Radical high pressure polymerization of ethylene with stable initiators

Abstract

und der spezifische Initiatorverbrauch bestimmt. Die erhaltenen Polymeren wurden durch Messung ihrer Dichte, der mittleren Molmasse sowie des Schmelzindexes charakterisiert. Die eingesetzten stabilen Initiatoren zeichnen sich alle durch einen sehr geringen Verbrauch aus. Die optimale Einsatztemperatur liegt bei den Dialkylperoxiden sowie dem Alkylhydroperoxid deutlich iiber 200 und bei dem C-C-labilen Initiator iiber 300OC. Unter diesen Bedingungen wurden Polymere mit niedriger Dichte, niedriger Molmasse, engerer Molmassenverteilung und h6herem Schmelzindex erhalten.

110th Anniversary: Nonideal Mixing Phenomena in High-Pressure Low-Density Polyethylene Autoclaves: Prediction of Variable Initiator Efficiency and Ethylene Decomposition

“…It has been shown that due to the spatial variation of initiator concentration in a LDPE autoclave (i.e., nonideal mixing) the specific initiator consumption expressed in grams of initiator consumed per kilogram of polyethylene produced often exhibits a U-shape behavior with respect to polymerization temperature. The observed variation in the specific initiator consumption with respect to polymerization temperature was experimentally investigated by Van der Molen, Luft and co-workers, − and Goto et al . Luft and his co-workers carried out a comprehensive experimental investigation, using a lab-scale LDPE autoclave, to study the effect of polymerization temperature (e.g., 110–300 °C) on the specific initiator consumption for different organic peroxides (see Figure ).…”

Inquiring into Structure of Hyperbranched Polyethylene Produced in Radical Polymerization Process

“…Reactor operation analysis with stepwise output increase demonstrates area length growth with reaction temperature 310-320 о С and taking into account temperature gradient along reactor section and thermocouple value logging in 15-30 meters that does not exclude the probability of local excesses. That creates conditions for preferential development of transfer constant sum and branching of polymer with density decrease but not the growth [9].…”

Modernization of “Polimir” Process of High-Pressure Polyethylene Production at “Tomskneftekhim” Company

“…It improved the extrusion process and increased yield of high quality (film grade) product from 50-60 % to 80-90 % [4]. In contrast with oxygen initiation the curves of molecular mass distribution have bimodal character with "high-molecular shoulder" that is caused by the polymer synthesis in the 1 st zone at comparatively low temperatures and medium viscosity [8].…”