Mechanical, Diffusion and Degradation Properties of Blends ofCellulose and Recycled Low Density Polyethylene
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Date
2013-10-17
Authors
Otieno, George Were
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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·g.o: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; a, PI and P2 were
observed. The a process is assigned to large scale chain motion where as PI and P2 suggest
lamellae shear of two different thicknesses. The intensities of the processes decreased
with increase in cellulose loading whereas the temperature shifts were 110tobserved.
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 ofRLDPE-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. Ther-
.'mo-gravimetric analysis (TGA) was carried out on the blends using Lindberg Blue tube
furnace (TF 55035C-l) from 80 to 620°C at a heating rate of 5 °C/ 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°C until the
consecutive weights obtained ~ere 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.
Description
Department of Physics, 89p. The TP 1180 .P65O8 2013
Keywords
Polyethylene