Study of the effect of a diluent on the rheological and technological properties of epoxy composites

   Conditions of agricultural machinery operation necessitate improving the operational characteristics and service life of parts. Polymer composite materials, unlike metals, are not subject to corrosion and have a long service life.

    Research was conducted to determine the influence of the type and concentration of a diluent on the rheological and technological properties of epoxy composites intended for manufacturing the exterior parts of agricultural machinery.

   Special attention was paid to studying the effect of the diluent on the viscosity and microstructure formation of the composite. Epoxy resin ED20 was used as the polymer matrix, and the filler was an emulsion glass mat EMC450-1250-E. Two types of diluents were investigated: inactive (white spirit and solvent 646) and active (DEG-1). The viscosity of the mixtures was measured according to GOST 25276-82 using a rotational viscometer. The porosity of the composite was determined by a multi-parameter microscopy method. The authors studied the relationship between the viscosity of ED-20 epoxy resin and the addition of active and inactive diluents at 5, 10, and 15 wt. %. As a result of the research, the active diluent DEG-1 was selected. An analysis was conducted of the porosity in the composite material based on epoxy resin and glass mat with 5, 10, and 15 wt. % of the DEG-1 diluent. Experimental results showed that the introduction of DEG-1 significantly reduces the resin viscosity, facilitating better penetration into the fibers of the filler. The optimal concentration of the DEG-1 diluent was determined to be 10 wt. %, which provides a 60 % reduction in resin viscosity, uniform distribution in the glass fiber matrix, and minimal porosity in the composite material (30 pores/cm²). For manufacturing polymer composites for exterior parts of agricultural machinery, it is recommended to use the DEG-1 diluent at a concentration of 10 wt. %.

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