Identification of Elastomers in Tire Sections by Total Thermal Analysis. III. White Sidewall Compounds of Neoprene Rubber Blends

1975 ◽  
Vol 48 (4) ◽  
pp. 640-652 ◽  
Author(s):  
A. K. Sircar ◽  
T. G. Lamond
Keyword(s):  
Thermal Analysis ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Exothermic Reaction ◽  
Crosslinking Reaction ◽  
Rubber Blends ◽  
Tg And Dtg ◽  
Dsc Curves ◽  
Residual Weight

Abstract DSC curves of sulfur-cured CR differ from peroxide-cured vulcanizates in the shape of the exotherm and the peak temperatures. The exothermic reaction, attributed to dehydrochlorination and subsequent crosslinking, is accelerated by sulfur. TG and DTG curves support this contention. In blends with NR, BR, or SBR, the second polymer intervenes in the crosslinking reaction, resulting in a lower residual weight for the CR network. White sidewall compounds of NR/CR or NR/CR/CSM can be identified by their DSC peaks in nitrogen, glass transition temperature, and DTG peaks. DSC and thermogravimetric curves supplement each other in the identification of these elastomers.

scholarly journals Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Jean Marc Saiter ◽  
Suhaila Idayu Abdul Halim ◽  
Romain Lucas ◽  
Chin Han Chan
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Teaching Activities ◽  
Sample Decomposition ◽  
Calibration Baseline

AbstractWe present an overview for the basic fundamental of thermal analysis, which is applicable for educational purposes, especially for lecturers at the universities, who may refer to the articles as the references to “teach” or to “lecture” to final year project students or young researchers who are working on their postgraduate projects. Description of basic instrumentation [i.e. differential scanning calorimetry (DSC) and thermogravimetry (TGA)] covers from what we should know about the instrument, calibration, baseline and samples’ signal. We also provide the step-by-step guides for the estimation of the glass transition temperature after DSC as well as examples and exercises are included, which are applicable for teaching activities. Glass transition temperature is an important property for commercial application of a polymeric material, e.g. packaging, automotive, etc. TGA is also highlighted where the analysis gives important thermal degradation information of a material to avoid sample decomposition during the DSC measurement. The step-by-step guides of the estimation of the activation energy after TGA based on Hoffman’s Arrhenius-like relationship are also provided.

Study on Glass Transition Temperature of Polyvinylamine Hydrochloride

2011 ◽  
Vol 217-218 ◽  
pp. 1066-1069 ◽  
Author(s):  
Hong Chi Zhao ◽  
Qi Li ◽  
Li Bin Bai ◽  
Fan Huang
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Differential Scanning Calorimeter ◽  
Degradation Rate ◽  
Average Molecular Weight ◽  
Weight Average Molecular Weight ◽  
Dsc Curves

Polyvinylamine (PVAm) was synthesized by Hofmann degradation of polyacrylamide (PAM). The thermal properties of the Polyvinylamine hydrochloride (PVAm•HCl) were studied by differential scanning calorimeter (DSC). The degradation rate (a) decreased with increasing weight-average molecular weight (Mw) of PAM and decreasing amount of NaOH, and a were the better values when the concentration of PAM was 5% and the amount of NaClO was 10 mL. DSC curves showed that the glass transition temperature (Tg) of PVAm•HCl increased with increasing Mw of PAM, concentration of NaClO and decreasing concentration of NaOH. Tg of PVAm•HCl appeared the minimum value when the concentration of PAM was 5.0%.

Polymer Degradation from the Thermal Analysis Point of View

2004 ◽  
Vol 851 ◽  
Author(s):  
Ramón Artiaga ◽  
Ricardo Cao ◽  
Salvador Naya ◽  
Ana García
Keyword(s):  
Thermal Analysis ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Elevated Temperatures ◽  
Chemical Degradation ◽  
Space Environment ◽  
Space Applications ◽  
Analysis Methods ◽  
The One

ABSTRACTThis work applies different thermal analysis methods to polymer based materials degradation, studying the degradation process itself and evaluating the degree of material damage as a consequence of chemical degradation by thermal or radiation effects. On the one hand, thermal degradation in varied atmospheres is investigated by means of thermogravimetric analysis (TGA) in dynamic experiments. The authors find that the evolution of the sample mass follows a mixture of logistics models, and these can fit an overall TGA curve. The fitting parameters have important physical meaning related to the kinetics of the different processes involved and to the relative amount of each component in the sample. The method itself entails separating overlapping processes. Other improvements made by the authors are related to reducing the noise and smoothing the TGA and differential scanning calorimetry (DSC) data, particularly when estimating TGA derivatives through logistic regression.Analyzing many materials by means of TGA results in more or less complex traces that do not allow a simple parametric fit like the one described above. Although it reproduces asymptoticity at the beginning and end of the reaction, there are times when many processes overlap, resulting in a complex trace that would need a high number of logistic components to be adequately fitted. However, it is possible to use a local polynomial regression model instead. This is also applicable to DSC traces, whose shapes are totally different from those found in TGA. The authors propose a model based on a nonparametric estimation, where the fit's suitability very much depends on the bandwidth selection, especially where derivatives are concerned. The proposed model gives a satisfactory fitting. It smoothes noise and always provides reliable values, different from those obtained by other methods strongly dependent on user choice.On the other hand, to evaluate the degree of damage by thermal analysis methods, dynamic mechanical analysis (DMA) is applied to polyamides. The glass transition temperature is measured before and after exposure to varying doses of proton radiation, emulating the space environment. Other examples show how exposure over long periods at moderately elevated temperatures results in reduction of some mechanical properties. Additionally, the effect of different nanofillers on styrene-isoprene-styrene block copolymers is evaluated by DMA. A shift in the glass transition temperature seems to be dependent on nanofiller content. The degradation of some materials suitable for space applications, such as polyethylene and polyamide, are also briefly reviewed.

