DTULDeflection Temperature Under Load
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3 Strength (MPa) Notched 96 144 26 81 Izod Impact Strength (J/m) DTUL at 77 65 77 90 0.
As a high-temperature material, the flexible PPS material has a melting point of 280[degrees]C and DTUL of 100[degrees]C, both of which are significantly higher compared to that of PA12 and PVDF.
If the DTUL of a material, such as a 40% glass-filled nylon 66, is given as 250 C, then a simple calculation gives us 80% of the DTUL as 200 C.
A reading of the ASTM or ISO method used to measure the DTUL will show that it is the temperature at which a certain deflection is obtained while placing a sample of a very specific and regular geometry under a constant stress.
Ironically, the much lower DTUL measured at 264 psi is a reflection of the effect of this glass transition.
It just so happens that the DTUL for amorphous polymers is in exactly the temperature region we just described, on the verge of going through the glass transition.
Michael Takemori's analysis was in his 1978 SPE ANTEC paper, the modulus values he calculated that should be associated with the stress levels specified in the DTUL test do not usually agree with the values related to the temperatures we find on the data sheets.
A further question is, does selecting candidate materials by setting a threshold value for the DTUL and then picking materials from the resulting list have any validity as a material selection strategy?
4 DTUL @ 66 psi ASTM [degrees]F 201 207 DTUL @ 264 psi ASTM [degrees]F 176 190 Vicat Softening Temp ASTM [degrees]F 208 219 Melt Flow Rate ASTM g/10 min 5.
However, between room temperature and the DTUL, most data sheets provide little guidance on the effects of temperature on load-bearing capabilities.
These data are automatically generated by DMRT, eliminating the need for the use of ASTM D 648 DTUL.