Polymer operations, simulations

Until the 1980s, most simulations of polymer operations related to thermoplastics problems. The special processing machinery of the rubber industry had receive little attention. It is only in the late 1980s that realistic simulations appeared for internal mixers [CIO, Cll, H20, H21, K6-8, W19] and pin barrel extruders [B31, B32, B34, K22]. These have used primarily lubrication theory-based simulations. 

The utilization of commercially available finite element packages in the simulation of routine operations in industrial polymer processing is well established. However, these packages cannot be usually used as general research tools. Thus flexible in-house -created programs are needed to carry out the analysis required in the investigation, design and development of novel equipment and operations. 

The most comprehensive simulation of a free radical polymerization process in a CSTR is that of Konopnicki and Kuester (15). For a mechanism which includes transfer to both monomer and solvent as well as termination by combination and disproportionation they examined the influence of non-isothermal operation, viscosity effects as well as induced sinuoidal and square-wave forcing functions on initiator feed and jacket temperature on the MWD of the polymer produced. 

The modern discipline of Materials Science and Engineering can be described as a search for experimental and theoretical relations between a material s processing, its resulting microstructure, and the properties arising from that microstructure. These relations are often complicated, and it is usually difficult to obtain closed-form solutions for them. For that reason, it is often attractive to supplement experimental work in this area with numerical simulations. During the past several years, we have developed a general finite element computer model which is able to capture the essential aspects of a variety of nonisothermal and reactive polymer processing operations. This "flow code" has been Implemented on a number of computer systems of various sizes, and a PC-compatible version is available on request. This paper is intended to outline the fundamentals which underlie this code, and to present some simple but illustrative examples of its use. 

We have begun to include detailed automatic alarm-handling in our control schemes, in order to begin unattended, eventually overnight operation. At present, any polymerization requiring more than one work day must be stopped and restarted on a second day. This prevents us from accurately simulating plant processes extending over more than one shift. Safe, unattended automatic lab reactor automation should, then, improve scale-up efficiency for many of our polymers. 

H. Nakajima, T. Konomi, and T. Kitahara. Direct water balance analysis on a polymer electrolyte fuel cell (PEFC) Effects of hydrophobic treatment and microporous layer addition to the gas diffusion layer of a PEFC on its performance during a simulated start-up operation. Journal of Power Sources 171 (2007) 457-463. 

Despite the widespread use of this machine for compounding an extensive range of polymer-based formulations, only very limited analytical work has been reported on its operational performance. In one report, a modified flow analysis network method of simulation was used to describe flow of a Newtonian... 

Among direct production costs, we can list raw materials, utilities, direct operation labour, maintenance, catalysts, royalties, etc. In our case, solvents (THF and pressurised CO2), polymer, and active ingredient are needed on a daily basis. The corresponding quantities were determined using the process simulator, as described in paragraph 8.3.3. In this discussion, additional solvent (THF) losses are supposed to equal 5% of the total flow rate entering the... 

Simulations based on kinetic modelling of the reduction of acetophenone with propan-2-ol, using polymer-enlarged and the unmodified catalysts, revealed that comparable performance cannot be obtained by batch operation. Polymer enlargement allowed a continuous operation of transfer hydrogenation in a chemical membrane reactor.353... 

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