=+J. of Materials Science Letters, 1996: 1343–1345).

The factors studied were the ratio of PP to LLDPE and the amount of red mud particles (in parts per hundred parts of resin). The levels at which these factors were studied are given in the following table:

Lower level Upper level PP/LLDPE ratio .25 4 RM particles 4 10 Composites made with each combination of factor levels were strength tested, with the following results:

Strength

(in MPa)

PP/ Repli- RepliLLPDE RM cation cation Run ratio particles 1 2 1 4 10 19.3 20.2 2 .25 10 8.1 9.7 3 4 4 20.3 24.5 4 .25 4 10.4 11.8