Effect of polycyclosilane microstructure on thermal properties

2021 ◽  
Author(s):  
Qifeng Jiang ◽  
Sydnee Wong ◽  
Rebekka S Klausen
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Side Chains ◽  
Phase Properties

Thermal characterization of polysilanes has focused on the influence of organic side chains, whereas little is understood about the influence of silane backbone microstructure on thermal stability, phase properties, and...

Dielectric and thermal characterization of fluorinated polyimides containing heterocyclic moieties

1993 ◽  
Vol 5 (2) ◽  
pp. 97-106 ◽  
Author(s):  
Frank W Mercer ◽  
Martin T McKenzie
Keyword(s):  
Thermal Stability ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Relative Humidity ◽  
Thermal Characterization ◽  
Dielectric Constants ◽  
Aromatic Diamines ◽  
Fluorinated Polyimides

A series of fluorinated polyinides and fluorinated polyimides containing heterocyclic moieties were prepared and investigated to determine their dielectric constants, dielectric constants as a function of relative humidity (RH) and thermal properties. Thle fluorinated polyimides containing heterocyclic moieties were prepared from diamines containing pyridine, pyridazine, oxadiazole or benzoxazole moieties. The properties of the fluorinated heterocyclic-containing polyimides were compared with those of fluorinated polyimides prepared from aromatic diamines. In most cases, the introduction of heterocyclic moieties caused an increase in dielectric constant, an increase in the dielectric constant as a function of relative humidity and a decrease in thermal stability compared with the polyimides prepared with aromatic diamines.

Mechanical and thermal characterization of polypropylene-reinforced nanocrystalline cellulose nanocomposites

2020 ◽  
pp. 089270572092512
Author(s):  
Mohammad Y Al-Haik ◽  
Saud Aldajah ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Nanocrystalline Cellulose ◽  
Injection Molding Process ◽  
Mechanical And Thermal Properties ◽  
Molding Process ◽  
Point Bend ◽  
Cellulose Nanocomposites

This article addresses the effect of nanocrystalline cellulose (NCC) on the mechanical and thermal properties of polypropylene (PP). A new approach was adopted to produce mechanically improved and thermally stable PP-NCC nanocomposite. This approach involved producing optimized PP-NCC nanocomposite by adding NCC nanoparticles to PP matrix at different concentrations by means of injection molding process. The aim of this work was to find the optimum NCC concentration to enhance the mechanical and thermal properties of the PP matrix. The mechanical and thermal behavior of PP-NCC nanocomposite was studied by performing three-point bend, nanoindentation, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy tests. The results showed that the mechanical properties of strength, modulus, and hardness of the nanocomposites increased with the addition of NCC by 6.5%, 19%, and 150%, respectively. DSC results showed that the addition of NCC to PP does not affect the thermal stability (melting temperature). However, TGA showed that upon inclusion of NCC nanoparticles, the thermal stability of the samples improved compared to pure PP except for the 5% added NCC. This is attributed to the presence of NCC rod-like particles that dissipated heat by generating tortuous paths, as depicted in the SEM results and verified by FTIR results.

Mechanical and thermal characterization of grafted PP-NCC nanocomposites

2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Properties ◽  
Interfacial Adhesion ◽  
Thermal Characterization ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Twin Screw ◽  
Thermal Stability Of

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.

scholarly journals Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Soccio ◽  
N. Lotti ◽  
L. Finelli ◽  
A. Munari
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Room Temperature ◽  
Crystallization Rate ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Aliphatic Polyesters ◽  
Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s were synthesized for comparison and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of the presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tgvalue, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions

Clay modification with silane compounds and characterization of the silicone rubber/clay composites

2012 ◽  
Vol 32 (8-9) ◽  
pp. 493-502 ◽  
Author(s):  
Kyeong Hoon Jang ◽  
Eung-Soo Kim ◽  
Young Ho Jeon ◽  
Jin-San Yoon
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Silicone Rubber ◽  
Cross Linking ◽  
Mechanical And Thermal Properties ◽  
Curing Agent ◽  
Thiol Groups ◽  
Rubber Composites ◽  
Clay Modification

