Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X
AN EXPERIMENTAL STUDY OF THE EFFECT OF SAGO PULP MESH SIZE ON
THE MECHANICAL PROPERTIES OF COMPOSITES
Aufar Dhaifullah1*.
Iqbal1 .
Mahyuddin1 .
Muhtadin1 .
Muhammad Faisal1 Department of Mechanical Engineering.
Faculty of Engineering.
Universitas Abulyatama.
Jl.
Blang Bintang Lama Km.
Lampoh Keude.
Kuta Baro District.
Aceh Besar Regency.
Aceh 24415.
Indonesia.
*Email: aufardhaifullah@gmail.
ABSTRACT
This study aims to analyze the effect of variations in the mesh size of sago pulp on the mechanical properties of polyester resin-based composites.
Sago pulp was used as a reinforcing material with mesh sizes of 20, 30, and 40, and a composition of 40% sago pulp and 60% polyester resin.
The method used was a laboratory experiment involving tensile, bending, and impact tests.
Test results show that the 30-mesh size has the highest tensile strength of 2.
76 kgf/mmA, while the 20mesh size exhibits the highest bending strength of 2.
88 kgf/mmA.
The 40-mesh size yields the lowest strength values in most tests.
These differences are influenced by particle distribution and the quality of the bond between the sago pulp and the resin.
It is concluded that mesh size significantly affects the mechanical properties of the composite, and sago pulp composites have the potential to serve as a more environmentally friendly alternative to Keywords: sago pulp, composite, mesh size, mechanical properties.
INTRODUCTION
1 Background The rapid development of material engineering technology has encouraged continuous innovation in composite materials with superior mechanical properties, lightweight characteristics, and environmentally friendly performance.
Composite materials are widely used in various industrial sectors such as automotive, construction, aerospace, marine, and household products because they offer advantages compared to conventional materials such as metals and solid wood.
In general, composite materials are formed by combining two or more constituent materials with different physical and chemical properties to produce a new material with improved performance characteristics.
The main components of a composite consist of reinforcement material and matrix material, where the reinforcement functions to improve mechanical strength while the matrix acts as a binder and load distributor .
Along with increasing environmental awareness and the global demand for sustainable materials, the development of natural fiber-based composites has gained significant attention in recent years.
Natural fibers and agricultural waste are considered attractive alternatives to synthetic reinforcement materials because they are renewable, biodegradable, lightweight, inexpensive, and readily Compared with synthetic fibers such as glass fiber and carbon fiber, natural fibers also provide lower environmental impacts during production and disposal .
Indonesia is known as one of the worldAos largest producers of sago.
Sago processing industries generate a large quantity of waste material in the form of sago dregs .
mpas sag.
During the extraction Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X process of sago starch, only a small percentage of the sago trunk is converted into starch, while the remaining material becomes waste residue.
This waste is commonly discarded into rivers or surrounding environments without proper environmental pollution and unpleasant However, sago dregs contain lignocellulosic compounds such as cellulose, hemicellulose, and lignin, which reinforcement materials in composite manufacturing .
The cellulose content present in sago dregs contributes to the mechanical reinforcement capability of composite Cellulose fibers possess relatively good tensile properties and can improve stiffness and strength when properly bonded with polymer matrices.
addition, the utilization of sago waste as composite reinforcement not only reduces environmental pollution but also increases the economic value of agricultural waste The development of composites from sago dregs can therefore contribute to sustainable material engineering while supporting waste management and renewable resource utilization .
Among various matrix materials used in composite fabrication, polyester resin is one of the most commonly utilized thermosetting polymers due to its good mechanical properties, low cost, ease of processing, and compatibility with natural reinforcement materials.
Polyester resin also exhibits good resistance to chemicals and environmental exposure, making it suitable for structural and semi-structural In composite systems, the particles and the polyester matrix significantly influences the resulting mechanical properties .
One of the important factors affecting the performance of particle-reinforced composites is particle size or mesh size.
The mesh size determines the distribution of reinforcement particles, surface area interaction, and the quality of bonding between the reinforcement and matrix Smaller particles generally provide larger surface areas, which can improve adhesion between particles and resin.
