The Effect of Sokka Clay on The Tensile and Burning Properties of rPP/Clay Composite Kuncoro Diharjo 1, a , NS Suharty 2,b, AEB Nusantara 3 and Ridwan Afandi 3,c 1 Mechanical Engineering Dept., Engineering Faculty, Sebelas Maret University, Indonesia 2 Chemistry Dept, Natural Science and Mathematics Faculty, Sebelas Maret University, Indonesia 3 Master Graduate in Mech. Eng. Dept., Engineering Faculty, Sebelas Maret University, Indonesia a kuncorodiharjo@ft.uns.ac.id; b nsuharty@yahoo.com; c afandiridwan@gmail.com Keywords: composite, recycled polypropylene, Sokka-clay, tensile properties, burning properties. Abstract: Materials engineering, in order to achieve weight reduction and cost saving, was widely developed using plastic-based composite materials, like polypropylene (PP). As the large consumption of PP, the recycled polypropylene (rPP) was potential for producing rPP-based composites for car body panels. However, it had to have high mechanical and burning properties, and it can be achieved using clay particle as filler, like local clay from Sokka Kebumen Indonesia. The clay particle was made from rejected Sokka tile pocessed using a grinding machine and sieved for several sizes (≤74µm; 74-100 µm; 100-125 µm). The mixure of rPP/clay were pressed using a hotpress for producing the composite and its specimens were tested using Universal Testing Machine and horizontal burning test apparatus, and the fracture surfaces were observed using SEM. The enhancing of tensile and burning properties of rPP/clay composite can be performed by using the addition of Sokka-clay and smaller particle of clay. The rPP/clay composite was competitive with the commercial panel of car interior and potential to be applied as car panel material. Introduction Depletion of petroleum reserves has fueled innovation on vehicles of energy-efficient and alternative-fueled. Some types of hybrid and electric vehicles has been manufactured and used in countries for reducing the fuel consumption, such as smart for two, GEA and prius. Generally, the vehicles have small size, powerless and light weight. The use of lighter materials can reduce the weight of vehicle up to 35% and it will save the fuel consumption between 12-20% [1]. The technology of polymer matrix composite (PMC) has been developed to obtain a light and strong material because its density is lower than metal [2]. The availability of polypropylene (PP), especially recycled polypropylene (rPP), is interesting for producing the rPP based composites . The consumption of polypropylene in Indonesia on 2010 reached 800 ton/year, especially drinking water cup. Some properties of PP are low density, high melting point, ductile, and it can be recycled into new products [3]. For application on vehicle, the PMC has to have high strength and high burning properties. The addition of filler (or clay) are generally aimed at improving physical properties of composites and aim to mix something cheaper than using pure polymers [4]. In addition to increase the strength, the use of clay as filler in composites is also to improve the fire resistant of the composite. As non-flammable material, the clay will be able to be used as fire retardant. The Sokka clay, with major content of Al 2 O 3 (54.59% ) and SiO 2 (19.62%), is capable of acting as a barrier the polymer's interaction with oxygen (O 2 ) as combustion gas [5, 6]. Therefore, it is essential to use the local Sokka-clay, which has high content of Al2O3 and SiO2, as additives in rPP/clay composite to increase the strength and burning properties. It is believed that the compounds (Al2O3 and SiO2) in the Sokka-clay can act as additives on char forming to inhibit the fire. The clay also has special properties where the Sokka-tile produced has higher strength compare the others, especially in Java Island, Indonesia. The use of Sokka-clay, obtained from Sokka, Kebumen, Central Java, Indonesia, also helps tile industries to use their rejected tiles. It is hoped the composite will satisfy the properties of car body panel and reduce the waste of PP. Advanced Materials Research Vol. 1123 (2015) pp 338-342 Submitted: 2014-08-28 © (2015) Trans Tech Publications, Switzerland Revised: 2015-03-25 doi:10.4028/www.scientific.net/AMR.1123.338 Accepted: 2015-04-05 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (ID: 182.253.123.15-12/06/15,15:10:50)