Study On Mechanical Properties Of Specimen Prepared By Vibration Injection And Rheological Behavior Of Melt Under Vibration Field

In this thesis, the mechanical property of HDPE and GFRPP specimen were studied with a self-made vibration injection device. In the work, SEM and WAXD were used to observe microstructure and analyze the relation between morphology and mechanical property. With these methods, the effect of vibration parameters on the microstructure and property of polymer specimen was discussed. Meanwhile, the effect of vibration parameters on apparent viscosity wad discussed. Based on the results, some conclusions were given as following:1. The HDPE specimen's mechanical performance (both longitudinal and transverse direction) could be enhanced significantly under vibration field and the performance varies with the vibration parameters. Compared with the normal injection specimen, the maximum increment of longitudinal tensile strength of HDPE reached 25.6% when the vibration amplitude reached 49.5 MPa.2. SEM data showed that vibration field had an effect on the fiber length and fiber distribution of GFRPP. SEM data and WAXD investigation indicated that the change of crystallization distribution was mostly composed of lamellae and that more orientation was obtained by vibration.3. The apparent viscosity of melts decreases significantly with the increase of vibrati-on frequency as well as vibration pressure amplitude. The dependence of viscosity on melt temperature was lowered by increasing vibration pressure amplitude which makes the processing temperature lower.