The color aberration of POM after UV ageing , thermal ageing and hot water ageing for 1000 hours are 5.9, 6.land 4.8, smaller than 34.5, 7.6 and 20.2, which are the value of unmodified POM .

• 1和4.；8，而未改性聚甲醛经紫外光、热氧和热水老化后色差高达34