Abstract Na+ montmorillonite (MMT) was modified with benzyldimethyltetradecylammonium chloride (B13) and further with (3-mercaptopropyl)triethoxysilane and vinyltrimethoxysilane to prepare B13-MMT, mercaptomethylorthosilicate modified MMT (MTMO), and vinyltrimethoxysilane modified MMT (VTMO), respectively. The pristine and modified clays were compounded with an HTV-type silicone rubber (GP-30®), and the physical properties and morphology of the resulting rubber composites were examined. Both HTV/MTMO and HTV/VTMO exhibited an intercalated/exfoliated coexisting morphology, but the degree of exfoliation of the former composite was higher than that of the latter. Moreover, the thermal stability, as assessed by the onset temperature of thermal degradation, as well as the tensile stress, elongation at the break, and tear strength of HTV/MTMO was higher than those of HTV/B13-MMT and HTV/VTMO. However, the cross-linking density of HTV/MTMO was the lowest among the composites examined because the thiol groups of MTMO extinguished and abstracted the radicals formed by the curing agent. Accordingly, the improved mechanical and thermal properties of HTV/MTMO were attributed to the enhanced interactions between HTV and MTMO due to the chemical reaction between the thiol groups of MTMO and the vinyl groups of HTV.

A Phase-Sensitive Technique for the Thermal Characterization of Dielectric Thin Films

1999 ◽  
Vol 121 (3) ◽  
pp. 528-536 ◽  
Author(s):  
S. W. Indermuehle ◽  
R. B. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Specific Heat ◽  
Temperature Response ◽  
Front Surface ◽  
Thermal Characterization ◽  
Fused Silica ◽  
Dielectric Thin Films ◽  
Phase Sensitive

A phase-sensitive measurement technique for determining two independent thermal properties of a thin dielectric film is presented. The technique involves measuring a specimen’s front surface temperature response to a periodic heating signal over a range of frequencies. The phase shift of the temperature response is fit to an analytical model using thermal diffusivity and effusivity as fitting parameters, from which the thermal conductivity and specific heat can be calculated. The method has been applied to 1.72-μm thick films of SiO2 thermally grown on a silicon substrate. Thermal properties were obtained through a temperature range from 25°C to 300°C. One interesting outcome stemming from analysis of the experimental data is the ability to extract both thermal conductivity and specific heat of a thin film from phase information alone. The properties obtained with this method are slightly below the bulk values for fused silica with a measured room temperature (25°C) thermal conductivity of 1.28 ± 0.12 W/m-K.

scholarly journals Further thermal characterization of an aspartate aminotransferase from a halophilic organism

1994 ◽  
Vol 298 (2) ◽  
pp. 465-470 ◽  
Author(s):  
F J G Muriana ◽  
M C Alvarez-Ossorio ◽  
A M Relimpio
Keyword(s):  
Thermal Stability ◽  
Aspartate Aminotransferase ◽  
Thermal Inactivation ◽  
Hydrophobic Interactions ◽  
Thermal Characterization ◽  
Haloferax Mediterranei ◽  
First Order Kinetics ◽  
Effects Of Temperature ◽  
Thermal Stability Of

Aspartate aminotransferase (AspAT, EC 2.6.1.1) from the halophilic archaebacterium Haloferax mediterranei was purified [Muriana, Alvarez-Ossorio and Relimpio (1991) Biochem. J. 278, 149-154] and further characterization of the effects of temperature on the activity and stability of the halophilic AspAT were carried out. The halophilic transaminase is most active at 65 degrees C and stable at high temperatures, under physiological or nearly physiological conditions (3.5 M KCl, pH 7.8). Thermal inactivation (60-85 degrees C) of the halophilic AspAT followed first-order kinetics, 2-oxoglutarate causing a shift of the thermal inactivation curves to higher temperatures. The salt concentration affected the thermal stability of the halophilic transaminase at 60 degrees C, suggesting that disruption of hydrophobic interactions may play an important role in the decreased thermal stability of the enzyme.

