Effect of TPU hard segment content on the rheological and mechanical properties of PLA/TPU blends

2020 ◽  
Vol 137 (45) ◽  
pp. 49387
Author(s):  
Mohammadreza Nofar ◽  
Mojtaba Mohammadi ◽  
Pierre J. Carreau
Keyword(s):  
Mechanical Properties ◽  
Hard Segment ◽  
Hard Segment Content

scholarly journals Influence of Hard Segment Content and Diisocyanate Structure on the Transparency and Mechanical Properties of Poly(dimethylsiloxane)-Based Urea Elastomers for Biomedical Applications

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 212
Author(s):  
Natascha Riehle ◽  
Kiriaki Athanasopulu ◽  
Larysa Kutuzova ◽  
Tobias Götz ◽  
Andreas Kandelbauer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Hard Segment ◽  
Phenyl Isocyanate ◽  
In Vitro Cytotoxicity ◽  
Chain Extender ◽  
Elongation At Break ◽  
Hard Segment Content ◽  
Hard Segments

The effect of hard segment content and diisocyanate structure on the transparency and mechanical properties of soft poly(dimethylsiloxane) (PDMS)-based urea elastomers (PSUs) was investigated. A series of PSU elastomers were synthesized from an aminopropyl-terminated PDMS (M¯n: 16,300 g·mol−1), which was prepared by ring chain equilibration of the monomers octamethylcyclotetrasiloxane (D4) and 1,3-bis(3-aminopropyl)-tetramethyldisiloxane (APTMDS). The hard segments (HSs) comprised diisocyanates of different symmetry, i.e., 4,4′-methylenebis(cyclohexyl isocyanate) (H12MDI), 4,4′-methylenebis(phenyl isocyanate) (MDI), isophorone diisocyanate (IPDI), and trans-1,4-cyclohexane diisocyanate (CHDI). The HS contents of the PSU elastomers based on H12MDI and IPDI were systematically varied between 5% and 20% by increasing the ratio of the diisocyanate and the chain extender APTMDS. PSU copolymers of very low urea HS contents (1.0–1.6%) were prepared without the chain extender. All PSU elastomers and copolymers exhibited good elastomeric properties and displayed elongation at break values between 600% and 1100%. The PSUs with HS contents below 10% were transparent and became increasingly translucent at HS contents of 15% and higher. The Young’s modulus (YM) and ultimate tensile strength values of the elastomers increased linearly with increasing HS content. The YM values differed significantly among the PSU copolymers depending on the symmetry of the diisocyanate. The softest elastomer was that based on the asymmetric IPDI. The elastomers synthesized from H12MDI and MDI both exhibited an intermediate YM, while the stiffest elastomer, i.e., that comprising the symmetric CHDI, had a YM three-times higher than that prepared with IPDI. The PSUs were subjected to load–unload cycles at 100% and 300% strain to study the influence of HS morphology on 10-cycle hysteresis behavior. At 100% strain, the first-cycle hysteresis values of the IPDI- and H12MDI-based elastomers first decreased to a minimum of approximately 9–10% at an HS content of 10% and increased again to 22–28% at an HS content of 20%. A similar, though less pronounced, trend was observed at 300% strain. First-cycle hysteresis among the PSU copolymers at 100% strain was lowest in the case of CHDI and highest in the IPDI-based elastomer. However, this effect was reversed at 300% strain, with CHDI displaying the highest hysteresis in the first cycle. In vitro cytotoxicity tests performed using HaCaT cells did not show any adverse effects, revealing their potential suitability for biomedical applications.

EFFECT OF INCREASING NCO/OH MOLAR RATIO ON THE CHEMICAL AND MECHANICAL PROPERTIES OF ISOCYANATE TERMINATED POLYURETHANE PREPOLYMER DERIVED FROM BIO-MASS

2016 ◽  
Vol 2 (2) ◽  
pp. 78-82
Author(s):  
K. Rathika ◽  
S. Begila David
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Castor Oil ◽  
Hard Segment ◽  
Molar Ratio ◽  
Curing Time ◽  
Percent Elongation ◽  
Hard Segment Content ◽  
Polyurethane Film ◽  
Polyurethane Prepolymer

The study deals the effect of increasing NCO/OH molar ratio on the physico-mechanical properties of isocyanate terminated polyurethane prepolymer. The prepolymer was prepared using castor oil and toluene-2,4-diisocyanate. The NCO/OH molar ratio has been varied from 1.6 to 2.0. The formation of the prepolymer was confirmed by UV and FTIR spectroscopy. The results reveal that the curing time of the prepolymer decreased with increase in NCO/OH molar ratio. When NCO/OH molar ratio increased, the tensile strength of the polyurethane film increased, while percent elongation decreased due to increase in hard segment content.

Contribution of Electrostriction in Polyurethane/Polyaniline Blends

2014 ◽  
Vol 1025-1026 ◽  
pp. 697-702
Author(s):  
Darika Jaaoh ◽  
Chatchai Putson ◽  
Nantakan Muensit
Keyword(s):  
Mechanical Properties ◽  
Dielectric Constant ◽  
Glass Transition ◽  
Transition Temperature ◽  
Polymer Blend ◽  
Hard Segment ◽  
Filler Content ◽  
Domain Formation ◽  
Space Charges ◽  
Electrostrictive Polymer

In this work, we present a series of electrostrictive polymer blend that can potentially be used as actuators for a variety of applications. This polymer blend combines an electrostrictive polyurethane with a conductivity polyaniline polymer. The effect of filler content has been investigated. The structures of the blends, the electrical and mechanical properties which affect electrostrictive behavior were studied. The results showed that both dielectric constant and glass transition temperature of the blends increase with increasing polyaniline contents. Moreover, it was noted that space charges distribution and hard-segment domain formation significantly related with electrostrictive coefficient of polymer blend. Therefore, electrostriction behavior in the polymer blends has been demonstrated, and optimal microstructure for electrostriction enhancement has been identified.

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