Abstract: Disclosed are novel non-linear vinyl polymers comprised of a multifunctional peroxide, and a cross-linking agent and/or a chain transfer agent, and methods of making such polymers having: at least 0.03 branches/1000 backbone carbons; linear portions with a molecular weight (Mw) of 350,000 or less; 0.2 to 3.0 branches/molecule; or, a Mz/Mw of from 1.7 to 5.7. Methods of quantifying branching are disclosed using a linear reference having 0.0 to 0.06 branches/1000 backbone carbons along with SEC techniques and measurements of molecular weight, molecular size, and concentration. Also discovered is a vinyl polymer resin comprised of from 0.1 to 50 weight percent of non-linear polymers having at least 0.06 branches/1000 backbone carbons, where branching is measured using a heat polymerized polystyrene having from 0.0 to 0.06 branches/1000 backbone carbons as a linear reference.

Abstract: A continuous process for producing high impact polystyrene comprising feeding at least one vinyl aromatic monomer, an elastomer, and a free radical initiator to a first linear flow reactor to form a reaction mixture, polymerizing the reaction mixture in said linear flow reactor to at least the phase inversion point of the mixture, and feeding the reaction mixture from the first linear flow reactor to a second reactor for post-inversion polymerization of the mixture. A method of producing an elastomer-reinforced polymer comprising inverting a reaction mixture comprising at least one vinyl aromatic monomer, an elastomer, and a free radical initiator in a plug flow reactor. A high impact polystyrene reactor system, comprising a linear flow reactor having an inlet and an outlet, and a continuously stirred tank reactor having an inlet in fluid communication with the linear flow reactor outlet and receiving an effluent from the linear flow reactor.

Abstract: A continuous process for producing high impact polystyrene comprising feeding at least one vinyl aromatic monomer, an elastomer, and a free radical initiator to a first linear flow reactor to form a reaction mixture, polymerizing the reaction mixture in said linear flow reactor to at least the phase inversion point of the mixture, and feeding the reaction mixture from the first linear flow reactor to a second reactor for post-inversion polymerization of the mixture. A method of producing an elastomer-reinforced polymer comprising inverting a reaction mixture comprising at least one vinyl aromatic monomer, an elastomer, and a free radical initiator in a plug flow reactor. A high impact polystyrene reactor system, comprising a linear flow reactor having an inlet and an outlet, and a continuously stirred tank reactor having an inlet in fluid communication with the linear flow reactor outlet and receiving an effluent from the linear flow reactor.

Abstract: Disclosed are novel non-linear vinyl polymers comprised of a multifunctional peroxide, and a cross-linking agent and/or a chain transfer agent, and methods of making such polymers having: at least 0.03 branches/1000 backbone carbons; linear portions with a molecular weight (Mw) of 350,000 or less; 0.2 to 3.0 branches/molecule; or, a Mz/Mw of from 1.7 to 5.7. Methods of quantifying branching are disclosed using a linear reference having 0.0 to 0.06 branches/1000 backbone carbons along with SEC techniques and measurements of molecular weight, molecular size, and concentration. Also discovered is a vinyl polymer resin comprised of from 0.1 to 50 weight percent of non-linear polymers having at least 0.06 branches/1000 backbone carbons, where branching is measured using a heat polymerized polystyrene having from 0.0 to 0.06 branches/1000 backbone carbons as a linear reference.

Abstract: It has been discovered that improved polystyrene products may be obtained by polymerizing styrene in the presence of at least one multifunctional initiator, at least one chain transfer agent, and at least one cross-linking agent. The presence of the multifunctional initiator tends to cause more branched structures in the polystyrene. A mathematical model that helps optimize the levels of these additives for given molecular weights, melt flow indices (MFIs) and zero shear viscosities (?0) has also been discovered.

Abstract: It has been discovered that improved polystyrene products may be obtained by polymerizing styrene in the presence of at least one multifunctional initiator, at least one chain transfer agent, and at least one cross-linking agent. The presence of the multifunctional initiator tends to cause more branched structures in the polystyrene. A mathematical model that helps optimize the levels of these additives for given molecular weights, melt flow indices (MFIs) and zero shear viscosities (&eegr;0) has also been discovered.

Abstract: A process is disclosed for improving the environmental stress crack resistance and other desirable properties of impact-resistant, elastomer-modified monovinylaromatic compounds, said process utilizing a combination of polymerization initiators, including perketals and peroxycarbonates.

Abstract: A system for pressurizing a propylene polymerization reactor includes: a pressurization vessel including an internal heat exchanger; a pressure sensor for monitoring the pressure in the vessel, the pressure sensor providing a signal indicative of the pressure in the vessel; a control valve for supplying heated gas to a first region of the vessel in response to signals from the pressure sensor, the first region of the vessel being maintained above the critical temperature and pressure of propylene; a temperature sensor for monitoring the temperature in a second region of the pressurization vessel, the temperature sensor providing a signal indicative of the temperature in the second region of the vessel; and a control valve for supplying a cooling medium to the internal heat exchanger to cool propylene in the second region below the critical temperature of propylene at the pressure in the pressurization vessel.

Abstract: A process is disclosed for improving the environmental stress crack resistance and other desirable properties of impact-resistant, elastomer-modified monovinylaromatic compounds, said process utilizing a combination of polymerization initiators, including perketals and peroxycarbonates.

Abstract: A system for pressurizing a propylene polymerization reactor includes: a pressurization vessel including an internal heat exchanger; a pressure sensor for monitoring the pressure in the vessel, the pressure sensor providing a signal indicative of the pressure in the vessel; a control valve for supplying heated gas to a first region of the vessel in response to signals from the pressure sensor, the first region of the vessel being maintained above the critical temperature and pressure of propylene; a temperature sensor for monitoring the temperature in a second region of the pressurization vessel, the temperature sensor providing a signal indicative of the temperature in the second region of the vessel; and a control valve for supplying a cooling medium to the internal heat exchanger to cool propylene in the second region below the critical temperature of propylene at the pressure in the pressurization vessel.

Abstract: A system for pressurizing a propylene polymerization reactor includes: a pressurization vessel including an internal heat exchanger; a pressure sensor for monitoring the pressure in the vessel, the pressure sensor providing a signal indicative of the pressure in the vessel; a control valve for supplying heated gas to a first region of the vessel in response to signals from the pressure sensor, the first region of the vessel being maintained above the critical temperature and pressure of propylene; a temperature sensor for monitoring the temperature in a second region of the pressurization vessel, the temperature sensor providing a signal indicative of the temperature in the second region of the vessel; and a control valve for supplying a cooling medium to the internal heat exchanger to cool propylene in the second region below the critical temperature of propylene at the pressure in the pressurization vessel.