No abstract

This research compared three methods for producing and processing nanocomposite polypropylene filament yarns with permanent antimicrobial efficiency. The three methods used to mix antimicrobial agents based on silver nano particles with PP were as follows: 1) mixing of PP powder and inorganic nanocomposite filler with the appropriate concentration using a twin-screw extruder and preparing granules, 2) method 1 with a singlerather than twin-screw extruder, and 3) producing the masterbatch by a twin-screw extruder and blending it with PP in the melt spinning process. All pure polypropylene samples and other combined samples had an acceptable spinnability at the spinning temperature of 240 o C and take-up speed of 2,000 m/min. After producing as-spun filament yarns by a pilot plant, melt spinning machine, the samples were drawn, textured and finally weft knitted. The physical and structural properties (e.g., linear density, tenacity, breaking elongation, initial modulus, rupture work, shrinkage and crystallinity) of the as-spun and drawn yarns with constant and variable draw ratios (the variable draw ratio was used to gain a constant breaking elongation of 50%) were investigated and compared, while DSC, SEM and FTIR techniques were used to characterize the samples. Finally, the antibacterial efficiency of the knitted samples was evaluated. The experimental results revealed that the crystallinity reduction of the as-spun yarn obtained from method 1 (5%) was more than that of method 2 (3%), while the crystallinity of the modified as-spun yarns obtained with method 3 remained unchanged compared to pure yarn. However, the drawing procedure compensated for this difference. By applying methods 2 and 3, the drawing generally improved the tenacity and modulus of the modified fibers, whereas method 1 degraded the constant draw ratio. Although the biostatic efficiency of the nanocomposite yarns was excellent with all three methods, the modified fabrics obtained from methods 1 and 2 showed a higher bioactivity.

In this research, investigating the possibility of producing, fiber to fabric processing and also characterization of antibacterial organic/inorganic polypropylene (PP) filament yarns for permanent antimicrobial efficiency has been presented. The development of bacteriostatic filament yarn has been realized from mixing of virgin PP granule and various blending contents of silver/zinc-concentrated masterbatch. After producing as-spun filament yarns by a pilot plant melt spinning machine at the take-up speed of 2,000 m/ min, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Tenacity and modulus of modified as-spun and drawn yarns were significantly higher than the pure PP. The investigation of antimicrobial activity showed a high percentage of biostatic efficiency on the modified samples.

In this research, possibility of producing and processing antibacterial organic/inorganic nanocomposite polypropylene filament yarns for permanent antimicrobial efficiency has been investigated. First PP powder and inorganic nanocomposite filler were mixed in a twin screw extruder and modified masterbatch was produced. Continuous filament yarn was made by a pilot plant melt spinning machine from the blend of PP granule and various blending contents of the prepared masterbatch. Pure PP and all other combined samples showed acceptable spinnability at the spinning temperature of 240 o C and take-up speed of 2000 m/min. After producing as-spun filament yarns, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and also tensile and crimp properties of textured yarns were evaluated. Moreover, the DSC, SEM, FTIR techniques have been used for characterization of samples. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified drawn yarns has reached to 5 %. The observed improvement in the tensile properties of modified as-spun yarns compared to the pure PP was significant. Drawing process improved generally the tensile properties of as-spun yarns. Tensile properties of modified textured and drawn yarns were higher than the pure PP. An optimum of antibacterial activity has been observed in the sample containing 0.75 wt% of nanofiller. It is interesting that the optimum of tensile properties has been also obtained for the sample with maximum bioactivity.

Summary: In this research, the possibility of producing and processing nanocomposite polypropylene filament yarns with permanent antimicrobial efficiency has been assessed by comparing two different methods. Therefore two approaches were used to mix various blending contents of antimicrobial agents based on silver/TiO 2 nano particles with PP: 1) mixing of PP powder and inorganic nanocomposite powder as an antibacterial agent with the appropriate concentration in a twin screw extruder, preparing modified granules and feeding them to the melt spinning machine, 2) producing masterbatch by a twin screw extruder and blending it with PP in the melt spinning process. In both methods, pure PP and all other combined samples had an acceptable spinnability at the spinning temperature of 240 8C and take-up speed of 2000 m/min. After producing as-spun filament yarns by a pilot plant melt spinning machine, samples were drawn, textured and finally weft knitted. Physical and structural properties of as-spun and drawn yarns with constant and variable draw ratios were investigated and compared. Moreover, the DSC, SEM and FTIR techniques have been used for samples characterization. Finally antibacterial efficiency of knitted samples was evaluated. The experimental results indicated that the maximum crystallinity reduction of modified as-spun yarns reached 5%. But by applying method 2 (masterbatch), crystallinity of modified as-spun yarns remained unchanged compared to pure yarn. However, drawing procedure has compensated this difference. By applying the second method, the drawing generally improved the increase of tenacity and modulus of modified fibers, whereas in method 1 the opposite effect was noticed in the case of constant draw ratio. Although the biostatic efficiency of nanocomposite fibers was excellent in both methods, modified fabrics obtained from method 1 showed higher bioactivity.