On evaluation of a limit separating amorphous and crystalline states based on thermal expansion measurements

Jurkowski, B.; Jurkowska, Barbara; Andrzejczak, Karol

doi:10.1016/s0142-9418(01)00059-9

Cited by 13 publications

(7 citation statements)

References 12 publications

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“…The glass‐transition temperature is slightly dependent on fullerene concentration (Table III, correlation coefficient r = 0.7). A similar conclusion could be made for the thermal expansion coefficients for rubbers in glassy and rubbery states; α 2 /α 1 ratio is between 2.5 and 5.12 and it is characteristic of materials in the amorphous state 11, 21, 22. The temperature of the beginning of the plateau of high‐elasticity of a low‐temperature region, T ∞ ′, slightly increases as fullerene concentration grows.…”

Section: Resultssupporting

confidence: 72%

“…The TMA allows11, 12 to determine temperatures of the glass transition T g and the beginning of flow T f . It is possible to identify several regions in the surface layer of polymers characterized by three states each and differing in linear thermal expansion coefficients in glassy and rubbery states as well as in the zone of melting of the crystalline portion.…”

Section: Methodsmentioning

confidence: 99%

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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: Resultssupporting

confidence: 72%

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%

“…The TMA allows38, 39 to determine temperatures of the glass transition T g and the beginning of flow T f . It is possible to identify several regions in a surface layer of the tested polymer material characterized by three physical states each and differing in linear thermal expansion coefficients in glassy and rubbery states 38, 39. TMA also makes possible to evaluate the molecular‐weight characteristic for the chain segments between junctions in individual regions.…”

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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“…11). It is well-known that amorphous materials possess a more incompact structure compared to crystalline materials [37]. Thereby, it is inferred that a probable reason for the above result should be ascribed to the partial replacement of crystalline Mg(OH) 2 by amorphous MgCO 3 during CO 2 capture, which can cause a reduced pore size of CHS in the whole pore range.…”

Section: Fractal Characteristics Of Pore Surfaces Of Sorbentsmentioning

confidence: 88%