Abstract: A high impact polystyrene reactor system includes a first continuously stirred tank reactor. The first continuously stirred tank reactor includes an inlet configured to receive (i) at least one vinyl aromatic monomer, (ii) an elastomer, and (iii) a free radical initiator; and an outlet configured to convey a first reactor effluent. In addition, the high impact polystyrene reactor system includes a second continuously stirred tank reactor. The second continuously stirred tank reactor includes an inlet in fluid communication with the first continuously stirred tank reactor outlet and configured to receive (i) a portion of the first reactor effluent from the first continuously stirred tank reactor, (ii) at least one vinyl aromatic monomer, (iii) an elastomer, and (iv) a free radical initiator; and an outlet configured to convey a portion of a second reactor effluent comprising high impact polystyrene.

Abstract: A process for producing high impact polystyrene comprising introducing to a reactor a partially-polymerized mixture comprising at least one vinyl aromatic monomer, an elastomer and reacted vinyl aromatic monomer wherein the partially-polymerized mixture has not undergone phase inversion; polymerizing the partially-polymerized mixture in the reactor to the phase inversion point to form a phase-inverted mixture; recovering a portion of the phase-inverted mixture from the reactor wherein the phase-inverted mixture comprises high impact polystyrene; and introducing another portion of the phase-inverted mixture to another reactor.

Abstract: A process for producing high impact polystyrene comprising introducing to a reactor a partially-polymerized mixture comprising at least one vinyl aromatic monomer, an elastomer and reacted vinyl aromatic monomer wherein the partially-polymerized mixture has not undergone phase inversion; polymerizing the partially-polymerized mixture in the reactor to the phase inversion point to form a phase-inverted mixture; recovering a portion of the phase-inverted mixture from the reactor wherein the phase-inverted mixture comprises high impact polystyrene; and introducing another portion of the phase-inverted mixture to another reactor.

Abstract: A method including operating a high impact polystyrene (HIPS) reaction system having a devolatilizer downstream of a polymerization reactor, and from which a HIPS product is obtained, and injecting an antioxidant into the HIPS reaction system prior to the devolatilizer, with the antioxidant being one or more aromatic antioxidants. A HIPS product produced by operating a HIPS reaction system to produce a HIPS product, with the HIPS reaction system including a devolatilizer downstream of a polymerization reactor, and including injecting an antioxidant into the HIPS reaction system prior to the devolatilizer, with the antioxidant being comprising one or more aromatic antioxidants. The antioxidant may comprise at least one thiol group, at least one cresol group, or both. A system for producing the HIPS product is also provided.

Abstract: High impact polystyrene may be formed with increased swell index and reduced or eliminated discoloration. A process of forming high impact polystyrene may include providing a polymerization system including a polymerization reactor and a devolatilizer. High impact polystyrene may be formed in the polymerization reactor, and sent to the devolatilizer. A polar antioxidant having a hindered phenol structure and an aliphatic amine group, and with a phosphite antioxidant may be added to the polymerization system. In another process, a chemical retarder and a fluorescent whitening agent may be added to the polymerization system. In another process, a chemical retarder that inhibits free radical rubber crosslinking may be added to the polymerization system.

Abstract: A method including operating a high impact polystyrene (HIPS) reaction system having a devolatilizer downstream of a polymerization reactor, and from which a HIPS product is obtained, and injecting an antioxidant into the HIPS reaction system prior to the devolatilizer, with the antioxidant being one or more aromatic antioxidants. A HIPS product produced by operating a HIPS reaction system to produce a HIPS product, with the HIPS reaction system including a devolatilizer downstream of a polymerization reactor, and including injecting an antioxidant into the HIPS reaction system prior to the devolatilizer, with the antioxidant being comprising one or more aromatic antioxidants. The antioxidant may comprise at least one thiol group, at least one cresol group, or both. A system for producing the HIPS product is also provided.

Abstract: High impact polystyrene may be formed with increased swell index and reduced or eliminated discoloration. A process of forming high impact polystyrene may include providing a polymerization system including a polymerization reactor and a devolatilizer. High impact polystyrene may be formed in the polymerization reactor, and sent to the devolatilizer. A polar antioxidant having a hindered phenol structure and an aliphatic amine group, and with a phosphite antioxidant may be added to the polymerization system. In another process, a chemical retarder and a fluorescent whitening agent may be added to the polymerization system. In another process, a chemical retarder that inhibits free radical rubber crosslinking may be added to the polymerization system.

Abstract: High impact polystyrene may be formed with increased swell index and reduced or eliminated discoloration. A process of forming high impact polystyrene may include providing a polymerization system including a polymerization reactor and a devolatilizer. High impact polystyrene may be formed in the polymerization reactor, and sent to the devolatilizer. A polar antioxidant having a hindered phenol structure and an aliphatic amine group, and with a phosphite antioxidant may be added to the polymerization system. In another process, a chemical retarder and a fluorescent whitening agent may be added to the polymerization system. In another process, a chemical retarder that inhibits free radical rubber crosslinking may be added to the polymerization system.

Abstract: High impact polystyrene may be formed with increased swell index and reduced or eliminated discoloration. A process of forming high impact polystyrene may include providing a polymerization system including a polymerization reactor and a devolatilizer. High impact polystyrene may be formed in the polymerization reactor, and sent to the devolatilizer. A polar antioxidant having a hindered phenol structure and an aliphatic amine group, and with a phosphite antioxidant may be added to the polymerization system. In another process, a chemical retarder and a fluorescent whitening agent may be added to the polymerization system. In another process, a chemical retarder that inhibits free radical rubber crosslinking may be added to the polymerization system.