Abstract: Composite manufacturing has been a wide area of research and it is the preferred choice due to its superior properties like low density, stiffness, light weight and possesses better mechanical properties. However, very little work has been reported on synthesizing composites for car internal door trim panel from reinforcing prospective of locally abundant Sisal fiber. The aim of this research is developing and characterization of Sisal fiber reinforced polypropylene composite material for car interior door trim panel application. In this research, fiber reinforced composites were prepared for fiber length 3mm, 6 mm,9mm and 12mm with both un treated and alkali (NaOH) treated fiber.
Matrix used in this study is polypropylene. The composites were synthesized at 5/95, 15/85 and 25/75 fiber to polypropylene weight percentages. Composite was produced by compressive moulding technique. The prepared composites were tested to study its mechanical properties such as tensile, flexural, compressive, impact, hardness, and surface roughness test, and physical properties such as chemical resistance test and flammability test.
Experimental result shows that impact strength increased up to maximum value of 3.77 J at 25/75 fiber to PP ratio for 9mm treated fiber length. Flexural strength increased up to 14.79MPa at 25/75 fiber to PP ratio for 9mm treated fiber length. Tensile load increased up to 420 N at 15/85 fiber to PP ratio for 6mm treated fiber length. Compressive strength increased up to 97.8MPa at 25/75 fiber to PP ratio for 9mm treated fiber length. Hardness performance increased up to maximum value of 3.94 BHN at 25/75 fiber to PP ratio for 9mm treated fiber length. Minimum Reduction of Surface roughness is up to Ra=0.42µm at 5/95 fiber to PP ratio for 3mm treated fiber length. Minimum Reduction of burring rate is up to 14.89 mm/min at 25/75 fiber to PP ratio for 12mm treated fiber length. Maximum chemical resistance (minimum weight loss) is 0.33g at 5/95 fiber to PP ratio for 3mm fiber length.Treated fiber (4%NaOH) was found better in its physical and mechanical properties of sisal fiber reinforced composite for car internal door trim panel application. Impact strength is the major properties for car internal door trim panel. Considering this major properties for car internal door trim panel the optimal properties is obtained at 25/75 fiber to Polypropylene ratio for 9mm fiber length.
Keyword: Sisal fiber, Polypropylene, compressive moulding, composite material technique`
Needless to say, Technological development depends on advances made in the field of materials. One need not be an expert to realize that an advanced design is of no use without the right materials Necessary to realize its building. In any industry, the final limitation on advancement depends on Materials. In this regard, composite materials represent a huge step in the constant endeavor of Optimization in materials
Fiber reinforced polymer composites are being used in almost every type of applications in our daily life and its usage continues to grow at an impressive rate. The manufacture, use and removal of traditional composite structures usually made of synthetic fibers are considered critically because of the growing environmental pollution. It creates interest in the use of bio fibers as reinforcing components for thermoplastics and thermo sets. Sisal fiber (SF), a member of the Agavaceae family is a biodegradable and environmental friendly plant. Sisal fiber is a strong, durable, stable and versatile material and it has been recognized as an important source of fiber for composites. It is generally accepted that the mechanical properties of fiber reinforced polymer composites are controlled by factors such as nature of matrix, fiber-matrix interface, fiber volume or weight fraction, fiber aspect ratio, fiber orientation etc. [1-14].
Strictly speaking, the idea behind the development of composite materials is not new. Nature is full of examples: Wood is a fibrous composite: cellulose fibers in a lignin matrix. Bones are yet another set of example of natural composites that support the weight of the body parts of vertebrates. On the other hand, we are familiar with materials which can be regarded as composites in the border sense of the term. The Portland cement or asphalt mixed with sand, and glass fibers in resin are common examples of composites that have been in use for very long time [15-26].
Nevertheless, composites constitute outcomes of deliberate human efforts of combining different materials to create a new one of improved quality. The recognition of the potential weight savings achievable by using advanced composites, which reduced cost and increased efficiency, was responsible for this growth in the technology of reinforcements, matrices, and fabrication of composites. As a result, there has been an ever-increasing demand for newer, stronger, stiffer and yet lighter-weight materials from industries as diverse as aerospace, energy and civil constructions [27-31].
