Page 690 - Carrahers_Polymer_Chemistry,_Eighth_Edition

Selected Topics 653

DMS introduced in 1990 nylon 4,6 called Stanyl (19.48), based on the reaction between adipic
o
acid and 1,4-diaminobutane. Stanyl can withstand temperature of about 310 C, allowing it to create
a niche between conventional nylons and high-performance materials. It was not able to break into

the film market and has only now begun to be accepted for tire cord applications. About 22 million
pounds of Stanyl was produced in 2001.
O

R O

(19.48)
NH

NH
n
R
Nylon-4,6

In 2007, DSM announced the development of PA4T nylon (19.49). It is intended to address new
needs for miniaturization and the convergence of electronic devices such as cell phones and com-
puters. It offers good dimensional stability, compatibility with lead free soldering, high melting
point, good mechanical strength at elevated temperatures, high stiffness, and good processabil-
ity. Specific applications include central processing unit (CPU) sockets, high-temperature bobbins,

notebook computer memory module connectors, and memory card connectors.

O

R

(19.49)
R NH
NH

O
PA4T

The development of PA4T nylon illustrates the use of polymers in the intermediate synthesis
scale, larger than specialty chemical use and smaller than bulk chemical use. The development of

polymers that fit into this category will greatly increase as special properties are needed and the
price per weight can be high.
In 1997, Dow introduced syndiotactic PS under the trade name Questra. The technology for the
production of Questra is based on relatively new technology and science involving soluble stereo-
regulating catalysts that produce PS that has a fixed and repeating geometry as each new styrene

monomer unit is added to the growing PS chain. Targeted areas include medical, automotive, and
electronic applications.
Several other produces have been developed based on the relatively new soluble stereoregulating
catalysis systems. Index, an ethylene-styrene interpolymer, was introduced in 1998 and is intended

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