethane or urea) phase, with very different solubility parameters, as already reported for both PFPE crosslinked coatings and linear PFPE urethane models 13. As known, phase segregation in a completely amorphous system is indicated by the presence of two or more well‐resolved glass transitions.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Fluoropolyether coatings: Relationships of electrochemical impedance spectroscopy measurements, barrier properties, and polymer structure

Delucchi

Turri

Barbucci

et al. 2001

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

Ten model coatings, selected and obtained from a family of fluorinated resins synthesized by the reaction of perfluoroether oligomeric diols of different molecular weights with polyisocyanurates of hexamethylenediisocyanate (HDI) and isophoronediisocyanate (IPDI), were characterized with differential scanning calorimetry, mechanical testing, and electrochemical impedance spectroscopy measurements. The electrochemical and chemico-physical measurements show that the glass-transition temperature of the starting isocyanate trimers greatly influences the properties of the final urethane coatings; the IPDI trimer gives harder coatings with lower water permeabilities than the corresponding HDI-based materials. Moreover, for each class of materials (from IPDI or HDI), the fluorine content plays a relevant role: the higher the fluorine percentage, the lower the water absorption into the coatings. Furthermore, the chain length of the polyols used for the synthesis of the prepolymers is a variable that exhibits great influence on the coating properties: coatings containing shorter perfluoropolyether segments show better barrier properties. orinated polyether to the cyclic trimers (polyisocyanurates) of hexamethylenediisocyanate (HDI) or isophoronediisocyanate (IPDI). The prepolymers can be self-cured by exposure to atmospheric moisture [monocomponent (MC), moisture-curing formulations] or crosslinked by the addition of stoichiometric amounts of ZDOL polyethers [BC (bicomponent) formulations]. Several properties of this new class of materials have been recently described, 1 including electrochemical impedance for TiO 2 -pigmented coatings. 2 PFPE coatings are characterized by high durability and peculiar surface properties and so are very interesting candidates for developing new anticorrosive protective systems for steel, concrete, and other engineering materials. As a matter of fact, the water permeability and barrier behavior of coating systems containing PFPE may depend

show abstract

Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Fluoropolyether coatings: Relationships of electrochemical impedance spectroscopy measurements, barrier properties, and polymer structure

Delucchi

Turri

Barbucci

et al. 2001

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

show abstract

“…First, the reduced solubility of the hard segment in NP would tend to enhance phase separation. Second, it has been shown in model compounds45 that even low concentrations of hard segments will phase separate when the solubility parameters are sufficiently different.…”

Section: Resultsmentioning

confidence: 99%

Dynamic mechanical signatures of a polyester‐urethane and plastic‐bonded explosives based on this polymer

Hoffman

2001

J of Applied Polymer Sci

View full text Add to dashboard Cite

ABSTRACT:The complex shear moduli of the segmented polyurethane Estane 5703p, Livermore explosive (LX)-14, and plastic bonded explosive (PBX)-9501, which use this polymer as a binder, have been investigated. Segmented polyurethanes, such as Estane 5703, contain microphase-separated hard segments in a rubbery matrix of soft segments. LX-14 is composed of 95.5% 1,3,5,7-tetranitroazacyclooctane (HMX) explosive with 4.5% Estane 5703 binder. PBX-9501 is composed of 94.9% HMX, 2.5% Estane 5703p binder, 2.5% nitroplasticizer (NP), and about 0.1% antioxidant Irganox 1010. In the temperature range from Ϫ150 to 120°C, two relaxations were observed as peaks in the loss modulus and tangent delta in Estane 5703p and LX-14. A third relaxation was found in PBX-9501. The low temperature relaxation associated with vitrification of the poly(ester urethane) soft segment occurred in the shear loss modulus (GЉ) at Ϫ29 and Ϫ26°C in Estane and LX-14, respectively, at 1 Hz. In PBX-9501 the Estane soft segment glass transition peak, T g (SS), in the loss modulus occurred at Ϫ40 Ϯ 3°C at 1 Hz. The reduction in soft segment glass transition in PBX-9501 is clear evidence of plasticization of the soft segment by NP. The apparent activation energy of the maximum in the loss modulus for LX-14 and PBX-9501 over the frequency range from 0.1 to 10 Hz was 230 kJ/mole (55 kcal/mole). The hard segment glass transition, T g (HS), was observed as a peak in the loss modulus at about 70°C. In LX-14 the transition was observed at lower temperatures (56 -58°C at 1 Hz) depending on thermal history. There was a low temperature shoulder on the T g (HS) of Estane 5703 associated with soft segment crystallinity. Modulated differential scanning calorimetry (MDSC) was used to verify the T g (HS) in Estane and 50/50 mixtures of Estane with NP. In PBX-9501 the hard segment glass transition occurred between 65 and 72°C. The presence of NP in PBX-9501 gave rise to a new transition, T eu (NP), between 8 and 15°C. This peak is believed to be associated with the eutectic melting of the plasticizer. Returns of fielded PBX-9501 that were 6 and 11 years old were also measured. Small variations in T g (SS) and the rubber plateau modulus were observed in these aged samples, consistent with migration of plasticizer and/or very low levels of chain scission.

show abstract

“…Thus, a number of studies have been reported on the extent of phase separation of block copolymers. [33][34][35][36][37][38] The block length plays a very important role in the microphase behaviors of multiblock copolymers, as reported with a PCL-based polyurethane by Velankar; a single phase was obtained when the block length was short enough (less than 1250 g mol À1 ), microphase separation occurred and its degree increased with block length. 39 In the present study, we synthesize and characterize a series of PES-b-PBS multiblock copolymers with different lengths of PBS and PES blocks, and investigate the effect of PBS and PES block lengths on the miscibility and crystallization behaviors of the multiblock copolymers employing DSC, TMDSC, POM, and WAXD.…”

Section: Introductionmentioning

confidence: 79%

From miscible to partially miscible biodegradable double crystalline poly(ethylene succinate)-b-poly(butylene succinate) multiblock copolymers

et al. 2012

View full text Add to dashboard Cite

Phase behavior and some calorimetric and physical properties of diurethanes from perfluoropolyether macromonomers

Cited by 10 publications

References 36 publications

Fluoropolyether coatings: Relationships of electrochemical impedance spectroscopy measurements, barrier properties, and polymer structure

Fluoropolyether coatings: Relationships of electrochemical impedance spectroscopy measurements, barrier properties, and polymer structure

Dynamic mechanical signatures of a polyester‐urethane and plastic‐bonded explosives based on this polymer

From miscible to partially miscible biodegradable double crystalline poly(ethylene succinate)-b-poly(butylene succinate) multiblock copolymers

Contact Info

Product

Resources

About