Synthesis and properties of polyimide (containing naphthalene) nanocomposites with organo‐modified montmorillonites

Abstract

2,7-Bis(4-aminophenoxy) naphthalene (BAPN), a naphthalene-containing diamine, was synthesized and polymerized with a 3,3Ј,4,4Ј-benzophenone tetracarboxylic dianhydride (BTDA) to obtain a polyimide (PI) via thermal imidization. To enhance the thermal and mechanical properties of the polymer, PI-Montmorillonite (MMT) nanocomposites were prepared from a DMAc solution of poly(amic acid) and a DMAc dispersion of MMT, which were organo-modified with various amounts of n-dodecylamine (DOA) or cetylpyridium chloride (CPC). FTIR, XRD, and TEM (transmission electron microscopy) were used to verify the incorporation of the modifying agents into the clay structure and the intercalation of the organoclay into the PI matrix. Results demonstrated that the introduction of a small amount of MMT (up to 5%) led to the improvement in thermal stability and mechanical properties of PI. The decomposition temperature of 5% weight loss (T d,5% ) in N 2 was increased by 46 and 36°C in comparison with pristine PI for the organoclay content of 5% with DOA and CPC, respectively. The nanocomposites were simultaneously strengthened and toughened. The dielectric constant, CTE, and water absorption were decreased. However, at higher organoclay contents (5-10%), these properties were reduced because the organoclay was poorly dispersed and resulted in aggregate formation. The effects of different organo-modifiers on the properties of PI-MMT nanocomposite were also studied; the results showed that DOA was comparable with CPC.

Effect of organic modification on the thermal transformations of abentonite during sintering up to 1250°C

“…The latter transformations are related to the complete decomposition of the aromatic groups of the ulvan polymers together with the dehydroxylation of montmorillonite mineral contained in the bentonite. 4,32,33 The mass loss occurs in a smooth and progressive evolution under argon atmosphere, suggesting a different decomposition mechanism compared to the behaviour under air. Furthermore, the DTA peaks associated to the polymer oxidation is highly exothermic under air and roughly endothermic under argon.…”

Dielectric and tensile behavior of nanoclay reinforced polyetherimide nanocomposites

“…Tsai et al1 have reported that well dispersed platelets of organoclay in polymer matrix can significantly enhance the mechanical properties of PNCs. Shabeer et al2 and Tsay et al3 have reported a drastic increase in tensile strength and modulus of nanoclay reinforced PNCs. Dwivedi et al4, 5 have reported that dispersion of organoclay in the matrix has an important role in the properties of PNCs.…”

Novel organosoluable aromatic polyimides derived from unsymmetrical 1,3-bis(4-aminophenoxy)naphthalene and aromatic dianhydrides

“…15,16 Unless carefully designed, however, polyimides have high softening temperatures and are often insoluble in most organic solvents in their imidized form, making them extremely difficult to fabricate. [17][18][19][20][21][22][23][24][25][26][27][28] To overcome this drawback, a large number of structural modifications have been attempted such as introduction of bulky lateral substituents, flexible alkyl side chains, unsymmetric, alicyclic or kinked structures in the polymers. [17][18][19][20] Generally, aromatic diamine with ether linkages and metaoriented phenylene groups led to an increase in polymer chain flexibility and solubility of polyimides, but has also lowered the effective upper use temperature of these polymers.…”

“…[17][18][19][20] Generally, aromatic diamine with ether linkages and metaoriented phenylene groups led to an increase in polymer chain flexibility and solubility of polyimides, but has also lowered the effective upper use temperature of these polymers. 21 To improve the heat resistance of polyimides, one of the approach is to introduce thermal resistant groups into the polymer backbone, such as triazole, 22 carbazole, 23,24 pyridine, [25][26][27][28] and naphthalene [28][29][30][31][32][33][34] etc. Several polyimides containing naphthalene group have been developed by Yang et al.…”