The Research On Mechanism Of Ultra-fine Comminution Of Thermoplastic Plastic With Turbulent Flow Pulverizer Under Ambient Temperature

This dissertation regard the application of turbulent flow pulverizing technology in thermoplastic as research object, introduces the application domain and preparation of plastic ultra-fine powder .The collision character of thermoplastic particles in pulverizer cavity was analyzed. The reasons of ultra-fine comminution of thermoplastic with turbulence mill under ambient temperature were investigated.Turbulent flow pulverization technology is an advanced technology of preparing super-fine powder. The experimental principle and flow of turbulent flow pulverizer are presented through experiments of pulverizing Low-Density Polyethylene(LDPE) powder and polytetrafluoroethylene (PTFE).The effect of operating factors such as rotating speed, raw material size feeding speed and discharging place are discussed on comminution effect.. According to the performance of thermoplastic , micrograph of plastic ultra-fine powder and comminuting feature of thermoplastic with turbulence mil, including high frequency, high speed, high stress and high strain velocity. A new opinion was presented that the ultra-fine comminution of thermoplastic with turbulence mill under ambient temperature is brittleness fracture. The fracture mechanism includes two reasons. Interior defects flaw (for instance, crack , grain boundaries,. dislocation, splay et al.) bring to the tendency of brittleness fracture. On the other hand, strain rate gets high because of high speed crash, so as to brittle temperature (T_b) of material gets high. Meanwhile, high frequency and ruleless stress cause to particles' endurance failure.