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.

Chitosan foams with promising mechanical properties, heat-insulating ability, and flame retardancy were produced through oven drying. The chitosan foams were reinforced with cellulose, boric acid, and different ratios of activated carbon. The foams showed desirable low density (80.2 to 109.8 kg/m3) and compression properties. The compression resistance and compression modulus of foams ranged between 53.6 and 98.5 KPa and 214 to 394 KPa, respectively. Thermal conductivity tests revealed that the foams endowed low thermal conductivity values (0.035 to 0.051 W/mK). The limiting oxygen index (LOI) of the foams was as high as 32.9% for activated carbon (20 g/L). The activated carbon reinforcement produced higher thermal properties and decreased the mass loss 48.1% at 600 °C. The produced foams exhibited good biodegradability (39% degradation in 15 days). The overall test results showed that the chitosan foams can be utilized as a promising environmentally friendly material in thermal insulation fields.

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/cm 3 -0.21 g/cm 3 ) 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.

In this work, rigid foams designed and manufactured using the freeze drying technique were made from polyvinyl acetate (PVAc), bleached kraft pulp and unbleached kraft pulp. The rigid foams designed as an environmentally-friendly product with no pentane or hydrochlorofluorocarbon included in the manufacturing process. The PVAc based foams were reinforced with different kraft pulp contents. Their performance properties such as compressive and flexural strength, physical and morphological properties were investigated according to relevant standards. The foam densities ranged from 0,017 g/cm 3 with %17,65 coefficient of variation (CV) to 0,137 g/cm 3 with %2,33 CV. The compression resistance was found between 0,001 N/mm 2 with %50,00 CV and 0,03 N/mm 2 with %5,98 CV. The flexural resistance was found between 0,005 N/mm 2 with %20,00 CV and 0,11 N/mm 2 with %6,06 CV. Optimum properties were observed at B-4 (PVAc/ Bleached Kraft pulp 1/0.8). Bleached kraft pulp reinforcement gave better results on performance characteristics of foam materials compared to unbleached kraft pulp reinforcement. Overall test results showed that the PVAc based rigid foams have promising results.

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