There are two major BPAbased industrial polycarbonate processes: two-phase interfacial process (or simply phosgene process) and melt transesterification process , In the interfacial process, a two-phase mixture of BPA, phosgene (carbonyl dichloride), and a small amount of chain stopper
dissolved in methylene chloride is polymerized with a tertiary amine catalyst and sodium hydroxide solution added to maintain the appropriate pH (10-12) at low temperature (40[degrees]C).
Parent company Aker Solutions says the fairlead chain stopper
is an innovative system designed to constrain the mooring load to a limited area on the hull.
Contrary to the poly(BTDA-DAB) synthesis described before (16), where a dianhydride solution in NMP was added to a DAB/NMP solution, in this study the dianhydride (and optionally the chain stopper
phthalic anhydride, PA) was added as a solid.
During polyurethane formation, high molecular weights can not be attained because the monol acts as a polymerization chain stopper
. In addition, the unreacted polyol chain end (carbon-carbon double bond) acts as an internal plasticizer.
Rising outputs have led to the industry growths in line with that of the global GDP, further driving the demand growth for Isatoic Acid Anhydride, which is used as a chemical intermediates and chain stoppers
in polymer and rubber manufacturing.
The order from Bluewater Industries covers design and delivery of eccentric fairlead chain stoppers
and roller RamWinches for a deep draft production unit owned by ATP Oil & Gas Corporation, while the DSME order covers similar equipment for the Pazflor FPSO under construction by DSME in Korea.
* D4 is polymerized in the presence of a strong base like KOH where the ring opens for chain formation, and chain stoppers
are used to terminate the process.
Norwegian industrial group Scana Industrier ASA said on Tuesday (30 October) that its subsidiary Scana Steel Stavanger has received an order for chain stoppers
from the Norwegian deck machinery manufacturer Karmoy Winch AS.