Produção e avaliação de desempenho físico-mecânico de fibrocimento produzido com fibras de celulose tratadas a plasma

Abstract

Fiber cements are cementitious matrix composites that have fibers as a dispersed phase, developed to improve the mechanical strength of the ceramic matrix.The use of cellulose fiber in these composites is extremely advantageous since these fibers have high tensile strength, can be easily acquired in nature or reused from agro-industrial waste.On the other hand, the durability of these fibers in the cementitious matrix can be affected by different factors, among which is the mineralization that they may suffer due to the presence of cement hydration products that may migrate inside (lumen).Thus, it was developed in this work the surface modification of pulp fiber bundles (pulps) through of plasma treatment.Sulfur hexafluoride (SF6) was used to increase cellulose hydrophobicity, decrease moisture absorption and improve the physical-mechanical properties of fiber cementand a mixture of hexamethyldisiloxane (HMDSO) / oxygen / argon gas was used, HMDSO being the precursor of the reaction, at different concentrations.This last treatment allowed the deposition of films on cellulose with distinct characteristics that promoted a better matrix / fiber interaction.In general, all the tested treatments allowed some kind of improvement for the extruded fiber cement, being the best mechanical properties, higher MOR and Tenacity, observed in those with silicon in its composition after accelerated aging cycles and better physical properties, lower water absorption and lower porosity, for fiber cement produced surface modified cellulose with 0,30 TorrSF6.