Temperature-modulated differential scanning calorimetric measurements on pre-melting behavior of nascent ultrahigh molar mass polyethylene

G.W.H. Hoehne, L. Kurelec, S. Rastogi, P.J. Lemstra

    Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

    11 Citaten (Scopus)

    Samenvatting

    Temperature-modulated differential scanning calorimetric (TMDSC) measurements on nascent ultrahigh molecular mass polyethylene (UHMMPE) in scanning as well as quasi-isothermal mode are presented. From these measurements different processes, which contribute to the modulated heat flow in the pre-melting region, both exothermic and endothermic in character, can be separated. One of them only occur on the first heating of the nascent material. Analysis of quasi-isothermal measurements, performed between 90 and 130 °C, show that there are two slow (exponential) relaxation processes with time constants of 2–5 and 10–100 min, respectively. One, exothermic in character, seems to be connected with irreversible structural changes (crystal thickening and ordering). The low activation energy (ca 40 kJ mol-1) points to a chain diffusion process rather than melting and crystallization. The other process (activation energy 60 kJ mol-1) seems to be endothermic. In the melting region, a slow (>100 min) 3rd relaxation process with high activation energy (300 kJ mol-1) can be separated.
    Originele taal-2Engels
    Pagina's (van-tot)97-108
    TijdschriftThermochimica Acta
    Volume396
    Nummer van het tijdschrift1-2
    DOI's
    StatusGepubliceerd - 2003

    Vingerafdruk

    Duik in de onderzoeksthema's van 'Temperature-modulated differential scanning calorimetric measurements on pre-melting behavior of nascent ultrahigh molar mass polyethylene'. Samen vormen ze een unieke vingerafdruk.

    Citeer dit