Study of the Effect of Soft-Segment Length and Concentration on Properties of Polyetherurethanes. II. The Effect on Mechanical Properties

1985 ◽  
Vol 58 (4) ◽  
pp. 701-712 ◽  
Author(s):  
Zoran S. Petrović ◽  
Jaroslava Budinski-Simendić
Keyword(s):  
Mechanical Properties ◽  
Chain Length ◽  
Plastic Flow ◽  
Soft Segment ◽  
Maximum Strength ◽  
Segment Length ◽  
Elongation At Break ◽  
Mechanical Methods ◽  
Soft Segments ◽  
Segmented Polyurethanes

Abstract Three series of segmented polyurethanes with different soft segment lengths and concentrations were examined by TMA, DMA, and mechanical methods. Maximum tensile strengths were obtained when ssc was 40–50%, which was explained by a specific interlocking morphology. No significant effect of soft-segment chain length on maximum strength was found, but higher values were found in the C series when ssc was 60%. Elongation at break increases linearly with ssc but indications that shorter soft segments produce higher extensions was attributed to plastic flow. TMA showed that Tg was independent of ssc in the C and, to a degree, in the B series, while temperature of α-transition in DMA was independent of ssc only in the C series at ssc above 50%.

Crystallinity and morphology of segmented polyurethanes with different soft-segment length

1996 ◽  
Vol 62 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Fengkui Li ◽  
Jianan Hou ◽  
Wei Zhu ◽  
Xian Zhang ◽  
Mao Xu ◽  
...  
Keyword(s):  
Soft Segment ◽  
Segment Length ◽  
Segmented Polyurethanes

Study of the Effect of Soft-Segment Length and Concentration on Properties of Polyetherurethanes. I. The Effect on Physical and Morphological Properties

1985 ◽  
Vol 58 (4) ◽  
pp. 685-700 ◽  
Author(s):  
Zoran S. Petrović ◽  
Jaroslava Budinski-Simendić
Keyword(s):  
Phase Inversion ◽  
Hard Segment ◽  
Soft Segment ◽  
Degree Of Polymerization ◽  
Morphological Properties ◽  
Segment Length ◽  
Hard Phase ◽  
Soft Phase ◽  
Soft Segments ◽  
Two Phases

Abstract 1. Densities of elastomers with crystallizing soft segments were higher than that of the noncrystallizing ones. However, the effect of the soft segment length is not regular and may reflect some specific interactions between two phases as well as instantaneous morphology. 2. Phase inversion as judged by drop of hardness takes place at about ssc=60° or more; a shift to higher ssc gives a greater segment length. 3. Tg of the soft segment in samples with well separated phases is independent of ssc, e.g., the presence of hard phase does not change mobility of the soft phase in samples with ssc=50° or more, in all series. However, Tg is strongly dependent on the soft-segment length. Tg for the soft segment of Mn=650 was −43°C, for Mn=1000 was −62°C, and for Mn=2000, Tg was −75°C. The effect of the presence of the hard phase on mobility of the soft phase seems to vanish for M>2500. 4. Tg of the hard segment at 77°C was clearly observed only in quenched samples with a high hard-segment concentration (80%) and at 93°C in a pure hard segment. 5. Melting of both phases were observed in polymers with long soft segments (Mn=2000). Soft segments of Mn=650 and 1000 do not crystallize. The hard phase crystallizes if its Mn is about 1000 or more or if the degree of polymerization of the hard segment is 3 or above, although exceptions were found in the A series. 6. Spherulitic structures were observed in polymers with low ssc (20% and 40%) polymers and in one with ssc=80°. Thus, both hard and soft phases can form spherulitic structures.

