Page 36 - KVIS Book

PHY01I

Measuring Thermal Conductivity and Young’s Modulus of
Glue-Bound, Compressed, Paper-Based Slabs

Thanapong Sommart, Pasuthorn Mitanee, Ekwarin Techapongkul
Kamnoetvidya Science Academy, Thailand
Supervisor: Kriangkamon Sawangsri
Email: 5900014@kvis.ac.th

This research aims to study two properties - thermal conductivity and Young’s modulus
of elasticity - of the multilayer paper slabs made by a simple compression. Two sets of
experiment are conducted with bound and compressed paper slabs, which have
different thickness, have different latex adhesive ratio, and undergo different
temperatures. For measuring the thermal conductivity of the material, the material is
used to create an air container, the container is then heated to raise the temperature
of the air inside, then a thermocouple is inserted in the container to measure how
quickly the air cools, then the characteristics of the measured graphs are analyzed to
calculate the thermal conductivity. The containers created are a 4-paper thick and 16-
paper thick box, but the calculated thermal conductivity are very different when they
-3
-3
-3
-3
should be the same (2.1 x 10 ± 0.2 x 10 W/m.K and 9.9 x 10 ± 0.5 x 10 W/m.K,
respectively). The difference is from the material’s anisotropy and also the fact that the
heat convection from air near the surface is not considered. The reliable results are the
measured heat transfer coefficients, which are at 5.1 ± 0.3 W/m²K and 5.7 ± 0.3 W/m²K
respectively. However, the values are smaller than expected because the extra air layer
that is trapped by the covering aluminum foil. For studying the modulus of the slabs,
they are made into rectangle slabs and are treated as solid beams. The moduli are
found by using the three-point bending method and a concept of beam deflection. The
procedures are repeated for the beams undergoing 25°C, 65°C, 145°C, and 225°C
respectively. According to the results, greater thickness, temperature, and adhesive
ratio increase the modulus of paper beams, and the condition which provides the
greatest modulus is thickness of 14 sheets under the temperature of 225°C, with the
adhesive ratio 2:1. However, its modulus appears to be 0.170 ± 0.001 kN/m², which is
hugely distant from the expected value of approximately 10 GPa. This may be due to
the fact that the characteristics observed are outside the proportionality range of the
material.