In this study, engineering thermoplastic composites were prepared from natural fiber blend-filled nylon 6. Natural fiber blend from a mixture of kenaf, flax, and hemp fibers were added to nylon 6 using melt mixing to produce compounded pellets. The natural fibers/ nylon 6 composites with varying concentrations of natural fibers (from 5 to 20 wt%) were prepared by injection molding. The tensile and flexural properties of the nylon 6 composites were increased significantly with the addition of the natural fiber blend. The maximum strength and modulus of elasticity for the nylon 6 composites were achieved at a natural fiber blend weight fraction of 20%. The Izod impact strength of composites decreased with the incorporation of natural fibers without any surface treatments and coupling agent. The melt flow index (MFI) also decreased with increasing natural fiber blend loading. The results of tensile and flexural modulus of elasticity (FMOE) are in accordance with the rheological data from the MFI measurements. The increase in the tensile and flexural properties indicated that efficient bonding occurred between the natural fibers and nylon 6. No fiber pullout was observed during the scanning electron microscopic analysis of the fracture surfaces. The higher mechanical results with lower density demonstrate that a natural fiber blend can be used as a sufficient reinforcing material for low-cost, eco-friendly composites in the automotive industry and in other applications such as the building and construction industries, packaging, consumer products, etc. POLYM. COMPOS., 34:544-553, 2013. ª

aThis study describes changes in the viscoelastic and thermal properties of composites made with various percentages (up to 20 wt.%) of a natural fiber blend (a mixture of flax, kenaf, and hemp fibers) and polyamide 6 (PA 6). According to the differential scanning calorimetry (DSC) analyses, the incorporation of natural fibers produced minor changes in the glass transition (Tg), melting (Tm), and crystallization temperature (Tc) of the PA 6 composites. Because of the reinforcing effect of natural fibers, the storage modulus (E') from dynamic mechanical thermal analysis (DMTA) increased as the natural fiber content increased. The E' values at room temperature and Tg were 3960 MPa and 1800 MPa, respectively, with the incorporation 20 wt.% fiber, which were 68% and 193% higher than the E' value of neat PA 6. As the natural fiber content increased, the thermal stability of the composites decreased, and thermogravimetric analysis (TGA) showed that the onset temperature of rapid thermal degradation decreased from around 440 (neat PA 6) to 420 °C (20 wt.% natural fiber blend). The addition of 20 wt.% single type fibers showed comparable DSC and TG results to the incorporation of 20 wt.% natural fiber blends.

This study is aimed to develop an eco-friendly wood stained extracted from beetroot (Beta vulgaris) and determine the color stability of this stain to UV light irradiation. Natural dyestuff were extracted from beetroot by ultrasonic-assisted method and prepared from aqueous solution with ferrous sulphate, aluminum sulphate, copper sulphate and vinegar mordant mixes. Scots pine (Pinus sylvestris), oriental beech (Fagus orientalis), oak (Quercus petraea) and walnut (Juglans regia) wood specimens were used for the study. After treatment with stain, wood specimens were exposed to UV irradiation for periods of 50, 100 and 150 hours. Results showed that the color change values for all wood specimens colored with beetroot extract had better performance compared to synthetic dye. Beetroot extracts may be used as an upper surface dyestuff for indoor application and toys. Therefore, alternative to synthetic dyes more economical and eco-friendly, wood paints may be developed.

The aim of this research was to investigate the effect of the microcrystalline cellulose reinforcement on some physical, mechanical, thermal, and morphological properties of the chitosan aerogels. The bio-based chitosan aerogels were produced using chitosan as a matrix and the microcrystalline cellulose as a reinforce material through the freeze-drying method. The aerogel suspensions were prepared in five different ratios to investigate the effect of microcrystalline cellulose content. The density, porosity, thermogravimetric analysis, and compressive resistance tests were conducted according to relevant standards. Morphological properties were investigated using a scanning electron microscope. The introduction of microcrystalline cellulose significantly improved the compressive resistance, thermal properties (T onset and T %50 ) of the chitosan aerogels. The optimum performance properties determined as 0,12 MPa for compressive resistance, 0,27 MPa for compressive modulus, 292,45 °C for T onset and 365 °C for T %50 . According to scanning electron microscope images, aerogels showed microporous structure as expected. As a result, the bio-based chitosan aerogels reinforced with microcrystalline cellulose were successfully manufactured. The mechanical and thermal properties including compressive resistance, compressive modulus, T onset and T %50 of chitosan-microcrystalline cellulose aerogels found promising.