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The main objective of these studies was the synthesis and characterization of new energetic binders and their use in some propellant formulations. Following the working plan elaborated, the synthesis and characterization of the following compounds has been done successfully: GAP; energetic Monomer BAMO; energetic Binders; copolymer GAP/PolyBAMO. The scale up for the synthesis of copolymer GAP/PolyBAMO and PolyBAMO using GAP as initiator has been done and they were fully characterized by IR, (1H, 13C) NMR-spectroscopy, GPC, elemental analysis, OH-functionality, differential scanning calorimetry (DSC) and sensitivity tests (friction, impact). For this two scale up synthesis some propellant formulations were carried out and the results of mechanical and burning properties have been compared with GAP propellants.

Phenolic resin has long been used as matrix for composites mainly because of its flame retardant behavior and high char yield after pyrolysis, which results in a self supporting structure. The addition of ceramic powders, such as SiC and B4C, as fillers to the phenolic resin, results in better thermo-oxidative stability, but as drawbacks, it has poor homogeneity, adhesion and processing difficulties during molding of the composites. The addition of single elements, such as boron, silicon and phosphorus in the main backbone of the thermo-set resin is a new strategy to obtain special high performance resins, which results in higher mechanical properties, avoiding the drawbacks of simply adding fillers, which results in enhanced thermo-oxidative stability compared to conventional phenol-formaldehyde resins. Therefore, the product can have several applications, including the use as ablative thermal protection for thermo-structural composites. This work describes the preparation of a boron-modified phenolic resin (BPR) using salicyl alcohol and boric acid. The reaction was performed in refluxing toluene for a period of four hours, which produced a very high viscosity amber resin in 90% yield.The final structure of the compound, the boric acid double, substituted at the hydroxyl group of the aromatic ring, was determined with the help of the Infrared Spectroscopy, 1H-NMR, TGA-DSC and boron elemental analysis. The absorption band of the group B-O at 1349 cm-1 can be visualized at the FT-IR spectrum. 1H-NMR spectra showed peaks at 4.97-5.04 ppm and 3.60-3.90 ppm assigned to belong to CH2OH groups from the alcohol. The elemental analysis was also performed for boron determination.The product has also been tested in carbon and silicon fibers composite for the use in thermal structure. The results of the tests showed composites with superior mechanical properties when compared with the conventional phenolic resin.

A new method using wet chemistry and instrumental analysis has been developed for evaluating the ring-opening of aziridine tris [1-(2 methyl) aziridinyl] phosphide oxide (MAPO) of the bonding agent used in composite propellant. A reduction was observed in the intensity absorption bands in 1400 and 1040 cmˉ ¹ , characteristic of aziridinic ring. It was also observed, in some cases, that when the number of open aziridinyl ring increases, the NH band in the range 3400-3300 cmˉ ¹ , that appears with ring-opening, is located in the region of lower wave numbers. The study of the synthesis of MAPO derivative indicated side reactions such as homopolymerization of rings and also, with secondary hydroxyl of the 12-hydroxy stearic acid and probable humidity existent in the original sample.

Synthesis and characterization of energetic ABA-type thermoplastic elastomers for propellant formulations has been carried out. Following the working plan elaborated, the synthesis and characterization of Poly 3- bromomethyl-3-methyl oxetane (PolyBrMMO), Poly 3- azidomethyl-3-methyl oxetane (PolyAMMO), Poly 3,3-bis-azidomethyl oxetane (PolyBAMO) and Copolymer PolyBAMO/AMMO (by TDI end capping) has been successfully performed. The thermoplastic elastomers (TPEs) were synthesized using the chain elongation process PolyAMMO, GAP and PolyBAMO by diisocyanates. In this method 2.4-toluene diisocyanate (TDI) is used to link block A (hard and mono- functional)) to B (soft and di-functional). For the hard A-block we used PolyBAMO and for the soft B-block we used PolyAMMO or GAP.This is a joint project set up, some years ago, between the Chemistry Division of the Institute of Aeronautics and Space (IAE) - subordinated to the Brazilian Ministry of Defense - and the Fraunhofer Institut Chemische Technologie (ICT), in Germany. The products were characterized by different techniques as IR- and ( ¹ H, ¹³ C)NMR spectroscopies, elemental and thermal analyses. New methodologies based on FT-IR analysis have been developed as an alternative for the determination of the molecular weight and CHNO content of the energetic polymers.