Composite materials have low specific gravity that makes their properties particularly superior in strength and modulus to many traditional engineering materials such as metals. As a result of intensive studies into the fundamental nature of materials and better understanding of their structure and relationship of properties, it has become possible to develop new composite materials with improved physical and mechanical properties. These new materials include high performance composites such as Polymer Matrix Composites (PMCs) [32-42],
Considerable research has been conducted so far on the production and characterization of PMCs. Most of the composites reported in the works investigated by this researcher were mainly fabricated using high strength synthetic fibers. However, recently, natural fiber reinforced polymer matrix composites are catching the attentions of researchers on account of their environment-friendliness and as cost effective alternatives to synthetic fiber reinforced composites. accordingly, to replace synthetic fiber with natural fiber, Jute, Sisal, Pineapple, Hemp, Nettle, Bamboo, Kenaf and Bagasse are possible candidates [43-56].
2. Problem Statement
At this time, the automotive industry in Ethiopia is developing and integrates assembling of different types of automobile cars including Mesfin Industrial Engineering (MiE) automotive assembly, Ethiopia. Besides, the parts to be assembled are not manufactured here rather imported from other car manufacturing industry outside Ethiopia among this China is the main supplier. However, which is imported directly from the market and they used without testing performance of the products. For example, according the data obtained from Mesfin Industrial Engineering the plant assembles 3 types of Peugeot cars (models 2008, 301 and 208) with a plan to assemble 30,000 vehicles per year.
The investment (in) the partnership with Peugeot (PSA) is related to specific assembly tools. The countrys growing economy have created a demand for cars in Ethiopia. In the last year (2017 G.C), out of the 1200 number of cars assembled with internal door trim panel 4% were damaged and the price per single internal door trim was $22.36 USD, totally 724,464 ETB were expenses to replace the damaged car door trim panel. Besides thus synthetic fiber made car door internal trim panel that was being used by MiE has lead the company to extra expenses, high order of lead time, deny the country’s resource to be used. In addition synthetic fiber has low fiber/matrix adhesion, fluctuations in fiber properties, low fire resistance and also cause Environmental pollution during the disposal of the used Composite Materials. Therefore this research is proposed in order to fill the gap which occurs on the composite manufacturing industry for automotive parts here in Ethiopia.
3.1 General objective
The general objective is to manufacturing of Interior Automobile Accessories from natural fibre reinforced recycled Plastics Waste Composite Materialfor sustainable automotive industry
3.2 Specific objective
The specific objective includes:
To examine effect of fiber length, fiber content and chemical treatment of fiber on sisal fiber reinforced polypropylene composite.
Experimental investigation and Study physical properties such as chemical resistance testing and flammability testing on sisal fiber reinforced polypropylene composite.
Experimental investigation and Study mechanical properties such as impact, tensile, compression, flexural, surface roughness and hardness testing on sisal fiber reinforced polypropylene composite.
To determine the optimal composition of sisal fiber and polypropylene composite material
4. Material and experimental procedure
The plant for fiber what we used as reinforcement more collected from Baati kendaro, near the town adigrat; Tigray; North Ethiopia as shown in figure 1.
Figure 1: Researchers while collecting sisal leaves from Baati Kendaro
4.2 Raw Material Preparation Technique
4.2.1 Sisal fiber
The sisal fibers were extracted through small hand extraction wooden materials. Originally the leaves cropped in longitudinal direction into strips for ease of fiber extraction without damage. The leave shell was compressed between the wood beam and extractor material and hand-towed through in longitudinal direction smoothly, removing the resinous material as shown in figure 2. the extracted fiber, then washed with pure water in order to loosen, and separate the fiber until individual fibers are obtained which already bleaches the fiber. Once dried, the sisal fibers are ready for fabrication of test pieces.
Figure 2: Sisal fiber preparation (Manual technique)
In chemical cleaning process, the 4% sodium hydroxide mixed with distilled water. Sisal fibers then dipped in the solution for 2 hours, and then it washed with running water. It was then dry at room temperature.
