新型螺杆元件对LDPE-g-MAH反应挤出的影响

Influence of novel screw elements of twin screw extruder on reactive extrusion of LDPE-g-MAH

改变同向双螺杆挤出机主反应区的螺杆元件,研究该螺杆元件对低密度聚乙烯(LDPE)熔融接枝马来酸酐(MAH)的接枝产物和接枝率的影响。傅里叶变换红外光谱分析证实,部分MAH成功接枝到LDPE分子链上。对挤出沿程4个在线取样位置的试样做了对比分析,结果表明具有高剪切性能的捏合盘元件的沿程试样接枝率最大,熔体流动速率最小;具有高分布混合性能的齿形盘元件的沿程试样接枝率较大,熔体流动速率较小;具有回混作用的非啮合多过程元件能够迅速提高该元件所在区域的接枝率。

The influences of novel screw elements on graft and grafting efficiency of low density polyethylene （LDPE） grafted with maleic anhydride （MAH） in melting state were studied after replacing the conventional screw elements with its novel counterparts in the main reactive zone of the extruder. The Fourier transform infrared spectra indicated that MAH already partially grafted on the molecular chains of LDPE. 4 specimens taken at on-line sampling points along the extrusion course were analyzed for comparison. The results verify that the specimen taken from the location of kneading block with high shear property exhibits the highest grafting ratio and the lowest melt flowability; the specimen taken from the location of the turbine mixing elements with high distributive mixing function possesses a higher grafting ratio and a lower melt flowability; the non-intermeshing multiple process element with reflux action can rapidly raise the grafting ratio of the specimen in the zone at which it is located.