Effect of degree of cure and fiber content on the mechanical and dynamic mechanical properties of carbon fiber reinforced PMR‐15 polyimide composites

Abstract

A unidirectional continuous carbon fiber reinforced polyimide composite is fabricated using the PMR‐15 polyimide as a matrix. Mechanical and dynamic mechanical properties of the composite are studied. The effect of variation of the fiber content ranging from 55% to 70% by volume on the properties of the composite is determined. The effects of the laminate thickness and degree of curing of the matrix on the Izod impact strength are examined. The effect of the degree of curing of the matrix on the dynamic mechanical spectrum is studied. Finally, variables such as humidity, environment temperature, vacuum, and pressure during laminate processing, and variation of monomer composition are discussed in terms of change in matrix structure, which is reflected in a variation of Tg between batches.

Electrical and mechanical properties of polyimide–carbon nanotubes composites fabricated by in situ polymerization

“…However, the reinforcement effect was not evident in the present experiment. Compared with the above researches [20,24], the content of nanotubes was much lower in the present experiment. Another reason may be considered that the addition of carbon nanotubes may be an obstacle to ensure the degree of polymerization and orientation of polyimide.…”

“…There are several reports on carbon fiber (CF) reinforced polyimide composites concerning the laminate thickness, the degree of curing of the matrix, crystallization conditions, and on the mechanical properties of the polyimide [23,24]. The fiber was thought to be nucleate crystallization on the surface and to induce a highly ordered trans-crystallinity, which may result in improved mechanical properties of the composites material in the fiber direction.…”

“…The nucleating ability is dependent strongly on the precursor of carbon fibers and the content. The storage modulus of the PI-CF composite increased nearly one order of magnitude when the volume of carbon fiber increased to 72% [24]. The high aspect ratio for the carbon nanotubes Table 1 The electrical conductivity of polyimide with different carbon fillers at a content of 1.5 wt%…”

Synthesis and properties of PMR type poly(benzimidazopyrrolone‐imide)s

“…The PMR process (in situ polymerization of monomer reactants), which was successfully employed in the preparation of high-performance polyimide composites, [11][12][13][14] was employed in this laboratory to synthesize poly(benzimidazopyrrolone-imide) by copolycondensation of diethyl ester of 4,4Ј-(hexafluoroisopropylidene)diphthalic acid (6FDE), monoethyl ester of cis-5-norboneneendo-2,3-dicarboxylic acid (NE), 3,3Ј-diaminobenzidine (DAB), and para-phenylenediamine (p-PDA) in ethyl alcohol/N-methylpyrrolinone (NMP) solution to yield an end-capped oligomer, which was then polymerized and crosslinked by thermal curing to produce a thermosetting polymer materials. The synthesis and properties of the polymer materials will be described in this article.…”

An improved simplified approach for curing kinetics of epoxy resins by nonisothermal differential scanning calorimetry

“…The physical properties of the cured epoxy resins depend on their structures, the degree of cure, the curing conditions, and the time and temperature of curing. 1,2 Particularly, most of the factors somehow make an impact through influencing the curing kinetics. 3,4 Therefore, it is necessary to investigate the curing kinetics of the resin for further research on determining the optimal cure cycle and to analyze the relationship between properties and processing for high performance manufacturing and utilization.…”