A. Gordillo

Thermal Degradation of Polyoxymethylene Evaluated with FTIR and Spectrophotometry

Thermooxidative degradation at and beyond processing temperatures of a polyoxymethylene copolymer has been progressively accelerated to carbonisation through oven-storage aging. The quantification of such degradation was carried out through FTIR spectrography and colour spectrophotometry methods. The state of thermo-oxidation was monitored through the FTIR spectra corresponding to the carbonyl aldehyde group (O=CH) and methylene bending (–CH2), as well as the chromaticity changes experienced on the sample surface. The results showed that the FTIR bands suggested are a reliable indicator during the initial conditions of degradation, however, the spectrophotometry becomes more appropriate method for more aggressive conditions leading to carbonisation.

Milled Glass Fiber Filled-Poly(Ethylene Terephthalate-co-Isophthalate) Composites - Thermal and Mechanical Properties

Fracture and thermal behavior of injection-molded poly (ethylene terephthalate-co-isophthalate) filled with milled glass fiber has been studied as a function of fiber content in the range 0-40% by weight. Composite Youngs modulus and tensile strength increased with fiber percentage, and good agreement was found with theoretical predictions. Low rate fracture tests were carried out on injection-molded SENB specimens. Fracture toughness (K ic ) and fracture energy (G ic ) could be obtained by applying Linear Elastic Fracture Mechanics (LEFM). Results seemed to indicate improved fracture toughness if compared with homopolymer poly (ethylene terephthalate) composites. The reason was attributed to a lower crystallinity developed in the matrix, which promoted higher plastic strain.

Essential Work of Fracture of Injection Moulded Samples of Pet and PET/PC Blends

ABSTRACT The fracture behaviour at low strain rates of “amorphous” injection moulded Poly(Ethylene-Terephthalate) (PET) samples (