However, excessively fine particles may dispersion within the matrix, reducing the Conversely, larger particles may create voids and weak interfacial bonding that can decrease mechanical strength.
Therefore, selecting an appropriate mesh size is essential to optimize the mechanical performance of natural fiber composites .
Several studies have investigated the use of natural fibers and agricultural waste as reinforcement in polymer composites.
Previous research has demonstrated that the mechanical properties of natural fiber composites are highly influenced by orientation, particle distribution, moisture content, and fabrication techniques.
However, studies specifically examining the influence of sago dregs mesh size on the mechanical behavior of polyesterbased composites are still limited.
involving tensile, bending, and impact performance using different mesh variations remain insufficiently explored .
Based on these considerations, this study aims to analyze the effect of sago dregs mesh size variation on the mechanical properties of polyester resin-based The research utilizes mesh sizes of 20, 30, and 40 with a composite composition consisting of 40% sago dregs and 60% polyester resin.
Experimental testing is conducted through tensile, bending, and impact tests to determine the optimal mesh size that produces the best mechanical performance.
The findings of this study are expected to provide scientific contributions regarding the development of environmentally friendly composite materials from agricultural waste and to Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X support the utilization of sago dregs as an alternative material for wood substitution and other engineering applications.
The equipment used during specimen fabrication and testing included a mixer, digital weighing scale, aluminum foil, spoon/spatula, mixing container, ruler, grinding machine, composite mold, steel weight plate, lubricating oil.
Universal Testing Machine (UTM), bending testing machine, and Charpy impact testing RESEARCH METHODS Research methodology Research Design This study employed an experimental research method to investigate the effect of sago dregs mesh size variation on the mechanical properties of polyester-based The experimental method was chosen because it enables direct observation and measurement of the influence of independent variables on the resulting composite performance.
The study focused on producing composite specimens using different mesh sizes of sago dregs and evaluating their mechanical properties through laboratory testing.
The study used a quantitative experimental approach in which the independent variable was the mesh size variation of sago dregs, namely mesh 20, mesh 30, and mesh 40, while the dependent variables were the mechanical properties of the composite, including tensile strength, bending strength, and impact resistance.
Preparation of Sago Dregs The sago dregs used in this study were obtained from a local sago processing The preparation process involved several stages.
First, the sago trunk was cut into smaller sections and processed using a crushing machine while water was added to extract the starch.
The remaining residue was collected as sago dregs.
The sago dregs were then dried under sunlight to reduce moisture content and facilitate After drying, the material was sieved using mesh sizes of 20, 30, and 40 to obtain uniform particle sizes for composite fabrication.
Composite Fabrication Process The composite specimens were fabricated using a hand lay-up method.
The composite composition consisted of 40% sago dregs and 60% polyester resin.
The fabrication procedure was carried out as Preparing dried sago dregs and all required equipment.
Covering the mold surface with aluminum foil and lubricant oil to prevent specimen adhesion.
Weighing the sago dregs and polyester resin according to the predetermined Mixing the sago dregs and polyester resin uniformly using a mixer.
Allowing the mixture to rest temporarily to remove trapped air Adding peroxide catalyst into the mixture according to the required ratio.
Pouring the mixture into the mold Time and Place of Research The preparation of sago dregs and composite specimen fabrication was conducted at the Mechanical Engineering Laboratory of Universitas Abulyatama.
Mechanical testing consisting of tensile, bending, and impact tests was carried out at the Material Testing Laboratory of Politeknik Negeri Lhokseumawe.
The specimen preparation and testing processes were conducted from December 2025 to January 2026.
Materials and Equipment The materials used in this research were sago dregs as reinforcement material with mesh size variations of 20, 30, and 40, polyester resin as the matrix material, and peroxide catalyst to accelerate the curing Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X Applying pressure using a steel weight plate to obtain a flat composite surface.
Allowing the composite to cure at room temperature until fully hardened.
