Single electrospun nanofiber and aligned nanofiber belts from copolyimide containing pyrimidine units

Abstract

Single electrospun co-PI nanofiber and aligned co-PI nanofiber belts containing pyrimidine units possessed superior mechanical strength and modulus.

Facile control of high temperature shape memory polymers

“…The asymmetric stretching, symmetric stretching and bending of CO vibrations, together with CNC stretching vibrations of imide ring are located around 1775, 1717, 738, and 1375 cm −1 , respectively. These IR peaks confirmed the successful and complete imidization of the shape memory copolyimides . Besides, there is no trace of residual monomers detected in the re‐precipitated products, which further confirmed the complete imidization of the copolyimides.…”

“…Copolymerization is an efficient and convenient method to obtain polymers with expected properties, and copolyimides have attracted attentions from various fields . The shape memory copolyimides of BPADA/BAB‐BAPB were synthesized with two‐step polycondensation process by employing BPADA as dianhydride and the combination of BAB and BAPB as diamines, and the sythesis process is shown in Figure .…”

“…IR has been a common way to characterize structure of polyimides, and here the structures of these shape memory copolyimides were also characterized with IR, as shown in Figure . The asymmetric stretching, symmetric stretching and bending of CO vibrations, together with CNC stretching vibrations of imide ring are located around 1775, 1717, 738, and 1375 cm −1 , respectively.…”

Nanofibre preparation of non-processable polymers by solid-state polymerization of molecularly self-assembled monomers

“…WDK, Japan), a digital camera, software for data acquisition and processing and a computerized control system. The test method was the same as that previously reported by us [9][10][11] . The testing process consists of five steps: 1) load the single nanofibre sample onto the paper framework (Figure S7a), 2) mount the paper framework carrying the single nanofibre sample in the clamps of the microtensile tester, 3) cut the 'rib' of the paper frame ( Figure S7c), 4) locate the nanofibre sample using the optical microscope to ensure that only one nanofibre sample is present, and 5) load the single nanofibre sample to break with the microtension tester (Figure S7c).…”

Crown ether-containing polyimides with high dielectric constant

“…The peak a could at 341-343 C could be attributed to the T g of PI lms, which was much higher than the bipyrimidine-containing PIs (291 C), 19 bipyridine-containing PIs (285 C), 20 and pyrimidine-containing co-PIs (262 C). 27 Due to the large amount of crown ether-groups, the PI molecular chains also exhibited a secondary kinetic movements, which led to the appearance of the peak b.…”