Figure 3: Extracted Sisal fiber
3.2.2 Recycled polypropylene
The recycled PP used as matrix material was collected from Mekelle University campus (private lunges and cafes) that was broken chairs and tables with print information Polypropylene grade-5 that is already wrote at the backseat of the chair or centres of the table and with different colours.
Figure 4: Smithereens of recycled polypropylene
5. Result and Discussion
5.1 Physical testing
4.1.1. Flammability testing
The test results are tabulated and presented in table1 based on the average value of the three specimen for each test condition. Flammability of PP and PP composites was examined by a horizontal burning test according to ASTM D635.
Figure 5: Effect of fiber length on the burring rate for SF/PP Composite
The samples burned with a lot of smoke and the sample after test was very easy to break. NPG Suardana et al.  obtained the burning rate as 13.82mm/min for 35% fiber volume fraction of sisal fiber composites Roshan K. Kejariwal et.al obtained the burning rate lowest burning rate is 17.04mm/min for 25% fiber volume fraction for 3mm thick samples. This result is quite similar to the present study in which lowest burning rate is 14.89 mm/min for untreated sisal fiber of 25% fiber volume fraction for 12 mm length samples.
4.1.2. Chemical testing
The test results are tabulated and presented in table 2 based on the average value of the three specimen for each test condition. It is evaluate the resistance of a composite material due to exposure to chemical reagents such sulfuric acid, sodium hydroxide, and distilled water according to ASTM 543-06.
Figure 6: Effect of fiber length on the chemical resistance for SF/PP Composite
C.P.L. Chow et.al  obtained water absorption (weight loss of 0.3 g) for 10/90 fiber/matrix ratio. This result is quite similar to the present study in which water absorption (weight loss of 0.33 g) mm/min for treated sisal fiber of 25/75 fiber/matrix ratio for 12 mm length samples.
Water absorption of agave Americana chopped 7mm fiber length untreated and treated ratio of (65: 35) for 24 hour immersion were (2.6 g and 2.1 g) Yusof et.al .
5.2 Mechanical testing
4.2.1 Impact testing
The 12.5 Kg hammer is released and allowed to strike through the specimen. If breakage does not occur, a heavier hammer is used until failure occurs. Specimen size ASTM D-256: (64 mm long x 12.7 mm wide x 3.2 mm thickness).
Figure 7: Effect of fiber length on the impact strength for SF/PP Composite
Some of other researchers working concerning impact properties of natural fiber composites are compared with the Current work. From table 4.8 the impact strength which is found in the current work is more similar /approximate to S. I. Durowaye ,G. I. Lawal, O. I. Olagbaju et al work which is 3.77 for 25/85 fiber/matrix ratio ,and 2.93 for 20/80 fiber/matrix ratio respectively with the same fabrication technique and thermoplastic ( polypropylene) as matrix the sisal fiber oriented randomly it can be concluded that the result getting from the current work is healthy and the local extracted sisal fiber from Ethiopian highland have similar impact properties with that of India’s sisal fiber.
4.2.2. Flexural testing
It is a 3-point bend test, which generally promotes failure by inter laminar shear. The loading arrangement is shown in figure 3.27. The dimension of the specimen is (125×12.7×3.2) mm. with support span-to-depth ratio of 16:1 and support span length 51.2mm rate of cross head motion 0.5mm/min. The flexural strength is expressed as modulus of rupture (MR) in psi (MPa).
Figure 8: Effect of fiber length on the flexural properties for SF/PP Composite
Some of other researchers working concerning Flexural properties of natural fiber composites are compared with the Current work. From table 4 the flexural strength and Flexural Modulus(GPa) which is found in the current work is more similar /approximate to 13.4 MPa, 238 GPa respectively for 20/80 of R.N. Turukmane et.al  work which is 14.79 MPa and 261.8 GPa for 25/85 fiber/matrix ratio fiber/matrix ratio respectively with the same fabrication technique and thermoplastic ( polypropylene) as matrix the sisal fiber oriented randomly it can be concluded that the result getting from the current work is healthy and the local extracted sisal fiber from Ethiopian highland have similar flexural properties with that of India’s sisal fiber.
