THE UTILIZATION OF BRUGUIRA GYMNORYZA MANGROVE FRUIT AS HYDROGEL: THE USE OF PVA/MF/PVP ON THE PHYSICAL-MECHANICAL PROPERTIES OF THE HYDROGEL HEATING METHOD
Bruguierra gymnoryza mangrove fruit (MF) which grows in coastal areas, is one of carbohydrates sources. The flour of MF in the form of starch can be used as a hydrogel that can improve the quality of the product when it mixed with PVA (Polyvinyl alcohol) or PVP (Polyvinyl pirolidone). This research aimed to determine the effect of MF mixture with PVA and PVP on the quality of the hydrogel. MF was obtained from Wonorejo, Surabaya, and East Java. This study used RAL (Completely Randomized Design) with special formulations, the treatments are repeated 3 times, and data analysis using ANOVA, followed by Tukey's test. The results showed that PVA/MF produces a hydrogel product with better water absorption quality, gel fraction, and cross-linking degree than PVP/MF. Meanwhile, a hydrogel with a mixture of PVA/MF/PVP at 1:1 ratio with 2.0% concentration provided the best proportion of water absorption about 292.45%. The FTIR of hydrogel made from MF mixed with PVA and PVP showed absorption at wave number 3645-3600 (narrow) Nonbonded hydroxy group - OH stretch. XRD showed that the highest and lowest Crystallinity Index (IC) at 54.75% and 23.10% were identified in PVA/MF and PVA/MF/PVP, respectively. It was concluded that PVA/MF gives the best gel fraction, tensile strength, and hardness. The PVA, PVP, and MF mixture significantly affected water absorption, water content, gel fraction, pH, tensile strength, and hardness. It could improve the hydrogel's physical, mechanical, and structural qualities. Additionally, the average use of PVA/MF had the highest water absorption and gel fraction values. Despite PVA/PVP/MF giving the best results, the quality decreased with the concentration of PVA/PVP used. Finally, the quality of the hydrogel depended on the absorption and gel fraction values.
Polyvinyl alcohol, Polyvinyl pirolidone, Tunjung pitat, Mangrove fruit flour.