چكيده لاتين :
Maleic anhydride (MA) modified syndiotactic polystyrene (sPS) was accomplished
via Friedel-Crafts acylation reaction in the presence of anhydrous aluminium
chloride in a heterogeneous process. The modified polymer, maleated
sPS (m-sPS), separated from the reaction mixture was purified and analyzed. FTIR
spectroscopy and 1H NMR studies indicate that this chemical reaction can introduce
both carboxyl groups and double bonds onto pendant aromatic groups of the polymer,
which is quite different from the MA-grafted sPS prepared by a radical process, where
MA attaches to the sPS aliphatic backbone in the form of single succinic anhydride
rings as well as short oligomers. The results obtained by titration analysis suggest that
the acylation reaction can be carried out to a higher degree of functionalization.
Moreover, the thermal properties of MA-modified sPS were also studied by means of
DSC. It is found that the thermal behaviour of the m-sPS exhibits considerable differences
in comparison to the neat sPS. The melting temperature (Tm), crystallization
temperature (Tc), and degree of crystallinity of the maleated polymers decrease with
increasing the content of carboxyl groups, while the glass transition temperature
increases.
