摘要:
A process for preparing halogenated polycarbonate wherein the total amount of base, the end pH of the aqueous phase, and the amount of coupling catalyst employed in the reaction are controlled to selected levels.
摘要:
A process for preparing halogenated polycarbonate wherein the total amount of base the end pH of the aqueous phaser and the amount of coupling catalyst employed in the reaction are controlled to selected levels.
摘要:
A process for preparing glutarimide resins by the amidization and cycloimidization of methacrylate resins in the presence of a solvent characterized in that the solvent consists essentially of cyclohexanol.
摘要:
The present invention is directed to a process for producing a high molecular weight condensation polymer by removing unwanted by-product(s) from a polycondensation equilibrium reaction mixture using a centrifugal force device equipped with a vacuum.
摘要:
A method for devolatilization of a thermoplastic polymer containing at least one volatile component which includes the following three steps: heating the thermoplastic polymer so that the thermoplastic polymer is a heated liquid or molten thermoplastic polymer, flowing the heated liquid thermoplastic polymer through a packed bed liquid-gas contactor by centrifugal force, and flowing a stripping gas through the packed bed countercurrent to the flow of the heated liquid thermoplastic polymer so that the volatile component volatilizes into the stripping gas from the heated liquid thermoplastic polymer by gas-liquid contacting in the packed bed; and an apparatus therefor.
摘要:
A process for producing a monovinylidene aromatic polymer having molecular weight (Mw) greater than 275,000 which comprises polymerizing a monomer mixture comprising a monovinylidene aromatic monomer in the presence of:A) from 10 to 2000 ppm by weight of at least one free radical generating, branching polymerization initiator; andB) from 10 to 2000 ppm of one or more organic gel reduction agent selected from the group consisting of:1) mercaptans, terpenes, halocarbons and halohydrocarbons, such agent having up to 20 carbons,2) distillate recovered from the reaction devolatilization process (recycle), and3) mixtures of 1) and 2).
摘要:
An improved polymer devolatilization apparatus including a flat plate heater having a multiplicity of flat plates defining a plurality of channels, each channel having a substantially uniform height but varying width over its length, each channel including three zones:a first zone in operative communication with the polymer solution supply device, characterized by decreasing width as a function of distance from its beginning,a second zone beginning at the terminus of the first zone, characterized by at least one occurrence of a restrictive cross-sectional area, anda third zone beginning at the end of the second zone and terminating at a liquid/vapor collection and separation region operating at reduced pressure, said third zone characterized by increasing width as a function of distance from its beginning, and provided further that the ratio of maximum width of the third zone to the maximum width of the second zone is from 2:1 to 20:1.