Jute fiber (woven fabric, 1 × 1 plain weave) reinforced polypropylene matrix composites were prepared by compression molding with various fiber loading such as 30 % , 40 % , 46 % , 50 %, 55% by weight. The mechanical properties such as tensile strength (TS), bending strength (BS), tensile modulus (TM), bending modulus (BM) and impact strength (IS) of the composite were assessed and analyzed. The highest value of TS, BS, TM, BM and IS were 68.1 MPa, 94.1 MPa, 2936 MPa, 4831 MPa and 14.5 kJ/m2 respectively with 50% fiber loading by weight. It was found that the mechanical properties of the composites were increased with the increase in jute fiber content up to 50% by weight ; however, further increase in fiber loading the value decreased. On the basis of fiber content, 50% fiber reinforced composites had the optimum set of mechanical properties. Initially the water absorption rate was high er and then it became slower and static with time. Chemical ageing test with various chemical media such as H2O2, NaOH, HCl and NaCl were performed up to 168 hours. After first 24 hours the composite samples showed gradual weight gain (%) and then the weight gain was become slow and steady in the chemical solution.
Fiber reinforced polymer matrix composites are versatile in applications with excellent physico-mechanical properties. They are widely used in various applications such as furniture, building materials, automotive industry, civil and military, biomedical and many other applications. Among various natural and synthetic fibers, the demand of natural fibers like jute, hemp, sisal, flax, coir, pineapple etc. are increasing day by day due to their ecofriendly nature and availability in the market [
Polypropylene (PP) is an amorphous polymer and is extensively used as an engineering thermoplastic due to its various important and convenient features like clarity, dimensional firmness, anti-flame properties, high heat distortion temperature and high impact strength. It can be applicable for filling, reinforcing and blending. The incorporation of PP with natural fibers can be an auspicious way to develop natural-synthetic polymer composites [
The purpose of this study is to fabricate and find out the mechanical properties of jute fabric reinforced PP composites with various fiber loading (weight%). The water uptake (%) and the resistance in various chemicals of the composites were also analyzed in this work.
Polypropylene (PP) granules were purchased from Polyolefin Company, Singapore. Jute woven fabric (Hessian Cloth, 1 × 1 plain weave) was used as reinforcement which was collected from the local market of Dhaka, Bangladesh.
PP sheets were fabricated using granules of PP (about 15 g) by placing the granules into two steel plates. The steel plates were then placed into the hot press (Carver, INC, USA, Model 3856). The presses were operated at 180˚C and 5 tons pressure was applied on steel plates for 5 min. Then it was cooled for 5 min in a separate press (cold press) under 5 tons pressure at room temperature. Then, the prepared PP sheets were cut into small pieces of desired dimension for composites fabrication.
Jute/PP composites were fabricated by sandwiching pre-weighed layers of jute fabric between the layers of PP sheets. Composites were prepared by pressing this sandwich at 190˚C for 5 minutes under a pressure of 5 tons using Carver Laboratory Press (Carver, INC, USA, Model 3856). After heating and pressing, the mold was cooled in a cooling system using another press. In this way, composite of mold size was prepared.
i) Tensile Test
Tensile tests were performed according to ASTM Designation: D638-03 using a Universal Testing Machine (model: H50KS-0404, Hounsfield Series S, UK) with a cross-head speed of 10 mm/min at a span distance of 50 mm. The dimensions of the test samples were 120 mm × 15 mm.
ii) Bending Test
Bending tests were conducted according to ISO 14125 methods using the same testing machine mentioned above with a cross-head speed of 60 mm/min at a span distance of 25 mm. The dimensions of the test specimen were 60 mm × 15 mm.
iii) Impact Test
The impact tests were carried out on unnotched mode composite samples according to ASTM D 6110-97 using a Universal Impact Tester (HUNG TA INSTRUMENT CO. LTD., Taiwan), hammer mass of 2.63 kg, gravity distance of 30.68 mm and lift angle of 150˚.
iv) Water Uptake
Composites specimens (20 × 10 × 2 mm2) were soaked in a static water bath at 25˚C for various time periods (up to 168 hours). Before immersion in water, the samples were dried in an oven at 105˚C, cooled in a desiccators using silica gel and weighed. After certain periods of time, samples were taken out from the bath and wiped using tissue paper, then weighed. Water uptake was measured by the subtraction from final weight to initial weight.
v) Chemical Ageing Test
Composites samples were immerged in 20% different types of chemical solution (H2O2, NaOH, HCl, NaCl) up to 168 hours. After certain periods of time, samples were taken out from the bath and wiped using tissue paper, then weighed. Weight gain or loss percentage was determined by the subtraction from final weight to initial weight.
