MODIFICATION OF INJECTION MOULDING MACHINE AND COMPARATIVE ANALYSIS OF CARBON NANOTUBE/ HIGH DENSITY POLYETHYLENE NANOCOMPOSITE
MODIFICATION OF INJECTION MOULDING MACHINE AND COMPARATIVE ANALYSIS OF CARBON NANOTUBE/ HIGH DENSITY POLYETHYLENE NANOCOMPOSITE
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Date
2013-05
Authors
GADIMOH, SYLVESTER
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Abstract
An injection moulding machine has been modified for the direct compounding of nanocomposites; the technique involves incorporating automated hopper feeders extruder onto conventional injection moulding machine which automatically feed carbon nanotube (CNT) into a molten stream of matrix in a nano-scale manner so that it is thoroughly dispersed by the action of the shear mixing of the extruder screw directly attached to the feeder and passing the material into the injection barrel where it is further mixed and dispersed before injecting into the mould. Single-walled carbon nanotube /high density polyethylene (SWCNT/HDPE) nanocomposites with several concentrations (0.2, 0.4, 0.6, 0.8, 1 wt %) were compounded using both conventional and the modified injection moulding machine for the purpose of comparative analysis of both compounding systems. A good dispersion of the CNT in the matrix and a good CNT–polymer interfacial adhesion were verified by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The Raman spectral measurements of the characteristic bands of the SWNTs in the sample of the modified injection moulding machine indicate an effective interaction between SWCNTs and HDPE matrix. The rheological percolation threshold of the nanocomposites was between 0.2 and 1 wt% for the nanocomposite from the modified system while 0.8 and 1 wt % was obtained for nanocomposite from the conventional injection moulding (CIM) system. The electrical properties test showed that by using the modified system, a very low percolation threshold was obtained (~0.20-0.4%). In contrast, a higher percolation threshold was obtained for the nanocomposite produced with the CIM (~0.8-1wt %). From the mechanical property analysis, on the overall, there was a good interfacial bond between CNT and HDPE which manifested as appreciable increment of storage modulus and decreasing tendency of loss modulus; this implied good dispersion.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF DOCTOR OF PHILOSOPHY IN FIBRE SCIENCE AND POLYMER TECHNOLOGY
DEPARTMENT OF TEXTILE SCIENCE AND TECHNOLOGY,
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
MAY, 2013
Keywords
MODIFICATION,, INJECTION,, MOULDING,, MACHINE,, COMPARATIVE,, ANALYSIS,, CARBON,, NANOTUBE,, HIGH,, DENSITY,, POLYETHYLENE,, NANOCOMPOSITE