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首页> 外文期刊>journal of applied polymer science >Study of the effect of annealing, draw ratio, and moisture upon the crystallinity of native and commercial gutta percha (transpolyisoprene) with DSC, DMTA, and X‐rays: Determination of the activation energies atTg
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Study of the effect of annealing, draw ratio, and moisture upon the crystallinity of native and commercial gutta percha (transpolyisoprene) with DSC, DMTA, and X‐rays: Determination of the activation energies atTg

机译：Study of the effect of annealing, draw ratio, and moisture upon the crystallinity of native and commercial gutta percha (transpolyisoprene) with DSC, DMTA, and X‐rays: Determination of the activation energies atTg

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AbstractThe transitions occurring in gutta‐percha (transpolyisoprene) below the melting point were determined with DMTA and DSC. A comparison of the results obtained with these two methods showed satisfactory agreement. The thermal properties of native and commercial gutta‐percha samples (Tg= 38 ± 2°C andTm= 69 ± 3°C) were investigated, both before and after annealing (at different times and temperatures), and at environments of different relative humidities. An increase in the draw ratio also proved to enhance the percentage crystallinity (K) and improve the thermal stability (higherTgs andTms) of gutta‐percha. Finally, the activation energies ΔE(33.9–40.2 kj/mol ×K) at glass transition temperature were determined and correlated to the percentage content () of the commercial gutta‐percha samples in native gutta‐percha. © 1993 Jo

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