Methods for simultaneously determining the concentrations of transition metal compounds in solutions containing two or more transition metal compounds are described. Polymerization reactor systems providing real-time monitoring and control of the concentrations of the transition metal components of a multicomponent catalyst system are disclosed, as well as methods for operating such polymerization reactor systems, and for improving methods of preparing the multicomponent catalyst system.

Methods for simultaneously determining the concentrations of transition metal compounds in solutions containing two or more transition metal compounds are described. Polymerization reactor systems providing real-time monitoring and control of the concentrations of the transition metal components of a multicomponent catalyst system are disclosed, as well as methods for operating such polymerization reactor systems, and for improving methods of preparing the multicomponent catalyst system.

The present invention discloses methods for removing volatile components from an ethylene polymer effluent stream from a polymerization reactor, and related polyethylene recovery and volatile removal systems. In these methods and systems, the polymer solids temperature is increased significantly prior to introduction of the polymer solids into a purge column for the final stripping of volatile components from the polymer solids.

The present invention discloses methods for removing volatile components from an ethylene polymer effluent stream from a polymerization reactor, and related polyethylene recovery and volatile removal systems. In these methods and systems, the polymer solids temperature is increased significantly prior to introduction of the polymer solids into a purge column for the final stripping of volatile components from the polymer solids.

The present invention relates to a method for separating an organozinc catalyst from a polyalkylene carbonate polymerization solution, and the method of the present invention includes: stirring and aging a polymerization solution including a polyalkylene carbonate resin, an organozinc catalyst, an alkylene oxide and a polymerization solvent; and filtering the polymerization solution after completing the aging.

The present invention relates to a method for separating an organozinc catalyst from a polyalkylene carbonate polymerization solution, and the method of the present invention includes: stirring and aging a polymerization solution including a polyalkylene carbonate resin, an organozinc catalyst, an alkylene oxide and a polymerization solvent; and filtering the polymerization solution after completing the aging.

According to one or more embodiments disclosed herein, the amount of one or more contaminants in an initial ultra high molecular weight polyethylene composition may be reduced by a method including contacting the initial ultra high molecular weight polyethylene composition with an acid to form a processed ultra high molecular weight polyethylene composition. The initial ultra high molecular weight polyethylene composition may include at least 0.02 wt. % of one or more contaminants. The contacting of the acid with the initial ultra high molecular weight polyethylene composition may be for a time, at a pressure, and at a temperature sufficient to reduce the amount of the one or more contaminants in the initial ultra high molecular weight polyethylene.

According to one or more embodiments disclosed herein, the amount of one or more contaminants in an initial ultra high molecular weight polyethylene composition may be reduced by a method including contacting the initial ultra high molecular weight polyethylene composition with an acid to form a processed ultra high molecular weight polyethylene composition. The initial ultra high molecular weight polyethylene composition may include at least 0.02 wt. % of one or more contaminants. The contacting of the acid with the initial ultra high molecular weight polyethylene composition may be for a time, at a pressure, and at a temperature sufficient to reduce the amount of the one or more contaminants in the initial ultra high molecular weight polyethylene.

According to one or more embodiments disclosed herein, the amount of one or more contaminants in an initial ultra high molecular weight polyethylene composition may be reduced by a method including contacting the initial ultra high molecular weight polyethylene composition with an acid to form a processed ultra high molecular weight polyethylene composition. The initial ultra high molecular weight polyethylene composition may include at least 0.02 wt. % of one or more contaminants. The contacting of the acid with the initial ultra high molecular weight polyethylene composition may be for a time, at a pressure, and at a temperature sufficient to reduce the amount of the one or more contaminants in the initial ultra high molecular weight polyethylene.

A process comprising polymerizing olefin monomers and optionally comonomers in a first reactor vessel, thereby forming a raw product stream comprising polymerized solids, unreacted monomer and optionally comonomer, the polymerized solids comprising olefin polymer, volatile organic compounds (VOC) and catalyst system. Then the polymerized solids are contacted with a catalyst poison selected from carbon monoxide, carbon dioxide, oxygen, water, alcohols, amines, or mixtures thereof, thereby forming a passivated stream. The passivated stream is maintained in an agitated state within a second reactor. The passivated stream within the second reactor is then contacted with a circulating gas comprising unreacted monomer for a residence time, thereby reducing the concentration of VOC in the polymerized solids by at least 10 wt % compared to the level before entering the second reactor, thereby forming a purified olefin polymer solids stream.