Bulk polymerization model description

Since process and properties are so closely linked in the production of emulsion polymers, a variety of processes have been devised as efforts to design and control the microstructure of latex particles have intensified. The central issue is whether, as a general rule, particle growth is better represented in terms of a surface growth model or of a bulk polymerization model. Results obtained by a variety of methods developed to study particle and film morphology will be reviewed, and the special case of water-soluble monomers will be considered along with descriptions of process techniques designed to control particle structure. 

Model Description of the Bulk Polymerization of MMA with Chain Transfer to Monomer... 

Auto-acceleration of free-radical polymerizations occurs in O Driscoll s model when polymeric radicals beyond a certain chain length are restricted in their segmental mobility by the development of a gel-like medium. Detailed descriptions have been given of the application of the model to the bulk polymerization of methyl... 

The main process control challenges in solution and bulk polymerizations are the control of molecular weight averages [103], molecular weight distribution (MWD) [104], monomer conversion [105], and copolymer composition and copolymer composition distribution (CCD) [106, 107]. The development of mathematical models for solution and bulk processes is relatively easy, as it is not necessary to take into account mass transfer between different phases. The main challenge in this field is the proper description of the glass and gel effects, which is usually performed with the help of anpirical models [108]. Therefore, reliable process models are usually available for solution and bulk processes. 

The complications for fhe fheoretical description of proton fransporf in the interfacial region befween polymer and water are caused by the flexibility of fhe side chains, fheir random distributions at polymeric aggregates, and their partial penetration into the bulk of water-filled pores. The importance of an appropriate flexibilify of hydrated side chains has been explored recently in extensive molecular modeling studies. Continuum dielectric approaches and molecular dynamics simulations have been utilized to explore the effects of sfafic inferfacial charge distributions on proton mobility in single-pore environments of Molecular level simulations were employed... 

In bulk and solution polymerization it is an advantage for process designers to have a knowledge of the phase separations that may occur during production. Such phenomena are mostly undesired and the best way to find methods to avoid them rests in a thorough study of the thermodynamic properties of the system in hand. This chapter provides the tools for such an approach. It is demonstrated that molecular models exist, capable of supplying a nearly quantitative description of available data on partial miscibility of polyolefin solutions. Such models cannot by themselves predict phase behavior some measured data will have to be fitted to the model for a given system, after which much experimental time can be... 

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