Further Exploration of Sucrose–Citric Acid Adhesive: Investigation of Optimal Hot-Pressing Conditions for Plywood and Curing Behavior

Abstract

In previous research, sucrose and citric acid were used to synthesize an eco-friendlyplywood adhesive. Herein, further research was performed to determine the optimal hot-pressingconditions and curing behavior of a sucrose-citric acid (SC) adhesive. The results of dry and wetshear strength measurements showed that the optimal hot-pressing temperature, hot-pressing time,and spread rate of plywood samples bonded by the SC adhesive were 190 °C, 7 min, and 140 g/m2,respectively. When plywood was bonded at the optimal hot-pressing conditions, the wet shearstrength met the requirements of the China National Standard GB/T 9846-2015. Thermal analysisshowed that the thermal degradation and endothermic reaction temperatures of the SC 25/75adhesive were lower than either sucrose or citric acid individually. In addition, the insoluble massproportion increased with the heating temperature and time. The Pyrolysis Gas Chromatographyand Mass Spectrometr (Py-GC/MS) analysis confirmed that the SC adhesive was cured by thereaction between furan compounds, saccharide, and citric acid, and the resulting polymer appearedto be joined by ether linkages.

A Review on Citric Acid as Green Modifying Agent and Binder for Wood

“…On the other hand, using CA as bonding agent for plywood is relatively new application as the only 2 literatures were found in the year of 2019 by Sun et al [77] and Zhao et al [76]. It was said that the low viscosity and solid content of CA was the main reason that restricted its use in bonding plywood.…”

Self-Healable Electro-Conductive Hydrogels Based on Core-Shell Structured Nanocellulose/Carbon Nanotubes Hybrids for Use as Flexible Supercapacitors

“…For all the samples, the broad bands at around 3330 cm −1 and sharp bands at around 2900 cm −1 were generally due to O-H stretching of the hydrogen bonds and asymmetrically stretching vibration of C-H in the CH 2 group, respectively [18][19][20][21]. The peaks around 1000 cm −1 and 1600 cm −1 were ascribed to the C-O-C vibration and the carbonyl functional groups of cellulose [22][23][24]. For the spectra of neat CNTs, the characteristic absorption around 1640 cm −1 was assigned to the quaking of the carbon skeleton [25,26].…”

Study on the Properties of Partially Transparent Wood under Different Delignification Processes

“…Finally, the samples were put into an oven at 70 • C for 5 h to complete the further polymerization reaction [15]. The above preparation process was repeated several times to obtain transparent wood under different experimental conditions [16]. In order to facilitate the following experimental test analysis, Betula alnoides is abbreviated as A and New Zealand pine is abbreviated as B; untreated wood samples are collectively referred to as OW, wood templates after removing some lignin are collectively referred to as FW, and the transparent wood after impregnation is collectively referred to as TW.…”

“…This kind of transparent wood appears a bright purple to colorless color change under light and shows about 65% good optical transmittance and 90% high optical haze, which is very important for the application of Smart windows and anti-counterfeiting materials. In the same year, Li et al [4] successfully assembled the perovskite solar cells treated at low temperature (<150 • C) directly on the transparent wood substrate for the first time, with the power conversion efficiency up to 16.8%, which confirmed that the transparent wood is suitable as a substrate for solar cell modules and has potential in energy-efficient building applications. Celine Montanari et al [5] also put forward the view that transparent wood should be endowed with multiple functions.…”