Characterization and Fabrication of Nano-Sized Patterns and Microfluidic Channels Derived from Polyvinylsilazane via Soft Lithographic Technique

2007 ◽  
Vol 544-545 ◽  
pp. 677-680 ◽  
Author(s):  
Hong Joo Lee ◽  
Jun Hong Park ◽  
Perumal Jayakumar ◽  
Tae Ho Yoon ◽  
Lan Young Hong ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Microelectromechanical Systems ◽  
Polymeric Materials ◽  
Thermal Characterization ◽  
Treatment Temperature ◽  
Microfluidic Channels ◽  
Inorganic Polymers ◽  
Total Analysis System ◽  
Chemical Inertness

Interests on the fabrication of microfluidic devices have increased in the fields of micro total analysis system (μ-TAS) and MEMS (Microelectromechanical systems) due to their chemical inertness and high thermal stability. The thermal characterization of the SiCN preceramic polymer, polyvinylsilazane, showed that the cured polymer has ceramic properties at heat treatment temperature of 600 oC or above. In the characterization of the mechanical properties, the characteristic values of the elastic modulus and hardness notably increased for the heat-treated SiCN. The present study describes the preparation of nano-sized patterns and microfluidic channels using a soft lithographic technique. The study shows that the fabrication of microchannels using the cured inorganic polymers holds tremendous potential in the field of microfluidics, where materials with high optical transparency, thermal stability and chemical inertness are in demand as niche between conventional microfluidics using glass and polymeric materials.

Preparation and Characterization of Polyurethane Foams from Modified Rosin-Based Polyether Polyol

2014 ◽  
Vol 887-888 ◽  
pp. 727-730
Author(s):  
Meng Zhang ◽  
Li Qiang Zhang ◽  
Yong Hong Zhou
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Compression Strength ◽  
Dimensional Stability ◽  
Polyurethane Foams ◽  
Mechanical And Thermal Properties ◽  
Foaming Behavior ◽  
Polyether Polyol ◽  
Better Than

Rosin based polyether polyols were synthesized from rosin formaldehyde adduct, propylene epoxide and ethylene epoxide in the presence of catalyst. Rigid polyurethane foams (PUFs) were prepared with these rosin-based polyols and compared with foam made with an industrial polyether polyol (TC-4110) and rosin-based polyester polyols. The mechanical and thermal properties of foams were analyzed by some methods. The experimental results show that the foaming behavior for the foams prepared from such rosin based polyether polyols is similar to that of industrial products, but the reaction activities were higher, the viscosities are much lower. Furthermore, their 10% compression strength and thermal stability were higher and the dimensional stability is similar or somewhat better than that of TC-4110 system. All these unique properties of rigid PUFs made with rosin based polyether polyols were more suitable for as industrial production.

scholarly journals Thermal Characterization of Non-Functionalized Low Content Graphene Nanoplatelets (GNP) Added Nylon 66 Polymer

2021 ◽  
Vol 89 (1) ◽  
pp. 13-25
Author(s):  
Mohammed Iqbal Shueb ◽  
Mohd Edeerozey Abd Manaf ◽  
Mahathir Mohamed ◽  
Noraiham Mohamad ◽  
Jeeferie Abd Razak ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Mechanical Analysis ◽  
Graphene Nanoplatelets ◽  
Degree Of Crystallinity ◽  
Minimal Amount ◽  
Nylon 66 ◽  
Degradation Temperature ◽  
Tan Δ

Thermal behaviour of graphene nanoplatelets (GNP) reinforced nylon 66 nanocomposites were investigated using differential calorimetric scanning (DSC), thermogravimetric analyzer (TGA) and dynamic mechanical analysis (DMA). The influence of low content GNP on thermal properties of GNP/nylon 66 nanocomposites was studied for low GNP content (0.3, 0.5 and 1.0 wt%). DSC results indicate that addition of GNP increases crystallization temperature and degree of crystallinity of the nanocomposites. Thermal stability and mass loss were studied through TGA analysis. The results show that thermal stability and weight loss of GNP/nylon 66 nanocomposites slightly improve with the GNP addition with an increase in the onset of degradation temperature as much as 10 °C. DMA analysis shows that GNP in the nylon 66 matrix act similar to plasticizer; it decreases the storage modulus and glass transition temperatures of the nanocomposites. GNP addition also reduces tan δ indicating an improvement in the damping property of the nanocomposites. Overall, this study concludes that a minimal amount of 0.3 wt% of GNP is effective in improving the thermal properties of nylon 66 composites.

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