Characterizations of transparent polyimide nanocomposite films with various equibiaxial stretching ratios: Optical transparency, morphology, and oxygen permeability

Abstract

A series of transparent polyimide (PI) nanocomposite films was synthesized from bicyclo(2,2,2)oct-7ene-2,3,5,6-tetracarboxylic dianhydride and 1,3-bis(3-aminophenoxy) benzene with various organoclay contents via solution intercalation polymerization to poly(amic acid)s, followed by thermal imidization. Varying the organoclay loading in the range 0-1.5 wt % produced variations in the optical transparency, morphology, and oxygen barrier properties of the hybrids. The optimum oxygen barrier properties were observed for the hybrids containing 1.0 wt % Cloisite 30B; these properties were degraded gradually by further increases in the clay content. The PI hybrid films were found to exhibit excellent optical transparency and to be almost colorless. However, the transparency of the hybrid films decreased slightly with increasing organoclay content. Transparent PI hybrid films containing 1.0 wt % Cloisite 30B were stretched equibiaxially with various stretching ratios in the range 100-140% to investigate their optical transparency and oxygen permeability in detail; the variations with equibiaxial stretching ratio of the clay dispersion and morphology were also determined. PI hybrid films with stretching of 120% or greater were found to contain homogeneously dispersed clay in the polymer matrix and exfoliated nanocomposites. The highest barrier to oxygen permeation was found to arise at an equibiaxial stretching ratio of 130%. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: E2-E11, 2012

Preparation of biaxially oriented polyamide 6/polyketone/graphene oxide films with enhanced barrier and mechanical behaviors

“…The mechanical and barrier properties of polymers can be remarkably improved when nano particles materials, such as clay and graphene, are incorporated. [13][14][15][16] Graphene makes up of carbon atoms in a honeycomb lattice on a 2D plane. Three atomic orbitals from carbon atoms are hybridized into sp 2 orbitals.…”

Colorless and Transparent Copolyimides and Their Nanocomposites: Thermo-Optical Properties, Morphologies, and Gas Permeabilities

“…However, an increase in oxygen permeability, to 10 cm 3 /m 2 /day, was observed at an organoclay concentration of 50 wt %. This increase in permeability is attributable to the agglomeration of the clay particles above a critical clay concentration [13,45].…”

“…The transmittances of the Co-PI hybrid films decreased with increasing clay concentration due to clay-particle agglomeration [14,44,45]. The transmittance at 500 nm decreased significantly, from 86 to 74%, as the STN concentration was increased from 0 to 50 wt % (Table 6); clay agglomeration was evidenced by XRD and TEM (Figure 5, Figure 6 and Figure 7).…”

Effect of uniaxial stretching on thermal, oxygen barrier, and mechanical properties of polyamide 6 and poly(m‐xylene adipamide) nanocomposite films

“…It seems that among the controlling factors in the gas permeation through the films (i.e., thickness, crystallinity, orientation and tortuosity path of permeant gas), the free volume plays an important role. In fact, during hot stretching of either the aliphatic or aromatic nylon films at low draw ratios, the chain mobility increases and as a result, the chain entanglements reduces and, accordingly, the free volume and gas permeation increases. After a critical draw ratio, the amorphous and crystalline chains alignment along the drawing direction increase.…”