Preparation and Characterization of Polyester Composites Reinforced with Bleached, Diospyros perigrina (Indian persimmon) Treated and Unbleached Jute Mat

Chowdhury Kaiser Mahmud1*, Md. Asanul Haque1, AM Sarwaruddin Chowdhury1, Mohammad Abdul Ahad2 and Md. Abdul Gafur3 1Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Bangladesh 2Department of Chemistry, Faculty of Science, University of Chittagong, Chittagong, Bangladesh 3Department of Pilot Plant and Product Development Center, Bangladesh council of Scientific and Industrial Research, Dhaka, Bangladesh


Introduction
Natural fiber-reinforced composites have attracted great research and economic interests because of their outstanding 'green' characteristics compared with glass fiber-reinforced composites [1]. But the superior resistance of glass fibers to environmental attack made glass-fiber-reinforced polymers more attractive for marine products and in the chemical and food industries [2][3][4][5]. On the other hand, the manufacture, use and removal of traditional composite structures usually made of glass, carbon and aramid fibers are considered critically because of growing environmental conscious [6,7]. Scientists have been faced with the difficult challenge of lowering the human impact on their surroundings while maintaining or even bettering the quality of life. The potential environmental and economic benefits of using natural renewable resource based materials have therefore, led to increased interest in the development of novel bio-composite materials. As a result, lingo cellulose fibers which are a natural fiber have been identified as a potential substitute for commonly applied man made synthetic fibers in the preparation of composites due to their lightweight, low cost, no hazardousness, biodegradability, renewability and above all environmental friendly characteristics [8][9][10][11][12][13][14]. However, some of the infirmities of natural fiber such as wet ability, noncompatibility with some polymeric matrices, low thermal stability, and hydrophilic nature of fiber surface, poor adhesion with the matrices and swelling and maceration of the fibers due to moisture absorption have prevented complete replacement of synthetic fibers. But the scientific and industrial path of Fiber Reinforced Polymer (FRP) composites was successful primarily because these materials was able to offer structural efficiency and strength to weight ratios over traditional materials such as metals, plastics and wood. Cellulose fibers from kenaf, hemp, ramie, flax, sisal, coir and jute are also being used as reinforcement and they have some advantages over synthetic fibers such as low abrasion, multi

Abstract
In this research work, jute mat reinforced polyester matrix composites have been developed by cold compression molding technique with varying process parameters, such as fiber condition (untreated, bleached and Indian persimmon juice treated). The developed jute fiber reinforced composites were then characterized by tensile test, flexural test, water absorption test, IR spectroscopy, thermal test and scanning electron microscopy. The results shows that tensile strength, flexural strength and value of elastic modulus increases in case of treated and bleached jute mat in compared to untreated fiber. The highest change in tensile strength, flexural strength and elastic modulus has been observed for bleached jute mat-UPR composite which means that the bleached jute mat-UPR composite is stronger than the other two. The water absorption property for the bleached jute mat-UPR composite is the lowest than the other two. The bulk density value shows that the bleached jute mat-UPR composite is denser than the other two. The thermo gravimetric analysis and thermo mechanical analysis also show that the bleached jute mat-UPR composite is more thermally and thermo mechanically stable. Microscopic observation suggests that the fracture behavior is brittle in nature and maximum fiber pull out has been occurred for unbleached jute mat-UPR composite. functionality, low density, low cost, unlimited availability and no waste disposal problems which encourage their applications in composite. One of the vastly available natural fibers is jute which is frequently used as reinforcing agent because it is non-abrasive, has low density and high strength. Jute appears to be a promising material because it is relatively inexpensive and commercially available in the required form. It has higher strength and modulus than plastic and is a good substitute for conventional fibers in many situations. Jute composite can be used as particleboard, ceiling, blocks for building construction and furniture.
There are several key factors that serve as a motivation for me in the development of bio-composite materials. Firstly, bio-composite materials offer high strength and stiffness at lighter weights than most traditional materials such as metals, glass fiber reinforced polymer (GFRP) composites and wood products. The seemingly endless supply of agricultural resources to serve as feedstock for bio-composite materials also allows for lower costs and makes them less subject to economic fluctuations. From an environmental and sustainability standpoint, bio based composites from renewable resources are superior to traditional FRP composites as they do not contribute to the depletion of the world's natural resources, require less energy and chemicals to produce [15][16][17][18], emit less greenhouse gases and toxins during their production, use and disposal [16,17] and have the potential to be biodegradable, recyclable or used for energy harvesting upon incineration [15,17].
In this research work, several experimental works were done on three different composites as well as comparative studies on the experimental works were done to find the best reinforcing agent for making a convenient composite.

