Mechanical, Diffusion And Degradation Properties Of Blends Of Cellulose And Recycled Low Density Polyethylen

ABSTRACT

Recycled Low Density Polyethylene waste pollutes the environment since it is nonbiodegradable. This work investigates the enhancement of disposal of these wastes without compromising their tensile strength and permeability by blending Recycled Low Density Polyethylene with Cellulose. Injection molded blends of Recycled Low Density Polyethylene and Cellulose were prepared in percentage ratios of 100:0, 95:5, 90:10, 85:15 and 80:20. Dynamic mechanical analysis, creep, diffusion, thermal degradation and biodegradation measurements were carried out on the molded samples. The dynamic mechanical analysis was carried out in the frequency range from 1 to 30 Hz and at a temperature range from -30 °C to 90 °C. Three relaxation processes namely; α, β1 and β2 were observed. The α process is assigned to large scale chain motion where as β1 and β2 suggest lamellae shear of two different thicknesses. The intensities of the processes decreased with increase in cellulose loading whereas the temperature shifts were not observed. Creep testing and creep recovery testing were carried out at 30 °C, 40 °C, 50 °C and 60 °C by applying a constant stress. Creep strain increased moderately with increasing loading intakes. Incorporation of cellulose decreased recovery. The time- temperature superposition principle was applied to predict the long term (108 s) creep behavior. Deformation behavior follows WLF law suggesting that free volume plays a crucial role. The influence of water environment on the sorption characteristics of RLDPE-CEL blend was studied by immersion in water at room temperature. The effects of cellulose loading on the sorption behavior were also evaluated. Water uptake was found to increase with cellulose loading. Weight change profiles for the blends at room temperature indicated that the diffusion is Fickian. Diffusion coefficients increased with cellulose intake. Thermo-gravimetric analysis (TGA) was carried out on the blends using Lindberg Blue tube furnace (TF 55035C-1) from 80 to 620 oC at a heating rate of 5 oC/ minute. The decomposition trend shifted from one stage to two stage with increasing cellulose intake. Biodegradation was determined by burial technique. After designated times, the degraded sheets were taken out of soil, rinsed carefully with water, and then dried at 50 ºC until the consecutive weights obtained were the same. The models of analysis for DMA and Creep data were VFT and WLF respectively. Thermal degradation data was analyzed using Arrhenius laws while Fick‟s laws were used in diffusion measurements. Biodegradation was enhanced with cellulose intake thus the composites can be adopted by policy makers to minimize environmental pollution.