Study on the Influences of Domain Structure of Hydrophilic Polyurethane with Partially Crystalline on its Moisture Permeability

2011 ◽  
Vol 233-235 ◽  
pp. 281-287
Author(s):  
Heng Quan ◽  
Zhen Ya Gu
Keyword(s):  
Chemical Structure ◽  
Hard Segment ◽  
Microphase Separation ◽  
Soft Segment ◽  
Moisture Permeability ◽  
Soft Segments ◽  
Separation Degree ◽  
Polyethylene Glycol 1000 ◽  
Segmented Polyurethanes ◽  
Hydrophilic Polyurethane

Multiphase, segmented polyurethanes with mixed soft segment phase were prepared from 4,4’- diphenylmethane diisocyanate (Pure MDI), polybutylene adipate (glycol) 2000 (PBA2000) and polyethylene glycol 1000 (PEG1000) with 1,4-butanediol (BDO) as the chain extender. Further more, the relationships between domain separation structure, crystallizability of soft segment and moisture permeability, hydrophilic property, phase inversion temperature (PIT) of the polyurethanes were investigated. The studies show that the chemical structure, concentration of hydrophilic soft monomers and the microphase separation degree of the mixed soft segments from hard segment domain have remarkable effects on the application properties of polyurethane.

Mechanical and Dynamic Mechanical Properties of Degradable Polyurethane Foams with PEG/PCL Mixed Soft Segments

2011 ◽  
Vol 183-185 ◽  
pp. 1611-1615 ◽  
Author(s):  
Jian Hua Wang ◽  
Shuen Liang ◽  
Yan Yan Wang ◽  
Chun Rong Tian ◽  
Xiu Li Zhao
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Compressive Strain ◽  
Dynamic Mechanical Properties ◽  
Polyurethane Foams ◽  
Elongation At Break ◽  
Dynamic Mechanical ◽  
Soft Segments ◽  
And Storage

Polyurethane (PU) with mixed poly(ethylene glycol) / poly(ε-caprolactone) (PEG/PCL) soft segments is a representatively kind of degradable polyurethane material. Polyurethane foams (PUF) with mixed PEG/PCL soft segments were synthesized by using one pot method, and their mechanical and dynamic mechanical properties were investigated. Influences of PEG/PCL weight ratio and molecular weight of soft segments on PUF's mechanical and dynamic mechanical properties were studied. The results showed that: with increasing content of PCL, PUF's tensile strength, elongation at break, stress at certain tensile/compressive strain and storage modulus increased gradually; with increasing molecular weight of soft segment, PUF's elongation at break increased, but tensile strength, stress at certain tensile/compressive strain and storage modulus all decreased accordingly; glass transition temperature (Tg) of PUF with various soft segments decreased according to the following sequence: PEG-400, PCL-210N, PEG-1000 and PTMG1000; loss factor of PUF with PEG/PCL mixed soft segments was higher than that of PUF with individual PEG or PCL soft segments.

scholarly journals Thermal and mechanical properties of linear segmented polyurethanes with butadiene soft segments

1981 ◽  
Vol 21 (11) ◽  
pp. 668-674 ◽  
Author(s):  
C. M. Brunette ◽  
S. L. Hsu ◽  
M. Rossman ◽  
W. J. MacKnight ◽  
N. S. Schneider
Keyword(s):  
Mechanical Properties ◽  
Thermal And Mechanical Properties ◽  
Soft Segments ◽  
Segmented Polyurethanes

scholarly journals The Crystallisation, Microphase Separation and Mechanical Properties of the Mixture of Ether-Based TPU with Different Ester-Based TPUs

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3475
Author(s):  
Yu-Hui Que ◽  
Ying Shi ◽  
Li-Zhi Liu ◽  
Yuan-Xia Wang ◽  
Chen-Chen Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Level ◽  
Microphase Separation ◽  
Soft Segment ◽  
Phase Region ◽  
The Other ◽  
Elongation At Break ◽  
Similar Chemical ◽  
Aggregation Structure ◽  
The Difference

