Enhanced thermal stability of biomedical thermoplastic polyurethane with the addition of cellulose nanocrystals

2015 ◽  
Vol 132 (22) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jen-Chieh Liu ◽  
Darren J. Martin ◽  
Robert J. Moon ◽  
Jeffrey P. Youngblood
Keyword(s):  
Thermal Stability ◽  
Cellulose Nanocrystals ◽  
Thermoplastic Polyurethane ◽  
Thermal Stability Of

Influence of trisilanol isooctyl POSS content on the structure, morphology and rheological properties of thermoplastic polyurethane (TPU)

2020 ◽  
Vol 40 (9) ◽  
pp. 727-735
Author(s):  
Rudinei Fiorio ◽  
Chaitanya Danda ◽  
João Maia
Keyword(s):  
Thermal Stability ◽  
Rheological Properties ◽  
Thermoplastic Polyurethane ◽  
Reactive Extrusion ◽  
Strain Rates ◽  
Force Microscopy ◽  
Atomic Force ◽  
Extensional Strain ◽  
Oligomeric Silsesquioxane ◽  
Thermal Stability Of

AbstractIn this study, thermoplastic polyurethanes (TPUs) containing trisilanol isooctyl polyhedral oligomeric silsesquioxane (POSS), a reactive nanofiller, were synthesized and characterized rheologically and morphologically, and the effects of POSS content on the melt thermal stability of the TPUs are investigated. Samples containing 0, 0.23, 0.57, 1.14, and 2.23% (w/w) POSS were synthesized by reactive extrusion and characterized by Fourier transform infrared spectroscopy (FTIR), oscillatory and extensional rheometry, atomic force microscopy (AFM), and small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). The rheological properties of molten TPU are time-dependent and the melt thermal stability of the TPU is maximal at 1.14% of POSS. The addition of 0.23 and 0.57% POSS promotes strain-hardening at low extensional strain rates (0.01 and 0.10 s−1), not affecting the extensional characteristics at higher strain rates. The addition of increasing amounts of POSS leads to the formation of POSS-rich clusters well dispersed in the TPU matrix. SAXS and WAXS results show that the POSS domains are amorphous and that POSS does not modify the crystalline structure of TPU. Therefore, this work indicates that synthesizing TPU in the presence of trisilanol isooctyl POSS can increase the melt thermal stability of the polymer, facilitating its processing.

Hybrid Nanocomposites of Poly(Lactic Acid)/Thermoplastic Polyurethane with Nanosilica/Montmorillonite

2019 ◽  
Vol 947 ◽  
pp. 77-81
Author(s):  
Natsuda Palawat ◽  
Phasawat Chaiwutthinan ◽  
Sarintorn Limpanart ◽  
Amnouy Larpkasemsuk ◽  
Anyaporn Boonmahitthisud
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Impact Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Thermoplastic Polyurethane ◽  
Hybrid Nanocomposites ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Thermal Stability Of

The aim of this study is to improve the physical properties of poly(lactic acid) (PLA) by incorporating thermoplastic polyurethane (TPU), organo-montmorillonite (OMMT) and/or nanosilica (nSiO2). PLA was first melt mixed with five loadings of TPU (10–50 wt%) on a twin-screw extruder, followed by injection molding. The addition of TPU was found to increase the impact strength, elongation at break and thermal stability of the blends, but decrease the tensile strength and Young’s modulus. Based on a better combination of the mechanical properties, the 70/30 (w/w) PLA/TPU blend was selected for preparing both single and hybrid nanocomposites with a fix total nanofiller content of 5 parts per hundred of resin (phr), and the OMMT/nSiO2 weight ratios were 5/0, 2/3, 3/2 and 0/5 (phr/phr). The Young’s modulus and thermal stability of the nanocomposites were all higher than those of the neat 70/30 PLA/TPU blend, but at the expense of reducing the tensile strength, elongation at break and impact strength. However, all the nanocomposites exhibited higher impact strength and Young’s modulus than the neat PLA. Among the four nanocomposites, a single-filler nanocomposite containing 5 phr nSiO2 exhibited the highest impact strength and thermal stability, indicating that there was no synergistic effect of the two nanofillers on the investigated physical properties. However, the hybrid nanocomposite containing 2/3 (phr/phr) OMMT/nSiO2 possessed a compromise in the tensile properties.

