Polyimide phenyl-substituted

Alston and Grants [19] described the structure-property relationship of polyimides derived from phenyl substituted monomers including the following dianhydride. 

Tg measurements have been performed on many other polymers and copolymers including phenol bark resins [71], PS [72-74], p-nitrobenzene substituted polymethacrylates [75], PC [76], polyimines [77], polyurethanes (PU) [78], Novolac resins [71], polyisoprene, polybutadiene, polychloroprene, nitrile rubber, ethylene-propylene-diene terpolymer and butyl rubber [79], bisphenol-A epoxy diacrylate-trimethylolpropane triacrylate [80], mono and dipolyphosphazenes [81], polyethylene glycol-polylactic acid entrapment polymers [82], polyether nitrile copolymers [83], polyacrylate-polyoxyethylene grafts [84], Novolak type thermosets [71], polyester carbonates [85], polyethylene naphthalene, 2,6, dicarboxylate [86], PET-polyethylene 2,6-naphthalone carboxylate blends [87], a-phenyl substituted aromatic-aliphatic polyamides [88], sodium acrylate-methyl methacrylate multiblock copolymers [89], telechelic sulfonate polyester ionomers [90], aromatic polyamides [91], polyimides [91], 4,4"-bis(4-oxyphenoxy)benzophenone diglycidyl ether - 3,4 epoxycyclohexyl methyl 3,4 epoxy cyclohexane carboxylate blends [92], PET [93], polyhydroxybutyrate [94], polyetherimides [95], macrocyclic aromatic disulfide oligomers [96], acrylics [97], PU urea elastomers [97], glass reinforced epoxy resin composites [98], PVOH [99], polymethyl methacrylate-N-phenyl maleimide, styrene copolymers [100], chiral... 

Pd-catalyzed polycondensation was extended to the synthesis of highly branched rigid-rod polyimide by incorporation of phenyl-substituted pyromel-... 

Often the substitution of fluorine atoms for hydrogen atoms in a polymer chain markedly increases the thermal stabiUty of the base polymer this is tme for polyimides. A typical fluorinated polyimide is prepared from the reaction of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 2,2-bis-(4-amino phenyl)hexafluoropropane according to the following reaction (36) ... 

Thermal dimerization of perfluoroalkcnes is also a good approach for obtaining interesting dimeric fluoro-substituted compounds. A -[4-Phenoxy-3-(trifluorovinyl)phenyl]phthalimide (3), which is a model for polyimides containing trifluorovinyl groups, undergoes thermal dimerization at 140-160"C to give predominantly the trtf .s-1,2,3,3,4,4-hexafluoro-l,2-bis(2-phenoxy-5-phthalimidophenyl)cyclobutane (4).6 See Section 2.1.1.6.2. for a more detailed discussion of this [2 + 2]-cycloaddition process. 

The reactivity of the maleimide monomer was dependent on the substitution pattern of the phenyl ring, with the substituents in the ortho position tending to lower the molecular weight of the polymer formed. The THP substituent is readily removed either chemically or thermally to yield poly(iV-(hydroxyphenyl)maleimides). All polymers exhibited excellent thermal stability and showed no evidence of degradation below 360 °C. Reaction occurs between the phenolic ring of the polyimide and HMTA, to form benzoxazine-type derivatives. These reactions have been studied comprehensively using the monomeric model systems, Ai-(hydroxyphenyl)succinimides (Figure 8) . 

Tao et al. prepared fluorinated polyimide (3-86 in Table 3.4) [126], from multi-trifluoromethyl-substituted diamine, which had a dielectric constant as low as 2.49. The dielectric constants decreased gradually with an increase in fluorene loading. The dielectric constant value was not only much lower than non-fluorinated polyimides such as PMDA-ODA (3.16) [127], it was also lower than some of the fluorinated polyimides such as those derived from 3,3, 5,5 -tetrafluoro-4,4 -diaminodiphenylmethane (TFDAM) and dianhydrides (2.73-2.82) [128] and from a,a-fcA(4-amino-3,5-difluorophenyl)phenyl-methane (4FMA) and dianhydrides (2.60-2.83) [129]. Wang et al. [130] prepared fluorinated poly-iinides (3-87 in Table 3.4) by incorporating diisopropyl-substituted fluorene moieties, which led to an improvement in solubility and dielectric properties. The dielectric constant obtained with the... 

Nitrile-Substituted Polyimide. Amorphous Polsrmers that contain polar fimctional groups were synthesized (61-63) and investigated for use as high temperature piezoelectric sensors. (jS-CN) APB/ODPA polyimide is one such system. The (jS-CN) APB/ODPA polyimide possesses the three dipole functionalities shown in Table 5. Typically, the functional groups in amorphous polymers are pendent to the main chain. The dipoles, however, may also reside within the main chain of the polsrmer, such as the anhydride imits in the ( -CN) APB/ODPA polyimide. The nitrile dipole is pendent to a phenyl ring in = 4.2 D), and the two anhydride dipoles (ft = 2.34 D) are within the chain, resulting in a total dipole moment of 29.4 X 10 ° C m (8.8 D) per repeat unit. 

The synthesis as well as the structure and properties of aromatic polyimides has been reviewed.This combination of synthesis, structure, and properties is a general characteristic of papers in this field. For example, the preparation of polyimides from di-isocyanates, poly(o-amino-o-carbonyl)amides, maleimides, and Af-(4-substituted phenyl)itaconimides, all follow this pattern. The preparation of polyimide fibres, wet spun from solution, has also been given. ... 

The decrease in intermolecular association (induced dipole-dipole interactions) is due to the lower heterocyclic content per repeat unit. The polyimide containing only pendant phenyl groups exhibited a Tg of 292 C, whereas substitution of two phenyl pendants with diphenylether groups lowers the Tg to 240 C. It is interesting to note that the same equivalent lowering of the Tg has been shown to occur for the as-triazine and quinoxaline polymer systems. ... 

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