Tribological Properties Of Polyetherimide Modified Epoxy Resin Composite Prepared By Morphology Controlling

Polymer based wear-resistant composites are widely used and play more and more important role in national economy fields. Attention has been drawn to the preparation of high performance wear-resistant materials by commodity polymers.In this dissertation, epoxy resin (EP) was used as matrix resin. Polymer chemical and physical methods were applied to prepare EP based wear-resistant composites with solid lubricants controlled in a particular phase.Fourier Transform Infrared Spectroscopy spectrometer (FTIR), Raman Spectrometer, Thermo Gravimetric Analysis (TGA), Dynamic Mechanical Analyzer (DMA) and Scanning Electron Microscope (SEM) were used to analyze the component, structure and morphology of the EP based composites and the worn surface and wear debris of them. Mechanical and tribological properties of the composites were tested by Universal Testing Machine and Reciprocating Tribometer. Relationship of the structure and morphology with mechanical and tribological properties of the composites was analyzed, in the basis of which, related mechanism was thoroughly analyzed.Main results achieved in this dissertation were listed as follows:1. Put forward the technical proposal of improving the tribological properties of polyetherimide (PEI) modified EP system by the way of controlling the morphology of the cured products. The availability of the proposal was verified. The order of the friction coefficient and wear rate of samples with different morphologies was:samples with bi-continuous phase-samples with phase inversion structure< samples with separated phase< unmodified EP.2. Taking advantage of viscosity difference of epoxy resin phase and PEI phase at the beginning of reaction induced phase separation, lubricant (graphite) was successfully controlled in PEI phase, In the basis of what, wear resistant composites with controllable lubricant dispersing state were prepared. Tribological properties of DGEBA/DDS/PEI/graphite composites were greatly improved by adding only 4.0wt% graphite. The friction coefficient and wear rate were 0.27 and 9.7×10-6mm3×(Nm)-1, which were 67% and two orders of magnitude less than unmodified DGEBA/DDS, respectively. Tensile and flexural strength were 52% and 10% higher than unmodified DGEBA/DDS.3. Poly (ether amide imide) (PEAI) grafted carboxylated graphene (HOOC-GNs) (PEAI-g-GNs) was successfully synthesized via imidization reaction under mild conditions and used to modify DGEBA/DDS. Composites with GNs only dispersing in PEAI phase were successfully prepared. Friction coefficient and wear rate of PEAI and PEAI-g-GNs (contents of PEAI and PEAI-g-GNs were 99.0wt% and 1.0wt% respectively) modified DGEBA/DDS composite were 0.61 and 5.8×10-5mm3×(Nm)-1, which were 25% and one order of magnitude lower than unmodified DGEBA/DDS. Tensile and flexural strength were 66% and 28% higher than unmodified DGEBA/DDS.In conclusion, two kinds of wear resistant composites with controllable lubricant or fortifier dispersing state were prepared by physical and chemical methods. The composites had both better mechanical and tribological properties than traditional materials with lubricant or fortifier dispersing in the whole matrix.