Mechanical and thermal behavior of cellulose nanocrystals-incorporated Acrodur® sustainable hybrid composites for automotive applications

2020 ◽  
Vol 54 (22) ◽  
pp. 3159-3169 ◽  
Author(s):  
Ezatollah (Nima) Amini ◽  
Mehdi Tajvidi
Keyword(s):  
Thermal Stability ◽  
Impact Strength ◽  
Flexural Strength ◽  
Cellulose Nanocrystals ◽  
Flexural Modulus ◽  
Natural Fibers ◽  
Cellulose Nanocrystal ◽  
Gravimetric Analysis ◽  
Automotive Applications ◽  
Thermal Stability Of

Utilization of cellulose nanocrystals as an additive in the formulation of biocomposites made with Acrodur® resin is presented. Natural fibers/polyethylene terephthalate mats were impregnated with Acrodur® and hot-pressed into the final thickness of 3 mm after drying. Biocomposites with 2 wt.% and 5 wt.% cellulose nanocrystal (dry-basis) were also produced. The produced biocomposite panels were then tested to determine the flexural strength, flexural modulus and Izod impact strength. The results revealed that adding cellulose nanocrystal to the composite formulation increased flexural modulus significantly up to 970 MPa (17.5% increase) at a panel density of 0.5 g/cm3, while it did not significantly affect flexural strength values. A slight reduction was observed in the impact strength of the samples by adding cellulose nanocrystal. The fractured samples of impact test were observed under a scanning electron microscope. It was shown that in all cases, the fracture happened due to the failure of the fibrous system and in particular natural fibers. Thermal stability of the composites was also investigated using thermo-gravimetric analysis. It was found that adding cellulose nanocrystal slightly reduced the thermal stability of the biocomposites. Potential compatibility of cellulose nanocrystal particles with Acrodur® resin is promising and the improvement in flexural modulus can lead to the design of lighter parts for automotive applications such as door panels, headliners, and underbody shields.

Insight into thermal stability of cellulose nanocrystals from new hydrolysis methods with acid blends

Cellulose ◽  
2018 ◽  
Vol 26 (1) ◽  
pp. 507-528 ◽  
Author(s):  
Oriana M. Vanderfleet ◽  
Michael S. Reid ◽  
Julien Bras ◽  
Laurent Heux ◽  
Jazmin Godoy-Vargas ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Cellulose Nanocrystals ◽  
Thermal Stability Of ◽  
Insight Into

Simultaneous improvement of mechanical properties and thermal stability of bacterial polyester by cellulose nanocrystals

2012 ◽  
Vol 89 (3) ◽  
pp. 971-978 ◽  
Author(s):  
Hou-Yong Yu ◽  
Zong-Yi Qin ◽  
Yan-Nan Liu ◽  
Long Chen ◽  
Na Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Cellulose Nanocrystals ◽  
Thermal Stability Of

scholarly journals Investigating Physio-Thermo-Mechanical Properties of Polyurethane and Thermoplastics Nanocomposite in Various Applications

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2467
Author(s):  
Tyser Allami ◽  
Ahmed Alamiery ◽  
Mohamed H. Nassir ◽  
Amir H. Kadhum
Keyword(s):  
Thermal Stability ◽  
Electrical Properties ◽  
Hard Segment ◽  
Soft Segment ◽  
Thermoplastic Polyurethane ◽  
Tensile Modulus ◽  
Scanning Calorimetry ◽  
Strain Behavior ◽  
Phase Separation Kinetics ◽  
Thermal Stability Of

