scholarly journals Thermal stability of segmented polyurethane elastomers reinforced by clay particles

2009 ◽  
Vol 63 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Jelena Pavlicevic ◽  
Jaroslava Budinski-Simendic ◽  
Mészáros Szécsényi ◽  
Nada Lazic ◽  
Milena Spirkova ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Chain Extender ◽  
Hexamethylene Diisocyanate ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Polyurethane Elastomers ◽  
Oh Groups ◽  
Clay Nanoparticles ◽  
Thermal Stability Of

The aim of this work was to determine the influence of clay nanoparticles on thermal properties of segmented polyurethanes based on hexamethylene- diisocyanate, aliphatic polycarbonate diol and 1,4-butanediol as chain extender. The organically modified particles of montmorillonite and bentonite were used as reinforcing fillers. The structure of elastomeric materials was varied either by diol type or chain extender content. The ratio of OH groups from diol and chain extender (R) was either 1 or 10. Thermal properties of prepared materials were determined using modulated differential scanning calorimetry (MDSC). Thermal stability of obtained elastomers has been studied by simultaneously thermogravimetry coupled with DSC. The glass transition temperature, Tg, of soft segments for all investigated samples was about -33?C. On the basis of DTG results, it was concluded that obtained materials were very stable up to 300?C.

Epoxy Cured with Anhydride Terminated Polydimethylsiloxane: Cure Kinetics and Thermal Properties

2011 ◽  
Vol 415-417 ◽  
pp. 261-264
Author(s):  
Yuan Ren ◽  
Zheng Xi ◽  
Wen Jun Gan ◽  
Liang Zhang ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Succinic Anhydride ◽  
Cure Kinetics ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Thermogravimetric Analyses ◽  
Isothermal Measurements ◽  
Thermal Stability Of

A siloxane-containing dianhydride, succinic anhydride terminated polydimethylsiloxane (DMS-Z21) was selected to cure diglycidyl ether of bisphenol-A based epoxy resin (DGEBA). The cure kinetics and thermal properties were investigated by nonisothermal and isothermal differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA), respectively. The activation energy (Ea) of the curing reaction was obtained based on the methods of Kissinger and isothermal measurements. The results of the thermogravimetric analyses of the DGEBA/DMS-Z21 system showed that the thermal stability of the DGEBA/DMS-Z21 system was slightly higher than the DGEBA/MeTHPA system.

scholarly journals Electrospun Silk-Boron Nitride Nanofibers with Tunable Structure and Properties

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1093
Author(s):  
Ye Xue ◽  
Xiao Hu
Keyword(s):  
Thermal Stability ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Environmental Research ◽  
Strong Interactions ◽  
Helical Structures ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Thermal Stability Of

In this study, hexagonal boron nitride (h-BN) nanosheets and Bombyx mori silk fibroin (SF) proteins were combined and electrospun into BNSF nanofibers with different ratios. It was found that the surface morphology and crosslinking density of the nanofibers can be tuned through the mixing ratios. Fourier transform infrared spectroscopy study showed that pure SF electrospun fibers were dominated by random coils and they gradually became α-helical structures with increasing h-BN nanosheet content, which indicates that the structure of the nanofiber material is tunable. Thermal stability of electrospun BNSF nanofibers were largely improved by the good thermal stability of BN, and the strong interactions between BN and SF molecules were revealed by temperature modulated differential scanning calorimetry (TMDSC). With the addition of BN, the boundary water content also decreased, which may be due to the high hydrophobicity of BN. These results indicate that silk-based BN composite nanofibers can be potentially used in biomedical fields or green environmental research.

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.

Polycarbonate-based polyurethane elastomers: temperature-dependence of tensile properties

2014 ◽  
Vol 68 (2) ◽  
Author(s):  
Zdeněk Hrdlička ◽  
Antonín Kuta ◽  
Rafał Poręba ◽  
Milena Špírková
Keyword(s):  
Tensile Properties ◽  
Hard Segment ◽  
Elevated Temperatures ◽  
Thermoplastic Elastomers ◽  
Chain Extender ◽  
Hexamethylene Diisocyanate ◽  
Polyurethane Elastomers ◽  
Oh Groups ◽  
Polycarbonate Diol ◽  
Polyurethane Composition

AbstractNovel polyurethane thermoplastic elastomers were prepared from polycarbonate diols, butane-1,4-diol (chain extender) and hexamethylene diisocyanate. They differ in the kind of macrodiol used and the ratio of macrodiol to chain extender OH groups (hence, in hard segment contents). The tensile properties of the elastomers at low and elevated temperatures were determined and discussed with regard to polyurethane composition and polycarbonate diol structure.

