Page 104 - rise 2017

Preparation of Rice Husk Fibers
Rice husks were washed under running tap water for 5 to 10 minutes. The washed rice husks were
then sun-dried until dried. The completely dried rice husks were then grinded into smaller pieces by
using a dry blender. After that, it was grinded once again by using a normal blender. The blended rice
husk was then dried in the drying over at the 80°C for 1 hour. The dried rice husks were then sifted in
order to obtain finer particles.

Preparation of Biodegradable Foam
The starch-rice husk fibers (RHF) were prepared as described by [10] with slight modifications. To
prepare each formulation (Table I), the indicated starches were mixed with 100 mL of water for 10-15
minutes with a magnetic stirrer and were added with RHF and glycerol. The mixtures were stirred
until the solution becomes homogenized. Then, the mixtures were poured onto tray and baked using
oven at 250°C for 5 minutes. Finally, trays were removed from the oven and cooled for 3 minutes at
room temperature before characterization of their physical and mechanical properties.

Table I
Composition of RHF reinforced starch-based foams
Formulation Tapioca Starch (g) RHF (g) Glycerol (g)
1 98 0 2
2 90.5 7.5 2
3 88 10 2
4 83 15 2
5 73 25 2
6 68 30 2
7 58 40 2
8 48 50 2

Physical Analysis
Foam Thickness: Before testing, material thickness was measured by a digital Vernier caliper
(Digimatic, Mitutoyo, Japan). For each formulation, the reported value is the average of three
measurements from every 8 tested samples.
Density: Density was calculated as the relationship between weight and volume [4][6][11]. Reported
values were the average of three measurements for each formulation.

Mechanical Test
The tensile strength tests were performed using a Universal Testing Machine brand Shimadzu with a
500 N load cell. The films were cut into dumbbell shape with 20 mm wide and 100 mm long. The
tensile properties were measured at a crosshead speed of 2 mm/min and an initial grip separation of
100 mm. Each formulation was assayed 3 times, and the reported values are the averages of 3 assays.

Soil Burial Degradation Test
Soil burial degradation was performed as described by [12] with a slight modification. Recycled bottle
(pot) with medium size were cut half and filled with soil taken from a field around Nilai Polytechnic’s
campus (PNS). The samples were cut into 2.0 cm x 2.0 cm pieces and buried in the soil at the depth
10 cm. The pots were placed in an uncovered placed. The soil was kept moist by sprinkling water at
regular time interval to maintain the humidity. The excess water was drained through the hole at the
bottom of the pot. The degradation of the sample was determined at a regular time interval (4 days) by
taking the sample carefully from the soil and washing it gently with distilled water to remove the soil.
The sample was dried in desiccator until constant weight was obtained. Weight losses of the sample
over time were used to indicate the degradation rate of the soil burial test.

The soil burial test was studied by evaluating the weight loss of the film over time. The weight loss
was determined every four days from the starting day, and was calculated using Equation 1:

(Equation 1)