Modification of Poly (ethylene telephthalate) by Reactive Extrusion without Catalyst

We have investigated the chemical improvement of plastic materials by crosslinking reactions but not the physical one by blending of other polymers or reinforcing with glass fiber. The present article is concerned with the improvement of poly (ethylene telephthalate) (PET) by the crosslinking reactions with various types of multifunctional epoxy compounds in the absence of any catalyst. The reactions of PET with small amounts of epoxy compounds, such as 4, 4′-diglycidyletherbisphenylmethane (DGEBF), tetraglycidyl-4, 4′-diaminodiphenylmethane (TGDDM) and 4, 4′-diglycidyletherbisphenylsulfone (DGEBS) were carried out in a single-screw extruder and cast into films. The PET film obtained after reactive extrusion in the presence of TGDDM (0.3∼0.4phr) (crosslinking agents) showed good tensile strength (83MPa, cf. PET=72MPa) and good tensile impact strength (30kJ/m2, cf. PET=15kJ/m2). The thermal stability and chemical resistance were also improved.