{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T03:22:01Z","timestamp":1790997721055,"version":"4.1.0"},"reference-count":32,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2019,10,28]],"date-time":"2019-10-28T00:00:00Z","timestamp":1572220800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["No. 31770631"],"award-info":[{"award-number":["No. 31770631"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"China and Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP) of China","award":["PPZY2015C221"],"award-info":[{"award-number":["PPZY2015C221"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Lignin, a byproduct from the chemical processing of lignocellulosic biomass, is a polyphenolic compound that has potential as a partial phenol substitute in phenolic adhesive formulations. In this study, HBr and HI were used as reagents to demethylate an alkali lignin (AL) to increase its hydroxyl content and thereby enhance its reactivity for the preparation of phenolic resins. Analyses by FT-IR, 1H-NMR and 2D-NMR(HSQC) demonstrated both a decrease in methoxyl groups and an increase in hydroxyl groups for each demethylated lignin (DL). In addition, the molar amounts of phenolic hydroxyls, determined by 1H-NMR, increased to 0.67 mmol\/g for the HI-DL, and 0.64 mmol\/g for the HBr-DL, from 0.52 mmol\/g for the AL. These results showed that HI, a stronger nucleophilic reagent than HBr, provided a higher degree of AL demethylation. Lignin-containing resins, prepared by copolymerization, met the bonding strength standard for exterior plywood with DL used to replace as much as 50 wt.% of phenol. The increased hydroxyl contents resulting from the lignin demethylations also imparted faster cure times for the lignin-containing resins and lower formaldehyde emissions. Altogether, the stronger nucleophilicity of HI, compared to HBr, impacted the degree of lignin demethylation, and carried through to measurable differences the thermal properties and performance of the lignin-containing PF resins.<\/jats:p>","DOI":"10.3390\/polym11111771","type":"journal-article","created":{"date-parts":[[2019,10,28]],"date-time":"2019-10-28T04:44:31Z","timestamp":1572237871000},"page":"1771","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":92,"title":["Demethylation of Alkali Lignin with Halogen Acids and Its Application to Phenolic Resins"],"prefix":"10.3390","volume":"11","author":[{"given":"Hao","family":"Wang","sequence":"first","affiliation":[{"name":"Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, 159# Longpan Road, Nanjing 210037, China"},{"name":"College of Chemical Engineering, Nanjing Forestry University, 159# Longpan Road, Nanjing 210037, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas L.","family":"Eberhardt","sequence":"additional","affiliation":[{"name":"Forest Products Laboratory, USDA, One Gifford Pinchot Drive, Madison, WI 53726, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chunpeng","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry, Nanjing 210042, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shishuai","family":"Gao","sequence":"additional","affiliation":[{"name":"Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry, Nanjing 210042, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hui","family":"Pan","sequence":"additional","affiliation":[{"name":"Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, 159# Longpan Road, Nanjing 210037, China"},{"name":"College of Chemical Engineering, Nanjing Forestry University, 159# Longpan Road, Nanjing 210037, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1175","DOI":"10.1039\/C5GC02616D","article-title":"Towards lignin-based functional materials in a sustainable world","volume":"18","author":"Kai","year":"2016","journal-title":"Green Chem."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Katahira, R., Elder, T.J., and Beckham, G.T. 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