Cushion performance of eco-friendly natural rubber latex foam composite with bamboo leaf fiber for impact protection of guava

Abstract

This study investigated the performance of an eco-friendly cushion foam net comprised of natural rubber latex and bamboo leaf fiber. It compared this innovative BambooLatex foam net (thickness of 2.52 and 3.57 mm) with a commercial expanded polyethylene foam net (EPE) (thickness of 5.85 and 7.30 mm) as well as a control group with no cushioning. Key cushioning properties including thickness, mass, modulus, compressive strength, damping coefficient, and energy absorption were investigated. To assess cushion performance was conducted a simulated impact test involving guavas dropped from varying heights (200, 300 and 400 mm). The impacted fruits were subsequently stored at 20 ºC and 75% relative humidity for 4 days. During this period, we monitored bruising development using an image analysis technique, evaluating bruise area, fractal dimension, and grayscale as fruit quality parameters. Our findings indicated that thicker cushions offered superior protection, exemplified by the 7.30 mm EPE. However, the cushion material's damping coefficient and energy absorption capacity significantly influenced its ability to reduce impact energy. This resulted in the thinner BambooLatex foam net performing comparably to the EPE foam net. All cushion treatments significantly reduced impact bruising of guava fruit to less than 2% of the bruise area) as compared to the control (4–7% of the bruise area). There was no significant difference in fractal dimension and grayscale values among the four cushioning treatments. The bruise area parameter was recommended as it gave a better resolution for classifying impact fruit bruising severity in the cushion study. Ongoing developments are aimed at further reducing the weight of the eco-friendly natural rubber latex cushion and incorporating additional active functions.