Polyimide nanocomposites synthesis

The kinetics of solid state imidization of PAA, synthesized from 4,4 -oxydianilinc and pylomellitic dianhydride, both without filler and with addition of 2 and 5 weight % Na+-montmorillonite [1], The nanofiller is processed by solution of P-phenylenediamine in HC1 and then washed with de-ionized water to ensure a complete removal of chloride ions. The conversion (imidization) degree Q was determined as a function of reaction duration t with the aim of Fourier transformation of IR-spectra bands 726 and 1014 cm 1. The samples for IR studies were prepared by spin-coating of mixture PAA/Na+-montmorillonite solution in N,N-dimethylacetamide on KBr disks. Then the KBr disks were dried in vacuum at 303 K for 48 h. It was shown, that the used in paper [1] method gives exfoliated nanocomposites. The other details of polyimide/Na+-montmorillonite nanocomposites synthesis and studies in paper [1] were cited. The solid state imidization process was made at four temperatures 7 423, 473, 503 and 523 K. 

Figure 7.18 Synthesis of NMS/polyimide nanocomposite. Reprinted with permission from C. Cheng, H. Cheng, P. Cheng and Y. Lee, Macromolecules, 2006, 39, 7583 2006, American Chemical Society...

D. Li, H.Y. Zhu, K.R. Ratinac, S.P. Ringer, H. Wang, Synthesis and characterization of soda-lite-polyimide nanocomposite membranes, Microporous Mesoporous Mater. 126 (1)... 

Polyimide/4,4 -bis(4-aiiiinophenoxy)phenylsulfone modified clay nanocomposites Synthesis and characterization... 

Chang J-H, Park D-K, Ihn K J, Polyimide nanocomposite with a hexadecylamine clay synthesis and characterization , J. Appl. Polym. Sci., 2002 84 2294—301. Chang J-H, Park K M, Cho D, Yang H S, Ihn K J, Preparation and characterization of polyimide nanocomposites with different oigano-montmorillonites , Polym. Eng. Sci., 2001 41(9) 1514-20. 

Polyimide-clay nanocomposites constitute another example of the synthesis of nanocomposite from polymer solution [70-76]. Polyimide-clay nanocomposite films were produced via polymerization of 4,4 -diaminodiphenyl ether and pyromellitic dianhydride in dimethylacetamide (DMAC) solvent, followed by mixing of the poly(amic acid) solution with organoclay dispersed in DMAC. Synthetic mica and MMT produced primarily exfoliated nanocomposites, while saponite and hectorite led to only monolayer intercalation in the clay galleries [71]. Dramatic improvements in barrier properties, thermal stability, and modulus were observed for these nanocomposites. Polyimide-clay nanocomposites containing only a small fraction of clay exhibited a several-fold reduction in the... 

In the case of the synthesis of polyimide, the polymerization solvent used for polyamic acid (a precursor of polyimide) is usually dimethyl acetoamide (DMAC). We found that clay ion-exchanged dodecyl ammonium ions could be homogeneously dispersed in DMAC. A solution of this organophilic clay and DMAC was added to a DMAC solution of polyamic acid. The film was cast from a homogeneous mixture of clay and polyamic acid, and was heated at 300 °C to achieve the desired polyimide clay nanocomposite film. Its permeability to water decreased to 50% upon addition of 2.0 wt% clay [13]. It was confirmed that its permeability to carbon dioxide also decreased by half [14]. 

Kovalev MK, Kalinina E, Androsov DA, Cho C. Synthesis of transparent and thermally stable polyimide-aramid nanocomposites -prospective materials for high-temperature electronic manufacture applications. Polymer 2013 54(l) 127-33. 

H. Liu, Y. Li, T. Wang, and Q. Wang, In situ synthesis and thermal, tribological properties of thermosetting polyimide/graphene oxide nanocomposites. Journal of Materials Science, 47 (4), 1867-1874,2012. 

Mo T-C, Wang H-W, Chen S-Y, Dong R-X, Kuo C-H, Yeh Y-C (2007) Synthesis and characterization of polyimide-silica nanocomposites using novel fluorine-modified silica nanoparticles. J Appl Polym Sci 104(2) 882-8W... 

Hsiue G-H, Chen J-K, Liu Y-L (2000) Synthesis and characterization of nanocomposite of polyimide-silica hybrid from nonaqueous sol-gel process. J Appl Polym Sci 76(11) 1609-1618... 

C.M. Leu, Y.T. Chang, K.H. Wei, Synthesis and dielectric properties of polyimide-tethered polyhedral oligomeric silsesquioxane (POSS) nanocomposites via POSS-diamine, Macromolecules 36 (24) (2003)9122-9127. 

On the other hand, clays modified with salts of aromatic amines, in which the N atom is directly linked to aromatic ring, exhibited higher thermal stability then those modified with alkylammonium compounds [117, 118]. The use of a combination of aromatic and aliphatic ammonium compounds was an effective strategy for synthesis of clays with sufficient thermal stability for thermoset polyimide resin (PI) [117]. In that case, the aromatic component of OLS provided higher thermal stability and the aliphatic component promoted intercalation. The benefits of combining aromatic and aliphatic surfactants to treat clay are also reported by other authors [ 119]. It was shown that clay treated with a 1 1 molar mixture of methylene dianihne (MDA) and dodecylamine resulted in an improvement in thermooxidative stability of Pl-based nanocomposites. 

Srisuwan S, Thongyai S, Praserthdam P (2010) Synthesis and characterizatirai of low-dielectric photosensitive polyimide/silica hybrid materials. J Appl Polym Sci 117 2422-2427 Tagam N, Okada M, Hira N, Ohki Y, Tanaka T, finai T, Harada M, Ochi M (2008) Dielectric properties of epoxy/clay nanocomposites—effects of curing agent and clay dispersion method. IEEE Trans Diel Electr Insul 15 24—32... 

Qu, L., et al. Polyimide-functionalized carbon nanotubes synthesis and dispersion in nanocomposite fi ms.Macromolecules.2004, 37(16), 6055-6060. 

As described in detail elsewhere, the preparation of Pl-based PNC involved the following steps (i) synthesis of a polyamic acid with ethoxysilane end-groups (PAAS), (ii) preparation of the nanocomposite precursors by the addition of the required amount of methyl triethoxysilane (MTS), (Hi) MTS hydrolysis in the cast NCP films, and (iv) imidization of the PAAS to the corresponding polyimide by stepwise heating of the thin NCP films for 2 h at each of the following temperatures 60,100,120,150,200, and 250 C and by post-cure for 5 hat300-315°C. 

Schematic representation of the synthesis of ACAT and electroactive polyimide/clay nanocomposite (EPCN). 

The proposed chapter reviews the work done on 6FDA based fluorinated Pis with respect to its synthesis and various copolymers, polymerisation methods, poly(ether-imide), photosensitive polyimide, hyperbranched polyimide, addition polyimide, poly(amide-imide), poly(urethane-imide), poly(epoxy-imide), poly(ester-imide), poly(siloxane-imide), nanocomposites and non-linear optical polyimides. Finally, its application in electronics and use as a material for gas separation and corrosion protection are discussed. 

Leu C-M, Reddy GM, Wei K-H, Shu C-F (2003) Synthesis and dielectric properties of polyimide-chain-end tethered polyhedral oligomeric silsesquioxane nanocomposites. Chem Mater 15(11) 2261-2265. doi 10.1021/cm0208408... 

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