To establish the relation between structure and properties of composite solid propellants it is important to know the structure of the elastomeric binder that has been used in the system. Therefore this study is focused on the characterization of polymers containing energetic groups that has been synthesized at ICT. The characterization uses the wide spectral band of infrared, NIR/MIR/FIR. This gives an identification of the analytical bands and allows quantitative and kinetic studies of these compounds.

Copper chromite (CuCr 2 O 4 ) catalysts were prepared by ceramic and coprecipitation methods and characterized by X-ray diffraction, scanning electron microscopy (SEM), elemental, differential calorimetric (DSC), thermogravimetric and granulometric analysis, mass spectroscopy and infrared spectroscopy (IR). Elemental and IR analysis have shown similarities among the samples for both synthetic methods. However, DSC, SEM and X-ray analysis of the samples synthesized by coprecipitation method presented different physical properties. For those samples, DSC could identify a tetragonal → cubic phase transition, SEM showed particles with defined crystalline shapes and X-ray analysis contains the main assignments which identify the formation of CuCr 2 O 4 . HTPB propellants containing CuCr 2 O 4 samples were manufactured, then burning rate and mechanical properties have been measured. The results were compared with HTPB propellants containing iron (III) oxide as catalyst. The highest burning rate values were obtained with samples which present a more defined crystalline shape, i.e., the ones synthesized by the coprecipitation method.

A series of 1,2-amino alcohol and 1,2-monotosylated diamine derivatives of indane have been applied as ligands in the asymmetric ruthenium(II)-catalysed transfer hydrogenation reaction of a series of ketones. Of these, the cis-1-aminoindan-2-ol derivative gives some of the highest asymmetric inductions reported for any amino alcohol ligand in this application.

The present study shows the synthesis of polyamide 6/6 (nylon 6/6) via interfacial polycondensation of hexamethylenediamine and adipoyl chloride, at room temperature, with the simultaneous impregnation of carbon fibers, using the reaction injection pultrusion (RIP) process. The polyamide 6/6 obtained was characterized by infrared spectroscopy, differential scanning calorimetry, and viscosity measurements. The impregnation of the carbon fibers was evaluated by scanning electron microscopy assisted by electron dispersive spectroscopy showing good carbon fiber/polymer matrix interface. These results show that the combination of the synthesis of polyamide 6/6, at room temperature, with simultaneous impregnation of carbon fiber amplifies the application of this structural thermoplastic composite with different arrangements of the reinforcement.

A rapid, expedient and enantioselective method for the synthesis of β-hydroxy amines and monosubstituted aziridines in up to 99% e.e., via asymmetric transfer hydrogenation of α-amido ketones, is described.

A new class of difluorovinylphosphonate analogues of PEP, 4,4-difluoro-4-(diethoxyphosphinoyl)-2-methylenebutanoic acid 15, methyl 4,4-difluoro-4-(diethoxyphosphinoyl)-2-methylenebutanoate 17, (E)- and (Z)-4,4-difluoro-4-(diethoxyphosphinoyl)but-2-enoic acid 14 and 4,4-difluoro-4-phosphono-2-methylenebutanoic acid 16 have been synthesized. Methyl 3,3-difluoro-3-(diethoxyphosphinoyl)-2-hydroxy-2-methylpropionate 21 and the corresponding acid 3,3-difluoro-3-phosphono-2-hydroxy-2-methylpropionic acid 23, have also been synthesized. These compounds are designed to act as potential inhibitors in the shikimic acid pathway.

