Papers by Keyword: High Performance Polymer

Abstract: Carbon fiber reinforced polymers (CFRPs) are promising composite materials for high-performance and lightweight applications, gaining increasing interest in aerospace and automotive industries. Epoxy thermosets are frequently used as polymer matrices of CFRPs, which are usually responsible for failure of the composite. In this work different types of carbon nanotubes (CNTs) and carbon nanofibers (CNF) are added to the epoxy resin to improve mechanical properties of the whole CFRP composite. The dispersion of the fillers on a three-roll mill (TRM) is shown comparing their dispersion behavior in the resin. Results of increased modulus and strength of the hierarchical composite in four-point bending tests are presented.

Abstract: A kind of Polyimide films (PI films) containing biphenyl and bis-benzimidazole rings were prepared from the its precursor Polyamic acid (PAA) solution synthesized by aromatic diamine containing biphenyl and bis-benzimidazole rings with different commercial aromatic dianhydrides. The PI films exhibited excellent hydrophobicity with the contact angle of higher than 90o and the hydroscopicity are lower than 1%. The PI films also have great dielectric properties of the dielectric constant ranges from 2.10 to 2.94 under the voltage frequency within 1 to 10⁶ H_Z.

Abstract: Multi-walled carbon nanotubes (MWCNTs) are incorporated into Polyimide (PI) film in both pristine and functionalized forms through in-situ polymerization. MWCNTs and NH₂-MWCNTs lead to improved mechanical properties such as better tensile strength and elongation at break, as well as increased surface friction coefficient. The NH₂-MWCNTs can reduce the total wear weight loss of the composite to a larger extent compared with MWCNTs. 1.0 wt% NH₂-MWCNTs/PI has the lowest weight loss of 20.6 % of pure PI. Mechanism of two-stage wear procedure is discussed. We found that PI composite films with lower friction coefficient tend to lose less weight in the first stage, and the ones with better mechanical properties show better wear resistance in the whole wear procedure. Owing to the low surface energy, Natural mica is employed as the substrate for PI film.

Abstract: The novel bis(2, 4-dihydro-2H-3-(4-N-maleimido) phenyl-1, 3-benzoxazine)isopropane (BMIPBI) was synthesized from maleic anhydride, p-nitroaniline, formaldehyde and 2,2-bis(4-hydr -oxyphenyl)propane by a few steps reactions via the N-(4-nitrophenyl)maleimide(NPMI), N-(4-amin -ophenyl)maleimide(APMI),1,3,5-three(4-(maleimido)phenyl)-1,3,5-triazine(TMIPT)intermediate production. The chemical structures of BMIPBI were confirmed by ¹H-NMR, FT-IR and EA. The results show that the production was the target object BMIPBI. The synthesized condition had been studied too. The BMIPBI was a loosened yellow solid and the yield of product was 58.8%.