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Silica is a versatile material employed in different applications fields including aerospace, especially for rocket engines thermal protections. It is known that particles diameter causes variations in the material properties, and the best-known methods for diameter determination in general consist of several steps in sample preparation such as drying, sieving and the determination of the refractive index according different methods. On the other hand, Fourier transform infrared spectroscopy techniques (FT-IR), in reflectance mode, related to the particle size, are less used for this type of determination. Moreover, methodologies in the near infrared region (NIR) are even less explored. Therefore, the aim of this paper is to present a FTIR methodology for diffuse reflectance (DRIFT) in the middle infrared region (MIR) and reflectance analysis in near infrared region (NIRA) for the determination of the particle diameter on silica samples. Both methodologies showed good results. As proven by a test sample analysis, NIRA methodology indicated better precision. Furthermore, considering small and intermediated particle sizes, a tendency towards smaller errors for the absorbance measurements of the samples was found, consistently with the available literature results.

Na área aeroespacial é constante a pesquisa em busca de novos materiais que permitam um melhor desempenho de foguetes, mísseis e explosivos. Entre outros, compostos mais energéticos, de maior estabilidade térmica e/ou química, menos agressivos ao meio ambiente, de menor custo e de mais fácil manuseio. Um destes materiais é o metil azoteto de glicidila (GAP), que pode ser utilizado para produzir propelentes mais energéticos e/ou sem fumaça, bem como composições explosivas de baixa sensibilidade. O GAP foi sintetizado e caracterizado por análises FT-IR, elementar, cromatográfica de permeação de gel e térmica.

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.

Resumo: Reações para obtenção de derivados de hidantoína foram conduzidas a partir de aldeídos de cadeia curta e da 5,5-dimetilhidantoína. O acompanhamento das reações foi realizado por espectroscopia na região do infravermelho médio (MIR) por meio da formação de novas bandas características da estrutura do composto desejado. A análise MIR revelou que estas alterações espectrométricas ocorrem somente na reação com o formaldeído, indicando a formação do produto 1,3-bis(hidroximetil)-5,5-dimetilhidantoína, em presença de água. As bandas de absorção que confirmam a reação foram observadas em 3334 cm-1 (υ OH), 1770 e 1710 cm-1 (υ C=O) e em 1056 cm-1 (υ C-O), sendo esta última, atribuída ao grupo contendo hidroxila primária. A reação da 5,5-dimetil hidantoína com acetaldeído e com propanaldeído não ocorreu sob as condições adotadas neste trabalho. Abstract: Reactions to obtain hydantoin derivatives were carried out with 5,5-dimethylhydantoin and short-chain aldehydes. Monitoring of the reactions was performed using qualitative mid-infrared spectroscopy (MIR) through the formation of new bands characteristic of the desired product. MIR analysis showed that these spectrometric alterations occur only in the reaction with the formaldehyde, indicating the formation of the desired product, 1,3-bis (hydroxymethyl) 5,5-dimethylhydantoin, in the presence of water. The absorption bands that confirmed the reaction were observed at 3334 cm-1 (υ OH), 1770 and 1710 cm-1 (υ C=O) and 1056 cm-1 (υ C-O), the last of which is assigned to the group containing primary hydroxyl.

In the Brazilian Complete Spacial Mission, the research of Vehicle Satellite Launcher is important. The solid propellant composite used in this vehicle is made with ammonium perchlorate, aluminiun powder and hydroxy terminated polibutadiene resin. In the propellant the bonding agent has a function to promote the interaction between solids and polimeric matrix, improving mechanical properties as stress, strain, aging characteristics and moisture embrittlement. Due its importance in propellant, bonding agent is consider as industrial secret and the literature about it is generic, without greater informations.

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.

Poly(epichlorohydrin) was synthesized using anhydrous and hydrate stannic chloride, separately, as initiator. Reactions were conducted in the presence of a diolat 70°C. Polymers were characterized by Fourier Transform Infrared I Spectroscopy (FT-IR), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and hydroxyl value determination. It was observed that water has influence in growing chain, but not in its structural backbone. Besides, the monomer/initiator relationship has a higher influence in overall poly(epichlorohydrin) properties.

This paper describes the action and results achieved during the optimization of Glycidyl Azide Polymer (GAP) characterization and process. Under different conditions, three different kinds of catalysts, BF 3 , SnCl 4 .5H 2 O and SnCl 4 were used to obtain polyepichlorohydrin and each sample was converted into GAP. All the samples were submitted for characterization analysis by FT-IR and determination of molecular mass and hydroxyl value. Finally, results were compared and the best method to obtain GAP was determined.

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.