Surface modification of poly(ethylene terephthalate) (PET) by laser irradiation.

摘要

The thesis is aimed to study the surface morphological modification of poly (ethylene terephthalate) (PET) by pulsed UV laser irradiation. A study on the physical and chemical properties of the irradiated PET was reported. Laser irradiated surfaces were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and some other traditional physical methods. The resulting properties and the potential industrial application of the irradiated PET were studied.; UV laser irradiation of polymers involves not only photothermal processes but also photochemical processes. In general, a chemical modification of the polymer by UV irradiation takes place in a limited thickness to the top several hundreds of nanometres or less and does not affect the bulk properties.; It was observed the PET modified by high fluence would normally result in the deposition of debris on the treated surface. These debris are ionized and carbon rich materials which finally condense forming higher aggregates, resulting in a reduction of the O/C ratio. Conversely, modification of PET surface by low fluence irradiation led to oxidation and almost no ablation was detected. The increase of oxygen concentration on low fluence modified surfaces was probably due to a subsequent reaction with atmospheric O2 during irradiation. Polar oxidized groups like carboxyls were induced, together with the increased oxygen content, which has given a more hydrophilic character to low fluence irradiated surface.; Modifications in textile properties due to laser irradiation were studied. Properties included fibre weight and diameter, tensile strength and elongation, yarn abrasion, bending, surface lustre, wetting, whiteness and air permeability. Some properties were observed to be advantageous to the material, while some would have adverse effects. Potential application of the laser treatment on polymer was conducted based on the study of the dyeing and adhesion properties. (Abstract shortened by UMI.)