Role of Increased Crystallinity in Deformation-Induced Structure of Segmented Thermoplastic Polyurethane Elastomers with PEO and PEO−PPO−PEO Soft Segments and HDI Hard Segments

2009 ◽  
Vol 42 (6) ◽  
pp. 2041-2053 ◽  
Author(s):  
Ryan S. Waletzko ◽  
LaShanda T. James Korley ◽  
Brian D. Pate ◽  
Edwin L. Thomas ◽  
Paula T. Hammond
Keyword(s):  
Thermoplastic Polyurethane ◽  
Polyurethane Elastomers ◽  
Soft Segments ◽  
Thermoplastic Polyurethane Elastomers ◽  
Hard Segments ◽  
Induced Structure

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.

Understanding the shape memory behavior of thermoplastic polyurethane elastomers with coarse-grained molecular dynamics simulations

MRS Advances ◽  
2017 ◽  
Vol 2 (6) ◽  
pp. 375-380 ◽  
Author(s):  
Md Salah Uddin ◽  
Jaehyung Ju
Keyword(s):  
Molecular Dynamics ◽  
Shape Memory ◽  
Shape Recovery ◽  
Thermoplastic Polyurethane ◽  
Coarse Grained ◽  
Polyurethane Elastomers ◽  
Weight Percentage ◽  
Shape Memory Behavior ◽  
Soft Segments ◽  
Hard Segments

ABSTRACTWe perform molecular dynamics (MD) simulations to understand thermally triggered shape memory behavior of a thermoplastic polyurethane (TPU) elastomer with an enhanced coarse-grained (CG) model. Hard and soft phases of shape memory polymers (SMPs) are known as fixed and reversible phase, respectively. Fixity depends on the content of hard segments due to their restricted mobility. On the contrary, recovery depends on the dynamic motion of the soft segments as well the degree of cross-linking, which is also affected by the quantity of hard segment. Several CG models of the TPU are constructed varying the weight percentage of soft segments to observe their effects on shape recovery and fixity. All of the models are equilibrated at 300K (above glass transition, Tg: 200-250 K) and deformed under uniaxial loading with NPT (isothermal-isobaric) ensembles. The deformed state is cooled to 100K (below Tg) and further equilibrated to estimate the shape fixity. Shape recovery is predicted by heating and equilibrating the structures back to 300K. By the end of this study, we may answer how much the shape fixities and recoveries are changed for varying concentration of hard segments from thermomechanical cycles with CGMD simulations.

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