Chitosan composite superfine fibers with a diameter of 321 ± 99 nm were prepared by electrospinning with PEO as the co-spinning polymer and itaconic acid as the in situ cross-linking agent.
The high-efficiency development and utilization of bamboo resources can greatly alleviate the current shortage of wood and promote the neutralization of CO2. However, the wide application of bamboo-derived products is largely limited by their unideal surface properties with adhesive as well as poor gluability. Herein, a facile strategy using the surfactant-induced reconfiguration of urea-formaldehyde (UF) resins was proposed to enhance the interface with bamboo and significantly improve its gluability. Specifically, through the coupling of a variety of surfactants, the viscosity and surface tension of the UF resins were properly regulated. Therefore, the resultant surfactant reconfigured UF resin showed much-improved wettability and spreading performance to the surface of both bamboo green and bamboo yellow. Specifically, the contact angle (CA) values of the bamboo green and bamboo yellow decreased from 79.6° to 30.5° and from 57.5° to 28.2°, respectively, with the corresponding resin spreading area increasing from 0.2 mm2 to 7.6 mm2 and from 0.1 mm2 to 5.6 mm2. Moreover, our reconfigured UF resin can reduce the amount of glue spread applied to bond the laminated commercial bamboo veneer products to 60 g m−2, while the products prepared by the initial UF resin are unable to meet the requirements of the test standard, suggesting that this facile method is an effective way to decrease the application of petroleum-based resins and production costs. More broadly, this surfactant reconfigured strategy can also be performed to regulate the wettability between UF resin and other materials (such as polypropylene board and tinplate), expanding the application fields of UF resin.
The utilization of bamboo resources can significantly alleviate the wood shortage and facilitate CO2 neutralization. However, the adhesive bonding performance of bamboo is not ideal, which greatly limits its application. Therefore, the biggest challenge is to explore a simple and effective method to enhance the bonding between bamboo and adhesive. In this study, we synthesized three butyl acrylate‐styrene (BS) emulsions with different monomer ratios and incorporated them into urea‐formaldehyde (UF) resins to prepare butyl acrylate‐styrene modified urea‐formaldehyde (BUF) adhesives. Results show that BS emulsion not only prolongs the workability time of UF adhesives (95 s–108 s), but also reduces the free formaldehyde content (0.38%–0.26%). Specifically, BS emulsion with the highest hard/soft monomer ratio makes BUF adhesive the lowest activation energy, showing the accelerated curing reaction. Specifically, the prepared laminated bamboo‐veneer lumber (LBVL) exhibits the best wet‐bonding strength and meets the Chinese National Standard, suggesting that BS emulsion with a higher hard/soft monomer ratio can enhance bonding performance. Thus, this efficient method can not only enhance various adhesive properties, but also improves the bonding performance on LVBL, which can greatly ease the shortage of wood resources and speed up the development of the bamboo industry.
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