New catalysts for poly(butylene terephthalate) synthesis

Chemical Modification of Terephthalate Polyesters by Reaction with Bis(hydroxyethyl ether) of Bisphenol A

“…The reaction has been carried out also starting from dimethyl terephthalate, butanediol and BHEEB according to the standard two‐step procedure used for the synthesis of terephthalate polyesters 22. The polymers obtained starting from the monomers, presented the same chemical structure of those obtained by reactive blending (from 1 H NMR analysis); however, the reaction times to reach comparable molecular weights were much longer.…”

“…PBT (Valox 315, $\overline M _{\rm w}$ 125 000) was a gift of General Electric Plastics. Poly(propylene terephthalate) (PPT, $\overline M _{\rm w}$ 78 000) and poly(ethylene terephthalate) (PET, $\overline M _{\rm w}$ 68 000) were synthesized in our laboratory from dimethyl terephthalate (DMT) and aliphatic diols with the usual polycondensation procedure22 in the presence of 115 ppm (as titanium with respect to the final polymer) of titanium(IV) butoxide (TBT) as catalyst. Terephthalate polyesters were dried overnight at 120 °C under vacuum before use.…”

“…The synthesis of the copolymers was also performed starting from the monomers according to the standard two step procedure for polyester synthesis 22…”

Telechelic polyesters of ethane diol and adipic or sebacic acid by means of bismuth carboxylates as non-toxic catalysts

“…This approach was also used for many decades for the technical syntheses of poly(ethylene terephthalate) and poly(butylene terephthalate). The most efficient and most widely used catalyst for this type of polycondensation is titaniumtetrabutoxide (or other tetraalkoxides) alone or in combination with additives [3][4][5][6][7]. For temperatures below 200 8C, tin(II) salts and tin(II) alkoxides have proven to be excellent transesterification catalysts particularly useful for ring-opening polymerizations of lactones and lactides [8][9][10].…”

Synthesis of high‐molecular weight poly(trimethylene terephthalate) catalyzed by MoO3 supported Al2O3‐TiO2 catalysts

“…Measurement of acidity was performed by temperature programmed desorption of NH 3 (NH 3 -TPD) using Chemosorb 2705 unit (Micromeritics Instrument, Amer) equipped with thermal conductivity detector. Typically, about 0.2 g of catalyst was pretreated in flowing helium at 300 C for 2 h, cooled to 100 C and allowed to expose 10% NH 3 in helium with a flow rate of 70 mL min À1 for 2 h, and subsequently the adsorbed NH 3 was purged with helium gas at the same temperature for 1 h to remove the physisorption NH 3 . The chemisorption NH 3 was measured in flowing helium gas with the flow rate of 40 mL min À1 from ambient temperature to about 900 C at the heating rate of 10 C min…”