Research On Preparation And Wear Resistance Of Nano-Al₂O₃ Reinforced PET Composite Materials

Polyethylene terephthalate (PET) is mainly used in the areas of synthetic fibers, packaging materials and engineering plastics possesses because of its excellent heat resistance, chemical resistance, electrical insulation and easy recycling. The disadvantages of PET include its low crystallization rate, low impact strength and poor abrasion resistance. In order to achieve high performance and to be used as the slider, gear and sliding bearings to replace some thermosetting engineering plastics and corrosive metal materials, the functional modification of PET has been an important research topic in recent years.In this paper, nano-Al₂O₃ particles were dispersed in EG solvent during the process of high-speed shearing and were simultaneously chemically treated by polyethylene glycol and silane coupling agent respectively, then they were used to prepare nano-Al₂O₃/PET composites by in-situ polymerization. Finally the properties of composite materials were tested and analyzed. The IR analysis indicated that on the surface of treated nano-Al₂O₃ particles there were characteristics groups of PEG and KH-560. TEM analysis showed that the untreated nano-Al₂O₃ got agglomerated seriously, while the treated nano-Al₂O₃ were dispersed uniformly in the EG solvent and PET matrix with an average diameter of 30⁸0nm. XRD and DSC analysis showed that nano-Al₂O₃ played a heterogeneous nucleation role in the PET crystallization process.Mechanical tests showed the impact strength of treated nano-Al₂O₃/PET composites was obvioulsly improved, while there was no decrease in the tensile strength. The friction and wear tests showed that in the dry friction condition, when the weight fraction of PEG and KH-560 treated nano-Al₂O₃ was 1.6%, the composites showed a lower wear rate, which were decreased by 51% and 70% respectively, compared with the untreated nano-Al₂O₃/PET composites, and were decreased by 68% and 81% than that of the PET. SEM analysis showed that with the increasing of the weight fraction of the treated nano-Al₂O₃, some dimples and tear occurs zone appeared on the impact fracture morphology of the composite materials, indicating the characteristic of toughness fracture. There were furrow shallow and slight plastic deformation on the friction surface, which showed the mild adhesive wear behavior.