In this study, foaming-agent free novel polyvinyl acetate (PVAc) foams reinforced with bio polymers were manufactured through freeze-drying technique. The physical, morphological and antibacterial properties of foams which were reinforced with different ratio of zinc borate and water-soluble chitosan were investigated according to relevant standards. The PVAc foams showed low densities (0.12 g/cm3 – 0.21 g/cm3) and high porosity rates (87.50% - 79.05%). The results showed that although the foams have no antibacterial character against Escherichia Coli, they have antibacterial character against Staphylococcus Aureus bacteria. This study mainly focusses on physical and morphological properties of the foams. However, researchers also performed accelerated weathering tests to determine its usability in different industries. The effects of accelerated weathering on the surface of foams were investigated by measuring surface color. The highest color difference was determined 8.09. This foam can be used as a low-density packaging material and/or medical box with its promising physical and morphological properties with hazardous-chemical free structure.

Abstract: 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 (Tonset 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 Tonset 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, Tonset and T%50 of chitosan- microcrystalline cellulose aerogels found promising.

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.