Synthesis and characterization of PCL–PLLA polyurethane with shape memory behavior

Peponi, Laura; Navarro-Baena, Iván; Sonseca, Águeda; Giménez, Enrique; Marcos‐Fernández, Ángel; Kenny, J. M.

doi:10.1016/j.eurpolymj.2012.11.001

Cited by 146 publications

(104 citation statements)

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“…Moreover, these polyesters can also be used to design and to synthesize poly(ester-urethane)s by their polycondensation with an isocyanate [20]. Polyurethanes in general, and more specifically, poly(ester-urethane)s, have been already successfully used for biomedical applications due to the possibilities to easily tailor their structure and final properties through a designed synthesis [21,22].…”

Section: Introductionmentioning

confidence: 99%

Biodegradable nanocomposites based on poly(ester-urethane) and nanosized hydroxyapatite: Plastificant and reinforcement effects

Navarro-Baena

Arrieta

Sonseca

et al. 2015

Polymer Degradation and Stability

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The processing and characterization of biodegradable nanocomposites based on poly(ester-urethane)s reinforced with different amounts (0.5, 1 and 3 wt %) of nanosized hydroxyapatite (nHA) are reported. The selected poly(ester-urethane) was synthesized starting from a tri-block copolymer based on poly(ε-caprolactone) (PCL) and poly(L-lactic acid) (PLLA). The nanocomposites were prepared by extrusion and by press molding. Several techniques were applied to investigate the properties of the nanocomposites. Electron microscopy revealed that the poly(ester-urethane) matrix is able to phase separate and that the addition of well-dispersed nanofillers modifies the dimension of the segregated phase. The thermal stability of the PU matrix, regulated by the PLLA block, decreased when low contents of nHA (0.5 and 1 wt %) were added, even if the thermal stability of the PCL-block was increased for each nHA amount. The good mechanical response of the nanocomposites confirmed the absence of agglomerates in the dispersion of the nanofillers in the polymeric matrix. The nHA presence also increased the surface hydrophilicity. Furthermore, rheology measurements, mechanical and thermal tests demonstrated the different behavior induced by the addition of nHA in different amounts. In fact, nHA acts as plasticizer at low concentrations (0.5, 1 wt %) and as reinforcement at a higher nHA amount (3 wt %). In vitro degradation tests were performed using a phosphate buffer solution. The results reported here are relevant for the development of nanocomposites based on a biodegradable and biocompatible polymeric matrix reinforced with small amounts of biocompatible nanofillers for different applications, especially in the biomedical field.Keywords: mechanical properties; phase morphology; nanocomposite; poly(lactide); biodegradable; poly(ester-urethane) Abbreviations DMA: Dynamic-mechanical analysis; DSC: Differential scanning calorimetry; FE-SEM: Field emission electron microscopy; HA: Hydroxyapatite; HDI: hexamethylene diisocyanate; nHA: Nanosized hydroxyapatite; PU: poly(ester-urethane); PU+0.5 HA: Nanocomposite of poly(ester-urethane) with 0.5 wt % of HA; PU+1 HA: Nanocomposite of poly(ester-urethane) with 1 wt % of HA; PU+3 HA: Nanocomposite of poly(ester-urethane) with 3 wt % of HA; PCL: Poly(ε-caprolactone); PLLA: Poly(Llactic acid); TEM: Transmission electron microscopy; Tg: Glass transition temperature; 3 TGA: Thermogravimetric analysis; Tm: melting temperature; WCA: water contact angle.

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Section: Introductionmentioning

confidence: 99%

Biodegradable nanocomposites based on poly(ester-urethane) and nanosized hydroxyapatite: Plastificant and reinforcement effects

Navarro-Baena

Arrieta

Sonseca

et al. 2015

Polymer Degradation and Stability

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“…Thus, the presence of a new peak at 3.15 ppm confirms the formation of urethane groups. [17][18][19][20][21][22][23][24] Moreover the signal corresponding to the PLLA end groups (peak at 4.35 ppm) disappears almost completely, confirming that the condensation reaction between the isocyanate groups of HDI and the hydroxyl 45 groups of the tri-block copolymer proceeded correctly. Fig.…”

Section: Synthesis Of Poly(ester-urethane)smentioning

confidence: 58%

“…23 The presence of these new peaks confirms the reaction between the hydroxyl end groups of tri-block copolymers and the isocyanate groups of HDI. 19 Another way to confirm urethane formation is by 1 H NMR. So, in Fig.…”

