Formaldehyde free tannin-based adhesive with epoxy as hardener for plywood

Liu, Bowen; Zhou, Yunxia; Essawy, Hisham; Chen, Qian; Liang, Jiankun; Zhou, Xiaojian; Zhang, Jun; Du, Guanben

doi:10.4067/s0718-221x2022000100433

Cited by 1 publication

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References 24 publications

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“…Interestingly, furfuryl alcohol, which is mainly extracted from corncob, has a stable furan ring and reactive hydroxymethyl group. It is often used to prepare bio-based materials with high hardness and good thermal performance, such as thermosetting rigid plastic [ 29 ], foams [ 30 , 31 , 32 , 33 ], wood adhesives [ 34 , 35 , 36 ], and grinding wheels [ 37 , 38 , 39 ]. Although the polycondensation of starch and furfuryl alcohol is considered to yield foams with good thermal stability and hardness, the hydroxymethyl group in furfuryl alcohol can react with the adjacent furfuryl alcohol under acidic conditions [ 29 ], so it is easy for it to undergo self-polycondensation under acidic conditions, while it is difficult for it to undergo further crosslinking with starch.…”

Section: Introductionmentioning

confidence: 99%

Facile Synthesis of Formaldehyde-Free Bio-Based Thermoset Resins for Fabrication of Highly Efficient Foams

Liu

Zheng

et al. 2022

Polymers

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Bio-based biodegradable foams were formulated from a crosslinkable network structure combining starch, furfuryl alcohol, glyoxal, and condensed tannin in the presence of p-toluenesulfonic acid (pTSA) and azodicarbonamide (AC) as a foaming agent. More importantly, the reinforcement of gelatinized starch–furanic foam using tannin, originating from forestry, resulted in an excellent compressive strength and lower pulverization ratio. Moreover, the addition of tannin guaranteed a low thermal conductivity and moderate flame retardancy. Fourier transform infrared (FTIR) spectroscopy approved the successful polycondensation of these condensing agents under the employed acidic conditions. Moreover, the catalytic effect of pTSA on the foaming agent induced liberation of gases, which are necessary for foam formation during crosslinking. Scanning electron microscopy (SEM) showed foam formation comprising closed cells with uniform cell distribution and appropriate apparent density. Meanwhile, the novel foam exhibited biodegradation under the action of Penicillium sp., as identified by the damage of cell walls of this foam over a period of 30 days.

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