At the completion of polymerization, the vessel is pressurized with nitrogen and the polymer is extruded through a slot into a cold-water quench system and cut to chips. It can be calibrated as an indicator for polymer melt viscosity. During polymerization, the electrical input to the agitator motor increases as the reaction mixture becomes more viscous. An evacuation system is connected to the glycol column to reduce its pressure. The polymerization vessel is equipped with heating facilities, a heavy-duty agitator and a short column for glycol vapor removal. Additives such as stabilizers, catalysts, and delustrants can be added at this stage. The product from the esterifier is then transferred to the polymerization vessel. Water produced from the polymerization reaction is removed by way of a column so that glycol is returned to the batch system. Terephthalic acid may be charged as a solid, or more probably as a dispersion in glycol, along with additives, to the esterifier. A fractionation column is employed from which the distillate, mainly methanol, is collected and sent for purification. Auxiliary vessels are provided for metering in ethylene glycol, molten dimethyl terephthalate, and catalyst. The ester interchange vessel is equipped with heating facilities and an agitator. YANG, in Comprehensive Composite Materials, 2000 1.11.4.1.1 Batch polymerizationīatch systems usually comprise two reaction vessels: an ester interchange vessel or an esterifier, and a polymerization vessel. Mass spectra and reconstructed chromatograms (TIC) were obtained by automatic scanning in the mass range m/z 35-750 u. The ionization occurred with a kinetic energy of the impacting electrons of 70 eV. The MS EI ion source temperature was kept at 230 ☌. The temperature of the split/splitless injector was 250 ☌ and the split ratio was 25:1. Helium, grade 5.0 (Westfalen AG) was used as a carrier gas at constant flow rate of 1 mL min − 1.
Programmed temperature of the capillary column DB-5ms (30 m long, 0.25 mm I.D., 0.25 μm film thickness) (J&W) from 60 ☌ (1 min hold) at 6 ☌ min − 1 to 280 ☌ (hold to the end of analysis) was used for GC separation of compounds. The resulting product was dissolved 1:1 (v/v) in methanol and 1 μL of the solution was injected into the GC/MS apparatus for analysis. The sealed vessel was placed in the block heater at 70 ☌ for 30 min. Approximately 100 μL of the investigated brake fluid sample was placed in the micro-reaction vessel and 300 μL of the silylation agent N-methyl- N-(trimethylsilyl)-trifluoroacetamide (MSTFA) was added. Micro- reaction vessels of 3 cm 3 with solid cap and PTFE liner (Supelco, Bellefonte, PA, USA) along with the block heater SBH 200DC (Stuart, Bibby Scientific Ltd., Stone, Staffordshire, UK) were used for derivatization. Johannes Steinhaus, in Handbook of Materials Failure Analysis with Case Studies from the Chemicals, Concrete and Power Industries, 2016 2.3 Derivatization and Direct GC/MS Analysis
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