Effect of the average soft-segment length on the morphology and properties of segmented polyurethane nanocomposites

2006 ◽  
Vol 102 (1) ◽  
pp. 128-139 ◽  
Author(s):  
Bradley Finnigan ◽  
Peter Halley ◽  
Kevin Jack ◽  
Alasdair McDowell ◽  
Rowan Truss ◽  
...  
Keyword(s):  
Soft Segment ◽  
Segment Length ◽  
Segmented Polyurethane ◽  
Polyurethane Nanocomposites

Influence of the soft segment length on the properties of water-cured poly(carbonate-urethane-urea)s

2014 ◽  
Vol 26 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Magdalena M. Mazurek ◽  
Karolina Tomczyk ◽  
Monika Auguścik ◽  
Joanna Ryszkowska ◽  
Gabriel Rokicki
Keyword(s):  
Soft Segment ◽  
Segment Length ◽  
Poly Carbonate

scholarly journals Study of waterborne polyurethane materials under aging treatments. Effect of the soft segment length

2020 ◽  
Vol 138 ◽  
pp. 105357 ◽  
Author(s):  
Anny C. Ospina ◽  
Víctor H. Orozco ◽  
Luis F. Giraldo ◽  
Mónica Fuensanta ◽  
José Miguel Martín-Martínez ◽  
...  
Keyword(s):  
Soft Segment ◽  
Waterborne Polyurethane ◽  
Segment Length

Selective Dispersion of Multi-Walled Carbon Nanotubes in Segmented Polyurethane with Different Melt Mixing Process

2017 ◽  
Vol 730 ◽  
pp. 237-241
Author(s):  
Kittimon Jirakittidul ◽  
Krittaya Khrongsakun ◽  
Kannika Khongkhaw ◽  
Kusuman Nernplod
Keyword(s):  
Carbon Nanotubes ◽  
Soft Segment ◽  
Mixing Time ◽  
Melt Mixing ◽  
Segmented Polyurethane ◽  
Soft Segments ◽  
Multi Walled Carbon Nanotubes ◽  
Lcr Meter ◽  
Internal Mixer ◽  
Walled Carbon Nanotubes

Polyurethanes (PU) have been widely used in many applications since their properties can be tailored as desire. In order to improve their electrical property, PU is incorporated with multi-walled carbon nanotubes (MWCNT). The effects of different mixing times and temperatures on selective dispersion of MWCNT in segmented PU were studied. Furthermore, segmented PU based on two different soft segments; i.e. polyester (PU-ester) and polyether (PU-ether), were used. PU/MWCNT nanocomposites were prepared by an internal mixer for 4-12 minutes at 190-210°C. FESEM, DSC and LCR meter were used to characterize morphology and thermal properties. It was found that MWCNT were dispersed in soft segment of PU-ether. Good MWCNT dispersion was able to achieve at high temperature with short mixing time or low temperature with long mixing time. On the other hand, PU-ester/MWCNT nanocomposites, MWCNT preferred to disperse in hard segment and could be dispersed well in PU-ester at low mixing temperature.

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

scholarly journals Preparation of Associative Polyurethane Thickener and Its Thickening Mechanism Research

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Gao Nan ◽  
Zhang Zhuo ◽  
Dong Qingzhi
Keyword(s):  
Molecular Weight ◽  
Particle Size ◽  
Soft Segment ◽  
Synthesis Process ◽  
Segment Length ◽  
Solvent Ratio ◽  
Aqueous Dispersions ◽  
Before And After ◽  
Size And Morphology ◽  
End Capping

Associative polyurethane (PU) thickener has been synthesized by preparing the prepolymer with the reaction of polyethylene glycol (PEG) and isophorone diisocyanate (IPDI), which then end-capping with long-chain alkanol. The synthesis process, as well as hydrophilic chain length, theoretical molecular weight, solvent ratio, and thickener percentages, has been researched. The results shows that it reaches the upmost thickening effect when the theoretical molecular weight is under 20000, soft-segment length is under 4000, solvent ratio is 1 : 1, and thickener percentages are controlled at 10%. Furthermore, thickening mechanism of PU thickener has been analyzed detailedly through the measurement of the critical micelle concentration (CMC) of PU thickener and analysis of the influence of PU thickener on the particle size and morphology of PU dispersions. It has been observed from the scanning electron microscopy (SEM) that the PU aqueous dispersions produce a certain degree of flocculation when the PU thickener was added, and this flocculation structure has been proved to be a thixotropic structure through the characterization of the change of particle size before and after the thickener is introduced into the PU aqueous dispersions. The CMC measurement results present that the thickening effect will be apparent when the concentration is controlled in a low range.

Structure — Property Behavior of New Segmented Polyurethanes and Polyureas Without Use of Chain Extenders

2005 ◽  
Vol 78 (5) ◽  
pp. 737-753 ◽  
Author(s):  
Derek B. Klinedinst ◽  
Emel Yilgör ◽  
Iskender Yilgör ◽  
Frederick L. Beyer ◽  
Jignesh P. Sheth ◽  
...  
Keyword(s):  
Single Molecule ◽  
Microphase Separation ◽  
Soft Segment ◽  
Weight Fraction ◽  
Structure Property ◽  
Segmented Polyurethane ◽  
New Novel ◽  
Low Weight ◽  
Chain Extenders ◽  
Temperature Window

Abstract New novel segmented polyurethane and polyurea copolymers have been synthesized without chain extenders and the structure-property behavior of these systems has been investigated. It is shown that by the proper choice of diisocyanate and its symmetry, one can obtain highly microphase separated systems without chain extenders and that the materials also display useful mechanical behavior. In particular, it is shown that due to the bidentate hydrogen bonding achieved in the segmented ureas, a significant modulus “service temperature window” is also obtained. It is also verified that not only can strong microphase separation be obtained with low weight fraction hard segment content (14%) but that the hard phase, which is comprised of monodisperse “single molecule” units, also displays a percolated thread-like structure throughout the dominant soft segment material — the latter being based on ca. 1000g/mol polytetramethylene oxide.

Tuning the properties of segmented polyurea by regulating soft-segment length

2018 ◽  
Vol 135 (21) ◽  
pp. 46284 ◽  
Author(s):  
Nahid Iqbal ◽  
Manorama Tripathi ◽  
Surekha Parthasarathy ◽  
Devendra Kumar ◽  
Prasun Kumar Roy
Keyword(s):  
Soft Segment ◽  
Segment Length
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