scholarly journals Control of Mechanical Properties of Thermoplastic Polyurethane Elastomers by Restriction of Crystallization of Soft Segment

Materials ◽  
2010 ◽  
Vol 3 (12) ◽  
pp. 5097-5110 ◽  
Author(s):  
Ken Kojio ◽  
Mutsuhisa Furukawa ◽  
Yoshiteru Nonaka ◽  
Sadaharu Nakamura
Keyword(s):  
Mechanical Properties ◽  
Soft Segment ◽  
Thermoplastic Polyurethane ◽  
Polyurethane Elastomers ◽  
Thermoplastic Polyurethane Elastomers

scholarly journals The Green Approach to the Synthesis of Bio-Based Thermoplastic Polyurethane Elastomers with Partially Bio-Based Hard Blocks

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2334
Author(s):  
Ewa Głowińska ◽  
Paulina Kasprzyk ◽  
Janusz Datta
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Polyurethane ◽  
Viscoelastic Behavior ◽  
Polymeric Materials ◽  
Building Blocks ◽  
Chain Extender ◽  
Sustainable Chemistry ◽  
Polyurethane Elastomers ◽  
Thermoplastic Polyurethane Elastomers ◽  
Hard Segments

Bio-based polymeric materials and green routes for their preparation are current issues of many research works. In this work, we used the diisocyanate mixture based on partially bio-based diisocyanate origin and typical petrochemical diisocyanate for the preparation of novel bio-based thermoplastic polyurethane elastomers (bio-TPUs). We studied the influence of the diisocyanate mixture composition on the chemical structure, thermal, thermomechanical, and mechanical properties of obtained bio-TPUs. Diisocyanate mixture and bio-based 1,4-butanediol (as a low molecular chain extender) created bio-based hard blocks (HS). The diisocyanate mixture contained up to 75 wt % of partially bio-based diisocyanate. It is worth mentioning that the structure and amount of HS impact the phase separation, processing, thermal or mechanical properties of polyurethanes. The soft blocks (SS) in the bio-TPU’s materials were built from α,ω-oligo(ethylene-butylene adipate) diol. Hereby, bio-TPUs differed in hard segments content (c.a. 30; 34; 40, and 53%). We found that already increase of bio-based diisocyanate content of the bio-TPU impact the changes in their thermal stability which was measured by TGA. Based on DMTA results we observed changes in the viscoelastic behavior of bio-TPUs. The DSC analysis revealed decreasing in glass transition temperature and melting temperature of hard segments. In general, obtained materials were characterized by good mechanical properties. The results confirmed the validity of undertaken research problem related to obtaining bio-TPUs consist of bio-based hard building blocks. The application of partially bio-based diisocyanate mixtures and bio-based chain extender for bio-TPU synthesis leads to sustainable chemistry. Therefore the total level of “green carbons” increases with the increase of bio-based diisocyanate content in the bio-TPU structure. Obtained results constitute promising data for further works related to the preparation of fully bio-based thermoplastic polyurethane elastomers and development in the field of bio-based polymeric materials.

scholarly journals Mechanoresponsive Elastomers Made with Excimer-Forming Telechelics

2020 ◽  
Vol 02 (04) ◽  
pp. 313-322
Author(s):  
Derek J. Kiebala ◽  
Zhiyuan Fan ◽  
Celine Calvino ◽  
Lauren Fehlmann ◽  
Stephen Schrettl ◽  
...  
Keyword(s):  
Soft Segment ◽  
Thermoplastic Polyurethane ◽  
Weight Fraction ◽  
Relaxation Processes ◽  
High Concentration ◽  
Polyurethane Elastomers ◽  
Optical Signals ◽  
Emission Color ◽  
Fluorescence Color ◽  
Thermoplastic Polyurethane Elastomers

Mechanoresponsive luminescent (MRL) elastomers, which change their fluorescence color or intensity upon deformation, can facilitate simple strain detection through optical signals. Several polymers have been endowed with MRL properties by blending them with excimer-forming dyes, whose assembly and emission color are affected by deformation of the blended materials. However, access to elastic MRL polyurethanes based on this approach has proven difficult and usually requires the covalent incorporation of such dyes in high concentration. Here, we show that much simpler access to MRL elastomers is possible by blending thermoplastic polyurethane elastomers with a small weight fraction of a telechelic sensor macromolecule carrying two excimer-forming oligo(p-phenylene vinylene) dyes at the termini. While the mechanical properties of the two polyurethanes, which were selected because of their dissimilar mechanical behaviors, remain unchanged, the additive imparts these materials with MRL characteristics. Notably, the reliable and reversible detection of strains as low as 5% is possible. The highly sensitive mechanochromic response mirrors the deformation and relaxation processes occurring in these model polyurethanes and enabled a detailed analysis of the processes underlying the shape-memory properties in one of the polyurethanes, in which such behavior was imparted by a crystallizable soft segment.

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