Fluorinated poly dianhydrides

It reduces the intermolecular CTC between alternating electron donor (diamine) and electron acceptor (dianhydride) moieties. In general, fluorinated poly-imides exhibit lighter color and greater transparency than non-fluorinated analogues [42]. 

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... 

A new aromatic diamine monomer with four pendant -CF3 groups was successfully synthesized by a three-step reaction using w(4-fluorophenyl)sulfone and A-bromosuccinimide as starting materials. Then, a series of fluorinated poly(ether sulfone imide)s was conveniently prepared from the diamine and three aromatic dianhydrides (BPDA, BTDA, and ODPA) via one-step solution polycondensation. 

H. Behniafar, H. Sadeghi-abendansari, Highly fluorinated poly(ether-imide)s derived from 2,2 - w(3,4,5-trifluorophenyl)-4,4 -diaminodiphenyl ether and aromahc dianhydrides, Polym. Int. 61 (2) (2012) 286-293. 

Sulfur tetrafluoride fluorination of aryl perfluoroalkyl esters provides a route to stable aryl perfluoroalkyl ether compounds (1). By using nitrophenyl esters of perfluoroalkyl-ene and perfluoroalkylene ether dicarboxylic acids, a, w-bis (m-nitrophenoxy) perfluoroalkylene ether intermediates were prepared. The conversion of these products to the corresponding amino and isocyanatophenoxy derivatives is described. Reaction of the diamines with benzophenone-tetracarboxylic dianhydride resulted in formation of poly-imides. Cyclotrimerization of the diisocyanate intermediates formed polyisocyanurates. Both the imide and iso-cyanurate polymers have high thermal, oxidative, and hydrolytic stability. 

Ishii J, Tanaka Y, Hasegawa M. Film properties of polyazomethines (2). poly(imide-azo-methine)s derived from ester-containing dialdehydes, tetracarboxylic dianhydrides, and a fluorinated diamine. High Perform Polym 2010 22(2) 145-58. 

Among various strategies that have been used to synthesize polyimides with lower dielectric constants, the most common approach is to incorporate fluorene, in the form of trifluoromethyl groups, into diamine and dianhydride units that minimize polarizability and increase the free volume [46]. It is well-known that fluorene atom has unique characteristics such as high electronegativity and low electric polarity. These properties give fluorinated polymers (e.g., poly[tetrafluoroethylene]) attractive features such as low water uptake, water and oil repellency, low permittivity, low refractive indices, resistance to wear and abrasion, and thermal and chemical stability. Fluorination is also known to enhance solubility and optical transparency and to lower the moisture absorption of polyimides. Therefore, it is expected that fluorinated polyimides will be widely applied in the electro-optical and semiconductor industries. The polymer series studied was essentially limited mainly to 6F dianhydride because it proved to be the only dianhydride with which many of the fluorinated diamines would form polymer films suitable for physical characterization. 

Banerjee et al. [47] synthesized a diamine monomer, namely, 4,4 -(7w(aminophenoxy)-3,3-trifluoromethyl terphenyl, and furthermore prepared fluorinated polyimides (3-70 to 3-72 in Table 3.4). The Tg of the polyimides depended on the rigidity of the dianhydride unit. The polyimide with PMDA as dianhydride had the highest Tg of 294 °C in the series, with a thermal stability as high as 532 °C in an air atmosphere. The TS of the poly(ether imide) s were in the range 96-112 MPa with an EB in the... 

An example of thermoplastic fluorinated polyimide adhesives is provided in Fig. 36. The first step is the reaction of 4,4 -[2,2,2-trifluoro(l-trifluoromethyl) ethylidene]bis(l,2-benzenedicarboxylic acid) dianhydride with either 4,4 -[[2,2,2-trifluoro-l-(trifluoromethyl)ethylidene]bis(4,l-phenyleneoxy)]bisbenzeneamine or 4,4 -[(l-methylethylidene]bis(4,l-phenyleneoxy)]bisbenzeneamine yielding the corresponding polyamic acids. Chemical dehydrocyclisation with trifiuoro-acetic anhydride and triethylamine provides the poly(ether-isoimides) 52 and 54 with 0.40 and 0.45 dl g , respectively, whereas acetic anhydride and pyridine gave polyimides 53 and 55 with tiji 0.75 and 0.71 dl g respectively [89]. 

Thesulphonatedpolyimidemembranesarebasedon4,4 -diaminobiphenyl-2,2 -disulphonic acid (BDSA), 4,4 -oxydianiline (ODA), 4,4 -oxydiphthalic anhydride (ODPA) and 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA). The study of the surface properties of fluorinated polyimides exposed to vacuum ultraviolet (VUV) radiation and atomic oxygen may help us understand the stability of these polymers. It will also be interesting to apply this sulphonation method to some novel high molar mass poly-etherimide, as reported by Hsio and Yang (1997). 

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