Removing the composite board from the mold and preparing it for specimen
RESULTS AND DISCUSSION
1 Research Results Results Testing Pull Based on the results of tensile testing conducted on January 12, 2026 at the Lhokseumawe State Polytechnic Materials Testing Laboratory at mesh variations of 20, 30, and 40 as shown in the following Table 1 Data results testing pull Specimen Preparation After the composite boards were fully cured, specimens were cut according to testing standards for each mechanical test.
Tensile test specimens were prepared according to ASTM D3039 standard.
Bending test specimens were prepared according to ASTM C1341-06 standard using rectangular dimensions suitable for three-point bending testing.
Impact test specimens were prepared according to ASTM D256-10 standard using the Charpy impact method with V-notch geometry.
Mechanical Testing Procedures Tensile testing was conducted using a Universal Testing Machine (UTM) to determine tensile strength, elongation, and modulus of elasticity.
Bending tests were carried out using the three-point bending method to determine flexural strength and deformation Impact testing was conducted using the Charpy impact method to determine impact resistance and energy absorption capability of the composite material.
The data in Table 4.
1 shows that the average maximum tensile strength value for mesh 20 (E.
60 kgf/mmA with an average breaking strain of 2.
The variation in values between samples is quite large, which indicates the nonuniformity of the distribution of sago pulp fibers and resin matrix bonds.
The highest strain occurs in A3.
This indicates that the distribution of fibers and matrixreinforcement bonds is not yet homogeneous, thus affecting the material's ability to withstand tensile loads.
At me sh 30, it has the highest tensile strength compared to other groups.
mark Eu average as big as 2.
76 kgf/mmA And strain separated 1.
This indicates a better fiber-matrix bond and a more allowing it to withstand greater tensile This means that mesh 30 is mechanically the best, with a combination of high tensile strength and still quite good This condition indicates that the composition or treatment of the specimen with mesh 30 is optimal.
Data Analysis The data obtained from tensile, bending, and impact testing were analyzed quantitatively by comparing the average values of each mechanical property for mesh 20, mesh 30, and mesh 40 The results were presented in tables and graphs to evaluate the effect of mesh size variation on the mechanical performance of sago dregs polyester Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X Meanwhile, mesh 40 showed the lowest tensile strength value with an average Eu of 24 kgf/mmA and a breaking strain of This indicates Power support pull Which more low, possibility consequence distribution fiber Which not enough optimal or existence disabled in composite.
decreased tensile strength and yield stress compared to the other groups.
The relatively small strain indicates the material tends to be more brittle, possibly due to less effective fiber-resin bonding or internal defects.
well as transfer burden Which more effective between dregs sago And matrix resin, so that capable guard stability strength pull during the deformation process.
Meanwhile, the 40 mesh composite exhibited lower tensile stress values and a less consistent pattern.
The particle size was too fine.
suspected of causing agglomeration and reduced effectiveness mechanical bonding with the resin matrix, thus reducing the material's ability to withstand tensile loads.
Based on the graph, mesh 30 can be stated as the most optimal mesh size because it provides the best balance between tensile strength and strain stability.
Table 2.
Data results testing bending Analysis Testing Pull
From data Which in can Can in Look
connection voltage And strain on the following image MATERIAL
TEST
Materials Eu Distance .
Kgf
20 x 6
20 x 6
SAMPLE
Cross-section Distance Support Specimen Suction .
20 x 6 Average COMPOSITE (Dregs Sago & Resi.
Information Kgf/mm 2 Remarks 20 x 6 20 x 6 20 x 6 Average Picture 1.
Chart voltage And strain 20 x 6 20 x 6 20 x 6 Average Bending tests are carried out to determine the capabilities of composite materials.
dregs sago resin in withhold burden flexible.
Which shown through the maximum load value (F.
, maximum bending stress (E.
, and bending strain (A).
The test was carried out under the same conditions for all specimens, namely the cross-section 20 y 6 mm And distance support 130 mm, so that difference results which is obtained reflect influence variation size mesh dregs sago And level resin against characteristic mechanic flexible composite.
Results bending test shown in Table 4.
Which show value of Fu.
Eu, and A For variation mesh 20, 30.