scholarly journals Catalytic Activity of Oxidized Carbon Waste Ashes for the Crosslinking of Epoxy Resins

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1011 ◽  
Author(s):  
Enrica Stasi ◽  
Antonella Giuri ◽  
Maurizio La Villetta ◽  
Domenico Cirillo ◽  
Gaetano Guerra ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Resin ◽  
Diglycidyl Ether ◽  
Crosslinking Reaction ◽  
Scanning Calorimetry ◽  
Cure Reaction ◽  
Carbon Based

In this study, two different fillers were prepared from carbon-based ashes, produced from the wooden biomass of a pyro-gasification plant, and starting from lignocellulosic waste. The first type was obtained by dry ball-milling (DBA), while the second one was prepared by oxidation in H2O2 of the dry ball-milled ashes (oDBA). The characterization of the fillers included wide-angle x-ray diffraction (WAXD), thermogravimetric, and Fourier-transform infrared spectroscopy (FTIR) analysis. The DBA and oDBA fillers were then tested as possible catalysts for the crosslinking reaction of a diglycidyl ether of bisphenol A (DGEBA) with a diamine. The cure reaction was studied by means of rheometry and differential scanning calorimetry (DSC). The oDBA filler exhibits both a higher catalytic activity on the epoxide–amine reaction than the DBA sample and improved mechanical properties and glass transition temperature. The results obtained indicate, hence, the potential improvement brought by the addition of carbon-based waste ashes, which allow both increasing the flexural properties and the glass transition temperature of the epoxy resin and reducing the curing time, acting as a catalyst for the crosslinking reaction of the epoxy resin.

Thermal Viscoelastic Analysis of 3D Fabric Nanocomposites

2008 ◽  
Vol 47-50 ◽  
pp. 1133-1136 ◽  
Author(s):  
Nan Jia Zhou ◽  
Andrey Beyle ◽  
Christopher C. Ibeh
Keyword(s):  
Thermal Analysis ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Loss Tangent ◽  
Viscoelastic Properties ◽  
Vinyl Ester ◽  
Loss Modulus ◽  
Viscoelastic Analysis ◽  
Storage And Loss Moduli

Viscoelastic properties of 3D fabric reinforced Vinyl Ester composites were studied in different directions using Dynamic Mechanical Thermal Analysis (DMTA). Such materials filled by nanoparticles (silicon carbide) with different concentrations were also investigated. The increases of storage and loss moduli with addition of nanoparticles and with increase of their concentrations were observed. The maximal tangent of the angle of mechanical losses was especially compared at below and over glass transition temperature. Below glass transition temperature the presence of nanoparticles increases storage and loss moduli and loss tangent. These effects achieved maximum at glass transition temperature. Over glass transition, the loss modulus and loss tangent are decreased with increase of the concentration of nanoparticles.

Comparison of Glass Transition Temperature Values of Composite Polymer Obtained by TMA and DSC

2015 ◽  
Vol 719-720 ◽  
pp. 91-95 ◽  
Author(s):  
Cirlene Fourquet Bandeira ◽  
Sérgio Roberto Montoro ◽  
Elton Luiz Espindola ◽  
Edson Cocchieri Botelho ◽  
Michelle Leali Costa ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Polymer Composites ◽  
Thermomechanical Analysis ◽  
Great Sensitivity ◽  
Superior Performance ◽  
New Materials ◽  
Technical Principles ◽  
Dsc Curves

In recent years a number of studies were conducted in order to obtain polymer composites with superior performance when compared to the metallic alloys. However, these new materials must meet a series of rigid project requirements. One way to evaluate the polymer composites is through their transition temperatures, especially the glass transition temperature (Tg). It is possible to evaluate the Tg of a polymeric material through the study of changes in dimensions of a sample as a function of temperature. These measurements can be made on an equipment of thermomechanical analysis (TMA), however, despite great sensitivity, this technique is basically unknown by most users when compared to others such as DSC or DMA. Even with different technical principles of operation, the results show similarity. Thus, this study aims to compare the results of Tg polymer composites obtained via TMA with those obtained from DSC curves in epoxy resin/carbon fiber laminates.

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