"Evaluation of plywood properties made using modified starch as environmental friendly binder. "

Common resin system used in wood-based panel preparation was
formaldehyde-based glue where they were believed to have fatal effects towards
environment and human’s health due to the release of free formaldehyde. The
objective of the study was to qualify and evaluate physical and mechanical properties
of experimental plywood made using sodium hydroxide (NaOH) and hot water
gelatinized glutardialdehyde modified starch as environmental friendly binder.
Plywood were manufactured using 10%, 20% and 30% of glutardialdehyde
percentages based on weight of starch. For physical testing, the range value of density
was 0.34 g/cm3 to 0.38 g/cm3, moisture content was 19.34% to 23.67%, water
absorption was between 24.56% to 71.60%, and thickness swelling between 1.18% to
7.27%. Plywood using NaOH gelatinized glutardialdehyde modified starch binder has
higher density, lower moisture content which are advantages for this type of plywood.
In mechanical testing, it has been found that plywood using NaOH gelatinized
glutardialdehyde modified starch binder has overall higher strength compared to
plywood using hot water gelatinized glutardialdehyde modified starch binder, in terms
of bending strength (MOR and MOE) and tensile shear strength. Range value of MOR
was between 124.88 N/mm2 to 179.32 N/mm2, MOE between 8027.50 N/mm2 to
10603.90 N/mm2, and tensile shear strength between 651.64 N/mm2 to 1385.16
N/mm2. It is also found that highest glutardialdehyde:starch ratio which is 30% of
glutardialdehyde used based on weight of starch in environmental friendly binder
produced showed better overall plywood physical and mechanical properties. The
results showed that glutardialdehyde modified starch can be used as an alternative
binder in plywood manufacturing.