Melt flow Index (MFI) analysis of sago based thermoplastic starch blend with polypropylene and polyethylene

Abstract

Eco-friendly plastic different from conventional plastic made from petroleum because it can be decomposed naturally. It is one of the solutions provided to reduce conventional plastic waste which harmed environment. Sago starch can be synthesized to become eco-friendly plastic. In order to be printed, thermoplastic starch should be mixed with polyethylene (PE) or polypropylene (PP) in a certain ratio. To maintain the ability to decompose, adjustment of the amount of PE/PP added need to be carefully done. Molding ability will be depending on Melt Flow Index (MFI), hence it is one of the critical aspect on plastic industry. In this research, we analyzed the effect of addition of polyethylene/polypropylene on the eco-friendly plastic’s melt characteristic and advice the molding technique suitable according to the MFI obtained. Thermoplastic starch was blended with polyurethane prepolymer from polyols and methylene diisocyanate. Polyol used were palm oil and castor oil based. Chitosan used as additive to improve the strength of plastic as well as an anti-bacterial agent. As the result, MFI of thermoplastic blend with polypropylene was 10.9 ± 0.1 gr/10 min, while for thermoplastic with polyethylene was 13.5 ± 0.1 gr/10 min. Those values improved significantly from the result obtained for MFI of thermoplastic only. Thermoplastic synthesized from palm oil based polyol and castor oil based polyol without blending with polypropylene/polyethylene have MFI index of 2.4800 ± 0.1237 gr/10 min and 0.5616 ± 0.0460 gr/10 min, respectively. MFI of thermoplastic starch blend with polypropylene/polyethylene obtain have showm the most suitable molding technique was injection molding.