scholarly journals Self-Healable and Recyclable Biomass-Derived Polyurethane Networks through Carbon Dioxide Immobilization

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4381
Author(s):  
Seohyun Baek ◽  
Juhyen Lee ◽  
Hyunwoo Kim ◽  
Inhwan Cha ◽  
Changsik Song
Keyword(s):  
Carbon Dioxide ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Polymer Materials ◽  
Self Healing ◽  
Scanning Calorimetry ◽  
Covalent Bonds ◽  
Thermal Mechanical Analysis ◽  
Carbon Dioxide Co2 ◽  
Combined Strategy

Due to growing environmental issues, research on carbon dioxide (CO2) use is widely conducted and efforts are being made to produce useful materials from biomass-derived resources. However, polymer materials developed by a combined strategy (i.e., both CO2-immobilized and biomass-derived) are rare. In this study, we synthesized biomass-derived poly(carbonate-co-urethane) (PCU) networks using CO2-immobilized furan carbonate diols (FCDs) via an ecofriendly method. The synthesis of FCDs was performed by directly introducing CO2 into a biomass-derived 2,5-bis(hydroxymethyl)furan. Using mechanochemical synthesis (ball-milling), the PCU networks were effortlessly prepared from FCDs, erythritol, and diisocyanate, which were then hot-pressed into films. The thermal and thermomechanical properties of the PCU networks were thoroughly characterized by thermogravimetric analysis, differential scanning calorimetry, dynamic (thermal) mechanical analysis, and using a rheometer. The self-healing and recyclable properties of the PCU films were successfully demonstrated using dynamic covalent bonds. Interestingly, transcarbamoylation (urethane exchange) occurred preferentially as opposed to transcarbonation (carbonate exchange). We believe our approach presents an efficient means for producing sustainable polyurethane copolymers using biomass-derived and CO2-immobilized diols.

scholarly journals The Influence of the Furan and Maleimide Stoichiometry on the Thermoreversible Diels–Alder Network Polymerization

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2522
Author(s):  
Ali Safaei ◽  
Seppe Terryn ◽  
Bram Vanderborght ◽  
Guy Van Assche ◽  
Joost Brancart
Keyword(s):  
Transition Temperature ◽  
Functional Groups ◽  
Polymer Networks ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Diels Alder ◽  
Stoichiometric Ratio ◽  
Self Healing ◽  
Scanning Calorimetry

In recent work, the thermoreversible Diels–Alder reaction between furan and maleimide functional groups has been studied extensively in the context of self-healing elastomers and thermosets. To elaborate the influence of the stoichiometric ratio between the maleimide and furan reactive groups on the thermomechanical properties and viscoelastic behavior of formed reversible covalent polymer networks, a series of Diels–Alder-based networks with different stoichiometric ratios was synthesized. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and dynamic rheology measurements were performed on the reversible polymer networks, to relate the reversible network structure to the material properties and reactivity. Such knowledge allows the design and optimization of the thermomechanical behavior of the reversible networks for intended applications. Lowering the maleimide-to-furan ratio creates a deficit of maleimide functional groups, resulting in a decrease in the crosslink density of the system, and a consequent decrease in the glass transition temperature, Young’s modulus, and gel transition temperature. The excess of unreacted furan in the system results in faster reaction and healing kinetics and a shift of the reaction equilibrium.

scholarly journals Influence of 1D and 2D Carbon Fillers and Their Functionalisation on Crystallisation and Thermomechanical Properties of Injection Moulded Nylon 6,6 Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Fabiola Navarro-Pardo ◽  
Ana L. Martínez-Hernández ◽  
Victor M. Castaño ◽  
José L. Rivera-Armenta ◽  
Francisco J. Medellín-Rodríguez ◽  
...  
Keyword(s):  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Reduced Form ◽  
Scanning Calorimetry ◽  
Graphene Nanocomposites ◽  
Moulding Process ◽  
Nylon 6,6 ◽  
Injection Moulding Process ◽  
The One ◽  
Carbon Fillers

