Effect of block ratio and strain amplitude on thermal, structural, and shape memory properties of segmented polycaprolactone-based polyurethanes

Momtaz, Milad; Razavi‐Nouri, Mohammad; Barikani, Mehdi

doi:10.1007/s10853-014-8466-y

Cited by 33 publications

(23 citation statements)

References 39 publications

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“…These RGO-PU composites can also be used as shape memory polymer composites as polyurethane has been previously used by several researchers [34][35][36][37][38][39] .…”

Section: Figure 10: Deformation Energy (U R ) Of Different Rgo-pu Commentioning

confidence: 99%

Superior nano-mechanical properties of reduced graphene oxide reinforced polyurethane composites

et al. 2015

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Polyurethane (PU) based composites were prepared by solvent casting techniques using different wt. % (0-5 wt. %) of reduced graphene oxide (RGO) as reinforcement. Nanoindentation study has been carried out on these composite sheets in order to investigate its nano-mechanical properties. Incorporation of different wt. % RGO in PU matrix led to significant increase in the hardness and elastic modulus of the composites. The maximum nanoindentation hardness of 140 MPa for 5.0 wt. % RGO loading was observed as compared to 58.5 MPa for pure PU (an overall improvement of 139 %). The nanoindentation elastic modulus for 5.0 wt % RGO loaded sample was 881.7 MPa as compared to 385.7 MPa for pure PU (an overall improvement of 129 %). The enhancement in the nano-mechanical properties was correlated with spectroscopic and microscopic investigations using Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Due to their excellent nano-mechanical properties, these composites find their usefulness in structural applications such as automobile and wind mill blade industries. These composites can also be used in hard and scratch-less coating on automotive vehicles. The experimental results were in good agreement with theoretical Raman studies of the GO, RGO and RGO-PU composite films were carried out using Renishaw inVia Raman spectrometer, UK with an excitation source of 785 nm. The nanoindentation study was carried out using IBIS-Nanoindentation (M/S Fisher-Cripps Laboratories Pvt. Limited, Australia), equipped with Berkovich indenter and the other details are given elsewhere 28 . The analysis of the functional groups attached to the GO and RGO planes were studied by FTIR (NICOLET 5700) techniques.In order to make the samples for TEM studies, films were grinded to make it thin (~200 µm). Circular slice of 2.3 mm is cut using ultrasonic cutter. The slice is polished and dimple grinded to make it electron transparent (~ 50 nm at centre).Scheme 2: Process for the synthesis formation of stretchable and flexible RGO reinforced PU composites film

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“…These RGO-PU composites can also be used as shape memory polymer composites as polyurethane has been previously used by several researchers [34][35][36][37][38][39] .…”

Section: Figure 10: Deformation Energy (U R ) Of Different Rgo-pu Commentioning

confidence: 99%

Superior nano-mechanical properties of reduced graphene oxide reinforced polyurethane composites

et al. 2015

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“…2,3 PUs can be easily deformed into a temporary shape when heated, and xed at the temporary shape aer fast cooling down, and then regain their original shape upon heating again. Four approaches have been set forth to overcome poor recovery ratio and mechanical properties of PUs by developing either chemical or physical modications: (1) adjusting the hard-to-so segment ratio, [4][5][6][7] (2) enhancing the strength and number of ionic forces or hydrogen bonding, 8,9 (3) incorporating crosslinking networks, 10,11 and (4) blending with inorganic materials or creating organic/inorganic hybrids. 2 Hard segment based domains play an important role in the recovery of the polymer shape above the melting point (T m ) of so segment domains, while the so segment domain based amorphous phase absorbs the external stress and keeps the polymer resilience at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Enhanced shape memory performance of polyurethanes via the incorporation of organic or inorganic networks

Shau

Liu

et al. 2015

RSC Adv.

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A diol compound with a reactive azetidine-2,4-dione group was prepared and introduced as a side chain moiety of poly(3-caprolactone) (PCL) based polyurethane (PU). The PUs with reactive pendants were crosslinked by 1,6-diaminohexane, or modified by an alkoxysilane (3-aminopropyltriethoxysilane, APTS) followed by a sol-gel reaction to bring about crosslinked PUs for shape memory applications. Thermal and mechanical properties of the crosslinked PUs are strongly dependent on the chemical structure of the interchain-linker between the polymer chains. Higher tensile strengths would be achieved for the PU samples crosslinked with alkoxysilanes in comparison with the ones crosslinked with an aliphatic diamine, while higher values of elongation at break were observed for the latter. As compared to the PCL based linear and side-chain PUs, much better shape memory performance was observed as the PU sample was crosslinked with the aliphatic diamine, or by the sol-gel reaction of alkoxysilanes, particularly the latter. Higher shape retention (91%) and recovery (99%) ratios were observed for the CPU samples with inorganic networks. By introducing the chemically crosslinked structures, the deformed PU samples completely recovered their original shape in less than 10 seconds without any deficiency during shape recovery measurements.Scheme 1 Synthesis route of 4-isocyanate-4 0 -(3,3-dimethyl-2,4-dioxo-azetidine)diphenyl methane based diol (IDD-diol).Scheme 2 Synthesis routes of MDI and PCL based LPUs and SPUs.This journal is Fig. 4 X-ray diffraction patterns of (a) LPUs (LPU45, LPU50, and LPU55) and SPUs (SPU45, SPU50, and SPU55), and (b) CPUs (CPU55-A05, CPU55-A10, CPU55-S20, CPU55-S40, and CPU55-S60).This journal is

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“…T g s of PCLAU also decrease from 49.0 C to 22.5 C as the increasing of CL content. No melting peaks of PTMEG segments are observed due to the incorporation of PCLA segments and lower molecular weight of PTMEG [39] . The shape memory behaviors of SMPs are mainly determined by the fixed and reversible phases.…”

Section: Thermal Propertiesmentioning

confidence: 94%

Biodegradable shape memory polyurethanes with controllable trigger temperature

Gao

Jin

et al. 2016

Chin J Polym Sci

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A series of random copolymers (PCLAs) were synthesized by ring-opening polymerization of D,L-lactide (LA) and ε-caprolactone (CL) with different molar ratios. PCLA based polyurethanes (PCLAUs) were obtained by chain-extending of PCLA and polytetramethylene ether (PTMEG) with hexamethylene diisocyanate (HDI). All the PCLAUs exhibit good shape memory properties with high shape fixity ratios above 98% and shape recovery ratios above 82% in the first cycle and 91% in the second cycle. PCLAUs with less CL content show faster recovery speed and PCLAUs with more CL content show higher shape recovery ratio. The trigger temperature can be tuned or controlled around body temperature by adjusting the molar ratio of LA to CL. The PCLAUs have potential applications in implant biomedical devices, especially for minimally invasive deployable devices.

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Effect of block ratio and strain amplitude on thermal, structural, and shape memory properties of segmented polycaprolactone-based polyurethanes

Cited by 33 publications

References 39 publications

Superior nano-mechanical properties of reduced graphene oxide reinforced polyurethane composites

Superior nano-mechanical properties of reduced graphene oxide reinforced polyurethane composites

Enhanced shape memory performance of polyurethanes via the incorporation of organic or inorganic networks

Biodegradable shape memory polyurethanes with controllable trigger temperature

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