乙烯-乙酸乙烯酯共聚物增韧改性聚甲醛的工艺研究

Study on Technology of Polyacetal Toughened by Ethylene-Vinyl Acetate Copolymer

通过熔融挤出共混的方法,选用乙烯-乙酸乙烯酯共聚物(EVA)增韧改性聚甲醛(POM)。分别研究了EVA用量和工艺参数(包括挤出机螺杆转速、加工温度以及注射压力)对POM/EVA共混物力学性能的影响。结果表明:EVA能有效地增韧改性聚甲醛,当EVA用量为25%时,缺口冲击强度由7.6 k J/m^2提高到22.9 k J/m^2;当EVA用量在15%时,POM/EVA体系的综合力学性能最好;加工工艺参数对体系的力学性能有一定的影响,当螺杆转速为200 r/min,加工温度在150~180℃,注射压力为8 MPa时,体系的力学性能最好。

Ethylene-vinyl acetate copolymer （EVA） was used to toughen polyacetal （POM） by melt mixing using a twin-screw extruder. The effects of EVA content and technical parameters on the mechanical properties of POM/EVA blends were studied, which technical parameters including screw speed of extruder, processing temperature and injection pressure. The results show that POM is effectively toughened by EVA, and the notched impact strength improves from 7.6 k Jim^2 to 22.9 kJ/m^2 after the incorporation of 25% EVA. When the content of EVA is 15%, the overall performance is at high point. Technical parameters have an effect on the mechanical properties, and while the screw speed is 200 rlmin, processing temperature from 150 to 180℃, injection pressure at 8 MPa, the mechanical properties of POM/EVA blends are optimal.