Carbon nanotubes (CNTs) and graphene were used as reinforcing fillers in nylon 6,6 in order to obtain nanocomposites by using an injection moulding process. The two differently structured nanofillers were used in their pristine or reduced form, after oxidation treatment and after amino functionalisation. Three low nanofiller contents were employed. Crystallisation behaviour and perfection of nylon 6,6 crystals were determined by differential scanning calorimetry and wide angle X-ray diffraction, respectively. Crystallinity was slightly enhanced in most samples as the content of the nanofillers was increased. The dimensionality of the materials was found to provide different interfaces and therefore different features in the nylon 6,6 crystal growth resulting in improved crystal perfection. Dynamical, mechanical analysis showed the maximum increases provided by the two nanostructures correspond to the addition of 0.1 wt.% amino functionalised CNTs, enhancing in 30% the storage modulus and the incorporation of 0.5 wt.% of graphene oxide caused an increase of 44% in this property. The latter also provided better thermal stability when compared to pure nylon 6,6 under inert conditions. The superior properties of graphene nanocomposites were attributed to the larger surface area of the two-dimensional graphene compared to the one-dimensional CNTs.

scholarly journals The Effect of POSS Type on the Shape Memory Properties of Epoxy-Based Nanocomposites

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4203
Author(s):  
Avraham I. Bram ◽  
Irina Gouzman ◽  
Asaf Bolker ◽  
Noam Eliaz ◽  
Ronen Verker
Keyword(s):  
Transition Temperature ◽  
Shape Memory ◽  
Crosslinking Density ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Space Environment ◽  
Scanning Calorimetry ◽  
Space Applications ◽  
Curing Conditions ◽  
Oligomeric Silsesquioxane

Thermally activated shape memory polymers (SMPs) can memorize a temporary shape at low temperature and return to their permanent shape at higher temperature. These materials can be used for light and compact space deployment mechanisms. The control of transition temperature and thermomechanical properties of epoxy-based SMPs can be done using functionalized polyhedral oligomeric silsesquioxane (POSS) additives, which are also known to improve the durability to atomic oxygen in the space environment. In this study, the influence of varying amounts of two types of POSS added to epoxy-based SMPs on the shape memory effect (SME) were studied. The first type contained amine groups, whereas the second type contained epoxide groups. The curing conditions were defined using differential scanning calorimetry and glass transition temperature (Tg) measurements. Thermomechanical and SME properties were characterized using dynamic mechanical analysis. It was found that SMPs containing amine-based POSS show higher Tg, better shape fixity and faster recovery speed, while SMPs containing epoxide-based POSS have higher crosslinking density and show superior thermomechanical properties above Tg. This work demonstrates how the Tg and SME of SMPs can be controlled by the type and amount of POSS in an epoxy-based SMP nanocomposite for future space applications.

Thermal and Mechanical Properties of Cyclized Polybutadiene Dielectrics

1986 ◽  
Vol 76 ◽  
Author(s):  
C. W. Wilkins ◽  
H. E. Bair ◽  
M. G. Chan ◽  
R. S. Hutton
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Physical And Mechanical Properties ◽  
Mechanical Analysis ◽  
Infrared Analysis ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
The Difference ◽  
Thermal Mechanical Analysis ◽  
Lower Glass Transition Temperature

ABSTRACTWe have studied some of the physical and mechanical properties of cyclized polybutadiene (CBR) dielectrics by dynamic mechanical analysis, thermal mechanical analysis, thermogravimetry, infrared analysis, and differential scanning calorimetry. Of interest is the difference in properties between thin (<30 μm) films which have been cured under vacuum and those which have been cured in air. Our results indicate that curing under vacuum prevents oxidation and reduces crosslinking. Vacuum cured films have 20% smaller moduli and 200 lower glass transition temperature than do films produced in air.

