Novel Miscible Blends Composed of Poly(Methyl Methacrylate) and 2,2-Bis(3,4-Carboxyphenyl)Hexafluoropropane Dianhydride-Based Polyimides with Optical Grade Clarity

Abstract

Several blends of polymers that varied concentrations of poly(methyl methacrylate) (PMMA) and polyimides based on 2,2 0 -bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) were prepared in film form by solution casting and using various solvents. The miscibility of the blended films was correlated through a differential scanning calorimeter (DSC), Fourier transform infrared spectroscopy (FTIR), and an image analyzer. DSC thermograms revealed two glass-transition temperatures (T g ) for specimens using tetrahydrofuran (THF) as a casting solvent, indicating immiscibility; on the other hand, samples using methyl chloride (MC) and cyclohexanone showed a single T g , indicating miscibility between the two polymers. The phase separation temperature for the miscible samples showed lower critical solution temperature type (LCST-type) behavior and reached its minimum when the content was about 70 mass% PMMA. Both the transmittance and haze of the miscible blended films were measured according to the American Standards Testing Method (ASTM) specification D1003. The transmittance for 6FDA-6FpDA/PMMA had a value of about 85% in the visual light range. However, 6FDA-6FpDA:DABA 2 : 1/PMMA showed a low transmittance below wavelengths of 550 nm. For haze, all of the films were clear with values of less than 1%. The mechanical scratch resistance was measured by pencil test (ASTM 3363). Increasing the 6FDA-6FpDA polyimide content was found to increase the scratch resistance of the films.

Electro conductivities of well‐dispersed PMMA‐g‐MWNTs/6FDA‐based polyimide composites: Effect of chemical structure

“…In particular, fluorinated carbon (FC) groups in the 6FDA‐based polyimide may show dipole‐dipole interactions with the CO groups of the PMMA‐ g ‐MWNTs. These results were confirmed by FT‐IR spectra, which indicated spectral shifts caused by interactions between the functional groups of each polymer, as shown in previous studies [24, 25]. The possible interactions between carbonyl and carboxyl acid are illustrated in Fig.…”

“…These results may be explained using the interaction forces between 6FDA‐based polyimide matrix and PMMA on the MWNTs. It is known that the presence of the DABA groups in polyimide facilitates intermolecular hydrogen bonding with adjacent chains because of the carboxyl acid groups in the DABA unit [24, 25]. This means that polyimide‐containing DABA groups may have supramolecular behavior due to intermolecular association.…”

“…We have previously investigated the miscibilities of these 6FDA‐based polyimides with various commercial polymers using a solvent casting method. It was found that 6FDA‐based polyimide with 4,4′‐(hexafluoroisopropylidene)diamine, (6FpDA), and 3,5‐diaminobenzoic acid (DABA) units in the chain were miscible with PMMA due to specific interactions between the carbonyl groups of PMMA and the fluorinated carbon of 6FDA polyimide at the molecular level [24, 25]. Thus, to form a conductive 6FDA‐based polyimide composite with well dispersed MWNTs, it may be necessary to modify the MWNTs using PMMA to permit specific interactions with the polymer matrix.…”

Improved gas selectivity of polyetherimide membrane by the incorporation of PIM polyimide phase

“…According to OP 1 values, opacity decreases as the amount of PIM‐B increases in the blends. Taking into account the referenced literature about opaque materials indicate low miscibility, it might state that PEI/PIM‐B membranes show higher miscibility as the amount of PIM‐B increases in the blends. This result is consistent with FTIR, fluorescence spectroscopy, and UV–vis analysis and demonstrates that miscibility increases according to the increase in CTC interactions.…”

“…In addition, polymer blends can be tailored by combining different polymers and changing the blend composition. Nevertheless, polymer blend membranes possess several drawbacks related to miscibility and homogeneity of blend components . Numerous research works have demonstrated that a large number of polymers with appropriate functional groups can form inter‐association such as hydrogen bonds (H‐bond) and charge transfer complex (CTC) that enhance compatibility of immiscible blends .…”