scholarly journals Impact of Macrodiols on the Morphological Behavior of H12MDI/HDO-Based Polyurethane Elastomer

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2060
Author(s):  
Shazia Naheed ◽  
Mohammad Zuber ◽  
Mahwish Salman ◽  
Nasir Rasool ◽  
Zumaira Siddique ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Chain Length ◽  
Microphase Separation ◽  
Soft Segment ◽  
Group Identification ◽  
Degree Of Crystallinity ◽  
Polyurethane Elastomers ◽  
Hard Segments ◽  
Morphological Behavior

In this study, we evaluated the morphological behavior of polyurethane elastomers (PUEs) by modifying the soft segment chain length. This was achieved by increasing the soft segment molecular weight (Mn = 400–4000 gmol−1). In this regard, polycaprolactone diol (PCL) was selected as the soft segment, and 4,4′-cyclohexamethylene diisocyanate (H12MDI) and 1,6-hexanediol (HDO) were chosen as the hard segments. The films were prepared by curing polymer on Teflon surfaces. Fourier transform infrared spectroscopy (FTIR) was utilized for functional group identification in the prepared elastomers. FTIR peaks indicated the disappearance of −NCO and −OH groups and the formation of urethane (NHCOO) groups. The morphological behavior of the synthesized polymer samples was also elucidated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The AFM and SEM results indicated that the extent of microphase separation was enhanced by an increase in the molecular weight of PCL. The phase separation and degree of crystallinity of the soft and hard segments were described using X-ray diffraction (XRD). It was observed that the degree of crystallinity of the synthesized polymers increased with an increase in the soft segment’s chain length. To evaluate hydrophilicity/hydrophobicity, the contact angle was measured. A gradual increase in the contact angle with distilled water and diiodomethane (38.6°–54.9°) test liquids was observed. Moreover, the decrease in surface energy (46.95–24.45 mN/m) was also found to be inconsistent by increasing the molecular weight of polyols.

Effect of Block Molecular Weight on the Mechanical Properties of PA1010-b-PEG Segmented Block Copolymers

2012 ◽  
Vol 512-515 ◽  
pp. 2127-2130
Author(s):  
Li Huo ◽  
Cai Xia Dong
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Microphase Separation ◽  
Soft Segment ◽  
Mechanical Measurements ◽  
Wide Range ◽  
Hard Block ◽  
Higher Temperature ◽  
Hard Segments

The mechanical properties were investigated of a series of PA-PEG thermalplastic elastomer based on PA1010 and polytetramethylene glycol (PEG) with varying hard and soft segment content. Dynamic mechanical measurements of these polymers have carried out over a wide range of temperatures. The block copolymers exhibit three peaks, designated as α, β and γ in the tanδ-temperature curve. The α transition shifts to higher temperature with increasing hard block molecular weight. However, at a constant hard molecular weight, the α transition shifts to higher temperature and the damping increases on increasing the soft segment molecular weight. DMA results show that the block copolymers exhibit a microphase separation structure and both soft and hard segments were found to be crystallizable. The degree of phase separation increases with increasing hard block molecular weight.

scholarly journals Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Polyethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Soft Segment ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

The Role of Soft Segment Molecular Weight on Microphase Separation and Dynamics of Bulk Polymerized Polyureas

2012 ◽  
Vol 45 (20) ◽  
pp. 8438-8444 ◽  
Author(s):  
Alicia M. Castagna ◽  
Autchara Pangon ◽  
Taeyi Choi ◽  
Gregory P. Dillon ◽  
James Runt
Keyword(s):  
Molecular Weight ◽  
Microphase Separation ◽  
Soft Segment

scholarly journals Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε- caprolactone) triblock copolymer

2011 ◽  
Vol 76 (12) ◽  
pp. 1703-1723 ◽  
Author(s):  
Marija Pergal ◽  
Vesna Antic ◽  
Sanja Ostojic ◽  
Milena Marinovic-Cincovic ◽  
Jasna Djonlagic
Keyword(s):  
Triblock Copolymer ◽  
Microphase Separation ◽  
Weight Fraction ◽  
13C Nmr Spectroscopy ◽  
Degree Of Polymerization ◽  
Degree Of Crystallinity ◽  
Water Contact ◽  
Good Thermal Stability ◽  
Hard Segments ◽  
Poly Caprolactone

