This paper presents an approach for hydrolyzing cellulose nanocrystals from oil palm empty fruit bunch (OPEFB) presented through hydrochloric acid hydrolysis under sonication–hydrothermal conditions. Differences in concentration, reaction time, and acid-to-cellulose ratio affect toward the yield, crystallinity, microstructure, and thermal stability were obtained. The highest yield of cellulose nanocrystals up to 74.82%, crystallinity up to 78.59%, and a maximum degradation temperature (T_max) of 339.82 °C were achieved through hydrolysis using 3 M HCl at 110 °C during 1 h. X-ray diffraction analysis indicated a higher diffraction peak pattern at 2θ = 22.6° and a low diffraction peak pattern at 2θ = 18°. All cellulose nanocrystals showed a crystalline size of under 1 nm, and it was indicated that the sonication–hydrothermal process could reduce the crystalline size of cellulose. Infrared spectroscopy analysis showed that a deletion of lignin and hemicellulose was demonstrated in the spectrum. Cellulose nanocrystal morphology showed a more compact structure and well-ordered surface arrangement than cellulose. Cellulose nanocrystals also had good thermal stability, as a high maximum degradation temperature was indicated, where CNC-D1 began degrading at temperatures (T₀) of 307.09 °C and decomposed (T_max) at 340.56 °C.

This research improves the strength of plastic using avocado seed starch and PLA. The effect of blending avocado seed starch and PLA was optimized using the RSM approach by using two variables: water absorption and biodegradability. Mixing them using RSM gave the best result: 1.8 g of starch and 3 g of PLA. Degradable plastic has a tensile strength of 10.1 MPa, elongation at a break of 85.8%, and a Young’s modulus of 190 MPa. Infrared spectroscopy showed that the plastic had a -OH bond at 3273.20 cm⁻¹, 3502.73 cm⁻¹, and 3647.39 cm⁻¹, a CH₂ bond at 2953.52 cm⁻¹, 2945.30 cm⁻¹, and 2902.87 cm⁻¹, a C=C bond at 1631.78 cm⁻¹, and a C-O bond at 1741.72 cm⁻¹. The plastic decomposed in the soil. It was organic and hydrophilic. Thermal tests demonstrated that the plastic can withstand heat well, losing weight at 356.86 °C to 413.64 °C, forming crystals and plastic melts at 159.10 °C—the same as PLA. In the melt flow test, the sample melted before measurement, and was therefore not measurable—process conditions affected it. A water absorption of 5.763% and biodegradation rate of 37.988% were found when the samples were decomposed for 12 days. The starch and PLA fused in the morphology analysis to form a smooth surface. The RSM value was close to 1. The RSM gave the best process parameters.

The research improves the strength of plastic using avocado seed starch and PLA. The effect of blending avocado seed starch and PLA was optimized using the RSM approach by using two variables: water absorption and biodegradability. Mixing them using RSM gave the best result: 1.8 g of starch and 3 g of PLA. Degradable plastic has a (tensile strength of 10.1 MPa; elongation at break of 85.8%; young modulus of 190 MPa). Infrared spectroscopy showed that the plastic had a -OH bond at 3273.20 cm-1, 3502.73 cm-1, 3647.39 cm-1, a CH2 bond at 2953.52 cm-1, 2945.30 cm-1, 2902.87 cm-1, a C=C bond at 1631.78 cm-1, and a C-O bond at 1741.72 cm-1. The plastic decomposed in soil. It was organic and hydrophilic. Thermal tests, the plastic can withstand heat well, losing weight at 356.86°C to 413.64°C, forming crystals and plastic melts at 159.10°C—the same as PLA. Melt flow test, sample melts before measurement, therefore not measurable—process conditions that affect. Water absorption of 5.763% and biodegradation rate of 37.988% decomposed for 12 days. In morphology analysis, the starch and PLA fused to form a smooth surface. RSM found value was close to 1. RSM gave the best process parameters.

Penelitian ini mengkaji tentang ekraksi dan karakterisasi selulosa yang diperoleh kulit pinang. Untuk menentukan kadar selulosa yang terdapat pada kulit pinang dapat dilakukan karakterisasi melalui uji XRD, uji FTIR, dan uji SEM. Kulit pinang yang telah dibersihkan kemudian dihidrolisis dengan konsentrasi HNO3 menggunakan variasi NaOH yaitu 1%, 2%, 3% dan 4% dan variasi suhu 40 oC, 50 oC, 60 oC, dan 70 oC. Kemudian didelignifikasi dengan NaOH dan Na2SO3 selama 1 jam dengan suhu 40 oC. Selulosa yang diperoleh diuji dengan uji XRD, uji FTIR, uji SEM, dan dihitung yield nya. Dari hasil uji XRD didapatkan persentase kristalinitas tertinggi terdapat pada konsentasi NaOH 4% pada suhu 70oC yaitu sebesar 76,79%. Sedangkan persentase kristalinitas terendah terdapat pada konsentrasi NaOH 1% pada suhu 70oC yaitu sebesar 75,11%. Kadar yield yang paling besar terdapat pada konsentrasi NaOH 4% pada suhu 70oC dengan kadar yield yang dihasilkan sebesar 39,96%. Kadar yield terendah terdapat pada dengan konsentrasi NaOH 1% pada suhu 40oC dengan kadar yield sebesar 39,16%. Dari hasil penelitian tersebut dapat diketahui bahwa semakin besar konsentrasi NaOH dan suhu yang digunakan berpengaruh terhadap selulosa yang dihasilkan.

This study reports on manufacturing cellulose from robusta coffee husks through a solid-liquid extraction process. A high yield of cellulose can be achieved by extraction using 3.5% HNO₃ at a temperature of 100 ^oC with a gain of 35.4%. Meanwhile, the extraction process with 4.5% HNO₃ at a temperature of 80 ^oC only achieved a yield of 32.8%. From the results of this study, it can be seen that the smaller the concentration of HNO₃ used and the higher the temperature, the greater the yield of cellulose produced. The X-ray diffraction pattern shows high peaks appearing at an angle of 2θ around 22.5^o; this area is a typical peak of the cellulose structure. High crystallinity was obtained at a concentration of 3.5% HNO₃ at a temperature of 100 ^oC at 82.47%, while the lowest crystallinity was found at a 5.5% HNO₃ concentration at a temperature of 100 ^oC at 74.27%. The decrease in crystallinity was caused by the high temperature and concentration of HNO_3, which caused the acid to penetrate quickly into the cellulose tissue layer and hydrolyze the crystalline regions of cellulose. FT-IR analysis showed a high absorption area at 3314 cm^-1 and a low absorption area at 1028 cm^-1, typical of Robusta coffee husk cellulose. The absorption located around the 3314 cm^-1 bands is a stretch of the –OH group and the absorption in the 1028 cm^-1 band is related to the -CH₂ group. SEM can show the morphology of cellulose with smaller and uniform crystal dimensions with a scale of 20 µm.