Microphase-separated structure and mechanical properties of norbornane diisocyanate-based polyurethanes

Kojio, Ken; Nakashima, Shohei; Furukawa, Mutsuhisa

doi:10.1016/j.polymer.2006.12.057

Cited by 132 publications

(92 citation statements)

References 16 publications

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“…The chemical structure of SPU soft segments is determined by structure of oligomers used for their synthesis [1,5,[9][10][11]. Hard segments are formed during reaction of diisocyanate with low-molecular bi-functional compounds, e.g., diols or diamines.…”

Section: Introductionmentioning

confidence: 99%

Interrelationship between ultimate mechanical properties of variously structured polyurethanes and poly(urethane urea)s and stretching rate thereof

et al. 2012

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The ultimate mechanical properties of polyurethane determine their possible applications under various conditions of mechanical action. The mechanical properties of nine polyurethane and polyurethane urea samples were investigated in a range of stretching rates 0.56÷0.002 s −1 . A part of experiments was performed at several temperature values under conditions of stepwise variable stretching rates. The interrelationship between rate dependence of strength-strain properties of polyurethane compositions and the structure thereof was ascertained. The influence of molecular structure's variations, of physical network density and of segmented polyurethane and polyurethane urea morphology on said interrelationship was examined on samples subjected to large strain values. The structure of some samples was radically distorted by plasticizers oppositely influencing micro-phase segregation of soft and hard segments. Multiple kinds of dependency (direct, inverse, moderate and strong) of elastomers' strength versus stretching rate were demonstrated. Produced data and ascertained regularities are useful to perceive reasons for diversity of mechanical behavior of polyurethane materials and to control properties thereof.

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Section: Introductionmentioning

confidence: 99%

Interrelationship between ultimate mechanical properties of variously structured polyurethanes and poly(urethane urea)s and stretching rate thereof

et al. 2012

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“…Their molecular structure is determined by the components used in the polymerization reaction and on stoichiometry, and they phase separate during the reaction forming a supermolecular structure [6][7][8][9][10]. Phase separation has been the subject of many studies [11,12].…”

Section: Introductionmentioning

confidence: 99%

Specific interactions, structure and properties in segmented polyurethane elastomers

Bagdi

Molnár

Sajó

et al. 2011

Express Polym. Lett.

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Abstract. Two sets of segmented polyurethane (PU) elastomers were prepared from 4,4!-methylenebis(phenyl isocyanate) (MDI), 1,4-butanediol (BD) and a polyester or a polyether polyol, respectively. The molecular mass of both polyols was 1000 g/mol. The stoichiometric ratio of isocyanate and hydroxyl groups was 1 and the polyol/total diol ratio changed from 0 to 1 in 0.1 steps. One step bulk polymerization was carried out in an internal mixer and the samples were compression molded for testing. The results proved that specific interactions determine the phase structure and properties of these materials. Crystallinity was approximately the same in the two types of polyurethanes and the amount of relaxing soft segments was also similar. The determination of interaction parameters from solvent absorption and differences in glass transition temperatures indicated stronger interaction between hard and soft segments in the polyester than in the polyether polyurethane. Larger transparency of the polyester PU indicated the formation of smaller dispersed particles of the hard phase. The larger number of smaller hard phase units led to the formation of more physical cross-links distributed more evenly in the polymer. These differences in the phase structure of the polymers resulted in stronger strain hardening tendency, larger strength and smaller deformations for the polyester than for the polyether polyurethane.

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“…To form the microphaseseparated structure in polymers, they need to possess block structures, which are chemically connected each other. It is well-known that the polyurethane elastomers (PUEs), which possess the multiblock structure, show the microphase-separated structure, [1][2][3][4][5][6] resulting in giving some unique properties, such as mechanical and adhesive properties [6][7][8][9][10][11][12][13][14][15][16] and biocompatibility. 17 To functionalize the PUs with the microphase-separated structure, one needs to control the structures precisely.…”

mentioning

confidence: 99%

“…There has been reported some factors to control the microphaseseparated structure. A polymerization method, 13 thermal treatment 3,14 and chemical structures of raw materials including molecular weight [6][7][8][9][10][11][12]15,16 can be given as examples. First, by changing the polymerization method, one can control the primary structure of the PUs.…”

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confidence: 99%

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

et al. 2009

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The microphase-separated structure of polyurethane bulk and thin films were investigated using atomic force microscopy (AFM). The polyurethane (PUs) were synthesized with poly(oxytetramethylene) glycol (PTMG), 4,4 0 -diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) by a prepolymer method. The hard segment contents were 34 and 45 wt %. Polarized optical microscopy (POM) revealed that the 34 wt % PUE is homogeneous at a macroscopic level, while the 45 wt % one is macrophase-separated into two phases. One phase forms spherulites of ca. 2-5 mm in diameter. AFM observation for the 34 wt % PUE showed the microphase-separated structure, consisting of hard segment domains and a soft segment matrix. In contrast, for the 45 wt % PUE, a lot of the hard segment domains were observed in the spherulite region, indicating that spherulites include much amount of hard segment component, in contrast, outside of spherulite exhibited similar structure to that of 34 wt % one. For the PU bulk, the different microphase-separated structure in the inside and outside of spherulite was successfully observed for the first time. Also, the microphase-separated structure of PU films was investigated as a function of the film thickness. The PU films exhibited similar microphase-separated structure. For the thicker film ($200 nm), the interdomain spacing almost corresponded to bulk one. On the other hand, that for the film thickness below 7 nm dramatically decreased. This seems to be simply related to a decreasing space. We obtained the experimental data, which the phase-separated domain size of multiblock copolymer decreased with decreasing film thickness.KEY WORDS: Polyurethane / Microphase-separated Structure / Atomic Force Microscopy / Thin Film / A microphase-separated structure formed in polymers plays a quite important role for their properties, such as electric, adsorption, mechanical properties. To form the microphaseseparated structure in polymers, they need to possess block structures, which are chemically connected each other. It is well-known that the polyurethane elastomers (PUEs), which possess the multiblock structure, show the microphase-separated structure, 1-6 resulting in giving some unique properties, such as mechanical and adhesive properties [6][7][8][9][10][11][12][13][14][15][16] and biocompatibility.17

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Microphase-separated structure and mechanical properties of norbornane diisocyanate-based polyurethanes

Cited by 132 publications

References 16 publications

Interrelationship between ultimate mechanical properties of variously structured polyurethanes and poly(urethane urea)s and stretching rate thereof

Interrelationship between ultimate mechanical properties of variously structured polyurethanes and poly(urethane urea)s and stretching rate thereof

Specific interactions, structure and properties in segmented polyurethane elastomers

The Microphase-separated Structure of Polyurethane Bulk and Thin Films

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