PENGARUH PERLAKUAN ALKALI TERHADAP KEKUATANBENDING KOMPOSIT SERAT RAMBUT MANUSIA DENGAN MATRIK POLYESTER

The purposes of this research are: (1) to find out the effect of Alkali on the bending strength of human hair fibre composite. (2) to find out the time needed on the alkali treatment to reach an optimum bending strength on the human hair fibre composite. This research was conducted in Material Laboratory of Engineering Faculty of Sebelas Maret University of Surakarta. The researcher used human hair fibre and polyester resin 157 BQTN which are added with MEXPO 1% catalyst as the main materials. Human hair fibre composite with variation of alkali treatment those are 0, 30, 60, 90 and 120 minutes was used as the research sample. The composite was made through press molding way with volume fraction ratio between matrix and filler in the amount of 60% : 40%. The composite was made based on ASTM D 790 standard. The results of this research show that alkali treatment give an effect on the bending strength of human hair fibre composite. Hair with longer alkali treatment shows higher bending strength. This is proven by the result of the research that shows the bending strengths without alkali treatment, within 30 minute of alkali treatment and within 60 minute of alkali treatment for each are 34,821 MPa; 38,012 MPa dan 43,679 MPa. Overlong alkali treatment (more than 60 minutes) will break the hair fibre thus it weakens the bending strength. This is proven by the result of the research that shows that the bending strength in 90 minute and 120 minute alkali treatment that is not higher than that reach 31,345 MPa dan 26,869 MPa. The conclution of this research are: (1) The longer of fibre alkali treatment is given, the stronger of bending strength of human hair fibre composite will be got. However, if alkali treatment is given too long (more than 60 minutes) it will decrease the bending strength of human hair fibre composite due to the damage of the hair. (2) The highest bending strength is reached when the alkali treatment up to 60 minutes that shows 43,679 MPa