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Abstract
Two EPDM roofing membranes were aged at 100C for 7 and 28 days. The Tr of these membranes was then determined by dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), and differential scanning calirometry (DSC) and the results comapred. It was found that: (1) Tr data can be obtained easily using DMA and TMA techniques. The DSC method requires greater care due to the broad step change in the baseline which is associated with heavily plasticized materials. (2) The closest corresopndence between techniques was for TMA and DSC (half-height). The latter, within experimental error, yielded the same glass transition temperature before and after heat-aging. (3) The peak maxima associated with tans and E" measurements should be cited with Tr values as significant differences can exist. (4) the Tg(E") values were closer to the Tg (TMA) and Tr(DSC) data than were the Tr (tano)values. Data obtained at 1 Hz (or possibly less)should be used when making comparisons based on various techniques. An assessment of Tr values indicated that EPDM 112 roofing membrane is more stable than the EPDM 111 membrane. The Tr for EPDM 112 did not change significantly with heat-aging for 28 days at 130C.
Two EPDM roofing membranes were aged at 100C for 7 and 28 days. The Tr of these membranes was then determined by dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), and differential scanning calirometry (DSC) and the results comapred. It was found that: (1) Tr data can be obtained easily using DMA and TMA techniques. The DSC method requires greater care due to the broad step change in the baseline which is associated with heavily plasticized materials. (2) The closest corresopndence between techniques was for TMA and DSC (half-height). The latter, within experimental error, yielded the same glass transition temperature before and after heat-aging. (3) The peak maxima associated with tans and E" measurements should be cited with Tr values as significant differences can exist. (4) the Tg(E") values were closer to the Tg (TMA) and Tr(DSC) data than were the Tr (tano)values. Data obtained at 1 Hz (or possibly less)should be used when making comparisons based on various techniques. An assessment of Tr values indicated that EPDM 112 roofing membrane is more stable than the EPDM 111 membrane. The Tr for EPDM 112 did not change significantly with heat-aging for 28 days at 130C.
Date
0/2000
0/2000
Author(s)
Ralph Paroli; James Penn
Ralph Paroli; James Penn
Page(s)
Keyword(s)
EPDM; glass transition temperature; dynamic mechanical analysis; DMA; thermochemical analysis; TMA; differential scanning calirometry; DSC; thermal analysis
EPDM; glass transition temperature; dynamic mechanical analysis; DMA; thermochemical analysis; TMA; differential scanning calirometry; DSC; thermal analysis