Vaccum pump

Before the experiments, the vessel was evacuated to 13 Pa, using a rotary vaccum pump. It was subsequently flushed with oxygen-free nitrogen, and then filled with nitrogen up to the desired pressure level. The samples were then ignited, and the whole experiment was recorded. Finally, the products were allowed to cool to room temperature before being removed for analysis and storage. 

Figure 5.4 Isentropic Efficiencies of vaccum pumps. (Source Ref. 3 with permission)... 

Glass Entrance Transfer Vaccum Pumps Transfer Exit... 

A mixture of 67.8 g (0.6 mol) e-caprolactam and 67 g (0.665 mol) of acetic anhydride is heated for 4 h in a 250-ml standard apparatus (round bottom flask, several inlets for stirrer, reflux condenser, nitrogen flux or vaccum, thermometer, heating bath). Finally, most of the excess anhydride, as well as the acetic acid, is distilled off and the remainder submitted to fractional distillation at low pressure, using an oil pump bp 134-136 C/26-27torr ... 

PLA pellets were vaccum dried at 70 °C for 24 h to remove residual moisture. Dried PLA was extruded by a single screw extruder. The processing temperature profile of the extruder was as follows Zone 1 (located near hopper) - 180 °C, zone 2 - 190 °C, zone 3 - 200 °C, pump - 200 °C, and die - 190 °C. After exihng the die, the polymer film was cooled on a chill roll. The nominal thickness of PLA film formed by this procedure was 125 pm. 

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