Materials and Methods
The raw materials for preparing the samples were unsaturated polyester resin (UPR), Monomer (Styrene), Jute mat, juice of Diospyros perigrina (Indian persimmon) and Hardener (Methyl ethyl ketone peroxide). The three different types of composite specimen are then prepared by the following way- For water intake measurement, the specimen was prepared according to ASTM-D570-98.The test specimen was 76 mm length, width above 25 mm.
The total water absorption was calculated following the rules given below.
Absorption %=100 (W s -W d )/ W d Where, W d = Conditioned weight of the specimen, W s =Saturated weight of the specimen after submersing in distill water.
Tensile specimen was prepared according to ASTM-638M-91a. Thermal analysis of the specimen includes a group of techniques where some physical property of the sample is monitored under controlled conditions with variation of temperature at a programmed rate. When the mass change is monitored the results, which indicated chemical reactions, are called Thermo gravimetry (TG). When heat absorption monitored, the result indicate crystallization, phase change etc. as well as reactions. This is called Differential Thermal Analysis (DTA). Together, they are a powerful method of analysis. SEM analyses have been carried out in the Centre for Advanced Research in Sciences (CARS) situated in university of Dhaka. This is a JEOL JSM-6490LA Scanning Electron Microscopy for image analysis. For SEM analysis, the fracture surface of the three different types of composite need to be analyzed. First the non-conducting samples were treated with powdered platinum for making the sample conductive and then set on a carbon tape for analysis. IR test was done by using Shimadzu IR prestige-21 Fourier Transform Infrared Spectroscopy (FTIR) technique.
Thermo-mechanical analyses of composites were carried out by using an S II-TMA/SS6300 analyzer.