Study on thermal properties of polyurethane-urea elastomers prepared with different dianiline chain extenders

2013 ◽  
Vol 33 (1) ◽  
pp. 87-94 ◽  
Author(s):  
Majid Barikani ◽  
Naghmeh Fazeli ◽  
Mehdi Barikani
Keyword(s):  
Thermal Properties ◽  
Chain Extender ◽  
Polymerization Reaction ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Polymer Characterization ◽  
Cast Films ◽  
Mechanical Measurements ◽  
Chain Extenders ◽  
Thermal Stability Of

Abstract A number of polyurethane prepolymers based on polycaprolactone diol (PCL) and 4,4′-diphenyl methane diisocyanate (MDI) were synthesized and extended with different dianilines such as: 4,4′-methylenebis(2,6-diisopropylaniline) (M-DIPA), 4,4′-methylenebis(2,6diethylaniline) (M-DEA), 4,4′-methylenebis(ortho chloroaniline) (MOCA), 4,4′-methylenebis(2-isopropyl-6-methylaniline) (M-MIPA) and 4,4′-methylenebis(3-chloro-2,6-diethylaniline) (M-CDEA). Infrared (IR) spectroscopy was used to check the end of the polymerization reaction in addition to the polymer characterization. The effect of the dianiline structure on the thermal properties of the cast films were studied through dynamic mechanical measurements (DMTA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. It was found that the thermal properties and thermal stability of polyurethane are strongly affected by the molecular structure of the dianiline chain extender.

Preparation and Thermal Properties of Polybenzoxazine/TiC Hybrids

2014 ◽  
Vol 887-888 ◽  
pp. 49-52 ◽  
Author(s):  
Noureddine Ramdani ◽  
Jun Wang ◽  
Wen Bin Liu
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
High Performance ◽  
Phenolic Resin ◽  
Scanning Calorimetry ◽  
New Class ◽  
Solution Blending ◽  
Tic Nanoparticles ◽  
Thermal Stability Of

In this work, typical polybenzoxazine, as new class of phenolic resin, has been used as a matrix for preparing a series of high performance hybrid materials using various amounts of titanium carbide (TiC) ranging between 0-10 wt% as fillers, via a solution blending technique. The thermal properties of bisphenol A-aniline base benzoxazine monomers (BA-a) and TiC mixtures have been studied by differential scanning calorimetry (DSC). The thermal stability of their cured hybrids has been tested by means of thermogravimetric analysis (TGA). The result showed that the glass transition temperature of the prepared composites increased with increasing the amount of TiC to reach a higher value at 194°C. Also, the incorporation of TiC nanoparticles has considerably improved the thermal stability of the hybrids including the char yield which increase by 50 % at 10 wt% TiC content.

scholarly journals The influence of bentonite and montmorillonite addition on thermal decomposition of novel polyurethane/organoclay nanocomposites

2013 ◽  
Vol 32 (1) ◽  
pp. 319 ◽  
Author(s):  
Jelena Pavličević ◽  
Milena Špírková ◽  
Oskar Bera ◽  
Mirjana Jovičić ◽  
Katalin Mészáros Szécsényi ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Hard Segment ◽  
Reaction Order ◽  
Hexamethylene Diisocyanate ◽  
Scanning Calorimetry ◽  
Degradation Kinetic ◽  
Polyurethane Elastomers ◽  
Hard Segment Content ◽  
Butane Diol ◽  
Thermal Stability Of

Polycarbonate-based polyurethane (PC-PUs) hybrid materials were obtained by the addition oforganically modified bentonite and montmorillonite (1 w/w %). PC-PUs and their nanocomposites wereprepared using prepolymerization with two polycarbonate diols (both of Mr ca 1000) differing in chainconstitution, hexamethylene-diisocyanate and 1,4-butane diol (chain extender) as starting components. All samples contained the same hard-segment content (30 w/w %). Thermogravimetry coupled with differential scanning calorimetry (TG-DSC) was performed to obtain information about the organoclays addition on the thermal stability of the prepared polyurethane elastomers. The effect of bentonite and montmorillonite nanofillers on the decomposition pattern has been evaluated. By deconvolution of derivative thermogravimetric (DTG) curves, it has been found that the thermal decomposition of polyurethane samples takes place in three overlapping processes. Degradation kinetic parameters (activation energy and reaction order) were calculated on the basis of thermal data obtained at only one heating rate.