A series of novel thermoplastic urethane-siloxane copolymers (TPUSs) based on a ?,?-dihydroxy-[poly(?-caprolactone)-bpoly( dimethylsiloxane)-b-poly(?-caprolactone)] (?,?-dihydroxy-PCLPDMS- PCL) triblock copolymer, 4,4?-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) was synthesized. The effects of the content (9-63 wt. %) of hard urethane segments and their degree of polymerization on the properties of the segmented TPUSs were investigated. The structure, composition and hard segment degree of polymerization of the hard segments were examined using 1H- and quantitative 13C-NMR spectroscopy. The degree of crystallinity of the synthesized copolymers was determined using wide-angle X-ray scattering (WAXS). The surface properties were evaluated by measuring the water contact angle and water absorption. In the series of the TPUSs, the average degree of polymerization of the hard segments was varied from 1.2 to 14.4 MDI-BD units. It was found that average values from 3.8 to 14.4 MDI-BD units were effective segment lengths for crystallization of hard segments, which resulted in an increase in the degree of microphase separation of the copolymers. Spherulite-like superstructures were observed in copolymer films by scanning electron microscopy (SEM), which are believed to arise from the crystallization of the hard segments and/or PCL segments, depending on the content of the hard segments. The surface of the copolymers became more hydrophobic with increasing weight fraction of PDMS. The synthesized copolymers based on a PCL-PDMS-PCL segment showed good thermal stability, which increased with increasing content of soft PDMS segments, as was confirmed by the value of the starting temperature of thermal degradation.

scholarly journals Rheological behaviour of thermoplastic poly(ester-siloxane)s

2010 ◽  
Vol 64 (6) ◽  
pp. 537-545 ◽  
Author(s):  
Vesna Antic ◽  
Marija Pergal ◽  
Malisa Antic ◽  
Jasna Djonlagic
Keyword(s):  
Dynamic Viscosity ◽  
Microphase Separation ◽  
Soft Segment ◽  
Rheological Behaviour ◽  
Thermoplastic Elastomers ◽  
Degree Of Crystallinity ◽  
Mass Ratio ◽  
Complex Dynamic ◽  
Constant Length ◽  
Soft Segments

Two series of thermoplastic elastomers (TPES) based on poly(dimethylsiloxane), (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were analyzed by dynamic mechanical spectroscopy. In the first TPES series the lengths of both hard and soft segments were varied while the mass ratio of the hard to soft segments was nearly constant (about 60 mass%). In the second series, the mass ratio of hard and soft segments was varied in the range from 60/40 to 40/60, with a constant length of soft PDMS segments. The influence of the structure and composition of TPESs on the rheological properties, such as complex dynamic viscosity, ?*, the storage, G?, and loss, G?, shear modulus as well as the microphase separation transition temperature, TMST, was examined. The obtained results showed that the storage modulus of the TPESs increased in a rubbery plateau region with increasing degree of crystallinity. The rheological measurements of TPESs also showed that a microphase reorganization occurred during the melting process. The microphase separation transition temperatures were in the range from 220 to 234 ?C. In the isotropic molten state, the complex dynamic viscosity increased with increasing both the content and lenght of hard PBT segments.

scholarly journals The influence of hard segment content on mechanical and thermal properties of polycarbonate-based polyurethane materials

2012 ◽  
Vol 66 (6) ◽  
pp. 853-862 ◽  
Author(s):  
Jelena Pavlicevic ◽  
Milena Spirková ◽  
Jaroslava Budinski-Simendic ◽  
Mirjana Jovicic ◽  
Oskar Bera ◽  
...  
Keyword(s):  
Phase Separation ◽  
Hard Segment ◽  
Soft Segment ◽  
Chain Extender ◽  
Melting Enthalpy ◽  
Degree Of Crystallinity ◽  
Elongation At Break ◽  
Hard Segment Content ◽  
Hard Segments ◽  
Polycarbonate Diol

Aliphatic segmented polyurethanes were prepared by one-step procedure in catalytic reaction between polycarbonate diol, hexamethylene-diisocyanate and 1,4-butandiol (as chain extender). The hard segment content TS was varied (17, 24, 30 and 42 wt. %) by changing the ratio of starting compounds. The soft segment is made from flexible aliphatic polycarbonate diol, while hard segments consist of chain extender and diisocyanate component. In order to study the hydrogen bonding formation and phase separation, Fourier transform infrared spectroscopy (FT-IR) was used. Wide angle X-ray scattering (WAXS) was performed to determine a degree of crystallinity and to investigate the phase behavior of prepared elastomers. The effect of TS content on mechanical properties (tensile strength, elongation at break and hardness) was tested. Thermal behavior of prepared novel polycarbonate-based polyurethanes was investigated using differential scanning callorimetry (DSC). It was determined that the elastomer which contains the highest amount of urethane groups in its structure (TS content of 42 wt. %) exhibits the most pronounced phase separation and the highest degree of crystallinity. All prepared polyurethanes exhibit high elongation at break (over 700%). The glass transition temperature Tg of prepared samples was in the temperature region from ?39 to ?36?C, and it was found to be slightly influenced by the soft segment content. The enthalpy of chain segments relaxation in diffused region between hard and soft domains (detected in the temperature range from 35 to 55 ?C) was decreased with the increase of hard segment content. The multiple melting of hard segments (connected with the dissruption of physical crosslinks) appeared above 100 ?C. It was found that the melting enthalpy linearly increases with the increase of urethane group content. Sample with 42 wt. % of TS has the highest value of melting enthalpy (41.5 J/g).