On the other hand, at mesh 30 with a coarser mesh size, the bond between phases becomes less optimal so that the The stress-strain graph shows that variations in the sago pulp mesh size significantly affect the tensile properties of the composite.
At 20 mesh, the maximum tensile stress increases to a maximum value at medium strains, then decreases sharply at higher strains.
This behavior indicates that coarser particle sizes are capable of withstanding high tensile loads, but cause stress concentration and failure at the fiber-resin interface at higher Composite with mesh 30 show response mechanic Which more stable compared to mesh 20 and mesh 40.
The maximum tensile stress tends to decrease slowly with This indicates that the mesh size of 30 produces a better reinforcement Which more homogeneous as Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X material's ability to withstand bending loads decreases.
The highest strain value was obtained at mesh 30, while mesh 20 had the lowest strain value.
This indicates that mesh 30 has more ductile properties than mesh 20.
The higher strain at mesh 30 can associated with combination size mesh And level resin which allows the material to undergo greater deformation before breaking.
While That, mesh 20 with strength flexible Which tall However strain Low values indicate stiffer and more brittle material At mesh 40, although the strain value is relatively high, the flexural strength is low, indicating that the material is easily deformed but unable to withstand large loads due to the weak matrixreinforcement bond.
particles on the flexural properties of the Composites with a 20-mesh size showed the highest flexural stress, around A2.
5Ae3.
Kgf/mmA, with low to moderate strain.
The finer sago pulp particles increased the contact surface area between the reinforcement and resin matrix, resulting in stronger matrixAereinforcement bonding and a more uniform stress distribution.
Consequently, the composite became stiffer and stronger, although it experienced less deformation before The 30-mesh composite exhibited lower flexural stress, approximately A1.
5Ae2.
Kgf/mmA.
The larger particle size caused distribution, leading to stress concentration at certain points.
As a result, the material could undergo greater deformation before fracture, making it more ductile than the 20-mesh composite, but with lower flexural strength.
Meanwhile, the 40-mesh composite produced the lowest flexural stress, around A1.
4Ae1.
8 Kgf/mmA.
The coarser particles matrixAereinforcement bonding and increased the possibility of This compositeAos ability to withstand bending loads, causing failure at lower flexural stress values.
Overall, the flexural stressAestrain results indicate that finer mesh sizes improve the flexural strength of the composite but reduce its strain capability.
In contrast, coarser mesh sizes produce more ductile materials with lower flexural strength.
Analysis Testing Bending From data bending in can connection between grace And bending strain as in the following figure.
Picture 2.
Chart voltage And strain From the flexural stress-strain graph shows the relationship between flexural strain (A) and maximum flexural stress (E.
in sago pulp-resin composites with mesh size variations of 20, 30, and 40.
This graph is used to describe the mechanical behavior of composite materials when subjected to flexural loading until reaching maximum Based on the graph, it can be seen that each mesh size variation shows stress-strain Which different.
Which indicates the existence of influence the size of the reinforcing Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X impact value indicates the material's ability to distribute and absorb shock energy more Improvement mark price impact from mesh 20 to mesh 40 shows that the mesh size of sago pulp mechanical properties of the composite.
specimens with a finer mesh size, the reinforcing particles tend to be distributed more evenly within the resin matrix.
Results Testing Impact Table 3.
Results testing impact Code Specimen E (Joul.
Price Impact (J/mA) 1,486 10391,608 1,486 10846,715 2,129 15316,546 1,700 12184,956 Average 2,544 17189,189 2,352 17954,198 2,729 2,542 18347,066 Average 2,763 18543,624 2,848 20788,321 2,856 18425,806 2,822 19252,584 Average Analysis testing Impact From data Which in Which in can.
Can in Look comparison mark impact each mesh as in the following image.
Impact testing is conducted to determine the composite material's ability to absorb shock energy before failure.
Key parameters Which analyzed in testing This is energy absorb impact (E) And impact value (J/mA), which is obtained from the comparison between the energy absorbed by the specimen and the fracture crosectional area.
