جستجوی مقالات مرتبط با کلیدواژه « انتشار فرم آلدهید » در نشریات گروه « جنگلداری »

There are adequate sources for wood adhesives, but scarcity of oil resources can affect the cost and future availability of oil based resins. For avoiding of this process, seeking for feasibility of replacement of these oil feedstocks is necessary. In present work, thermal behavior of urea formaldehyde resin modified by furfural was investigated. The thermo-gravimetry was used for this purpose, and FTIR spectroscopy also was used to determine the functional groups in adhesives. In this study, three types of resins including industrial urea formaldehyde, and urea formaldehyde furfural in 25% and 50% of formaldehyde replacement by furfural were considered as variables. The formaldehyde emission from manufactured particle-board also was measured. Results of thermal studying of adhesives indicated that resin modification had improving influence on thermal properties of resin, especially in higher temperatures (around 220-380˚C). Obtained FTIR spectrums also revealed the much similarity between groups and bonds of industrial resin and modified resins. Modification of resin by furfural reduced the formaldehyde emission of particleboard to E1 level.

Partial replacement of formaldehyde with furfural in the urea-formaldehyde resin on the formaldehyde emission, physical and mechanical properties of particleboard was investigated. The modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), water absorption (WA), thickness swelling (TS) and formaldehyde emission (FE) of Poplar particleboards made with the modified resins were measured and were compared with the conventional UF resin. Also, chemical structures of the synthesized Resins were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The results indicated that modulus of rupture (MOR), modulus of elasticity (MOE) and formaldehyde emission (FE) from boards was decreased by partial replacement of formaldehyde. Boards prepared with modified resin with 50% furfural showed the highest internal bond (IB). Two and 2 hours water uptake test of the boards prepared with modified resin unlike thickness swelling was decreased compared to the conventional resin. Boards prepared with industrial urea-formaldehyde resin presented the least thickness swelling. Best treatment and condition of preparing boards in terms of MOR, MOE and stableness of dimensions, it can be introduced using urea-formaldehyde resin (except formaldehyde emission), also in terms of IB and water absorption, using resin modified with 50% furfural. Boards cured with conventional UF resin presented the least formaldehyde emission.