聚丙烯熔融接枝马来酸酐反应机理的研究

改变聚丙烯（PP）熔融接枝马来酸酐（MAH）反应中的单体和引发剂的浓度以及添加适当助剂，考察了接枝产物的接枝率和恒定剪切应力（600kPa)及温度（210℃）下的剪切粘度，验证了作先前所提出的PP熔融接枝MAH的反应机理。即：在PP熔融接枝MAH的过程中，过氧化物自由基在熔融接枝过程中直接引发MAH单体及MAH单体在聚丙烯的大分子链段发生β断裂前直接被其引发而产生的接枝反应是影响产物的接枝率和分子量的关键。在不改变单体和引发剂浓度的情况下，降低过氧化物自由基在熔融接枝过程中直接引发MAH单体反应的程度而提高聚丙烯的大分子自由基直接引发MAH单体的反应趋势，是提高接枝产物接枝率和分子量的有效途径。

On the Mechanism of Melt Grafting of Isotactic Polypropylene with Maleic Anhydride

The grafting degree and shear viscosity under constant shear stress of PP g MAH as function of contents of MAH, dicumyl peroxide(DCP) and additives has been investigated. The mechanism of melt grafting of polypropylene(PP) with maleic anhydride(MAH) proposed previously by authors is proved to be correct through reactive extrusion. It is evident that decreasing the tendency of reaction between the peroxide radicals and the MAH monomer and enhancing the tendency of reaction between the macromolecular radicals and MAH will result in the formation of final product having higher grafting degree and higher molecular weight simultaneously.