[reaction: see text] A rhodium(III) catalyst for asymmetric transfer hydrogenation of ketones has been designed. The incorporation of a tethering group between the diamino group and the cyclopentadienyl unit provides extra stereochemical rigidity. The catalyst is capable of enantioselective reduction of a range of ketones in excellent ee using formic acid/triethylamine as both the solvent and the reducing agent.

A new class of difluorovinylphosphonate analogues of PEP, 4,4-difluoro-4-(diethoxyphosphinoyl)-2-methylenebutanoic acid 15, methyl 4,4-difluoro-4-(diethoxyphosphinoyl)-2-methylenebutanoate 17, (E)- and (Z)-4,4-difluoro-4-(diethoxyphosphinoyl)but-2-enoic acid 14 and 4,4-difluoro-4-phosphono-2-methylenebutanoic acid 16 have been synthesized. Methyl 3,3-difluoro-3-(diethoxyphosphinoyl)-2-hydroxy-2-methylpropionate 21 and the corresponding acid 3,3-difluoro-3-phosphono-2-hydroxy-2-methylpropionic acid 23, have also been synthesized. These compounds are designed to act as potential inhibitors in the shikimic acid pathway.

A series of 1,2-amino alcohol and 1,2-monotosylated diamine derivatives of indane have been applied as ligands in the asymmetric ruthenium(II)-catalysed transfer hydrogenation reaction of a series of ketones. Of these, the cis-1-aminoindan-2-ol derivative gives some of the highest asymmetric inductions reported for any amino alcohol ligand in this application.

Glycidyl azide-r-(3,3-bis(azidomethyl)oxetane) copolymers were synthesized by cationic copolymerization of epichlorohydrin and 3,3-bis(bromomethyl)oxetane, using butane-1,4-diol as an initiator and boron trifluoride etherate as a catalyst, followed by azidation of the halogenated copolymer. The main objective of this work is the preparation of an OH-terminated amorphous polymer with energetic content higher than that of the well-known glycidyl azide homopolymer. The effect of experimental conditions, i.e., the rate of monomer feeding, on the final molecular weight and functionality of the copolymer has also been investigated. The obtained copolymers were extensively characterized to determine their composition and thermal stability. The heat of reaction for the polymerization of the halogenated key precursors has also been measured. It was found that even though both the operating conditions and the catalytic system were chosen in order to favor a living character of the polymerization, the final product seems to be the result of a combined living and active chain end mechanism. In particular, the latter is responsible for the formation of oligomers and not hydroxyl-terminated chains. Nevertheless, the average number of OH groups is high enough to allow a cross-linking of the polymeric chains, by addition of polyisocyanates and subsequent formation of inter-chain urethanic bonds.

Halomethylsilanes (MeSiCl3, Me3SiI, Me2SiCl2, Me3SiCl, and Me3SiBr) undergo oxidative addition to IrH(pipr3)2 in situ generated from IrH5(pipr3)2 and two equivalent neohexene to form halo(organosilyl)iridium(III) complexes. In addition, the resulting (methylsilyl)iridium complexes undergo β-hydride elimination reactions leading to the formation of dihydroiridium species.

