Chiang Mai J. Sci. 2004; 31(3) : 233-241
www.science.cmu.ac.th/journal-science/josci.html
Contributed Paper
The Mechanical Properties of Polypropylene / Glass
Fiber Composites Prepared Using Different Samples
Preparation Methods
Abdul M. Ya’acob [a], Salit M. Sapuan* [b], Mansor Ahmad [a] and Khairul Z. M. Dahlan [c]
[a] Advanced Material Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia,
43400 Serdang, Selangor,Malaysia.
[b] Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400
Serdang, Selangor, Malaysia.
[c] Radiation Processing Technology Division, Malaysian Institute for Nuclear Technology Research,
Bangi, 43400 Kajang, Selangor, Malaysia.
*Author for correspondence, e-mail : sapuan@eng.upm.edu.my
Received : 2 February 2004
Accepted : 24 August 2004
ABSTRACT
Experimental study was carried out to investigate the mechanical properties such as tensile
strength and modulus of polypropylene/glass fiber composite materials prepared using injection
molding and compression molding. In the initial stage the samples with 5, 10 and 15 wt %
glass fiber loading were compounded using a single screw extruder before undergoing injection
and compression molding process. Results show that the tensile strength decreased with the
increasing of glass fiber loadings which are attributed to the absence of adhesion between
polypropylene and electrical type glass (E-glass) due to the difference in polarity between
polypropylene and the hydroxyl groups on the fiber surface. Tensile modulus increased with
increasing of glass fiber loadings but the maximum value seemed to be very low, i.e. in the
order of 500 MPa. In terms of fiber length, the samples prepared by using a 12 mm fiber
showed higher tensile modulus and strength particularly at higher fiber loadings compared to
samples prepared by using 3 mm or 6 mm fiber length but these results did not reveal anything
significant because of the absence of adhesion between fiber surface and polypropylene matrix.
Keywords : compression mold, injection mold, polypropylene/glass fiber (PP/GF) composite.