SYNOPSIS2,2'-Dimethyl-4,4'-diamino-biphenyl was used to prepare a lyotropic amine-terminated polyamide (PBTA) prepolymer with terephthaloyl dichloride, and an amide oligomer with reactive endcaps of maleimide, respectively. The former was employed in a n attempt to increase the solubility of P A / P I block copolymers, and the latter to produce a three-dimensional (isotropic ) reinforced molecular composite through the technology of a semiinterpenetrating polymer network ( semi-IPN ). PBTA prepolymer was copolymerized with an amine-terminated polyimide via a coupling reaction using terephthaloyl dichloride. The resultant block copolymers were characterized by IR, NMR, qinhr and GPC to confirm that the copolymerization reaction was precisely accomplished, as well as to determine their composition and molecular weight. Thermal analysis and lyotropic behavior were also studied for these copolymers. Rigid-rod amide oligomer was crosslinked in the presence of another flexible polyimide. Five sets of semi-IPN films were prepared under varying compositions. The curing conditions were investigated by DSC; in addition, the cured semi-IPNs exhibited a single phase (1 T,) according to examination by an instrument for thermally stimulated current (TSC) . No large-scale phase separation was observed in SEM images of the fractured surfaces.

2,2-Bis[4-(2-hydroxy-3-methacryloyloxy-propoxy)phenyl]propane (Bis-GMA) wasused as the main ingredient for a dental composite. The dental composite was prepared by mixing high viscosity Bis-GMA with a low-viscosity diluent monomer. Three monomers were used: triethylene glycol dimethacrylate (TEGDMA), trimethylol propane trimethacrylate (TMFTMA), and trimethylol propane triacrylate (TMPTA). The mixed components were allowed to polymerize under visible light. The degree of conversion was higher for the sample with lower viscosity. The silica which was used as filler in the dental composite was modified by using the radiation-induced polymerization method in which methyl methacrylate (MMA) was grafted onto the silica gel. The higher the content of PMMA in the modified filler, the lower the hardness of the composite. Most properties of the samples are the same as those of a commercial product. The compressive strength is higher due to the strong filler-matrix interface which is provided by 6oCo y-ray radiation. ZUSAMMENFASSUNG: Hochviskoses 2,2-Bis[4-(2-hydroxy-3-methacryloyloxy-propoxy)phenyl]propan(Bis-GMA) wurde als Hauptbestandteil eines Zahnfiillungsmaterials mit niedrigviskosem Verdunner (Tkiethylenglykol-dimethacrylat (TEGDMA), Trimethylolpropantrimethacrylat (TMPTMA) oder Trimethylolpropan-triacrylat (TMPTA)) und einem Fullstoff gemischt und durch Initiierung mit sichtbarem Licht polymerisiert. Der Umsatz nahm mit abnehmender Viskositat der Mischung zu. Das als Fullstoff verwendete Siliciumdioxid wurde durch strahlungsinduzierte Polymerisation von Methylmethacrylat auf der Oberflache modifiziert. Mit haherem PMMA-Gehalt im Fullstoff nahm die Harte des damit hergestellten Zahnfiillungsmaterials ab. Die meisten Eigenschaften dieses Materials sind mit denen eines handelsiiblichen Zahnfullmaterials identisch. Die Druckharte ist wegen der starken Fullstoff-Matrix-Grenzflache jedoch hoher.

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