مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

In the present study, the linear low-density polyethylene (LLDPE)/Zr02 nanocomposites were synthesized via in-situ polymerization with rac-Et(lnd)2ZrCI2/MAO catalyst. First, the nano-Zr02 filler was impregnated with the desired amount of MAO. Then, copolymerization of ethylene/1-octene was performed in the presence of nanoZr02/ MAO filler to produce the LLDPE/Zr02 nanocomposites. The amounts of nanoZr02 filler employed were varied at 0.1 and 0.3 g corresponding to [AI]MAO/[Zr] ratios=1135 and 3405, respectively. It can be observed that the polymer yield increased with increasing the ratios of [AI]MAo/[Zr]. However, the observed polymer yields were much lower (about 5-30 times) compared to the yield with no filler addition. The filler contents in polymer were in the range of 23-25 wt%. The characteristics of LLDPE/Zr02 nanocomposites obtained were determined by means of DSC, SEM/EDX, TEM, 13C NMR, and XPS. It was observed that the LLDPE/Zr02 nanocmposites exhibited slightly lower melting temperature (Tm) and crystallization temperature (Tc), SEM Micrographs demonstrate the homogeneous matrix of the samples. In addition, with EDX mapping technique, it was also revealed that the nano-Zr02 filler was well distributed over the polymer matrix. Based on the TEM result, it was also revealed that the smaller and more uniform particles can be observed after polymerization.These observations suggested that the fragmentation of nano-Zr02 particles or segregation of the secondary particles could occur resulting in good dispersion of the particles. The distribution of comonomer was studied by 13C NMR. It was shown to be random as seen in the similar catalytic system without filler addition. The binding energy (BE) for C 1s obtained from XPS to be 285.7 eV indicating no significant change in the polymer microstructure with the addition of nano-ZiO, filler.