Results and Discussion
From Figure 1   Thermal Analysis (DTA) and Differential Thermo Gravimetry (DTG) curves of bleached, treated and unbleached jute mat-UPR composite respectively. The top (blue) one is the TG, bottom (red) one is the DTG and middle (black) one is the DTA curve. The major degradation occurs in one stage. The lighter substances remove initially and then heavier material removed. Initially, the composites loss their weight due to moisture removal. Figure 2d shows the overall Thermo Gravimetric (TG) curves of bleached, treated and unbleached jute mat-UPR composite. The top (blue) one is for bleached comp., bottom (green) one is for unbleached comp. and middle (red) one is for treated comp. The TG curve reveals that the onset temperature of unbleached, treated and bleached jute mat-UPR composite is 333.4°C, 313.5°C and 307.7°C respectively which means the unbleached jute mat-UPR composite is              and bleached jute mat-UPR composite is 333.4°C, 313.5°C and 307.7°C respectively which means the unbleached jute mat-UPR composite is more thermally stable than the other two. Figure 2f shows the Differential Thermo Gravimetric (DTG) curves of bleached, treated and unbleached jute mat-UPR composite. The top (green) one is for unbleached comp., bottom (red) one is for treated comp. and middle (blue) one is for bleached comp. Then the DTG curve reveals that the maximum degradation rate of unbleached, treated and bleached jute mat-UPR composite is 0.886 mg/min at 374°C, 0.341 mg/min at 351.4°C and 0.410 mg/min at 353.2°C respectively which also means the unbleached jute mat-UPR composite is more thermally stable than the other two. Figure 2e shows the Differential Thermal Analysis (DTA) curves of bleached, treated and unbleached jute mat-UPR composite. The top (green) one is for unbleached comp., bottom (red) one is for treated comp. and middle (blue) one is for bleached comp. The DTA curve yields one endothermic peak for treated and bleached jute mat-UPR composite which is 395.9°C and 400.1°C respectively. The DTA curve yields two endothermic peak for unbleached jute mat-UPR composite is 378.3°C and 455.7°C respectively. Figure 3a shows the Thermo Mechanical Analysis (TMA) and Differential Thermo Mechanical Analysis (DTMA) curves of treated jute mat-UPR composite. The top (blue) one is for DTMA, bottom (green) one is for TMA. The TMA curve shows that the onset of contraction occurs in the range of 24.6 to 51.6°C, the value of which is 7.53 µm. From DTMA curve we can see that there are two stages of contraction occurs at a rate of 0.719 µm/°C at 63.6°C and at a rate of 0.847 µm/°C at 96.2°C. Figure 3b shows the Thermo Mechanical Analysis (TMA) and Differential Thermo Mechanical Analysis (DTMA) curves of bleached jute mat-UPR composite. The top (blue) one is for DTMA, bottom (green) one is for TMA. The TMA curve shows that the onset of contraction occurs in the range of 23.9 to 61°C, the value of which is 5.20 µm and there is also an expansion occurs in the range of 79.9 to 109.9°C the value of which is 0.55 µm. The maximum contraction occurs at 67°C, the value of which is 9.41 µm. From DTMA curve we can see that there is one contraction occurs at a rate of 0.705 µm/°C at 66.9°C. Figure 3c shows the Thermo Mechanical Analysis (TMA) and Differential Thermo Mechanical Analysis (DTMA) curves of unbleached jute mat-UPR composite. The top (blue) one is for DTMA, bottom (green) one is for TMA. The TMA curve shows that the onset of contraction occurs in the range of 28.1 to 58.5°C, the value of which is 6.68 µm. The maximum contraction occurs at 66.9°C, the value of which is 16.05 µm. From DTMA curve we can see that there is one contraction occurs at a rate of 1.111 µm/°C at 66.6°C Figure 3d shows the Thermo Mechanical Analysis (TMA) curves of bleached, unbleached and treated jute mat-UPR composite. The top (green) one is for bleached jute mat-UPR composite, bottom (red) one is for treated jute mat-UPR composite and middle (black) one is for unbleached jute mat-UPR composite. The TMA curve shows that for bleached, unbleached and treated jute mat-UPR composite, the onset of contraction occurs at 23.9°C, 28.1°C and 24.6°C respectively, the value of which is 8.20 µm, 6.68 µm and 7.53 µm respectively which means that bleached one is thermo mechanically unstable than the other two composite. Figure 3e shows the Differential Thermo Mechanical Analysis (DTMA) curves of bleached, unbleached and treated jute mat-UPR composite. The top (black) one is for unbleached jute mat-UPR composite, bottom (green) one is for bleached jute mat-UPR composite and middle (red) one is for treated jute mat-UPR composite. From DTMA curve we can see that there are two stages of contraction occurs for treated jute mat-UPR composite at a rate of 0.719 µm/°C at 63.6°C and at a rate of 0.847 µm/°C at 96.2°C. For bleached and unbleached jute mat-UPR composite we can see that there is one contraction occurs at a rate of 0.705 µm/°C at 66.9°C and 1.111 µm/°C at 66.6°C respectively.   ester group appeared at wavenumber of 1728 cm -1 for bleached and unbleached jute mat-UPR composite. For treated jute mat-UPR composite ester group appeared at wavenumber of 1724.36 cm -1 . The C=O absorption band of saturated aliphatic esters with intense appearance is presenting the 1750-1725cm -1 region. The more intense peak for C-O appeared at wavenumber of 1041.56,1043.49 and 1039.63 cm -1 for bleached, treated and unbleached jute mat-UPR composite       fiber pull-out is observed in bundle form whereas in bleached jute mat + UPR composites agglomeration of the fibers into bundle form is relatively prevented. Between the bleached samples and unbleached samples (Figure 4a and 4b) shows significant change of morphology and this is effective for better mechanical bonding between fiber and polymer matrix.

Conclusions
The result of the present study reveals that composites with good strength could be successfully developed by using bleached jute mat as the reinforcing agent. From characterization of three layered jute mat-UPR show high strength but composite's SEM analysis indicating a strong adhesion between lignocellulose bleached jute mat and polyester. So from the thesis work we concluded that bleached fiber was the best one for reinforcement although medium performance Indian persimmon treated jute fiber can be used where there is a cost concern involved with the bleaching agent.