Made available in DSpace on 2019-09-12T16:25:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2007 No presente trabalho duas técnicas de manufatura de compósitos termoplásticos estruturais são investigadas: a de moldagem por compressão a quente convencional e a de pré-impregnação via suspensão polimérica. A primeira consiste na impregnação do reforço via polímero fundido; enquanto que a segunda faz uso de suspensões poliméricas aquosas, onde a impregnação do reforço ocorre pelo contato deste com a suspensão aquosa de partículas da matriz polimérica. Esta técnica combina a matriz polimérica em pó com um outro polímero formador da suspensão, um poli(ácido âmico - PAA), sendo que os dois polímeros são simultaneamente depositados sobre o reforço, durante a impregnação. Este mesmo PAA, em uma segunda fase do processo, é convertido termicamente em uma poliimida (PI) podendo formar uma região de interfase entre o reforço e a matriz polimérica. Este trabalho tem como objetivo a síntese e a caracterização de um PAA, à base de BTDA/DDS, e a avaliação de sua influência na formação da região de interfase em compósitos de poli(sulfeto de fenileno) (PPS)/fibras de carbono. Resultados de DSC e TG mostram o sucesso da síntese do PAA e de sua conversão em PI, esta com estabilidade térmica até 396 °C. O compósito processado pela técnica de suspensão polimérica apresenta resistência ao cisalhamento interlaminar (56,3 MPa) 12,6% superior ao compósito obtido por moldagem por compressão a quente convencional (50,0 MPa). Estes resultados são confirmados por análises das superfícies de fratura, que mostram que o uso do PAA melhora a interfase do PPS/fibra de carbono. In the present work two different manufacturing techniques of thermoplastic composites are investigated: the conventional hot compression molding and the aqueous suspension prepregging. The first one involves the impregnation of the reinforcement with molten polymer; while the second one uses aqueous polymeric suspensions, where the reinforcement impregnation occurs by its contact with the particle aqueous suspension of a polymeric matrix. This technique combines the powder polymeric matrix with another polymer which forms the suspension, a poly(amic acid - PAA). In this technique, both polymers are deposited simultaneously on the reinforcement during the impregnation. In a second phase of the processing, the PAA is thermally converted in a polyimide (PI) that can form an interphase region between the reinforcement and the polymer matrix. The objective of this study is the synthesis and the characterization of a PAA, based on BTDA/DDS, and the evaluation of its influence on the interphase region in the poly(phenilene sulphite) (PPS)/carbon fiber composite. DSC and TG results show the success of the PAA synthesis and its conversion into PI, which exhibits thermal stability up to 396 °C. The processed composite by polymeric aqueous suspension showed interlaminar shear strength (56.3 MPa) 12.6% higher than the composite obtained by conventional hot compression molding (50.0 MPa). Fracture surface analyses confirm these results, showing that the use of PAA improves the PPS/carbon fiber interphase. [Kawamoto, Aparecida M.] CTA Nohara, Evandro L.] Universidade de Taubaté, Brazil Nohara, Liliana B.; Rezende, Mirabel C.] CTA

Resumo: Um metodo SEC com dupla deteccao para determinacao de distribuicao de funcionalidade de resina polibutadienica hidroxilada HTPB foi desenvolvido, verificando-se a influencia desse parâmetro no comportamento mecânico de poliuretano utilizado em motor-foguete fabricado no Centro Tecnico Aeroespacial (CTA). O metodo mos- trou-se sensivel a pequenas diferencas de funcionalidade e sua distribuicao podendo ser utilizado para a caracterizacao mais completa da resina. Ensaios de tracao realizados em amostras de PU sem carga refletiram pequenas diferencas de distribuicao de funcionalidade existentes entre os lotes de polibutadieno hidroxilado. Palavras-chave: Resina polibutadienica hidroxilada (HTPB), funcionalidade, poliuretano, propriedades mecânicas. Determination of Functionality Distribution of HTPB and Evaluation of its Influence in the Mechanical Behaviour of Polyurethane Used in Rocket Cases Abstract: A size exclusion chromatography (SEC) method, with double detection, was developed to determine the functionality distribution of hydroxyl polybutadiene (HTPB) resin, evaluating the influence of that parameter on the mechanical behavior of HTPB polyurethane used as binder in the rocket motors manufactured at Centro Tecnico Aeroespacial (CTA). The method showed to be sensitive to small differences in the functionality distribution of the HTPB resin and, thus, can be used for a more complete characterization of the resin. Tensile tests performed on HTPB polyurethane reflected the small differences observed in the functionality distribution of three batches of HTPB.

