The chemical transformations taking place when poly- (ethylene terephthalate) (PET) or poly(ethylene naphthalate) (PEN) are blended in the melt with different low molar mass substances containing hydroxyl, carboxyl, or amine functional groups have been investigated as models of the transreactions, undergone by the polyesters in reactive blending operations. The polyester molecular weight changes caused by the alcoholysis, acidolysis, aminolysis, and esterolysis reactions have been monitored by torque-rheometry, using a Brabender Plasticorder static mixer. The degradation of the polyesters by hydrolysis was also studied, under similar conditions, by the addition of a water-releasing substance (wet polyamide-6), and was shown to occur quite rapidly, although most of the added water was lost by flash vaporization caused by the high temperature of the polyester melt. It has been shown that the rate constants of the reactions leading to breakage of the inner ester bonds of the polyester macromolecules decrease in the following order: aminolysis (with aliphatic amines, either primary and secondary) > alcoholysis (with aliphatic alcohols) > hydrolysis > acidolysis (with aromatic acids) ≥ acidolysis (with aliphatic acids) >> aminolysis (with aromatic amines) > alcoholysis (with phenols) >> esterolysis.

Torque rheometry investigation of model transreactions involving condensation polymers: I. Polyesters

FILIPPI, SARA;POLACCO, GIOVANNI;MAGAGNINI, PIER LUIGI;
2006

Abstract

The chemical transformations taking place when poly- (ethylene terephthalate) (PET) or poly(ethylene naphthalate) (PEN) are blended in the melt with different low molar mass substances containing hydroxyl, carboxyl, or amine functional groups have been investigated as models of the transreactions, undergone by the polyesters in reactive blending operations. The polyester molecular weight changes caused by the alcoholysis, acidolysis, aminolysis, and esterolysis reactions have been monitored by torque-rheometry, using a Brabender Plasticorder static mixer. The degradation of the polyesters by hydrolysis was also studied, under similar conditions, by the addition of a water-releasing substance (wet polyamide-6), and was shown to occur quite rapidly, although most of the added water was lost by flash vaporization caused by the high temperature of the polyester melt. It has been shown that the rate constants of the reactions leading to breakage of the inner ester bonds of the polyester macromolecules decrease in the following order: aminolysis (with aliphatic amines, either primary and secondary) > alcoholysis (with aliphatic alcohols) > hydrolysis > acidolysis (with aromatic acids) ≥ acidolysis (with aliphatic acids) >> aminolysis (with aromatic amines) > alcoholysis (with phenols) >> esterolysis.
Filippi, Sara; L., Madrigali; Polacco, Giovanni; Magagnini, PIER LUIGI; F. P., LA MANTIA; D., Acierno
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/206311
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 5
social impact