Section: Synthesis Of Poly(ester-urethane)smentioning

confidence: 99%

“…They found that the addition of PCL at low concentrations enhanced the shape memory 75 parameters at different strain rates. Also Peponi et al 19 synthesized a poly(ester-urethane) based on PCL-PLLA block copolymers with shape memory behaviour with a transition temperature of about 40 ºC for deformations up to 350 %. In the research reported here the attention has been focused on the 80 synthesis and the characterization of PLLA-b-PCL-b-PLLA triblock copolymers and of their corresponding poly(esterurethane)s, analysing the effects of their molecular weight and of their composition on the crystallisation behaviour of the synthesized polymers.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of PLLA-b-PCL-b-PLLA linear tri-block copolymers and their corresponding poly(ester-urethane)s: effect of the molecular weight on their crystallisation and mechanical properties

et al. 2014

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With the general objective to design polymer based materials with specific thermal and mechanical properties, a systematic study on the crystallinity and the mechanical properties of synthesized linear tri-block copolymers based on poly(L-lactic acid) and poly(ε -caprolactone) and of their corresponding poly(ester-urethane)s has been performed. In particular, eleven tri-block copolymers were 10 synthesized varying both the molecular weight of the blocks as well as the relative content of each block in the copolymer, focusing the attention on the relationship between their chemical compositions and their tailored final properties in order to tune them taking into account their possible applications (i.e. as shape memory materials). From them, eleven poly(ester-urethane)s were synthesized by condensation with hexamethylene diisocyanate (HDI). The chemical composition of the synthesized polymers was studied and correlated with their thermal and crystalline properties obtained by both dynamic scanning calorimetry (DSC) and small angle X-ray diffraction 15 (SAXS) experiments. The relationship between their crystalline structure, thermal and mechanical properties with the molecular weight as well as with the relative content of each comonomer in the copolymers and the amount of HDI in the poly(ester-urethane) was analysed. The results obtained demonstrate that these bio tri-block copolymers and the corresponding poly(ester-urethane)s can be tailored with interesting crystalline and mechanical properties. Future applications as shape memory systems are thus envisaged.

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“…During the programming, the material is deformed above the softening temperature, where the conformational entropy of the material is decreased. Subsequently the material is cooled to temperatures below the segmental transition under constrained conditions to reach the "temporary shape" owing to the reduced molecular mobility at temperatures below transition temperature (Ttrans) 3,4 . Finally, the material recovers its initial permanent "fixed shape" upon the application of the external stimulus which triggers the shape memory effect (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of shape memory polyurethanes

Sáenz-Pérez

Laza

León

et al. 2015

Proceedings of MOL2NET, International Conference on Multidisciplinary Sciences

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Shape memory polymers (SMPs) have attracted extensive attention from basic and fundamental research to industrial and practical applications because they have emerged as a cheap and efficient alternative to well-known metallic shape-memory alloys. Among them, shape memory polyurethanes (SMPUs) own different applications such as the textile finishing, adhesives, coatings, automotive, furniture, construction, and thermal insulation and footwear industries, due to it can be synthesized with different types of molecular architectures by manipulating their composition and choosing properly the chemical structure of their components. In this work, the synthesis and characterization of shape memory polyurethanes, based on two-step polymerization, is reported. The hard segment of SMPU was composed of diisocyanate and a chain extender. On the other hand, the soft segment was prepared by polyols with different molecular weights. Depending on the structure of the synthetized polyurethanes, the materials presented different properties. Thermal characterization was performed by means of Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Furthermore, mechanical properties and shape memory effect were also determined by Dynamic Mechanical Analysis (DMA) and Thermo-Mechanical Analysis (TMA).

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Synthesis and characterization of PCL–PLLA polyurethane with shape memory behavior

Cited by 146 publications

References 50 publications

Biodegradable nanocomposites based on poly(ester-urethane) and nanosized hydroxyapatite: Plastificant and reinforcement effects

Biodegradable nanocomposites based on poly(ester-urethane) and nanosized hydroxyapatite: Plastificant and reinforcement effects

Synthesis of PLLA-b-PCL-b-PLLA linear tri-block copolymers and their corresponding poly(ester-urethane)s: effect of the molecular weight on their crystallisation and mechanical properties

Synthesis and characterization of shape memory polyurethanes

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