| Developed a sonicated mixer by ourselves, and did the research on the rhe-ology behavior,mechanical performance,thermodynamic performance and crys-tallization behavior of UHMWPE and UHMWPE/HDPE/EVA by it.This sonicated mixer was developed by ourselves, and it is composed of ultrasonic equipment (20KHz,400W-1000W) and polymer mixer. The two parts were united successfully by a fixer, so the ultrasonic field could be introduced during blending, and we got favourable experiment results .This equipment is f-it for the physical blending of polymer. In order to get favourable blending stat-e we can adjust the temperature and time ect. according to the physical and che-mical properties of the polymer, and the vibration time and power of the ultras-onic field can also be adjusted during blending according to the requirement. B-ecause of the time of design was so short that there are still many disadvantag-es, and it should be improved later. During the blending of UHMWPE , we set the power value of ultrasonic field as 400W,500W,600W,700W, and the time v-alue as 5min,10min,15min. Studied on the rheology behavior,mechanical perfo-rmance etc.of UHMWPE under different ultrasonic field conditions.The results showed the effect of ultrasonic field did great influence on the properties of the UHMWPE. One side, the long chain of the polymer was dista-ngled by the vibration cavitating effect of the ultrasonic field ,so the tangle poi-nts decreased greatly, and the resistance of movement decreased too, finally the viscosity reduced, and the rheology was improved. The results showed, the rhe-ology was best when the ultrasonic vibration time was 10min. Furthermore, the curve of logηa Vs logγw is linear, and it showed that the shear flow of UHM-WPE obeyed exponential law under the ultrasonic field;on the other hand, the results showed, the yield strength, elongation at break increased evidently. From the results of DSC analysis we could see the Tm , the Peak Height and the ΔHm of UHMWPE increased by the effect of ultrasonic field. Furthermore, the cryst-allization peak became narrower and higher, and the value of (Tonset-Tc)became smaller, so it showed the cavitating effect of ultrasonic field broke the UHMWPE particle smaller, and accelerated the velocity of crystallization, and increased the degree of crystall-ization. The effect of ultrasonic field have great influence on the blending of UHMWPE/H-DPE/EVA too. Because the molecular weight of UHMWPE is so high that its viscosity is very high and the rheology is bad. Beyond the melting temperature, the polymer is gelatinous, and it is very difficult to measure the flow rate, so if we want to process the UHMWPE with the common equipment for PE we sho-uld improve the rheology. At present, the feasible way is physical blending, but because it is so difficult for the compatibility of the different material to get the best state that the effect of the blending is not perfect, and it is not compatible well between the different phase, and the disperse phase is not homogeneous. It occurs cavitating effect when the ultrasound wave is spreading inside the poly-mer melting, and this effect will blend and break the particle of polymer meltin-g so the blending will be homogeneous.From the SEM photograph we saw that the particle of EVA became sma-ller evidently after inducing ultrasonic field . It was not only the size of EVA particle was decreased a lot , but also the dispersing was improved, and the dis-perse phase was more homogeneous, viz. the compatibility is better. So ultraso-nic field can effectively improve not only the compatibility of polymer blends, but also the dispersibility of the additive in polymer.It is a perspective novel technology to apply high power ultrasonic field to the polymer melts during processing. Ultrasonic field is a quite effective means in controlling crystallization of the polymer, improving the compatibility of polymer blends, preventing the reuniting of the nano-powder, and enhancing the dispersibi...
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