Calcium carbonate modified urea–formaldehyde resin adhesive for strength enhanced medium density fiberboard production. Issue 40 (19th July 2021)

• Record Type: Journal Article
• Authors: Lu, Li; Wang, Yan; Li, Tianhua; Wang, Supeng; Yang, Shoulu; Qing, Yan; Li, Xingong; Wu, Yiqiang; Liu, Ming
• Is Part Of: RSC advances. Volume 11:Issue 40(2021)
• Page Start: 25010
• Page End: 25017
• Publication Date: 2021-07-19
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra04316a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Reactions between CaCO3 and CH2 O2 during polycondensation of UF resin produce Ca 2+ . Ionic bond complexation binds Ca 2+ with UF resin. The UF resin crystalline percentage decreases from 26.86% to 22.71%. IB strength of resin bonded fiberboard increases from 0.75 to 0.94 MPa. Abstract : This study investigated the improved properties of calcium carbonate (CaCO3 ) modified urea–formaldehyde (UF) resin adhesive for medium density fiberboard (MDF) production. The CaCO3 modified UF resins were prepared by adding different proportions of CaCO3 to a low molar ratio UF resin at the initial stage of a typical synthetic process of the resin. The physicochemical properties of the resins were measured. The mechanical and environmental performances of the resin-bonded MDF panels were tested. The results show that the viscosity and free formaldehyde content of UF resins with or without CaCO3 modification were not significantly different. The solid content of the CaCO3 modified UF resin was significantly lower than that of the control group. In addition, the measured gel time of the CaCO3 modified UF resin was 111–149 s, which was longer than that of the control resin (82 s). The gel time was further extended with the increase of the CaCO3 content in the UF resin. The chemical group and crystal structure of UF resins with or without the modification of CaCO3 were not significantly different. The internal bonding (IB) strength of the MDF panels significantly increased from 0.75 MPa to 0.97 MPa when the UF resin was modified with 2% of CaCO3 . This study provides scientific support for the preparation of inorganic mineral modified UF resins for strength enhanced wood-based panel manufacturing.