4.2.3. Compression testing
This section of the laboratory experiment involved in subjecting SFRPPC specimen to axial compression loading using the UTM The dimension of the specimen is (155x25x2.5) mm.
Figure 9: Effect of fiber length on the compressive strength for SF/PP composite
Compressive properties which is found in the current work is more similar to Garvit?, Abhisek Mitra et.al  work which is 84.8 MPa compressive strength and compressive modulus 43.6Gpa for 15/85 fiber/matrix respectively with similar fabrication technique which is Compressive molding technique. Compressive strength which is found in the current work is higher when compared to Garvit?, Abhisek Mitra et.al  work which is 97.8 MPa compressive strength and compressive modulus 46.2 GPA for 25/75 fiber/matrix respectively.
4.2.4. Tensile testing
Typical points of interest when testing a material include: ultimate tensile strength (UTS) or peak stress using ASTM D-3039.
Figure 10: Effect of fiber length on the tensile load for SF/PP Composite
It is clear show that addition of sisal fibre improve the tensile strength of composites at 15/85 fiber/matrix ratio owing to better tensile strength. This is due to producing the strong interfacial bonding between fibre and matrix. However, increasing fibre content there is no remarkable improvement in tensile strength. We obtained tensile load and tensile strength 420 N and 7.04 MPa for 15/85 fiber/matrix ratio using 6mm fiber length respectively and this is more similar /approximate to 408 N and 6.53 MPa for 20/80 of S. I. Durowaye et.al .
4.2.5. Hardness testing
Test specimens were made according to the ASTM D 785-08 and ASTM E 18-11 (10?10?6mm3) [55, 56]. The diameter of the ball indenter used was 0.25 inches and the maximum load applied was 60 kg as per the standard L-scale of the tester.
Figure 11: Effect of fiber length on the hardness strength for strength for SF/PP Composite
It is observed that hardness performance increased as fiber content increased.Due to the fact that sisal fiber has high density, good bonding nature and consistency of the matrix as well as better wettability at the composite. We obtained that 3.94 BHN at fiber content 25/75 using treated fiber length of 9mm and which is more similar /approximate to 3.83 BHN at fiber content 25/75 fiber/matrixS. I. Durowaye*, G. I. Lawal, O. I. Olagbaju 
4.2.6. Surface roughness testing
It has the main technical Parameters such as Parameters (µm) (Ra, Rz), Traverse Length (mm): (6) Sampling Length (mm): (0.25, 0.80 and 2.5), Evaluation Length (mm): (1.25, 4.0 and 5.00. Measuring Range (µm): (Ra: 0.05–10.0 Rz: 0.150).
Figure 12: Effect of fiber length on the surface roughness for SF/PP Composite
Rough surface of the composite resulted from adding more fiber content. Adding more fiber content would produces unevenly interfacial stress distribution on the composite and it does not allow frictional transfer along fiber/matrix of the composite. Currently we obtained a good surface at fiber content 5/95 which is 0.42µm more similar /approximate 2.5?µmfiber/matrix M. Mudhukrishuan et. al .
Based on its physical and mechanical properties of the experiment data studies of this work, few points can be concluded as follows:
Sisal fiber reinforced polypropylene composite was successfully fabricated.
From the impact energy test (3.77J), flexural strength test (14.79Mpa), compression strength test (97.8MPa), and hardness performance test (3.94BHN) results it is found that 25/75 treated fiber to PP ratio for 9mm fiber length have better as compared to other fiber to PP ratio and fiber length.
From the surface roughness test (Ra=0.42µm) and chemical resistance test (0.33g) results it is obtained that 5/95 treated fiber to PP ratio for 3mm fiber length have better as compared to other fiber to PP ratio and fiber length.
From the tensile experimental test (420 N) results it is found that 15/85 treated fiber to PP ratio for 6mm fiber length have better as compared to other fiber to PP ratio and fiber length. From the flammability experimental test (14.89mm/min) results it is found that 25/75 treated fiber to PP ratio for 12mm fiber length have better as compared to other fiber to PP ratio and fiber length.
Treated fiber was found better in its physical and mechanical properties for car internal door trim panel. Impact strength is the major properties for car internal door trim panel application. Considering this major properties for car internal door trim panel the optimal