Process for High-Molecular-Weight PPS

The Edmonds and Hill process provided modest-molecular-weight PPS that could be apphed to a wide variety of apphcations. One logical appb-cation for a thermally resistant, chemically inert, and inherently flame-resistant polymer was fiber. The Edmonds and Hill polymer was, however, not well suited for fiber apphcations. In the unciured state, the polymer lacked sufficient molecular weight to have good fiber properties. In its cured state, the Edmonds and Hdl polymer displayed poor spinability. It was clear that higher-molecular-weight hnear PPS was needed. 

Another commercial process for the synthesis of high-molecular-weight PPS is currently being practiced by Ticona. The basic process as originaUy taught by Kureha Chemical Industry [16] has been reviewed elsewhere [1, 3, 5]. The essential difference of the Kureha process from the CampheU process is the use of a different polymerization modifier. The Kureha 

TABLE 15.1 Molecular Weight and Melt Flow of PPS from the Campbell Process 

Synthetic method Polymerization modifier Melt flow Weight average MW 

Melt flow was measured according to American Society for Testing and Materials (ASTM) test method D-1238, determined at 316°C (600 F) with a 5-kg driving weight, modified to use a 5-min preheat time. 

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