Analysis of the area of material really tested by TMA

Zielnica, J.; Wasilewicz, Piotr; Jurkowski, B.; Jurkowska, Barbara

doi:10.1016/j.tca.2004.01.012

Cited by 7 publications

(9 citation statements)

References 21 publications

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“…However, little is known about the usability of these characteristics to optimize the composite formulation and processing parameters. It is due to several factors: TMA tests concern surface layers up to 0.5 mm thick,14 whereas in mechanical measurements, a specimen is usually much thicker depending on the test. This fact influences the gradient of crosslink density of the specimen and both the gradient of crystallinity degree and crystals' sizes distribution if the material is crystallizable.…”

Section: Methodsmentioning

confidence: 99%

Properties of fullerene‐containing natural rubber

Jurkowska

Jurkowski

Kamrowski

et al. 2006

J of Applied Polymer Sci

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Addition of fullerene in concentration between 0.065 and 0.75 phr increases Schob elasticity, hardness, and modulus of NR-based rubber. There is no substantial influence of fullerene on T g , tan ␦, and G-modulus all evaluated by DMA at twisting within a temperature range Ϫ150 to Ϫ50°C (glassy state). At temperatures between 0 and 150°C (rubbery state) it is different, namely an increase in modulus and some changes in the slope of segments in G(T) curves were observed. It could be resulted from additional strong physical junctions of the rubber network. This suggests the growth of degradation energies of the branching junctions and related rise in the aging resistance as concentration of fullerene increases. Simultaneously, it could be expected some reduction of tire temperature at service. Because of this, introduction of fullerene could be reasonable for tread rubbers in case of reduction of its price. Permittivity and dielectric loss angle are correlated with fullerene concentration. Compounding technology when fullerene dispersed within carbon black is mixed with raw rubber on available machines could be easily implemented in the industry.

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Section: Methodsmentioning

confidence: 99%

Properties of fullerene‐containing natural rubber

Jurkowska

Jurkowski

Kamrowski

et al. 2006

J of Applied Polymer Sci

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“…14 and Table III). The α 2 /α 1 ratio of thermal expansion coefficients in rubbery and glassy state is between 2.5 and 5.12 and it is characteristic for amorphous materials 38, 42…”

Section: Resultsmentioning

confidence: 99%

“…Simultaneously, evaluation of the compaction factor $ V_c^{{\rm{TMA}}} \approx 3\left({\alpha _{\rm{1}}-\alpha _{\rm{2}}}\right) $ T g could be done,39–41 where α 1 is the coefficient of linear thermal expansion in a glassy state = (Δ H / H o )/Δ T , where Δ H / H o is a relative change in the initial height H o (specimen thickness) within the temperature interval, Δ T , α 2 —as α 1 but in a rubbery state. However, usability of these characteristics for optimizing the composite formulation and processing parameters is limited due to several factors: First, TMA tests a surface layer up to 0.5 mm thick42 when in mechanical measurements a specimen is usually much thicker depending on which test is considered. This fact influences the gradient of all crosslink density of specimen, crystallinity degree and crystals' sizes distribution while the material is crystallizable.…”

Section: Methodsmentioning

confidence: 99%

Properties of montmorillonite‐containing natural rubber

Jurkowska¹,

Jurkowski

Oczkowski

et al. 2007

J of Applied Polymer Sci

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A melt compounding process was used to prepare hybrid nanocomposites based on natural rubber (NR) and montmorillonite (MMT) modified with octadecylamine. Cured rubber was subjected to complex testing. Most likely modified MMT participates in physical networking of a low-temperature topological region (soft amorphous fraction) of NR networked by low energy junctions. There was a significant difference between behavior of NR containing modified and neat montmorillonite and also those measured at low strain (5-50%) and above 150-170%. Because of this, to optimize compounding process of nanocomposite it is necessary to apply properties those determined under conditions as much as possible close to the usage conditions.

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“…The technique is based on the measurement of sample deformation under very low load as the temperature is increased and two main modes of deformation, defined by the probe/sample contact area and the applied load, can be performed: (i) expansion, when low forces are applied to large contact areas, and (ii) penetration, with small contact areas and high forces. [1][2][3][4][5] In general, a combination of expansion/penetration is observed. TMA has been used successfully for the measurement of several properties of polymers, such as the glass transition temperature, 1,3,4 softening temperature, 1,2,4 thermal expansion coefficient, 1,2,6 degree of crosslinking 1,2,7 and the average number of degrees of freedom of polymer segments between crosslinks.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5] In general, a combination of expansion/penetration is observed. TMA has been used successfully for the measurement of several properties of polymers, such as the glass transition temperature, 1,3,4 softening temperature, 1,2,4 thermal expansion coefficient, 1,2,6 degree of crosslinking 1,2,7 and the average number of degrees of freedom of polymer segments between crosslinks. 8 A transition temperature is generally taken as a temperature at which the rate or direction of probe deflection changes abruptly.…”

Section: Introductionmentioning

confidence: 99%

Characterization of thermally crosslinkable polyester films by thermomechanical analysis: a versatile and very sensitive technique for the evaluation of low crosslinking degree in polymers

Prataviera

Pessan

Carvalho

2018

Polymer International

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Thermomechanical analysis (TMA) is an effective technique for the characterization of small samples such as thin films of micrometric thickness, allowing the determination of thermal events such as glass transition, softening temperature and thermal expansion. Here we describe use of the TMA technique to investigate the drying and curing properties of polyester thin films ranging from 40 to 70 μm thick. The main purpose of this study was to investigate the effects of residual solvent and crosslinking on the glass transition and softening temperatures of the polyester films subjected to thermal cycling. Despite the fact that the analysed films were thinner than 100 μm, TMA proved to be very sensitive to small changes in residual solvent content and to the effects of the degree of crosslinking on the glass transition and softening temperatures of the polymer films. The most important finding is the possibility of detecting very small degrees of crosslinking in an easy, fast and quantitative way. Other methods such as swelling were not sensitive enough to differentiate the crosslinked samples and data for thicker films are not comparable to the data for thin films. © 2018 Society of Chemical Industry

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Analysis of the area of material really tested by TMA

Cited by 7 publications

References 21 publications

Properties of fullerene‐containing natural rubber

Properties of fullerene‐containing natural rubber

Properties of montmorillonite‐containing natural rubber

Characterization of thermally crosslinkable polyester films by thermomechanical analysis: a versatile and very sensitive technique for the evaluation of low crosslinking degree in polymers

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