Made available in DSpace on 2019-09-12T16:25:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2004 O objetivo do presente trabalho é apresentar a síntese de um poli (ácido âmico) (PAA) a ser utilizado como formador de interfase no processamento de compósitos termoplásticos de alto desempenho. Os materiais compósitos termoplásticos constituídos de um reforço rígido e de uma matriz dúctil têm as suas propriedades mecânicas fortemente dependentes do mecanismo de transferência de carga fibra/matriz. Por esse motivo, a região da interface/interfase nos materiais compósitos possui um papel fundamental nas propriedades finais do material. O PAA surge como uma alternativa para melhorar a adesão fibra/matriz na região interfacial em compósitos de alto desempenho, constituídos de matrizes termoplásticas, reforçadas com fibras de carbono ou vidro. O PAA é utilizado na forma de sal, na preparação de suspensões poliméricas de matrizes termoplásticas. O PAA estudado neste trabalho foi sintetizado utilizando-se os reagentes BTDA e DHPr. Em seguida, o PAA foi convertido em PI por imidização em solução. Análises por FTIR mostram o sucesso da síntese do PAA e da sua conversão em PI. As técnicas de DSC e TGA determinaram as temperaturas de transição vítrea (~213 °C) e de decomposição (~310 °C), respectivamente. Estes resultados motivam a utilização do PAA/PI como formador de interfase na obtenção de compósitos termoplásticos com temperaturas de processamento abaixo de 310 °C. This work is aimed at presenting the synthesis of a poly (amic acid) (PAA) to be used as interphase precursor in the manufacturing of high performance thermoplastic composites. Thermoplastic composites comprising a rigid reinforcement and a ductile matrix have their mechanical properties strongly dependent on the load transfer mechanism between the reinforcement and matrix. For this reason, the interface/interphase region plays a fundamental hole in the final properties of the composite materials. PAA appeared as an alternative to improve the fiber/matrix adhesion when it is transformed in polyimide (PI) favoring the link between the reinforcement and the thermoplastic matrix. This work shows the PAA synthesis from BTDA and DHPr reagents and its conversion into PI by imidization in a liquid medium. Mass spectrometry analysis confirmed the synthesis of PAA from the precursor reagents and the FTIR analysis evaluated the success of the conversion of PAA into PI. DSC and TGA analysis of the PI determined their glass transition (~213 °C) and decomposition (~310 °C) temperatures, respectively. These results motivate the use of PAA/PI as precursor of interphase to obtain thermoplastic composites with processing temperatures below 310 °C. [Kawamoto, Aparecida M.; Takahashi, Marta F. K.] CTA Wills, Martin] Warwick University, United Kingdom Nohara, Liliana B.] ITA Nohara, Evandro L.] UNITAU Rezende, Mirabel C.] CTA

The synthesis and application to asymmetric reduction of acetophenone, of a novel class of Rh(III) catalyst containing a tether between the cyclopentadienyl group and a homochiral aminoalcohol, is described. The complex is a highly active catalyst for asymmetric ketone reduction, however it appears to be unstable to the extended reaction conditions. The well-defined stereochemical structure of the catalyst offers potential for significant improvement and ‘fine tuning’ towards specific substrates.

A rapid, expedient and enantioselective method for the synthesis of beta-hydroxy amines and monosubstituted aziridines in up to 99% e.e., via asymmetric transfer hydrogenation of a-amino ketones and cyclisation through treatment with tosyl chloride and base, is described. (1R,2R)-N-(para-toluenesulfonyl)-1,2-ethylenediamine with formic acid has been utilised as a ligand for the Ruthenium (II) catalysed enantioselective transfer hydrogenation of the ketones.The chiral 2-methyl aziridine, which is a potentially more efficient bonding agent for Rocket Solid Propellant has been successfully achieved.

A rapid, expedient and enantioselective method for the synthesis of β-hydroxy amines and monosubstituted aziridines in up to 99% e.e., via asymmetric transfer hydrogenation of α-amido ketones, is described.

Alkenes react with disilanes in the presence of platinum phosphine complex catalysts to give alk-1-enylsilanes.