Thermal and Thermomechanical Properties of Poly(butylene succinate) Nanocomposites

2008 ◽  
Vol 8 (4) ◽  
pp. 1679-1689 ◽  
Author(s):  
Mamookho E. Makhatha ◽  
Suprakas Sinha Ray ◽  
Joseph Hato ◽  
Adriaan S. Luyt
Keyword(s):  
Thermal Stability ◽  
Tensile Modulus ◽  
Melting Behavior ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Butylene Succinate ◽  
Modulated Differential Scanning Calorimetry ◽  
Thermal Stability Of

This article describes the thermal and thermomechanical properties of poly(butylene succinate) (PBS) and its nanocomposites. PBS nanocomposites with three different weight ratios of organically modified synthetic fluorine mica (OMSFM) have been prepared by melt-mixing in a batch mixer at 140 °C. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) analyses and transmission electron microscopy (TEM) observations that reveal the homogeneous dispersion of the intercalated silicate layers into the PBS matrix. The thermal properties of pure PBS and the nanocomposite samples were studied by both conventional and temperature modulated differential scanning calorimetry (DSC) analyses, which show multiple melting behavior of the PBS matrix. The investigation of the thermomechanical properties was performed by dynamic mechanical analysis. Results reveal significant improvement in the storage modulus of neat PBS upon addition of OMSFM. The tensile modulus of neat PBS is also increased substantially with the addition of OMSFM, however, the strength at yield and elongation at break of neat PBS systematically decreases with the loading of OMSFM. The thermal stability of the nanocomposites compared to that of the pure polymer sample was examined under both pyrolytic and thermooxidative environments. It is shown that the thermal stability of PBS is increased moderately in the presence of 3 wt% of OMSFM, but there is no significant effect on further silicate loading in the oxidative environment. In the nitrogen environment, however, the thermal stability systematically decreases with increasing clay loading.

Thermomechanical Properties of Nanosilica Reinforced PEEK Composites

2007 ◽  
Vol 351 ◽  
pp. 15-20 ◽  
Author(s):  
Y.H. Lai ◽  
M.C. Kuo ◽  
J.C. Huang ◽  
M. Chen
Keyword(s):  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Surface Pretreatment ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Simple Compression ◽  
Sio2 Nanocomposites ◽  
Thermal Mechanical Analysis

The nano-sized silica particulates reinforced poly(ether ether ketone) (PEEK) composites were fabricated by means of simple compression molding technique. The nano-sized silica, measuring 30 nm in size, was firstly modified by surface-pretreatment with stearic acid. The thermomechanical properties of the resulting PEEK/SiO2 nanocomposites were measured using dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA). The TMA results show that the coefficient of thermal expansion (CTE) becomes lowered when the content of the nanosilica increases. Furthermore, the CTE of the modified-silica filled PEEK nanocomposites shows higher CTE values, as compared with those of the unmodified counterparts. The dynamic modulus of the PEEK nanocomposites shows over 40% increment at elevated temperatures from 100-250oC, indicating the apparent improvement of elevated temperature mechanical properties.

Thermomechanical Characterization of Bismuth Telluride Based Thermoelectric Materials

2001 ◽  
Vol 691 ◽  
Author(s):  
Witold Brostow ◽  
Kevin P. Menard ◽  
John B. White
Keyword(s):  
Bismuth Telluride ◽  
Van Der Waals ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Direction Parallel ◽  
Crystalline Polymers ◽  
Structural Metals ◽  
P Type

ABSTRACTThe thermoelectric properties of bismuth telluride based thermoelectric (TE) materials are well-characterized, but comparatively little has been published on the mechanical and thermomechanical properties of these materials. In this paper, we present the initial dynamic mechanical analysis (DMA) data for n-type and p-type bismuth telluride based TE materials. The materials' tan δ values, indicative of viscoelastic energy dissipation modes, approach that of glassy or crystalline polymers and are greater than ten times the tan delta of structural metals. TE samples measured perpendicular to the van der Waals planes have higher tan δ values. Thermal scans in the DMA compressive mode showed changes in mechanical properties versus temperature with clear hysteresis effects. These changes were correlated to differential scanning calorimetry (DSC) thermal transitions. The expected anisotropy was shown in flexural 3-point bending results for one n-type material that showed a storage modulus of 0.10 to 0.45 GPa in the direction parallel to the van der Waals planes and 0.07 to 0.2 GPa in the perpendicular direction.

