TY - JOUR A1 - Bruma, Maria A1 - Schulz, Burkhard A1 - Köpnick, Thomas A1 - Stiller, Burkhard A1 - Hamciuc, Elena A1 - Mercer, Frank W. A1 - Cassidy, Peter T1 - Aromatic polyamides with hexafluoroisopropylidene groups and study of the thin Y1 - 1998 ER - TY - JOUR A1 - Sava, Ion A1 - Szesztay, Marta A1 - Bruma, Maria A1 - Mercer, Frank W. A1 - Schulz, Burkhard T1 - Compared properties of aromatic polyamides containing silicon in the chain N2 - Two series of aromatic polyamides incorporating silicon together with phenylquinoxaline or with hexafluoroisopropylidene groups have been synthesized and their properties have been characterized and compared with those of related polymers. These polymers are easily soluble in polar amidic solvents such as N-rnethyl-2-pyrrolidinone and dimethylformamide, and in tetrahydrofuran, and can be cast into thin, transparent films from solution. The polyamides have weight- and number-average molecular weights in the range of 10000-40000 and 3000-6000, respectively, and polydispersities in the range of 3-10. They show glass transition temperatures in the range of 236 °C-275 °C and decomposition temperatures above 400 °C. The polymer films have low dielectric constants in the range of 3.26-3.68, and good mechanical properties (tensile strength 74-100 MPa, tensile modulus 180-386 MPa), thus being comparable with other high performance dielectrics. Y1 - 1997 ER - TY - JOUR A1 - Bruma, Maria A1 - Mercer, Frank W. A1 - Schulz, Burkhard A1 - Dietel, Reinhard A1 - Neumann, Werner T1 - Fluorinated poly(benzoxazole-imide)s Y1 - 1994 ER - TY - JOUR A1 - Bruma, Maria A1 - Hamciuc, Corneliu A1 - Hamciuc, Elena A1 - Mercer, Frank W. A1 - Belomoina, Nataliya A1 - Schulz, Burkhard T1 - Heterocyclic polyamides containing hexafluoroisopropylidene groups Y1 - 1996 ER - TY - JOUR A1 - Bruma, Maria A1 - Hamciuc, Corneliu A1 - Hamciuc, Elena A1 - Mercer, Frank W. A1 - Belomoina, Nataliya A1 - Schulz, Burkhard T1 - Heterocyclic polyamides containing hexafluoroisopropylidene groups N2 - New heterocyclic polyamides have been synthesized by solution polycondensation of aromatic diamines containing phenyl- quinoxaline units with diacid chlorides having both imide and hexafluoroisopropylidene (6F) groups. These polymers are soluble in polar aprotic solvents, such as N-methylpyrrolidone (NMP) or N,N-dimethylformamide (DMF), and can be cast into flexible thin films from solutions. They show high thermooxidative stability with decomposition temperatures above 400°C and glass transition temperatures in the range of 225 - 300°C. The polymer films exhibit good chemical resistance towards deluted acids and good electrical insulating properties with dielectric constants in the range of 3.2 - 3.7. Y1 - 1997 ER - TY - JOUR A1 - Bruma, Maria A1 - Hamciuc, Corneliu A1 - Sava, Ion A1 - Hamciuc, Elena A1 - Mercer, Frank W. A1 - Fritzsche, P. A1 - Schulz, Burkhard T1 - High temperature polyamides containing pendant imide groups Y1 - 1996 ER - TY - JOUR A1 - Bruma, Maria A1 - Schulz, Burkhard A1 - Köpnick, Thomas A1 - Dietel, Reinhard A1 - Stiller, Burkhard A1 - Mercer, Frank W. T1 - Investigation of thin films made from silicon-containing poly(phenylquinoxaline-amide)s N2 - Thin films in the range of 50 nm to 10 mm thickness have been prepared from NMP solutions of silicon-containing polyphenylquinoxaline-amides which had been synthesized by the polycondensation reaction of aromatic diaminophenylquinoxalines with bis(p-chlorocarbonylphenyl)diphenylsilane. A spin-coating technique onto glass plates or onto silicon wafers was used to make the film, followed by gradual heating to remove the solvent. The resulting films were very smooth and free of pinholes when studied by atomic force microscopy (AFM). They showed a strong adhesion to silicon wafers, were thermally stable in air to above 400 °C and their dielectric constant was in the range of 3.5-3.7. Thermal treatment of the films was performed in order to induce crosslinking. Such treated films became completely insoluble in organic solvents, maintained their smoothness and strong adhesion to the silicon substrate, and did not show any Tg, in DSC experiments. Their FTIR spectra in reflection mode did not show any changes compared with the untreated films, meaning on the one hand that the polymers maintain their structural integrity at high temperature and on the other hand that the number of crosslinks was very low and could not be detected by IR spectroscopy. Y1 - 1998 ER - TY - JOUR A1 - Bruma, Maria A1 - Schulz, Burkhard A1 - Mercer, Frank W. T1 - Polyamide copolymers containing hexafluoroisopropylidene groups Y1 - 1995 ER - TY - JOUR A1 - Bruma, Maria A1 - Sava, Ion A1 - Mercer, Frank W. A1 - Reddy, Victor N. A1 - Köpnick, Thomas A1 - Stiller, Burkhard A1 - Schulz, Burkhard T1 - Silicon-containing poly(amide-ether)s N2 - New aromatic poly(amide-ether)s (II) have been synthesized by solution polycondensation of various aromatic diamines having two ether bridges (I) with a diacid chloride containing silicon, namely bis(chlorocarbonylphenyl)- diphenyIsilane. These polymers are easy soluble in polar amidic solvents such as N-methylpyrrolidinone or dimethylformamide and can be cast into thin flexible films or coatings from such solutions. They show high thermal stability with initial decomposition temperature being above 400 °C. Their glass transition temperatures lie in the range of 220-250 °C, except for polymer He which did not show a clear Tg when heated in a differential scanning calorimetry experiment up to 300 °C. The large interval between the glass transition and decomposition temperatures of pnlymers Ia-Id could be advantageous for their processing via compression molding. The polymer coatings deposited by the spincoating, technique onto silicon wafers showed a very smooth, pinhole-free surface in atomic force microscopy investigations. The free-standing films of 20-30 mm thickness show low dielectric constant, in the range of 3.65-3.78, which is promising for future application as high performance dielectrics. Y1 - 1998 ER - TY - JOUR A1 - Bruma, Maria A1 - Mercer, Frank W. A1 - Schulz, Burkhard A1 - Dietel, Reinhard A1 - Fitch, J. A1 - Cassidy, Peter T1 - Study of crosslinking process in fluorinated poly(imide-amide)s containing pendant cyano groups Y1 - 1994 ER -