MODIFIKASI PERMUKAAN PRECIPITATED CALCIUM CARBONATE (PCC) DENGAN COATING AGENTS ASAM STEARAT DAN GAMA MERCAPTOSILANE SEBAGAI REINFORCING FILLER PADA PEMBUATAN KOMPON KARET

Precipitated Calcium Carbonate (PCC) is a type of filler which has been developed into semi reinforcing filler. To make this semi reinforcing filler improved to reinforcing type, it needs a treatment in the surface of the PCC filler by giving coating agents. The research aims to gain information on the best process condition in the surface of PCC filler modification process. Also, it aims to identify the completion in modification process in the form of the distribution on particle size, the surface area, and the porosity of filter product. Surface modification process started with eliminating contaminant and level of water in the oven. PCC heating process conducted in the temperature of 100 o C for an hour. The PCC which had no contaminant and fluidized mixed with coating agent in a mixer with 1 � 5% concentration and 75 g of PCC. The researcher used stearic acid (CH 3(CH 2 ) 16COOH)and gama mercaptosilane(HSC 3H6Si(OCH3 ) 3 ) as the coating agents. PCC resulted from coating process was refluidized for an hour to achieve maximum mixing. PCC surface modification process cannot significantly change the parameter of PCC�s total particle surface area, porosity, and particle size distribution. An addition of 1-5% of coating agents will not give a complete coat, only some particles surface will be coated as a more active PCC surface. Which will strengthen the vulcanized rubber. Asam stearat can improve tensile strength, tear resistance and hardness of rubber. Gama mercaptosilane can improve abrasion resistance