Effect of alkali treatment on the thermal properties of wheat straw fiber reinforced epoxy composites

2016 ◽  
Vol 51 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Varun Mittal ◽  
Shishir Sinha
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Wheat Straw ◽  
Fiber Composite ◽  
Alkali Treatment ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Ftir Studies ◽  
Four Levels ◽  
Thermal Stability Of

This paper focuses on the study of the effect of fiber content and alkali treatment on the thermal properties of wheat straw epoxy composite. Four levels of fiber loading (10, 20, 30, and 40 wt%) of wheat straw and three levels of alkali treatment (1, 3, and 5%) were considered and merged into epoxy composites. The composites were prepared by hand layup technique. The thermal stability of the components was studied by thermogravimetric analysis and differential scanning calorimetry, as well as by the differential thermogravimetric. The experimental results show that the thermal stability of the composites prepared from 3% alkali-treated fibers is superior as compared to the untreated and another level of alkali-treated fiber composite. This is mainly due to the efficient fiber–matrix adhesion in the alkali-treated wheat straw epoxy composites. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) studies were carried out to evaluate the microstructure and composition of wheat straw fiber/epoxy composites, respectively.

scholarly journals THE INFLUENCE OF BIO-BASED CHAIN EXTENDER ON THE POLYURETHANE PROPERTIES

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Vladan Mićić ◽  
Milojko Jokić ◽  
Milovan Jotanović ◽  
Ivan Ristić ◽  
Suzana Cakić ◽  
...  
Keyword(s):  
Renewable Resources ◽  
Raw Materials ◽  
Chain Extender ◽  
Hexamethylene Diisocyanate ◽  
Scanning Calorimetry ◽  
Polyurethane Elastomers ◽  
Renewable Raw Materials ◽  
Stage Process ◽  
Poly Propylene

The development of polymers obtained from renewable raw materials is important because it is known that the fossil sources will be depleted in the future. Due to this fact, the possibilities for the synthesis of polyurethanes based on renewable resources increases. This work analyzes the properties of polyurethane materials obtained from the renewable resources. Polyurethane elastomers were prepared by a two stage process in solution, which involved the synthesis of the pre-polymer and synthesis of the polyurethane elastomer. As a polyol component, poly (propylene glycol) was used. Isophorone-diisocyanate and hexamethylene diisocyanate were employed as isocyanate components. For some samples, petrochemically obtained chain extender, butanediol, was replaced by biobased product isosorbide. Characterization of polyurethane materials was carried out by infrared spectroscopy with Fourier transformation, thermogravimetric analysis and differential scanning calorimetry. The properties of synthesized polyurethane materials were improved by adding the nanoparticles in various proportions.

Effect of chemical treatment on thermal properties of bagasse fiber-reinforced epoxy composite

2017 ◽  
Vol 24 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Varun Mittal ◽  
Shishir Sinha
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Chemical Treatment ◽  
Epoxy Composite ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Scanning Calorimetry ◽  
Chemical Treatments ◽  
Bagasse Fiber ◽  
Thermal Stability Of

AbstractThe present paper deals with a study of the thermal properties of bagasse fiber (BF)-reinforced epoxy composites. BFs are subjected to untreated and chemical treatments with 1% sodium hydroxide followed by 1% acrylic acid at ambient temperature before the composites are made. The thermal stability of the components was studied by thermogravimetric analysis and differential scanning calorimetry, as well as by differential thermal gravimetric analysis. Thermal analysis results of untreated BF-reinforced epoxy composite were compared with treated BF-reinforced epoxy composite. The chemical treatment of BF induces reasonable changes in the thermal stability of the polymer composites.

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