The effect of various enzyme treatments on the mechanical properties of jute fiber-reinforced polyester composites was investigated in this study. Prior to composite production, jute fabrics were treated with pectinase, laccase, cellulase and xylanase enzyme solutions with varying enzyme mixtures and treatment time according to experimental design. The comparison of NaOH and enzyme-treated samples was also investigated. Jute fabric-reinforced polyester composite samples were produced using compression molding. The effect of enzymatic and NaOH treatment on fibers and fiber-matrix interface was investigated by scanning electron microscopy study. The mechanical properties of enzyme-treated and control (without enzyme treatment) samples were evaluated by means of tensile and flexural tests. It was observed that enzymes destroyed pectin, hemicelluloses and lignin substances from the fiber bundle interface which reduced the technical fiber diameter and hence increased the fiber aspect ratio. Therefore, a greater fiber-matrix interface area was created after enzymatic treatment, which facilitated better fiber-matrix adhesion and improved mechanical properties of the composites. The data indicated that enzyme treatment can be used as an effective, cheap and environmentally friendly fiber modification method for natural fiber-reinforced composite production.

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This investigation deals with the property characterization of polymeric composites from abundantly available and renewable jute fibers. The aim of this article is to explore the possibility of using carpet waste jute yarn for value added fiber-reinforced composite materials and to investigate the physical and mechanical properties of these low-cost composites. Jute yarn was treated with 25 wt% NaOH solution to improve fiber-matrix interface. NaOH-treated jute yarn was crimpier, bulkier, more hairy, and flexible. The investigation of the mechanical properties of composites was performed as a function of yarn type, reinforcement form, matrix type, alkali treatment, and fiber content. For this purpose, the tensile, flexural and charpy impact tests were performed. It was found that composite samples from alkali treated reinforcement had better mechanical properties based on the investigated parameters. SEM analyses showed that alkali treatment improves bonding across the fiber-matrix interface. Jute-epoxy composites showed better tensile and flexural strength in comparison to jute-polyester composites, whereas impact strength of epoxy matrix composites were almost half that of polyester matrix composites. Composites from double ply jute yarns showed better flexural strength. Taking into account the reinforcement form, jute composites from random reinforcement form showed higher tensile strength and modulus. The study strongly suggests that the jute fiber waste-reinforced polymer composite materials are quite capable to serve as a potential cost effective, technologically viable, and attractive substitute to the conventional glass fiber composites.

The effect of thermal properties on the three-dimensional knitted spacer fabrics made from functional fibers (i.e. Outlast®, Coolmax®) with different fiber compositions was studied. The spacer fabrics were specifically designed for mattress ticking applications. Samples were manufactured with two fabric tightness and knit designs, and four Outlast® fiber compositions. Thermal conductivity, thermal resistance, thermal absorptivity, thermal diffusivity, and relative water vapor permeability were considered as thermal comfort properties. Alambeta and Permetest devices were used for the measurement of thermal properties. Fabric design was the leading criteria on the thermal resistance and water vapor permeability, while fiber compositions became more important on the thermal absorptivity. The contribution of Outlast® fiber on the thermoregulatory efficiency of spacer fabrics was analyzed using a differential scanning colorimeter. The thermoregulatory effect of Outlast® fiber was slightly observed in the 33% Outlast® fiber composition. Water vapor permeability of open-skin samples was higher than the closed-skin samples, which was due to the holed/meshed structure of the open-skin structure for the same fiber content and fabric construction. Statistical analysis was also performed and confirmed the contribution of each factor, including their interactions. In particular, the interaction became more significant than the main factors for thermal diffusion behavior of samples.

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