Optimal Process Parameters of the Binder to Reduce Air Pollution and to Improve the Emission Effect from Composite Production

Abstract

Today the prepreg technology for the manufacture of products from polymer composite materials is widely used in the global industry. This technology involves the use of prepregs obtained by preliminary impregnation of the reinforcing materials with binder solutions, which contain up to 50% environmentally sensitive and fire hazardous solvents. However, in many cases no systematic approach is used to solve the issues of choosing the optimal values of the solvent content in the binder solution to ensure its specified viscosity according, as well as the issues of safety of the industrial activity; instead, these issues are solved independently. It results in the unreasonable expense, loss of quality of the composite products and insufficient level of safety of production activity at the relevant workplaces. This study deals with the systematic prediction of the process parameters, taking into consideration the safety of operational procedures during the impregnation of prepregs and permissible range of deviations from their regulated value. The method and the relevant implementing technique for the prediction of optimal process parameters of the binder solutions for impregnation of prepregs in view of safety of the production activity have been developed. Dependences of the viscosity of the binder on its temperature and volume content of one-component, binary and three-component solvents have been obtained, with the tolerance band specified for the volume and weight contents of the solvent in the binder, which provides an acceptable deviation in the solution viscosity for the effective impregnation of prepreg. The paper proposes and substantiates the criterion of content of the binary solvent in the binder being optimal one in terms of process conditions. This criterion provides both the specified quality of impregnation of the reinforcing material and requirements for the safety of production activity. The actual hands-on examples are considered as related to the determination of optimal content of the binary solvent with the components for the specific binder and alcohol-acetone solvent. It is shown that the optimal weight concentration of acetone in the solvent is 0.085, with the solvent weight content in the mixture of 0.279. These parameters provide the maximum allowable concentration of solvent vapors, ensuring the safety of production activity. It should also be noted, that the solvent weight content differs by maximum 5% from the value required when using alcohol only, which provides high safety margin of the production activity.