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℃ to 200℃,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℃.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.

Production of carbon anodes by high-temperature mould pressing

Laboratory-scale carbon anodes were produced by a new method of high temperature mould pressing, and their physico-chemical properties were studied. The influence of mould pressing conditions and coal pitch addition on the bulk density, crushing strength, and oxidation resistance was analyzed. The mierostructure of carbon anodes was investigated by scanning electron microscopy （SEM）, and the mechanism of producing carbon anodes by high-temperature mould pressing was analyzed. The results show that when the anodes are produced by high-temperature mould pressing, coal pitch can expand into the coke particles and fill the pores inside the particles, which is beneficial for improving the quality of prebaked anodes. The bulk density of carbon anodes is 1.64-1.66 g/cm3, which is 0.08-0.12 g/cm3 higher than that of industrial anodes, and the oxidation resistance of carbon anodes is also significantly improved.

Mechanical behaviour of wood compressed in radial direction:Part II.Influence of temperature and moisture content

This study investigated the influence of pressing temperature and moisture content on the me-chanical properties of wood compressed in radial direction.Jack pine(Pinus banksiana)and bal-sam poplar(Populus balsamifera)specimens were tested under a combination of pressing temper-ature(20℃,55℃,90℃,and 125℃)and wood moisture content(2%,7%,12%,and 17%).The yield stress(_(δ)y)and modulus of elasticity(MOE)of the specimens were determined from the stress-strain response.It was found that an increase in either pressing temperature or moisture content of wood generally caused a decrease in the mechanical properties for both species.The t-test results revealed that jack pine specimens are more sensitive to changes in pressing tem-perature and wood moisture content than balsam poplar.For jack pine specimens,at any of the pressing temperatures,the moisture content of 12%was found to be a crucial level to start a significant decrease in𝜎y and MOE,while at any of the moisture content,a change in temper-ature from 55℃to 90℃exhibited a significant change in𝜎y and MOE.The regression models developed can be used to predict𝜎y and MOE as a function of temperature and moisture content.