Protech Biosystems Journal

The Effect of Pennisetum Purpureum Fiber Addition On The Tensile Strength and Morphology Of Polyester Composite

Purna Putrawan — 2026-04-13

This study analyze the effect of fiber volume fraction variation of elephant grass fibers on the tensile strength properties of polyester resin matrix composites. The research was conducted in five stages: fiber extraction, alkaline treatment using a 1% NaOH solution, composite fabrication with polyester resin at a ratio of 2% of resin volume, SEM analysis, and tensile strength testing. The highest tensile strength (21,934 MPa) was obtained at a fiber-resin ratio of 10/90. Variation of fiber 5/95, tensile strength of (21.737 Mpa), modulus of elasticity of (1776.9 MPa) and elongation of (2.1788 mm), shows the dominance of the resin matrix in supporting loads. Fiber variation of 20/80, decrease in tensile strength to (21.169 MPa) and elongation of (2.2255 mm) due to uneven resin distribution. The most significant decrease occurred in the 30/70 fiber variation, the total tensile strength was (18.833 Mpa), the modulus of elasticity was (1390.3 MPa), although the elongation increased to (2.606 mm). Increased elongation indicates weak interface bonds due to fiber agglomeration and increased void, making the composite more susceptible to deformation before breaking. The SEM results support the tensile test results, where the 10/90 variation, shows the most homogeneous structure with good fiber distribution and minimal void count. Overall, the composition of fiber and 10/90 resin is concluded to be the most optimal composition because it provides the best balance between tensile strength, rigidity, and deformation ability of the material.

Characteristics Of Coconut Husk Briquettes Using Tapioca And Rice Flour Binders At Various Concentrations

Ahmad Akromul Huda — 2026-06-04

This study aimed to evaluate the effects of binder type and concentration on the quality of coconut husk charcoal briquettes and to assess the potential of rice flour as an alternative binder to tapioca flour. A two factorial Completely Randomized Design (CRD) with three replications was employed. The first factor was binder type (tapioca flour and rice flour), while the second factor was binder concentration (10%, 15%, and 20%). The quality parameters evaluated were moisture content, ash content, and calorific value. Data were analyzed using two-way Analysis of Variance (ANOVA) followed by Duncan’s Multiple Range Test (DMRT) at a 5% significance level. The results showed that binder type and concentration significantly affected the quality characteristics of the briquettes (p < 0.05). Moisture content and ash content increased with increasing binder concentration, whereas calorific value decreased. Moisture content ranged from 6.6% to 7.7%, while ash content ranged from 6.5% to 7.9%. The highest calorific value was obtained from briquettes produced with 10% tapioca flour binder (5405 cal/g), whereas the lowest value was observed in briquettes produced with 20% rice flour binder (4780 cal/g).. All treatments met the moisture and ash content requirements of SNI 01-6235-2000, while only briquettes containing 10–15% binder satisfied the minimum calorific value standard. Overall, 10% tapioca flour binder produced the best briquette quality, although rice flour showed potential as an alternative binder at appropriate concentrations.

Kapok-Based Agricultural Biomass Inhibitor for Steel Corrosion Control in H₂SO₄: Kinetic and Thermodynamic Study

Syarif Hidayatullah — 2026-06-07

Steel corrosion in acidic environments is a critical issue affecting material durability and service life. This study aims to analyze the effect of kapok peel extract inhibitor concentration on the corrosion rate of steel in sulfuric acid media and to determine kinetic and thermodynamic parameters using Arrhenius plots and transition state theory. The weight loss method was employed with inhibitor concentrations (blank, 1000, 2000, and 3000 ppm) and temperatures (27, 35, and 45°C). Results indicate that corrosion rate significantly decreases with increasing inhibitor concentration, achieving a maximum inhibition efficiency of 74.06% at 3000 ppm and 27°C. Conversely, higher temperatures increase the corrosion rate. Kinetic analysis shows linear relationships in ln(CR) vs 1/T and ln(CR/T) vs 1/T plots. Activation energy increased from 15.82 to 26.75 kJ/mol, while ΔH° increased and ΔS° was negative. These findings suggest an adsorption-controlled inhibition mechanism forming a protective layer on the steel surface, indicating that kapok peel extract is a promising eco-friendly corrosion inhibitor.