Process synthesis temperature change

As we have already mentioned, the cure of resoles takes place primarily through further extension of the condensation process, though the conditions are usually considerably different from those of synthesis. The changes in conditions normally include exposure to much higher temperatures and higher concentrations of polymer than are seen in resin synthesis. The pH of the medium may also... 

A different approach to process synthesis is offered by means-ends method. It is based on the observation that the purpose of material processing is to apply various operations in such a sequence that the differences in properties between the raw materials and the products are systematically eliminated. As a result, the raw materials are transformed into the desired products. The means-ends method starts with an initial state and successively applies transformation operators to produce intermediate states with fewer differences until the goal state is reached. The hierarchy for the reduction of property differences is as follows identity, amount, concentration, temperature, pressure, and finally form. This property changing method has its limitations, as it ignores the influences and the impacts on other properties. Moreover, the search method takes an opportrmistic approach, which cannot guarantee the generation of a feasible flowsheet. The means-ends analysis approach has been used as a systematic process synthesis method for overall process flowsheet synthesis, as well as for the more detailed case of a separation system to resolve the concentration differences in nonideal systems that include azeotropes. 

Often there are significant differences in the phases that exit from one process operation and enter another. For example, hot effluent gases from a reactor are condensed, or partially condensed, often before entering a separation operation, such as a vapor-liquid separator (e.g., a flash vessel or a distillation tower). In process synthesis, it is common to position a phase-change operation, using temperature- and/or pressure-reduction operations, such as heat exchangers and valves. 

In this method, electric field-assisted polymerization of monomer units takes place over the electrically conducting substrate. Any electrically conductive substrate can be used for the same purpose like metal plate, steel plate, etc. Application of electric field results in the formation of polymer chains. The electric field can be adjusted in two ways either in terms of electric potential or in terms of electric current. There will be a threshold potential for the polymerization to start. Knowledge on this optimal potential is mandatory for the polymer synthesis as the potential may be different for different polymers. For different nanostructures such as nanoparticles, thin films, etc., there should be proper optimization in various parameters such as electric field, processing time, temperature, and the process atmosphere. Any variation in these parameters may lead to a change in size and shape of the polymer. For example, in a prolonged elec-tropolymerization process, thick polymeric films are formed. 

---