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All Journal Jurnal Penelitian Pendidikan IPA (JPPIPA) Makara Journal of Science Greensusmater
Waresindo, William Xaveriano
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Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education Environmental Science Materials Science & Nanotechnology Physics

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Effect of Varying Chitosan Molecular Weights on the Morphology and Physical Characteristics of PVA/Chitosan Composite Hydrogels Sihombing, Yuan Alfinsyah; Luthfianti, Halida Rahmi; Waresindo, William Xaveriano; Rodhiyah, Marathur; Nafisah, Nur’aini; Hapidin, Dian Ahmad; Edikresnha, Dhewa; Khairurrijal, Khairurrijal
Makara Journal of Science Vol. 29, No. 3
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

We employed the innovative freeze–thaw method to investigate the effect of chitosan (CS) molecular weights incorporated into polyvinyl alcohol on the morphology and physical characteristics of the hydrogel. This study aimed to unravel the intricate relationships between CS molecular weight variations, CS concentration, and the number of freeze–thaw cycles (4 or 6 cycles) on hydrogel swelling degree and weight loss. Incorporating CS improved the hydrogel structure and enhanced its porosity, resulting in remarkable increases in swelling degree ranging from 2 to 6 times the initial weight. Higher molecular weight CS (310,000–375,000 Da) exhibited a lower swelling degree than medium molecular weight CS (190,000–310,000 Da), attributed to its ability to prevent crystal formation during the freeze–thaw process. Increased freeze–thaw cycles led to a decreased swelling degree, which indicated enhanced rigidity and stability due to more significant hydrogen bond formation with hydroxyl groups. Higher CS content amplified hydrogel weight loss, and additional cycles accentuated this effect, highlighting the challenge of maintaining an effective gel structure. CS with medium molecular weight emerged as the more suitable choice for applications demanding superior water absorption.
Cross-linking formation of taro starch (colocasia esculenta)-based hydrogel using freeze-thaw method: synthesis and physical characterization Luthfianti, Halida Rahmi; Nafisah, Nuraini; Waresindo, William Xaveriano; Sawitri, Asti; Hapidin, Dian Ahmad; Noor, Fatimah Arofiati; Elfahmi, Elfahmi; Edikresnha, Dhewa; Khairurrijal, Khairurrijal
Greensusmater Vol. 2 No. 2 (2025)
Publisher : Green and Sustainable Materials Society

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62755/greensusmater.2025.2.2.36-48

Abstract

This study successfully made starch from taro tuber flour using immersion methods (AQ, SM) and centrifugation methods (CE). Taro starch with the AQ method produced the most starch content, thus improving the viscosity parameter in the pasting properties test. A simple mathematical model was used to control the taro starch pasting process and product. The highest R-value in the AQ sample was 309.88 s, indicating the strongest starch granule resistance. Meanwhile, the S-value in this study showed that all samples were above 1, which indicated that water penetration affected the swelling rate of starch granules. Taro starch with different isolation methods was analyzed for hydrogel formation using optical microscopy, SEM, swelling degree test, weight loss, color analysis, and texture profile analysis (TPA). The morphological images show three phases of a taro starch hydrogel formation: granular, potential cross-linking, and cross-linking hydrogel with a firm structure. Optimization of freeze-thaw process parameters was carried out to determine the optimum parameters of starch hydrogel formation, which was obtained under freezing conditions for 17 hours at -23°C and thawing for 7 hours at 4°C. The sample CE resulted in the most stable hydrogel formation, showing the highest amylose content, protein content, and the lowest impurities or ash content. The CE starch concentration of 10% resulted in the highest swelling degree and the lowest weight loss, indicating that the ability of the hydrogel to maintain its structure was stronger and more elastic. The textural properties of CE hydrogel at a concentration of 10% showed the most stability. It had the highest hardness, fracturability, chewiness, and springiness. Physical characteristics showed that the starch hydrogels had a dense, porous surface and formed a cross-linking structure. It can potentially be used in functional food applications to control the release of bioactive compounds. 
Honing Scientific Logic: Cognitive Intervention Strategies in Scientific Literacy and Numeration for Primary School Children Susianna, Nancy; Damayanti, Yosephine Debbie; Perdani, Anggie Siti; Putri, Rinda Angghita; Waresindo, William Xaveriano; Zai, Elvinda Juita Grace; Salaisek, Bernadus Albertus; Salolosit, Theresia Susanti
Jurnal Penelitian Pendidikan IPA Vol 11 No 12 (2025): December
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v11i12.13383

Abstract

This community service activity was carried out at MIS Nyalindung, Cisarua, with the aim of improving the scientific literacy and numeracy skills of elementary school students through a literacy- and STEM-based approach. This activity involved 53 students from grades 3 to 6, who were divided into two phases based on grade level. The intervention was carried out through a combination of reading literary and information texts, as well as simple experiments on changes in the states of objects. Evaluation was carried out through pretests and posttests, which showed a significant increase in students' average scores in both phases, with normalized gains of 0.38 and 0.47, respectively. The results of the paired t-test showed a statistically significant increase. In addition to cognitive improvements, this activity also showed a positive impact on the affective aspect, where 85% of students felt more motivated to learn science, and 90% expressed satisfaction with the learning methods used. The questionnaire data showed that most students had visual (43%) and kinesthetic (39%) learning styles, which supports the effectiveness of the multimodal approach in learning. This activity also contributed 450 literacy- and STEM-themed reading books as a form of ongoing support for strengthening literacy culture in schools. The results of observations showed an increase in active participation, the ability to work together, and communication skills of students. The role of teachers as facilitators also contributed to creating a fun and productive learning environment. Overall, this activity demonstrates that the literacy- and STEM-based approach is effective when implemented at the elementary school level and has a positive impact on fostering active, contextual, and sustainable learning.
Co-Authors Damayanti, Yosephine Debbie Edikresnha, Dhewa Elfahmi Elfahmi, Elfahmi Fatimah Arofiati Noor Hapidin, Dian Ahmad Khairurrijal khairurrijal Luthfianti, Halida Rahmi Nafisah, Nuraini Nafisah, Nur’aini Nancy Susianna Perdani, Anggie Siti Putri, Rinda Angghita Rodhiyah, Marathur Salaisek, Bernadus Albertus Salolosit, Theresia Susanti Sawitri, Asti Yuan Alfinsyah Sihombing Zai, Elvinda Juita Grace