Poly(trimethy1ene terephthalate) was synthesized on a semi-technical scale following the trans-esterification route. Ester exchange as well as polycondensation were catalyzed by titanium tetrabutylate. The polymer formed shows a remarkable degree of whiteness, contrary to poly(ethy1ene terephthalate) when synthesized with the aid of titanium compounds. Polymers having molar masses up to 70000 (weight average) were obtained suitable for melt spinning. The Mark-Houwink parameters for solutions in 1,1 ,2,2-tetrachloroethane/phenol (1 : 1, w/w) were determined using static light scattering as a calibration. The melt volume index (235 "C, 1.2 kg) was typically in the range 20-30 mL/10 min for a polymer having a weight-average molar mass of 50000-60000 g mol-'.
ZUSAMMENFASSUNG:Poly(trimethylenterephtha1at) wurde durch Umesterung von Dimethylterephthalat und Polykondensation im halbtechnischen MaBstab hergestellt. Als Katalysator fur beide Reaktionsschritte wurde Titantetrabutylat eingesetzt. Die erhaltenen Polymeren mit gewichtsmittleren Molekulargewichten von bis zu 70000 konnen aus der Schmelze versponnen werden und zeigen, im Gegensatz zu mit Titanverbindungen hergestelltem Poly(ethylenterephthalat), einen bemerkenswerten WeiBheitsgrad. Die Mark-Houwink-Parameter in 1,1,2,2-Tetrachlorethan/Phenol-Liisung (1 : 1, w/w) wurden rnit Kalibrierung durch statische Lichtstreuung bestimmt. Die MVI-Werte (235 "C, 1,2 kg) lagen typischerweise zwischen 20 und 30 mL/ 10 min bei Polymeren mit einer gewichtsmittleren Molmasse von 50000-60000 g mol-'.
A series of branched poly(ethylene terephthalate) samples was prepared by employing 0.07-0.42 mol % trimethylolpropane (TMP) for melt polycondensation. These polymers were characterized with respect to molar mass, intrinsic viscosity, and melt viscosity. Spinning into fibers took place at spinning speeds ranging from 2500 to 4500 m/min. The molecular orientation of the fibers as measured by birefringence and polarized fluorescence decreases with growing amounts of TMP, as does crystallinity. Thus with slightly branched polymers, higher spinning speeds than with a linear polymer can be used to achieve a certain property profile.
A series of branched poly(ethylene terephthalate) samples was prepared by employing 0.07-0.42 mol % trimethylolpropane (TMP) for melt polycondensation. These polymers were characterized with respect to molar mass, intrinsic viscosity, and melt viscosity. Spinning into fibers took place at spinning speeds ranging from 2500 to 4500 m/min. The molecular orientation of the fibers as measured by birefringence and polarized fluorescence decreases with growing amounts of TMP, as does crystallinity. Thus with slightly branched polymers, higher spinning speeds than with a linear polymer can be used to achieve a certain property profile.
ZUSAMMENFASSUNG :Beim direkten Abbau von kommerziellem Polyathylenterephthalat im Massenspektrometer IaBt sich bei Temperaturen unterhalb des einsetzenden thermischen Abbaus des Polymeren das zu etwa 1 % enthaltene cyclische trimere Athylenterephthalat ohne vorherige Isolierung nachweisen und durch Vergleich mit den EI-und FD-Massenspektren eines authentischen Trimeren identifizieren.
SUMMARY:By direct pyrolysis of commercial polyethyleneterephthalate in the mass spectrometer a content of about 1 % of the cyclic trimer ethyleneterephthalate is indicated at temperatures below thermal degradation of the polymer. The comparison with EI-and FD-mass spectra of the authentic cyclic trimer allows its identification without previous isolation.
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