Study on Microphase Separation of Waterborne Polyurethane by the Infrared Spectroscopy Peak Fitting

2014 ◽  
Vol 548-549 ◽  
pp. 164-171 ◽  
Author(s):  
Man Zhao ◽  
Wen Cai Xu ◽  
Shi Yong Luo
Keyword(s):  
Molecular Weight ◽  
Infrared Spectroscopy ◽  
Phase Separation ◽  
Qualitative Analysis ◽  
Microphase Separation ◽  
Soft Segment ◽  
Waterborne Polyurethane ◽  
Peak Fitting ◽  
Structure Adjustment ◽  
Separation Degree

A series of waterborne polyurethane (WPU) with different soft segment structures were sythesised, and the effects of the structure and molecular weight of the soft segment on the degree of PU microphase separation were evaluated by the infrared spectroscopy (FTIR) computer peak fitting. The experiment results indicated that phase separation between hard and soft segments of poly (ether–urethane) was more significant than poly (ester–urethane), based on the qualitative analysis on the N–H stretching region of the FTIR spectrum. And the qualitative analysis on the carbonyl stretching region showed that PU with lower soft segment molecular weight had a higher relative amount of hard segment, and possesses higher microphase separation degree. The addition of polyether soft segment PEG had an internal plasticization by actuating the PCD molecular chain. Therefore, it becomes easier for PU to conduct structure adjustment and increased the phase separation degree.

PEG-POSS Hybrid Polyurethanes: Mechanically Robust Nanostructured Hydrogels

2007 ◽  
Vol 1060 ◽  
Author(s):  
Jian Wu ◽  
Qing Ge ◽  
Patrick T Mather
Keyword(s):  
Molecular Weight ◽  
Hard Segment ◽  
Soft Segment ◽  
Phenyl Isocyanate ◽  
Hybrid Network ◽  
Molar Ratio ◽  
Organic Hybrid ◽  
Hybrid Hydrogels ◽  
Hard Segments ◽  
Equilibrium Swelling Ratio

ABSTRACTA series of unique hybrid thermoplastic polyurethanes (TPUs) was synthesized using PEG as soft segment and incorporating an isobutyl-functionalized POSS diol (TMP POSS diol) in the hard segment. The molecular weight of PEG was systematically varied to include 10, 20, and 35 kDa, while the mole ratio of POSS diol (as chain extender) to PEG was in range from 3:1 to 8:1 with samples featuring a PEG molecular weight of 10 kDa. The diisocyanate employed for TPU polymerization was 4,4'-methylenebis(phenyl-isocyanate) (MDI). We found that the hydrophobic hard segments (POSS) can form crystalline structures driven by micro-phase separation, this being due to significant thermodynamic incompatibility between POSS and ethylene oxide units. The POSS nano-crystals thus formed serve as physical crosslinking sites within an inorganic-organic hybrid network. This affords a new hybrid organic-inorganic hydrogel in the water-swollen state. The equilibrium swelling ratio increased monotonically with PEG loading and ranged from ∼70% to ∼600%. The shear modulus, G, of the hybrid hydrogels was observed to span 0.3 < G < 4.0 MPa – C values commonly found for elastomers, not hydrogels. Indeed, the hydrogel stiffness can be finely tuned through the POSS:PEG molar ratio, as this predictably controls swelling in water.

Effect of Soft Segment Molecular Weight and 3-Methyl Side Group on Microstructural Separation in Polyurethane Elastomers

1992 ◽  
Vol 29 (7) ◽  
pp. 567-587 ◽  
Author(s):  
Wen-Pin Chen ◽  
Kurt C. Frisch ◽  
Donald J. Kenney ◽  
Shaio-Wen Wong ◽  
Ralph Moore
Keyword(s):  
Molecular Weight ◽  
Soft Segment ◽  
Side Group ◽  
Polyurethane Elastomers
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