The influence of jute content on the mechanical features of jute/PP composite was measured and the results are showed in Figures 1-3. The TS and BS of the composites were found to increase on increasing the percentage of jute fiber content in the composites. The higher TS and the BS at 50% jute content were found to be 68.1 and 94.1 MPa respectively. The TM and BM of the composite also followed the same way like TS and BS. The highest TM and BM of the composites were obtained as 2936 and 4831 MPa respectively as shown in
The maximum values of mechanical properties displayed by 50% fiber loading composite may be illustrated in terms of orientation and homogeneity of fibers within the matrix. At this stage, jute fibers get highest level of orientation and mixed homogeneously within the matrix. When the load is applied, stress is uniformly distributed among the fibers. As a result, mechanical properties of the composites obtained highest values. At low fiber content, poor fiber population contributes low load transfer capacity among the fibers. As a result, accumulation of stress occurs at certain points of the composite and strains are also found highly localized in the matrix [
fibers get agglomerated within the matrix which produces non-uniform stress transfer capacity. Also, too many fiber ends promote micro crack formation in the interface. As a result, strength and modulus of the composite again decrease [
The impact strength (IS) of a material is its capacity to absorb and dissipate energies under impact or shock loading. IS of the composites were 7.3, 9.0, 13.1, 14.5 and 11.9 kJ/m2 for the fiber content of 30%, 40%, 46%, 50% and 55% in the composites respectively as shown in
first, the absorption rate was very high which was 12.5% for first 24 hour, then it steadily increased up to 17.5% till 96 hours and after 168 hours the absorption rate was same due to it reached into the saturation point.
Jute is basically made up of cellulose, which is a hydrophilic glucan polymer. The elementary unit of jute is anhydro-d-glucose, that carry 3 hydroxyl (-OH) groups. The presence of these -OH groups in the cellulose structure is the main reason for the highly hydrophilic character of jute fiber. Hence, when immersed into water, jute absorbs huge amount of water within first hour [
During various ageing period of 24, 48, 72, 96, 120, 144, 168 hours, the weight gain were 17.5%, 17.5%, 20%, 20%, 20%, 17.5% and 15% respectively for H2O2 solution, 6%, 8%, 8%, 8%, 10%, 10%, 10% respectively for NaOH solution, 11.1%, 11.1%, 10%, 10%, 10%, 10%, 10% respectively for acid (HCl) solution and 12.5%, 15%, 17.5%, 17.5%, 17.5%, 20%, 20% respectively for NaCl solutions as shown in
When the composite is immersed into the chemical solution such as acid, alkali or salt solution, the solution penetrates through the matrix and separates out in micro-cracks. On the other hand, the degradation of the fiber/matrix interface is caused by the dehydration of the matrix and penetration of solutions through micro-cracks, crazes or similar voids in the matrix [
Jute/polypropylene composites successfully fabricated with the increase of jute fiber loading by weight (%). It was observed that by the addition of jute content in the composites, the mechanical properties were improved significantly and the maximum improvements were found for 50% jute fiber loading. The addition of fiber weight% on composites increased the mechanical properties up to 50% fiber but after that it showed a decreasing trend. Water absorption and weight gain in different chemical solutions such as alkali, acid and salt were revealed that initially the absorbency was very high and after that the absorption were steady and static with time. Finally, it can be concluded that fiber loading (%) has significant influence on the mechanical properties of jute/polypropylene composites. The proper optimization of these processing parameters can be a better or viable solution of this composite for our domestic applications such as chair, table, fences, decking, bathtub etc.
The authors have been acknowledged to the Institute of Radiation and Polymer Technology (IRPT), Atomic Energy Research Establishment (AERE), Bangladesh Atomic Energy Commission, Savar, Dhaka for providing the laboratory facilities to complete this work.
The authors declare no conflicts of interest regarding the publication of this paper.
Das, S.C., Paul, D., Fahad, M.M., Das, M.K., Shafiur Rahman, G.M. and Khan, M.A. (2018) Effect of Fiber Loading on the Mechanical Properties of Jute Fiber Reinforced Polypropylene Composites. Advances in Chemical Engineering and Science, 8, 215-224. https://doi.org/10.4236/aces.2018.84015