RESUMO
Binders, or tackifiers, have become widespread in the production of new composite materials by liquid composite molding (LCM) techniques due to their ability to stabilize preforms during laying-up and impregnation, as well as to improve fracture toughness of the obtained composites, which is very important in aviation, automotive, ship manufacturing, etc. Furthermore, they can be used in modern methods of automatic laying of dry fibers into preforms, which significantly reduces the labor cost of the manufacturing process. In this article, we review the existing research from the 1960s of the 20th century to the present days in the field of creation and properties of binders used to bond various layers of preforms in the manufacturing of composite materials by LCM methods to summarize and synthesize knowledge on these issues. Different binders based on epoxy, polyester, and a number of other resins compatible with the corresponding polymer matrices are considered in the article. The influence of binders on the preforming process, various properties of obtained preforms, including compaction, stability, and permeability, as well as the main characteristics of composite materials obtained by various LCM methods and the advantages and disadvantages of this technology have been also highlighted.
RESUMO
The method of optical wedge revealed that the optimum temperature for compatibility of hexakis(4-acetamidophenoxy)cyclotriphosphazene (ACP) and DER-331 epoxy resin is in the range of 220-260 °C. The interdiffusion time of components at these temperatures is about 30 min. The TGA and differential scanning calorimetry (DSC) methods revealed the curing temperature of 280 °Ð¡ for this composition. IR spectroscopy confirmed that the reaction between the resin and ACP is completed within 10 min. According to the DSC data, a glass transition temperature of 130 °Ð¡ was estimated for the cured resin. Combustion test UL-94 demonstrated that the obtained material can be assigned to the fireproof category of V-0. Burning droplets were not formed during the burning. The coke formed during the combustion of samples possessed a dense and porous structure. The shape of pores is closed, while their size is in the range of 0.2-200 µm.
