Previously we discussed a principle that employing a mold temperature above the glass-transition temperature
([T.sub.g]) of the polymer ensures a degree of crystallinity high enough to provide for dimensional stability, even if the part must be used at elevated temperatures.
He says the resin has a glass-transition temperature
160[degrees]C, which is higher than other PPAs, including existing ForTii grades, and at least 80[degrees]C higher than PA66.
Ultem EXSP0023 features a glass-transition temperature
(Tg) of 245[degrees]C, has a dielectric strength of 4,700 V/mil and good tear resistance.
It produces a glass-transition temperature
of more than 120 [degrees] C, and high bond strength to glass ceramic, metals and most plastics--allowing it to pass the most stringent specifications for both single- and multimode terminations.
Making use of the fact that the glass-transition temperature
([T.sub.g]) is cooling-rate dependent allows one to introduce a cooling-rate parameter into a P-V-T equation.
The glass-transition temperature
may be determined by taking the middle of the change in baseline (half-height method).
With Vicat B120 softening temperatures as high as 190 C/374 F and glass-transition temperature
(Tg) of up to 195 C/383 F, the CXT resins can withstand demanding assembly processes, such as cold reflow or wave soldering onto printed circuit boards.
Results from DSC and torsional pendulum measurements showed that the glass-transition temperature
of polypropylene in the blends decreased with decreasing concentration of polypropylene.
* ForTii Ace WX51-FC is a 30% glass-reinforced PPA based on nylon 4T chemistry with a high glass-transition temperature
of 160 C/320 F.
Meanwhile, its modulus is 50% greater at temperatures below the glass-transition temperature
(Tg) of PEEK (302 F).
Amorphous PC exhibits only one transition temperature, known as the glass-transition temperature
Unfilled Victrex ST G45 has a melting point of 389 C, glass-transition temperature
(Tg) of 164 C, and HDT @ 1.8 MPa of 172 C.