Influence of Formulation and Hot-Pressing Conditions on the Performance of Bio-Based Molasses Adhesive for Plywood

Molasses can serve as a natural adhesive for plywood and particleboard.However,several disadvantages remain,including lower dimensional stability and low bonding strength compared to other adhesives.Therefore,modifications are needed to use molasses as an adhesive for plywood.This research aims to improve bio-based molasses(MO)adhesive for plywood using citric acid(CA)adhesive.In addition,this research aims to analyze the effect of adding citric acid and to investigate the optimum hot-pressing temperature to produce the best quality plywood.In the first stage,the molasses and citric acid were combined in a ratio of 100:0,75:25,50:50,25:75,0:100 w/w%.Then,the second stage focuses on analyzing the influences of pressing temperature based on an optimum first stage.The research demonstrated that the addition of CA altered the gelation time,solid content,viscosity,and pH of the molasses adhesives.In addition,the thermal properties of molasses adhesives were changed after mixing with citric acid.These phenomena indicate changes in characteristics,such as the curing of adhesive.Overall,the characteristics of plywood showed a steady improvement as the CA ratio increased but revealed a significant decline for the 25:75 MO-CA ratio.By raising the pressing temperature from 180°C to 200°C,the quality of plywood was effectively improved.The plywood that was bonded using adhesives with a 50:50 MO-CA ratio exhibited superior mechanical properties and improved dimensional stability compared to the plywood bonded solely with MO.Furthermore,the optimal mechanical and physical properties resulted in plywood bonded with a 50:50 MO-CA ratio when subjected to a pressing temperature of 200°C.The Thermal and FTIR measurements revealed that CA established ester bonds with both the MO and wood veneers.In conclusion,the mechanical characteristics of plywood were improved,while maintaining its excellent dimensional stability.

Overview of the Synthesis, Characterization, and Application of Tannin-Glyoxal Adhesive for Wood-Based Composites

More than a century after its initial synthesis,urea-formaldehyde(UF)resins still have dominant applications as adhesives,paints,and coatings.However,formaldehyde in this industry produces formaldehyde emissions that are dangerous to health.Scientists have spent the last decade replacing formaldehyde and phenol with environmentally friendly substances such as glyoxal and tannin to create bio-based adhesives.This review covers recent advances in synthesizing glyoxal tannin-based resins,especially those made from sustainable raw material substitutes and changes made to synthetic processes to improve mechanical properties.The efficacy of using tannin-glyoxal adhesives in producing wood-based composites has been proven.The glyoxylate reaction forms cross-linked bridges between the aromatic sites of the tannin and glyoxal molecular structures.Glyoxal tannin adhesive with a greater percentage of glyoxal than tannin will produce an adhesive with better characteristics.The gel time reduces as the hardener concentration rises from 7.5%to 15%when glyoxal is used in adhesives.However,excessive amounts of glyoxal will result in a decrease in viscosity values.Glyoxal exhibits faster delivery degradation when it reaches a maximum temperature of approximately 130°C,although it initiates the curing process slightly slower at 110°C.Adding glyoxal to tannin-based adhesives can improve the mechanical properties of composite boards.The wet shear strength of the resulting plywood is increased by 105.4%with the addition of 5-weight percent tannin-based resin with glyoxal as a cross-linker in Soy Protein Adhesive.With glyoxal as a hardener,the panels produced showed good internal bond strengths(>0.35 MPa)and met the international standard specifications for interior-grade panels.

Anti-acetylcholinesterase activity of the aglycones of phenolic glycosides isolated from Leonurus japonicus

Objective: To find the genuine structure with anti-acetylcholinesterase(anti-ACh E) from the phenolic glycosides abundant in Leonurus japonicus(Lamiaceae). The assay for antiACh E activity is often used to lead anti-Alzheimer's drugs.Methods: The five phenolic glycosides, tiliroside, leonurusoside C, 2’’’-syringoylrutin,rutin, and lavanduliofolioside were isolated from L. japonicus. The activities of the glycosides were relatively low. Seven compounds including p-coumaric acid, caffeic acid, hydroxytyrosol, salidroside, syringic acid, kaempferol, and quercetin, which are produced by the hydrolysis of the five glycosides, were also assayed for anti-ACh E activity.Results: Of those seven compounds, the five compounds other than salidroside and syringic acid exhibited potent anti-ACh E activities. In particular, the IC_(50)s of caffeic acid and quercetin were(1.05 ± 0.19) and(3.58 ± 0.02) mg/m L, respectively. Rutin was the most abundant flavonoid in the extract(9.18 mg/g as measured by HPLC).Conclusion: The substances with potent anti-ACh E were caffeic acid, quercetin, pcoumaric acid, kaempferol, and hydroxytyrosol that can be produced from their glycosides.

Identification and quantification of flavonoids in Carica papaya leaf and peroxynitrite-scavenging activity

Objective: To characterize the types, contents, and peroxynitrite-scavenging activities of flavonoids in the leaf of Carica papaya(C. papaya).Methods: Chromatographic and spectroscopic techniques along with high performance liquid chromatography quantitative analysis and peroxynitrite-scavenging assay were performed to isolate and quantify flavonoid compounds in the flavonoid-rich fraction(Bu OH fraction) derived from Me OH extract of C. papaya leaves and evaluate their peroxynitrite-scavenging activities.Results: Seven flavonoids were isolated from the leaves of C. papaya, including quercetin 3-(2~G-rhamnosylrutinoside), kaempferol 3-(2~G-rhamnosylrutinoside), quercetin 3-rutinoside, myricetin 3-rhamnoside, kaempferol 3-rutinoside, quercetin, and kaempferol. All of the substances exhibited potent activities on peroxynitrite scavenging(IC50 4.15 mmol/L), which were stronger than the positive control, L-penicillamine(6.90 mmol/L). The content of kaempferol 3-(2~G-rhamnosylrutinoside) was significantly higher than other identified compounds(123.18 mg/g Bu OH fraction and 7.23 mg/g Me OH extract).Conclusions: The results of the present study demonstrate the potent antioxidant flavonoids of C. papaya leaf, with kaempferol 3-(2~G-rhamnosylrutinoside) as the major one.

Value Analysis among the Parties on Imported Product in Indonesia Using Process Activity Mapping： Freight Forwarder, Distributor, and Retailer

National logistics system in Indonesia can be categorized as inefficient logistics system due to current number of non-value added （NVA） activities. The unreliable National logistics system and the complexity of distribution system are the big obstacles. This study aims to analyze the value and to propose recommendation for further improvement of National distribution system for imported product. This study employed convenience sampling through in-depth interview to analyze the activity in freight forwarder （FF）, distributor and retailer. To demonstrate and analyze the activity process in each party, Process Activity Mapping （PAM） was used as a tool. The study results showed that the delivery speed in Jakarta （8.4 min/km） is slower than that of Surabaya （6.6 min/km）. The government support through creating adequate infrastructure, good bureaucracy system and good collaboration directly affects the activities of FF, distributor and retailer. Improving FF performance in a timely and reliable manner is required to reduce errors that may occur. Moreover, encouraging the practice of cold chain management is also necessary in distributing the product throughout Indonesia. The pull strategy can be chosen by retailer to eliminate storage activity. Meanwhile, the use of information technology （IT） system is essential to encourage better inventory management, database management and sharing information in distributor and retailer stage.