Characterizing Of Polymer Morphologies & In-situ Monitoring Of Injection Molding Process Using Ultrasonic Techniques

In-situ monitoring and controlling are of importance for improving final product performance during processing. Ultrasound, a kind of mechanical wave, has extremely potential applications in the field of polymer processing for its super advantages, such as convenient installation, non-invasion and non-destruction, quick feedback, et al. In this dissertation, the miscibility and phase morphologies of polymer blends like PP/PS, PS/EPDM, PS/SBS, PVC/NBR, and orientation structures of HDPE/iPP blend obtained by dynamic packing injection molding were investigated using ultrasonic technique, and the relationships between ultrasonic signals and polymer structures had been found. In addition, ultrasonic technique was employed to monitor the injection molding process. Therein, the solidification behaviors of amorphous polymer and crystalline polymer, as well as the effect of temperature, pressure and injection mount on solidification were studied using ultrasound. This work is important for the optimization of process and product performances theoretically and practically.Major results are:1. Ultrasonic attenuation can characterize the miscibility and phase morphologies of polymer blends. Attenuation varies linearly with composition in miscible blends like PVC/NBR in that good miscibility results in a homogenous system and no ultrasonic scattering loss occurs. However, the comparable dispersed particles in immiscible polymer blends cause scattering loss which increases with increasing in particle size and dispersed phase content, consequently, the...