氧化镁辐射接枝苯乙烯共聚物的表征

CHARACTERIZATION OF THE RADIATION GRAFT COPOLYMER OF STYRENE ONTO MgO

本文用傅里叶交换红外光谱、X线衍射、XPS和GPC等手段表征了氧化镁与苯乙烯的辐射接枝共聚物。结果表明,在接枝共聚物的红外谱图和X线衍射图上出现有氧化镁和聚苯乙烯的谱带。氧化镁与聚苯乙烯共混物XPS谱图中的C_(1S)、O_(1S)以及Mg_(2S)能级的峰位分别为285.0、530.0和87.6 eV,而氧化镁与苯乙烯接枝聚合物的C_(1S)、O_(1S)和Mg_(2S)峰位分别为284.0、531.7和88.4 eV。说明氧化镁与苯乙烯辐射接枝聚合时,氧化镁被辐射后镁原子引起照射缺陷而成为接枝活性中心,与苯乙烯碰撞时镁原子与电负性大的碳原子相配位产生自由基。然后按自由基机理进行接枝聚合反应。接枝物中的O/C比随接枝率的增加而下降。接枝共聚物的分子量要比均聚物分子量大,但分子量分布较宽。

The radiation graft copolymer of styrene onto MgO has been cha-racterized by FT-IR, X-ray diffaction, XPS and GPC. It is shown that the graftcopolymer has some peaks of MgO and polystyrene in IR and X-ray diffractionspectra respectively. It was found that there were some at 285. 0, 530. 0 and 87 .6 eVin the spectra of the blend, which blongs to C_(1S), O_(1S). and Mg_(2S) respectively, whilethe peak position of C_(1S), O_(1S) and Mg_(2S) of the MgO～g-styrene copolymer were284. 0, 531. 7 and 88. 4 eV respectively. This shows that the active centers caused bythe defect of Mg atom after irradiation react with styrene to form monomer free ra-dical, then grafting reaction occurs by the free radical mechanism. The ratio of oxy-gen to carbon (O/C) of graft products decreases with the increasing of the graftingyield. The molecular weight of graft copolymer is higher than that of homo-polymer.but the molecular weight distribution is broader in the graft copolymer.