The difference in compatibility at the molecular level can lead to a change of microphase separation structure of thermoplastic polyurethanes blend systems, which will improve their thermal and mechanical properties. In this study, TDI-polyester based TPU was blended with MDI-polyether-based TPU and MDI-polyester based TPU, with different ratios. In the blend system, the obvious reduction of the melting temperature of the high-temperature TDI-polyester based TPU component indicates its hard segments can be mutually integrated with the other component. For TDI-polyester based TPU/MDI-polyether based TPU blends, their similar hard segment ratio and similar chemical structure of the soft segment give the molecular chains of the two components better compatibility. The aggregation structure of the two kinds of chains can rearrange at the molecular level which makes the hard domains mutually integrate to form a new phase separation structure with larger phase region distance. As a result, the yield strength of this blend increased by almost 143% when the elongation at break was only reduced by 12%. In contrast, the other group of blends still partly maintain their respective micro domains, forming a weak interface and leading to a decreased of elongation at break.

Structural Characterization of Segmented Polyurethanes by Small Angle Neutron Scattering

2001 ◽  
Vol 707 ◽  
Author(s):  
Loren I. Espada ◽  
Joseph T. Mang ◽  
E. Bruce Orler ◽  
Debra A. Wrobleski ◽  
David A. Langlois ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Hard Segment ◽  
Microphase Separation ◽  
Soft Segment ◽  
Chain Scission ◽  
Segmented Polyurethanes

ABSTRACTThe beneficial mechanical properties of segmented polyurethanes derive from microphase separation of immiscible hard and soft segment-rich domains at room temperature. We are interested in the structure of the domains, how these are affected by hydrolytic aging, and how the structure is modified by low molecular weight plasticizers. To assessed the distribution of the plasticizer in polyurethane, we did small-angle neutron scattering measurements on mixtures of 23% hard segment poly(esterurethane) with different amounts of either non-deuterated or deuterated plasticizer. We analyzed the results using a simple model in which the contrast, Δ=H-, between the hard and soft segment-rich domains is varied by the amount of deuterated or hydrogenated plasticizer, using the fact that I(Q) ∼ Δ2. The result demonstrated that the plasticizer is largely associated with the soft segment rich domains. The structure of PESU with the chain extender of the hard segment was assessed after aging under hydrolytic conditions. The results show that the microphase structure coarsens and segregates and that the hard and soft segments segregated as a result of the loss of constraints from hydrolytic soft segment chain scission. The results on plasticizer distribution and the effects of hydrolytic aging give insight on the loss of mechanical properties that occur in each case.

Effects of Hard Segment Contents on Dynamic Mechanical Properties of Gap-Based Polyurethane Elastomers

2013 ◽  
Vol 376 ◽  
pp. 125-129
Author(s):  
Hai Qin Ding ◽  
Le Qin Xiao ◽  
Wei Liang Zhou ◽  
Li Rong He ◽  
Huai Long Zhang
Keyword(s):  
Mechanical Properties ◽  
Hard Segment ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Polyurethane Elastomers ◽  
Elongation At Break ◽  
Dynamic Mechanical ◽  
Soft Segments ◽  
Hard Segments ◽  
Fragility Parameter

Gap-based polyurethane elastomer (GAPE) with different hard segment contents are synthesized with 44-Diphenylmethane diisocyanate (MDI), 1,4 butylene glycol (BDO) as hard segments and GAP as soft segments. Dynamic mechanical analysis (DMA) is applied to investigated the dynamic mechanical properties and the mechanical properties of GAPE are studied by materials laboratorial instrument. The results show that GAPE-2 with 33 wt% hard segment has better mechanical properties, of which the tensile strength is 11.3MPa and elongation at break is 460.5%.As shown in DMA, T g of GAPE-2 is-18.4°C, and the low-temperature fragility parameter and activation energy of GAPE-2 are lower, 55.6 and 271.0 KJ·mol-1 respectively. Elastomer with good stiffness and flexibility is obtained.

Sign in / Sign up

Export Citation Format

Share Document