Investigation Of Coating Materials On Recycled Polypropilene and Rubber Composite Under * Weather Exposure

Abstract

The recycled polypropylene (rPP) –rubber composite tends to depict the mechanical strength decreasing and physically degradation as well when installed as an outdoor application. The research investigated several materials which they can be applied as a protective coating materialsfor the composite. Oil based paint, waterproof paint, unsaturated polyester, and repoxy resins were selected materials to be examined.The raw materials of the composite were recycled rPP and tire after used in the powder state with mesh of 20 both. The composite consisted of rPP and rubber mixing with volume ratio of 7:3. Pressured sintering process was adopted for producing the composite with main parameters setting of temperature, pressure and holding time were 120 o C, 1 MPa and 5 minutes respectively. The coating materials were sprayed on the composite surface with the thickness could be neglected. The speciments were just layed on the special table during weather exposuring for three months continuously. The investigation included macro and SEM immages and bending test.The result reveals that the color degradation occured on the composite surface without coating after one month exposuring while cracks appear after exposuring takes time of two months and they tend to become propagated until the end of the third month. The SEM immages observation on fracture bending test showsthat the bonding between the plastic and the rubber began to be separated due to the influence of photo-degradation. The fracture are begun after the first month of weather exposuring. The waterproof coating provides the most stable of composite under bending test whereas unsaturated polyester coating has the highest bending strength overall exposuring periodes