Recent Advances in the Synthesis and Application of Thermoplastic Semicrystalline Shape Memory Polyurethanes

Gorbunova, M. A.; Anokhin, Denis V.; Бадамшина, Э. Р.

doi:10.1134/s1560090420050073

Cited by 19 publications

(10 citation statements)

References 186 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such an organization of segmented PU often makes it possible to implement the shape memory effect (SME) in them. For its manifestation, as a rule, it is necessary to have the coexistence of a phase fixing the shape of the polymer through chemical or physical crosslinks, as well as a phase allowing the reversibility of thermodynamic states through relaxation or phase transitions, when the system passes from low to high molecular mobility [ 11 , 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Domain Structure, Thermal and Mechanical Properties of Polycaprolactone-Based Multiblock Polyurethane-Ureas under Control of Hard and Soft Segment Lengths

et al. 2022

View full text Add to dashboard Cite

A series of multiblock polyurethane-ureas (PUU) based on polycaprolactone diol (PCL) with a molecular mass of 530 or 2000 g/mol, as well as hard segments of different lengths and structures, were synthesized by the step-growth polymerization method. The chemical structure of the synthesized multiblock copolymers was confirmed by IR- and NMR-spectroscopy. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to determine the relaxation and phase transition temperatures for the entire series of the obtained PUU. The X-ray diffraction (XRD) method made it possible to identify PUU compositions in which the crystallizability of soft segments (SS) is manifested due to their sufficient length for self-organization and structuring. Visualization of the crystal structure and disordering of the stacking of SS with an increase in their molecular mobility during heating are shown using optical microscopy. The change in the size of the hard phase domains and the value of the interdomain distance depending on the PCL molecular mass, as well as the length and structure of the hard block in the synthesized PUU, were analyzed using small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS). The evolution of the domain structure upon passing through the melting and crystallization temperatures of PUU soft blocks was studied using SANS. The studies carried out made it possible to reveal the main correlations between the chemical structure of the synthesized PUU and their supramolecular organization as well as thermal and mechanical properties.

show abstract

Section: Introductionmentioning

confidence: 99%

Domain Structure, Thermal and Mechanical Properties of Polycaprolactone-Based Multiblock Polyurethane-Ureas under Control of Hard and Soft Segment Lengths

et al. 2022

View full text Add to dashboard Cite

show abstract

“…They are present in a wide range of applications such as coatings, elastomers and sealants for example, but two third of their production is devoted to foams. [13][14][15][16][17][18] PU foam (PUF) production represents around 12 Mt per year, mostly from fossil-based resources and leads to accumulation of foam wastes.…”

Section: Introductionmentioning

confidence: 99%

“…To initiate this transition, the production of biobased monomers has been widely developed to achieve sustainable polymers such as polyamides, polyurethanes, epoxy-resins, and polyesters. − Polyurethanes (PUs), produced via step growth polymerization of polyisocyanates and polyols, are the sixth most produced polymer in the world with almost 20 Mt per year, and their demand is constantly growing because of their excellent properties and their high versatility. They are present in a wide range of applications such as coatings, elastomers, and sealants, for example, but two third of their production is devoted to foams. − PU foam (PUF) production represents around 12 Mt per year, mostly from fossil-based resources and leads to accumulation of foam wastes.…”

Section: Introductionmentioning

confidence: 99%

Upcycling Biobased Polyurethane Foams into Thermosets: Toward the Closing of the Loop

Quienne

Cuminet

Pinaud

et al. 2022

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

With the growing environmental concerns that society is nowadays facing, the development of biobased materials intensified and biobased polyisocyanates have emerged in the market. Their commercialization enabled to synthesize the first four biobased polyurethanes foams (PUFs) from biobased isocyanates, containing up to 93 % of renewable carbons. Their mechanical and thermomechanical properties were compared. In particular, one of the four PUF formulations was very promising: it foamed at room temperature and produced a low density foam 78 kg/m 3 comparable to conventional fossil-based PUFs. To consider the full life cycle of such materials, these PUFs were upcycled and reshaped to bulk PUs by transcarbamoylation reaction up to 5 cycles. Moreover, a unique material (mixPU) composed of the four PUFs was prepared and reshaped, by compression molding at 160 °C for 30 min, thus demonstrating the potential of this recycling pathway for PUFs from different origins. Finally, stress-relaxation experiments were carried out to evaluate the dynamic properties of the mixPU material which was shown to behave as a CAN.

show abstract

“…Apart from chemical composition, the mechanical, thermal, and relaxation properties of TPU and TPUU depend on the thermal history [ 10 , 11 , 12 ]. Thus, semi-crystalline polyurethanes are able to fix their temporary shape during deformation and further restore the original shape after heating above a switching temperature, i.e., they show the shape memory effect (SME) [ 13 , 14 ]. In a previous publication, it was shown that SME is determined by transition of the TPUU between three morphological states: (1) semi-crystalline lamellar morphology of isotropic film in a permanent shape, (2) fibrillar morphology with extended-chain crystals of the soft block after film stretching to a temporary shape, and (3) phase-separated state of the block copolymer in the amorphous state after shape recovery above the switching temperature [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain

et al. 2021

View full text Add to dashboard Cite

The structural evolution of multiblock thermoplastic polyurethane ureas based on two polydiols, poly(1,4-butylene adipate (PBA) and poly-ε-caprolactone (PCL), as soft blocks and two diisocyanites, 2,4-toluylene diisocyanate (TDI) and 1,6-hexamethylene diisocyanate (HMDI), as hard blocks is monitored during in situ deformation by small- and wide-angle X-ray scattering. It was shown that the urethane environment determines the crystal structure of the soft block. Consequently, two populations of crystalline domains of polydiols are formed. Aromatic TDI forms rigid domains and imposes constrains on the crystallization of bounded polydiol. During stretching, the TDI–polydiol domains reveal limited elastic deformation without reorganization of the crystalline phase. The constrained lamellae of polydiol form an additional physical network that contributes to the elastic modulus and strength of the material. In contrast, polydiols connected to the linear semi-flexible HMDI have a higher crystallization rate and exhibit a more regular lamellar morphology. During deformation, the HMDI-PBA domains show a typical thermoplastic behavior with plastic flow and necking because of the high degree of crystallinity of PBA at room temperature. Materials with HMDI-PCL bonding exhibit elastic deformation due to the low degree of crystallinity of the PCL block in the isotropic state. At higher strain, hardening of the material is observed due to the stress-induced crystallization of PCL.

show abstract

Recent Advances in the Synthesis and Application of Thermoplastic Semicrystalline Shape Memory Polyurethanes

Cited by 19 publications

References 186 publications

Domain Structure, Thermal and Mechanical Properties of Polycaprolactone-Based Multiblock Polyurethane-Ureas under Control of Hard and Soft Segment Lengths

Domain Structure, Thermal and Mechanical Properties of Polycaprolactone-Based Multiblock Polyurethane-Ureas under Control of Hard and Soft Segment Lengths

Upcycling Biobased Polyurethane Foams into Thermosets: Toward the Closing of the Loop

Multiblock Thermoplastic Polyurethanes: In Situ Studies of Structural and Morphological Evolution under Strain

Contact Info

Product

Resources

About