The effect of the soft and hard polyurethane (PU) segments caused by the hydrogen link in phase-separation kinetics was studied to investigate the morphological annealing of PU and thermoplastic polyurethane (TPU). The significance of the segmented PUs is to achieve enough stability for further applications in biomedical and environmental fields. In addition, other research focuses on widening the plastic features and adjusting the PU–polyimide ratio to create elastomer of the poly(urethane-imide). Regarding TPU- and PU-nanocomposite, numerous studies investigated the incorporation of inorganic nanofillers such as carbon or clay to incorporating TPU-nanocomposite in several applications. Additionally, the complete exfoliation was observed up to 5% and 3% of TPU–clay modified with 12 amino lauric acid and benzidine, respectively. PU-nanocomposite of 5 wt.% Cloisite®30B showed an increase in modulus and tensile strength by 110% and 160%, respectively. However, the nanocomposite PU-0.5 wt.% Carbone Nanotubes (CNTs) show an increase in the tensile modulus by 30% to 90% for blown and flat films, respectively. Coating PU influences stress-strain behavior because of the interaction between the soft segment and physical crosslinkers. The thermophysical properties of the TPU matrix have shown two glass transition temperatures (Tg’s) corresponding to the soft and the hard segment. Adding a small amount of tethered clay shifts Tg for both segments by 44 °C and 13 °C, respectively, while adding clay from 1 to 5 wt.% results in increasing the thermal stability of TPU composite from 12 to 34 °C, respectively. The differential scanning calorimetry (DSC) was used to investigate the phase structure of PU dispersion, showing an increase in thermal stability, solubility, and flexibility. Regarding the electrical properties, the maximum piezoresistivity (10 S/m) of 7.4 wt.% MWCNT was enhanced by 92.92%. The chemical structure of the PU–CNT composite has shown a degree of agglomeration under disruption of the sp2 carbon structure. However, with extended graphene loading to 5.7 wt.%, piezoresistivity could hit 10-1 S/m, less than 100 times that of PU. In addition to electrical properties, the acoustic behavior of MWCNT (0.35 wt.%)/SiO2 (0.2 wt.%)/PU has shown sound absorption of 80 dB compared to the PU foam sample. Other nanofillers, such as SiO2, TiO2, ZnO, Al2O3, were studied showing an improvement in the thermal stability of the polymer and enhancing scratch and abrasion resistance.

scholarly journals Surface Modification of Cellulose Nanocrystals with Succinic Anhydride

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 866 ◽  
Author(s):  
Agnieszka Leszczyńska ◽  
Paulina Radzik ◽  
Ewa Szefer ◽  
Matej Mičušík ◽  
Mária Omastová ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Surface Modification ◽  
Thermal Properties ◽  
Reaction Time ◽  
Cellulose Nanocrystals ◽  
Succinic Anhydride ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
Degree Of Esterification ◽  
Thermal Stability Of

The surface modification of cellulose nanocrystals (CNC) is a key intermediate step in the development of new functionalities and the tailoring of nanomaterial properties for specific applications. In the area of polymeric nanocomposites, apart from good interfacial adhesion, the high thermal stability of cellulose nanomaterial is vitally required for the stable processing and improvement of material properties. In this respect, the heterogeneous esterification of CNC with succinic anhydride was investigated in this work in order to obtain CNC with optimised surface and thermal properties. The influence of reaction parameters, such as time, temperature, and molar ratio of reagents, on the structure, morphology and thermal properties, were systematically studied over a wide range of values by DLS, FTIR, XPS, WAXD, SEM and TGA methods. It was found that the degree of surface substitution of CNC increased with the molar ratio of succinic anhydride to cellulose hydroxyl groups (SA:OH), as well as the reaction time, whilst the temperature of reaction showed a moderate effect on the degree of esterification in the range of 70–110 °C. The studies on the thermal stability of modified nanoparticles indicated that there is a critical extent of surface esterification below which only a slight decrease of the initial temperature of degradation was observed in pyrolytic and oxidative atmospheres. A significant reduction of CNC thermal stability was observed only for the longest reaction time (240 min) and the highest molar ratio of SA:OH. This illustrates the possibility of manufacturing thermally stable, succinylated, CNC by controlling the reaction conditions and the degree of esterification.

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