The effect of high pressure on the individual steps of free radical polymerization

1960 ◽  
Vol 48 (150) ◽  
pp. 335-341 ◽  
Author(s):  
Cheves Walling
2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Dimitrios Meimaroglou ◽  
Apostolos Krallis ◽  
Costas A. Kiparissides

An efficient Monte Carlo (MC) algorithm and a two-dimensional fixed pivot technique (2-D FPT) are described for the calculation of the average and distributed molecular properties of polymers in batch free-radical polymerization and copolymerization reactors. Simulations are carried out, under different reactor conditions, to calculate the individual monomer conversions, the leading moments of the 'live' and 'dead' polymer chain length distributions as well as the dynamic evolution of the distributed molecular properties (i.e., molecular weight distribution (MWD), long chain branching distribution (LCBD), copolymer composition distribution (CCD), joint LCB-MW and CC-MW distributions, etc.). The validity of the numerical calculations is examined via a direct comparison of the simulation results, obtained by the two numerical methods, with experimental data on the styrene-methyl methacrylate and vinyl acetate batch free-radical polymerization systems. Additional comparisons between the MC and the 2-D FPT methods are carried out for both polymerization systems, under different polymerization conditions. It is clearly shown that both numerical methods are capable of predicting the distributed molecular, branching and copolymer properties, with high accuracy, up to very high monomer conversions.


RSC Advances ◽  
2020 ◽  
Vol 10 (36) ◽  
pp. 21593-21601
Author(s):  
Paulina Maksym ◽  
Magdalena Tarnacka ◽  
Dawid Heczko ◽  
Justyna Knapik-Kowalczuk ◽  
Anna Mielańczyk ◽  
...  

High-pressure classical free-radical polymerization allowed to eliminate the current limitation of the ambient-pressure synthesis of 1-vinyl-2-pyrrolidone and production of well-defined polymers.


2007 ◽  
Vol 61 (6) ◽  
pp. 357-363 ◽  
Author(s):  
Dragoslav Stoiljkovic ◽  
Slobodan Jovanovic ◽  
Jovica Djordjevic ◽  
Budimir Damjanovic

In the production of low density polyethylene by free radical polymerization of ethylene at high pressure, ethylene and polyethylene occasionally decompose to carbon, hydrogen and methane resulting in an enormous increase of pressure and temperature. Huge explosions occur in a polymerization reactor and in other parts of the installation. In addition to the well known reasons of decompositions, in this work it is pointed out that the polymerization under critical entropy conditions is an additional cause of explosions, which has not been recognized and elaborated in scientific literature and industrial practice.


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