Study On Injected Polymer's Strength And Toughness In Pressure Vibration Field

When the strength of polymer is increased, the material normally becomes fragile and a part of tenacity is lost. In this paper the primary aim is to strengthen and toughen the polymeric injected parts, we designed and manufactured a device called vibration injection molding. During injection and holding pressure stages a special vibrating field was superposed to the melt in the mould. By controlling the processing conditions, the state of aggregation of injected moldings had been changed with enhanced and toughened properties for semi-crystalline polymer.With the vibration injection-molding device, polypropylene, high-density polyethylene and acrylonitrile-butadiene-styrene (ABS) were studied and the relationship between mechanical properties (e.g. break and yield strengths and elongation at break) and processing conditions (such as vibration frequency, vibration pressure amplitude and injection temperature) was investigated. And the testing results are as follows:1. With the vibration injector's frequency increasing, the toughness of semi-crystalline polymer will gradually ascend .At the same time, PP(F401) part is strengthened in intension and enhanced in tenacity. The partial HDPE(6098) part is done, too.2. The breaking and yield strengths of PP and HDPE injection moldedparts are promoted gradually, but part of tenacity is lost. 3. This kind of vibration injection molding, main pressure vibration, has great influence on mechanical strength and tenacity of semi-crystalline polymer, but the effect on amorphous polymer is very little.