The Malaysia’s tropical climate is extremely favourable for the production of various type of unique fruits and vegetables as well as or palm oil and paddy. This country is seldom affected by hurricane or other natural disaster. Malaysia has a wetness level of 90% due to its location which is near to the equator. The weather is hot and wet throughout the year which are appropriate for several sort of agriculture such as rubber, oil palm, and rice. Hence, there’ll be a waste from agricultural production which might cause the hazards resulting from burning it or leaving it to deteriorate in the field. So, the application of waste material from agricultural production operation will assist in reducing some waste management issues.
Rice straw is an agricultural waste which may perform as a raw material source for building material. Straw is defined as a stems or stalks of certain agricultural product which can get from cereals especially wheat, rice, barley, oat and rye. When cereal crops are processed after harvest a variety of “by-products” are created, every cereal crops containing variable quantities of chaff, straw, and weed seeds, as well as some grain (Hilman, 1981). Same goes to the rice straw. Rice straw could be a low-value material, renewable nature of straw, easy to find and even appropriate for building material. In the making of rice straw building material, their physical, mechanical, thermal insulation and chemical properties are should be considered.
The term thermal insulations refers to material that used to reduce the rate of heat transfer, or the ways and processes used to reduce heat transfer. Thermal insulation can keep an enclosed area such as building warm, or it can keep the inside cold. Rice straw are tend to be fascinating interesting material as the filler in biodegradable polymer composites, due to its good thermal stability compared to other agricultural residue (Lee SY, 2004a).
Straw bales provide a decent thermal insulation values of 0.067 W/mK that abundant less than the wood and other building raw material (Goodhew and Griffiths, 2005). Most studies dealing with insulation material (cork, bark, rice straw, hemp, etc.) shows that the low densities between 170 kg/m³ and 260 kg/m³ and low thermal conductivity coefficients between 0.0475 W/mK and 0.0697 W/mK. (Kain et al., 2013; Wei et al., 2015; Ali and Alabdulkarem, 2017). Besides that, an experiment of low density boards with a mix of wheat straw and corn pith of has been done. Different experiment has been done shows that the bale density ranges from 54.6 kg/m³ -78.3 kg/m³ for barley straw bales and 81 kg/m³ – 106.3 kg/m³ for each oat and wheat straw bales (Watts et al., 1995). Furthermore, another experiment has been done and the results shows that the equilibrium wetness content is not affected by the density of the sample. The results also shows that the thickness swell is larger than linear growth because of the orientation of fibres, parallel to the faces board (Wang, D. Sun, 2002).
In this paper, the investigation of this experiment are going to be done to seek out the effect of heating of rice straw board using hot-press, rice straw board density, rice straw board particle size and ambient temperature on the properties of the rice straw as a thermal insulation board. Besides, this experiment will also determine whether or not the rice straw thermal insulation board tend to be interest for energy saving for purposes when it is used in building insulation material.
1.1 PROBLEM STATEMENT
Brick is a core material that is commonly used to build the wall of building especially in Malaysia. At present, brick defects are usually found in buildings. This problem is getting more serious from time to time. Not everybody knows that in brick making use a very high energy consumption and can cause environmental pollution as wall materials have major impact on the building development. There are various ways should be taken to develop a new eco-friendly building material to protect nature from being pollute and to overcome the energy consumption. One of the ways to protect the nature is to produce an insulating material by using agriculture waste product or in other words from renewable resources such as wheat straw, oat straw and others. These agriculture waste have their own advantages as a thermal insulating material due to their hollow structure, low density and have a great characteristics of heat insulation. Furthermore, the uses of straw not only solve the problem of straw as a waste product but is also help the building to be more comfortable during summer so that it fits with Malaysia’s weather. So, an investigation will be carried out to develop the rice straw’s ability to become a new thermal insulation material. Previously, there was an experiment were carried out using thermo-pressed straw-based thermal insulation due to its simple and efficient production process. This experiment used methylene diphenyl diisocyanate resin. However, the experiment took a very long time to prepare thick insulation materials by traditional platen-pressing process. Therefore, to improve the rice straw thermal insulating properties and efficiencies, a hot-press machine is developed to consolidate the board and cure the adhesive. Besides, density profile were generated during hot-press.
The following objectives is made in order to achieve the target of this project:
To produce the thermal insulation board from rice straw material using hot-press.
To develop a suitable test for the rice straw board using mechanical and physical properties.
1.3 SCOPE OF STUDY
The scope of the experiment is listed as below:
The percentage of the mixture of the rice straw that will be used in the composite is 100%.
To test the rice straw thermal insulating board, hot-press machine will be used to consolidate the board and use certain temperature which is between 110 °C to 150 °C.
The experiment will be carried out to test three different types of mechanical test to prove the mechanical and physical properties which is tensile test, hardness test and thermal conductivity test.
In this experiment, there will be 5 samples of rice straw boards named A, B, C, D and E have same dimension which is 4 mm × 4 mm respectively were made by the same maximum applied pressure, 5 MPa and different temperature in the process of forming and drying. 5 different level of heating temperature will apply on the rice straw board which are 110 °C, 120 °C, 130 °C, 140 °C and 150 °C. Table 1 shows the experimental condition in the making of rice straw board in this experiment.
Board Name Rice Straw Length (mm) Maximum Pressure (MPa) Temperature
(°C) Pressing Time
A 4 5 110 100
B 4 5 120 200
C 4 5 130 300
D 4 5 140 400
E 4 5 150 500
Thermal Conductivity Test
3) Expected Analysis
Effect of high frequency heating on the properties of rice straw board
The experiment will seek out to find the relationship between the pressing times towards the rice straw board and the different heating temperature using hot-press machine. The expected result will be based on the graph :
Figure 1.1: Effect of high frequency heating on the properties of the rice straw board
Effect on board density on of rice straw board
The experiment will seek to find the relationship between the rice straw board density and the thermal conductivity of the rice straw board. The expected result will be based on the graph :
Figure 1.2: Effect of board density on thermal conductivity of rice straw board
Effect of the stress-deflection of the rice straw board
The experiment will seek out to find the relationship between the effect of the stress towards the rice straw boards and the deflection of the rice straw board. The expected result will be based on the graph:
Effect the hardness test of the rice straw board
The experiment will seek out to find the relationship between the hardness of the rice straw board and the tensile strength properties. The expected result will be based on the graph: