Hardware Design of Continuous Polymerization of Methyl Methacrylate in Suspension using Pulsating Mixing
- PDF / 1,076,686 Bytes
- 10 Pages / 594 x 792 pts Page_size
- 83 Downloads / 135 Views
HARDWARE DESIGN OF CONTINUOUS POLYMERIZATION OF METHYL METHACRYLATE IN SUSPENSION USING PULSATING MIXING P. A. Galkin, Yu. T. Selivanov, and S. I. Lazarev
UDC 66.095.26
The periodic method for the production of suspension polymethylmethacrylate of injection molded grades has a number of significant drawbacks: it does not ensure the stability of the properties of the finished product in various batches, it involves significant manual labor. The designs of reactors for carrying out the process in a continuous mode are proposed. These designs allow ensuring the stability of the properties of the finished product, excluding the granulation operation in the manufacture of polymethylmethacrylate products. A mathematical model of the structure of flows in the reactor using the mathematical apparatus of stationary processes and Markov chains has been developed. The proposed reactor can be used by factories of the chemical industry for the polymerization of methyl methacrylate and its copolymers, as well as, possibly, for the polymerization of other monomers that form similar reaction systems. Keywords: suspension polymethylmethacrylate, suspension polymerization, polymerizable particle, polymerization reactor.
Due to the need to increase the depth of raw materials processing, to reduce the energy costs and consumption of material resources in the chemical industry, the tasks of switching from periodic processes (low-tonnage and labor-intensive) to more efficient continuous processes are urgent. The currently implemented periodic process for the production of suspension polymethylmethacrylate (PMMA) of injection molded grades has a number of drawbacks: instability of the properties of the finished product in various batches; significant manual labor costs; loss of raw materials and finished product when washing the product due to its fineness (the presence of granules less than 0.1 mm); the impossibility of processing such a product into items without the granulation operation (which leads to mechanical and thermal degradation of the polymer and to an increase in processing costs). The periodic process of PMMA synthesis is carried out in an enamelled reactor made of corrosion-resistant steel (with a jacket for thermostating) with a capacity of 1–10 m 3 under a pressure of 0.3–0.5 MPa while mixing with a blade, turbine or impeller mixer (rotation frequency of 50–300 min −1 ). Water with stabilizing substances dissolved in it and a monomer containing an initiator are dosed into the reactor. Dispersion of the hydrocarbon phase (monomer with an initiator) in water is carried out with a mixer. The process temperature is 70–80°С. When the polymerization ends and the mixer is turned off, solid granules fall to the bottom of the reactor and are discharged through the bottom gate. The reason for the significant scatter in the PMMA particle size distribution is the presence of zones with an increased dynamic effect on the polymerizable particles in the reactor, which leads to the destruction of the stabilizing adsorption shells of p
Data Loading...
