Thermal decomposition of poly(butylene terephthalate)

Abstract

Detailed results of the overall thermal degradation of poly(butylene terephthalate) are reported. Laser microprobe analysis and dynamic mass spectrometric techniques were used to identify the primary volatile degradation products and initial pyrolysis reactions that control polymer degradation. A complex multistage decomposition mechanism was observed which involves two major reaction pathways. Initial degradation occurs by an ionic decomposition process that results in the evolution of tetrahydrofuran. This is followed by concerted ester pyrolysis reactions that involve an intermediate cyclic transition state and yield 1,3‐butadiene. Simultaneous decarboxylation reactions occur in both decomposition regimes. Finally, the latter stages of polymer decomposition were characterized by evolution of CO and complex aromatic species such as toluene, benzoic acid, and terephthalic acid. Activation energies of formation for the main pyrolysis products were determined from the dynamic measurements of the major ion species and indicate values of E = 27.9 kcal/mole for the production of tetrahydrofuran and E = 49.7 kcal/mole for the production of butadiene.

Thermal degradation kinetics and decomposition mechanism of PBSu nanocomposites with silica-nanotubes and strontium hydroxyapatite nanorods

“…8), it was revealed that the first gaseous products evolving through PBSu decomposition were tetrahydrofuran, 1,3-butadiene and succinic acid anhydride, detected along with water and CO or CO 2 during the first 3.5 and 7 min of retention respectively. Similar decomposition products, except succinic anhydride, were also View Article Online observed during decomposition of poly(butylene terephthalate) (PBT) and are due to the existence of 1,4-butylene glycol 37 while CO and CO 2 are due to the carboxyl end groups of polyesters. 38,39 At higher retention times allyl and diallyl compounds with characteristic vinyl groups and higher molecular weights were detected.…”

Thermal degradation of polymer systems having liquid crystalline oligoester segment

“…Blends of oligoester with the commercial polystyrene did not present any shift on the melting or isotropization temperature. [11][12][13] . These results clearly indicate an extensive miscibility in the polystyrene amorphous phase, in the block copolymer or polymer blend.…”

“…The degradation proceeds by free radical mechanism after the primary breakage of the ester linkage of the terephthalic acid ( Figure 1). This mechanism involves a cyclic transition state with the hydrogen at the β position, followed by a chain rupture process in which vinyl ester groups and carboxylic acids are formed [11][12][13] (Figure 1). A second stage was reported to be the thermal scission of the mesogenic group with phenylenic residues formation.…”

Effect of Hydroxyapatite Nanoparticles on the Degradability of Random Poly(butylene terephthalate-co-aliphatic dicarboxylate)s Having a High Content of Terephthalic Units

“…Although decomposition seems to proceed as a single step (e.g., Figure 5 for PBST), different mechanisms are probably involved, as reported for PBT [27]. In this case, degradation started with an ionic decomposition process that results in the production of tetrahydrofuran.…”

“…In this case, degradation started with an ionic decomposition process that results in the production of tetrahydrofuran. The subsequent process was associated with ester pyrolysis reactions that yield 1,3-butadiene at the beginning and finally produced aromatic species [27]. Thermal degradation of several poly(butylene succinate-co-butylene terephthalate)s has also been previously reported [28], indicating a single weight-loss step.…”