Influence of Carbon Nanofibers and Piezoelectric Particles on the Thermomechanical Behaviour of Epoxy Mixtures

2007 ◽  
Vol 121-123 ◽  
pp. 1419-1424 ◽  
Author(s):  
S. Tsantzalis ◽  
P. Tsotra ◽  
P. Karapappas ◽  
A. Vavouliotis ◽  
N. Fanis ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Lead Zirconate Titanate ◽  
Lead Zirconate ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Vapor Growth ◽  
Curing Reaction ◽  
Thermomechanical Behaviour ◽  
Dynamic Thermal Mechanical Analysis ◽  
Thermal Mechanical Analysis

Vapor growth carbon nanofibers (CNFs), lead zirconate titanate piezoelectric (PZT) particles, as well as a combination of these two were added in an epoxy resin (EP), and their influence on the curing reaction was investigated. Moreover, the cured samples were characterised by dynamic scanning calorimetry and dynamic thermal mechanical analysis. The presence of the fillers had no significant effect of the curing reaction of the EP system and the glass transition temperature, Tg.

Application of dynamic mechanical analysis techniques to bismuth telluride based thermoelectric materials

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Witold Brostow ◽  
Kevin P. Menard ◽  
John B. White
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Bismuth Telluride ◽  
Polymeric Materials ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Tan Δ ◽  
Te Material

Abstract Dynamic mechanical analysis (DMA) techniques are commonly applied to characterize polymer-based materials - but little if at all to characterize semiconductor thermoelectric (TE) materials. TE materials may be coupled with polymeric materials in advanced thermoelectric devices, and the knowledge of TE material properties will be useful in the choice of materials for future applications. We have obtained DMA results for both n-type and p-type bismuth telluride based TE materials. We find that tan δ values, indicative of viscoelastic energy dissipation modes, approach the values for glassy or semi-crystalline polymers, and are larger by more than a whole order of magnitude than the tan δ of structural metals. DMA thermal scans show clear hysteresis-type effects and a correlation with differential scanning calorimetry thermal transitions. DMA properties as a function of frequency are briefly discussed. Our results show that DMA techniques are useful in the evaluation of thermophysical and thermomechanical properties of these TE materials and of assembled coolers. The viscoelastic effects we report may provide a damping mechanism for severe stresses inherent to service conditions of the TE coolers.

scholarly journals Tough Materials Through Ionic Interactions

2021 ◽  
Vol 9 ◽  
Author(s):  
Linda Salminen ◽  
Erno Karjalainen ◽  
Vladimir Aseyev ◽  
Heikki Tenhu
Keyword(s):  
Thermal Properties ◽  
Ion Pairs ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Polymer Materials ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Shape Stability ◽  
Chemical Crosslinks ◽  
Unique Approach

This article introduces butyl acrylate-based materials that are toughened with dynamic crosslinkers. These dynamic crosslinkers are salts where both the anion and cation polymerize. The ion pairs between the polymerized anions and cations form dynamic crosslinks that break and reform under deformation. Chemical crosslinker was used to bring shape stability. The extent of dynamic and chemical crosslinking was related to the mechanical and thermal properties of the materials. Furthermore, the dependence of the material properties on different dynamic crosslinkers—tributyl-(4-vinylbenzyl)ammonium sulfopropyl acrylate (C4ASA) and trihexyl-(4-vinylbenzyl)ammonium sulfopropyl acrylate (C6ASA)—was studied. The materials’ mechanical and thermal properties were characterized by means of tensile tests, dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric analysis. The dynamic crosslinks strengthened the materials considerably. Chemical crosslinks decreased the elasticity of the materials but did not significantly affect their strength. Comparison of the two ionic crosslinkers revealed that changing the crosslinker from C4ASA to C6ASA results in more elastic, but slightly weaker materials. In conclusion, dynamic crosslinks provide substantial enhancement of mechanical properties of the materials. This is a unique approach that is utilizable for a wide variety of polymer materials.

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