Incorporation of Kenaf Core Fibers into Low Density Polyethylene/Thermoplastic Sago Starch Blends Exposed to Natural Weathering

Abstract

The landfill disposal of a high volume of plastics that take a long time to decompose has led to a tremendous environmental problem. Incorporation of natural polymers and fibers into synthetic polymers accelerates the degradation rate by exposure to atmospheric agents such as sunlight, temperature and rainfall. In this work, thermoplastic sago starch (TPSS) and kenaf core fibers (KCF) from agricultural feed stocks were blended with low density polyethylene (LDPE) for natural weathering studies. The melt-mixed and compressed composite sheets had fiber loadings ranging from 0 to 40 wt.%, and were exposed to natural weathering conditions for a period of 3 and 6 months. The deterioration in mechanical, thermal, morphological and weight properties were investigated.

Linear Low Density Polyethylene/Poly (Vinyl Alcohol)/Kenaf Composites: Effect of Natural Weathering on Functional Group, Weight Loss Characteristics, Tensile, Morphological and Thermal Properties

“…Thus, the deformability of the composites declined after weathering. This is similar to the earlier reports by Sarifuddin et al (2014) and Zaaba et al (2015). Figure 6 demonstrates the tensile modulus of LLDPE/ PVOH/KNF composites before, after 3 months and 6 months of natural weathering exposure, respectively.…”

“…Moreover, all peaks (1245, 1144-1056, 990, 898-719 cm -1 ) belong to cellulose, hemicelluloses or lignin of KNF (Harini & Harsojo 2014;Pang et al 2017). As can be seen in Figure 2(b) and 2(c), the peak intensity of C=O (carbonyl group) and OH (hydroxyl group) increased with increasing weathering duration due to the oxidation of composites surface (Badji et al 2017) and KNF being exposed on the weathered composite surface (Sarifuddin et al 2014). In addition, it is obvious that the characteristic peaks of cellulose, hemicelluloses or lignin of KNF decreased with prolonged weathering duration is probably attributed to KNF being detached from the exposed composite surfaces, as shown in the later surface morphology micrographs.…”

“…The degradation of LLDPE/PVOH matrices is due to photo-oxidation that is promoted by the combination of UV radiation and oxygen. Fabiyi and McDonald (2014) and Sarifuddin et al (2014) claimed that the exposure of polymers to UV radiation resulted in chain scission and/ or chain crosslinking due to oxidation of polymers. The absorption of UV radiation by LLDPE/PVOH matrices can probably induce chain scission reaction of the polymer main chain.…”

“…where is the heat of fusion for fully crystalline LLDPE (290 J/g) (Ismail et al 2009) (C-C, C-OH, CH vibrations) and 898-719 cm -1 (CH and CH 2 stretching vibration) (Onggo & Pujiastuti 2010;Pang et al 2016;Sarifuddin et al 2014). Moreover, all peaks (1245, 1144-1056, 990, 898-719 cm -1 ) belong to cellulose, hemicelluloses or lignin of KNF (Harini & Harsojo 2014;Pang et al 2017).…”

“…KNF based polymer composites are being increasingly used in automotive parts such as car door panels, seat back board and door trim due to their light weight, low cost and environmental friendly (Kamal et al 2014;Pai & Jagtap 2015). However, KNF based polymer composites are vulnerable to outdoor environment factors; comprising Ultra-violet (UV) light, temperature, moisture and chemical agents (acids, bases, ozone, organic solvents) (Nechifor 2016;Sarifuddin et al 2014). In regard to this, it is essential to diversify researches on the degradability of KNF based polymer composites under various weathering conditions.…”