@article {1860,
	title = { Direct reuse at industrial level of ion-exchange resin regeneration wastewater in MDF manufacturing },
	journal = { EUROPEAN JOURNAL OF WOOD AND WOOD PRODUCTS },
	volume = {78},
	year = {2020},
	pages = {523-531},
	abstract = {<p>Industrial wastewater is currently a big challenge for authorities due to its environmental issues when disposed to the ecosystem. From an economic perspective and long treatment time, it is yet more reasonable to recover and reuse wastewater in industries. In this work, the wastewater from an ion exchange resin regeneration process was directly and without any further treatment reused in the wood industry for manufacturing medium density fiberboards (MDF). Comparing with the disposal criteria of international standards, the reused wastewater exhibited much higher electrical conductivity, turbidity, total dissolved solid, total suspension solid, and inorganic salt content than the permissible limits; therefore, it is categorized as hazardous material. The highly saline wastewater was added during and after synthesizing of the urea-formaldehyde (UF) resin but before mixing with the wood fibers. The Fourier transform infrared spectroscopy and differential scanning calorimetry analyses of the UF resin samples, respectively, demonstrated the high stability of the chemical structure and higher strength against decomposition for the UF resins after being treated with the wastewater. The physico-mechanical properties of MDFs prepared by reused wastewater were significantly improved whilst the formaldehyde emission of the boards was noticeably reduced (~ 17\%) to the benefit of the environment.</p>},
	author = {M.V. KIAMAHALLEH and M.K. DAZMIRI and A. PIZZI}
}
@article {1781,
	title = { Effect of the initial F/U molar ratio in urea-formaldehyde resins synthesis and its influence on the performance of medium density fiberboard bonded with them },
	journal = { INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES },
	volume = {95},
	year = {2019},
	abstract = {<p>The formaldehyde to urea molar ratio (F/U) plays an important role on the properties of urea formaldehyde (UF) resins and of the medium density fiber board (MDFs) bonded with them. This work presents a hypothesis that besides the final F/U molar ratio in UF resin preparation, the initial F/U affects both the formaldehyde emission levels and the physico-mechanical properties of the boards. Three initial molar ratios F/U of 1.9, 2.1 and 2.3 in resin synthesis have been examined in this work. The structural changes and thermal curing behavior of UF resins were tracked by C-13 NMR and DSC, respectively. At parity of final F/U molar ratio, the resin with initial F/U = 2.1 yielded the highest proportion of linear methylol groups, resulted in the best internal bond strength and lowest thickness swelling of the board. A resin synthesized with the initial F/U = 1.9 provided the highest proportion of total methylene linkages, most methylene ether linkage and lowest free formaldehyde, consistently yielding the lowest formaldehyde emission. These results partially explained why UF resins with lower F/U molar ratios showed relatively poor adhesion when used to manufacture wood-based composites. MDFs bonded with a UF resin having the initial F/U = 2.3 had a relatively good performance with the exception of free formaldehyde, but also showed the best storage stability compared to the other resins having lower initial F/U molar ratios.</p>},
	author = {M.K. DAZMIRI and M.V. KIAMAHALLEH and A. DORIEH and A. PIZZI}
}