Based on results testing, energy absorb impact show the increase that significant from mesh 20 to mesh 40.
Mesh 20 own energy absorb lowest with an average value of 1,700 Joules, while mesh 30 and 40 each showed average values of 2,542 Joules and 2,822 Joules, respectively.
The low absorption energy at mesh 20 indicates that the material is relatively not enough capable withhold burden shock, so that failure happen more fast.
On the other hand, the increase in absorbed energy at mesh 30 and 40 indicates that the material has a better ability to absorb energy before fracture occurs.
The impact value obtained shows an increasing trend.
Which in line with improvement energy absorb.
Mesh 20 own average value price impact as big as 12,184,956 J/mA, whereas mesh 30 And 40 each showing an average value of 18,347.
066 J/mA and 19,252.
584 J/mA.
The increase in the impact value indicates that the specimens with variations applied to mesh 30 and 40 have better impact toughness compared to mesh 20.
A high Picture 3.
Chart impact value From the graph above, we can see that this homogeneous distribution allows for better load transfer from the matrix to the reinforcement when the specimen is subjected to shock loading.
Furthermore, the finer mesh size increases the surface contact between amplifier And matrix, so that the bond interface becomes stronger and more stable.
Conversely, in specimens with coarser mesh sizes, the distribution of reinforcement tends to be uneven and causes particle agglomeration.
This condition causes stress concentration at certain points, so that cracked more easy formed And develop in a way fast moment impact testing is performed CONCLUSION 1 Conclusion Based on the results of the research and discussion regarding the experimental study of the effect of sago pulp mesh size Jurnal Reaksi (Journal of Science and Technolog.
Jurusan Teknik Kimia Politeknik Negeri Lhokseumawe Vol.
24 No.
June 2026 ISSN 1693-248X on the mechanical properties of resinbased composites through tensile, bending, and impact testing, the following conclusions can be drawn:
Variations in sago pulp mesh size have a significant effect on the tensile properties of the composite.
Mesh 30 produced the highest tensile strength of 76 kgf/mmA with an elongation of 49%, indicating the most optimal matrixAereinforcement bond.
In the bending test, mesh 20 had the 88 kgf/mmA due to a distribution, while mesh 30 exhibited greater toughness with higher flexural Impact test results indicate that the finer the mesh size, the higher the materialAos ability to absorb impact Mesh 40 had the highest impact value of 19,252.
584 J/mA, while Mesh 20 had the lowest at 12,184.
J/mA.
Overall, the 30-mesh variant is the most optimal because it provides the best balance between tensile strength, stiffness, and impact toughness compared to the other variants.
fiber-reinforced advanced ceramic ASTM International.
American Society for Testing and Materials.
ASTM D25610: Standard test methods for determining the Izod pendulum impact resistance of plastics.
ASTM International.
American Society for Testing and Materials.
ASTM
D3039/D3039M: Standard test method for tensile properties of ASTM International.
Bledzki.
, & Gassan.
Composites cellulose based fibres.
Progress in Polymer Science, 24.
, 221Ae274.
https://doi.
org/10.
1016/S00796700.
Callister.
, & Rethwisch.
Materials science and engineering: An introduction .
th Wiley.
Fakri.
, & Juhan.
Analisis pengujian impak Charpy terhadap sifat mekanik material.
Jurnal Teknik Mesin, 6.
, 85Ae92.
Faruk.
Bledzki.
Fink.
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Sain.
Biocomposites reinforced with natural fibers:
2000Ae2010.
Progress in Polymer Science, 37.
, 1552Ae1596.
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2 Suggestions Based on the conclusions obtained, it is recommended that further research be conducted on the effect of variations in resin and sago waste composition, as well as pretreatment of sago waste to improve the interfacial bonding of the composite.
In addition, further tests such as microstructure, density, and hardness tests are needed to better understand the material characteristics and evaluate the stability of the compositeAos mechanical properties over a certain period of use.
Gibson.
Principles of composite material mechanics .
th CRC Press.
Hull.
, & Clyne.
introduction to composite materials .
nd ed.
Cambridge University Press.
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