The effect of the ring opening polymerization and chain spacing on the coefficient of thermal expansion and modulus of polyimide

Abstract

The features of norbornene (NE) cross-linked polyimide (PI) were investigated as the ratio of the norbornene monomer was varied. The coefficient of thermal expansion and modulus are important parameters of materials used in the microelectronic industry. Therefore, in this study, 5-norbornene-2, 3-dicarboxylic acid (NE) was introduced as a crosslinking agent to increase the thermal stability at elevated temperatures. 4,4 0 -Benzophenonetetracarboxylic dianhydride was utilized as a dianhydride and 4,4 0 -diaminodiphenyl ether was introduced as a diamine monomer. By changing the ratio of each monomer, we were able to control the spacing of the chain and ring opening polymerization, which resulted in improved properties. Each sample was thermally cured which led to a ring opening mechanism of the norbornene through the reverse Diels-Alder reaction. Thermal mechanical analysis was utilized to determine the coefficient of thermal expansion and dynamic mechanical analysis was used to determine the storage modulus (e 0 ) and loss modulus (e 00 ) of the PI film.

Reduction of dielectric constant by nanovoids formed through chemical treatment on silica crosslinked polyimide and its effect on properties

“…A peak at 1516 cm −1 was observed for the double bond of the benzene ring in the structure. CO stretching was observed at 1720 cm −1 , which is the peak of the vibration of the benzophenone ring . The silanol (SiOH) vibration spectrum was observed at 950 cm −1 with a very weak peak .…”

Self-formation of thickness tunable Bi2Te3 nanoplates on thin films with enhanced thermoelectric performance

“…This is mainly due to the densi-cation of atoms in the process from an amorphous structure to a crystalline structure. Since the coefficient of thermal expansion of the polyimide substrate (2.0 Â 10 À5 per K) 34 is smaller than that of Bi 2 Te 3 (5.08 Â 10 À5 per K), 35 a compressive thermal stress will be induced in the Bi 2 Te 3 thin lms because of smaller expansion of polyimide substrates during the heating process. Hence, the lattice will be further reduced.…”