تاثير افزودن اسيد سيتريك بر ويژگي هاي تخته خرده چوب

Effect of the addition of citric acid on particleboard properties

در اﯾﻦ ﺗﺤﻘﯿﻖ ﺗﺄﺛﯿﺮ اﻓﺰودن اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ ﺑﺮ ﺧﻮاص ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ ﺗﺨﺘﻪ ﺧﺮده ﭼﻮب ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺴﺒﺖ وزﻧﯽ اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ ﺑﻪ ﺧﺮده ﭼﻮب در ﭼﻬﺎر ﺳﻄﺢ )70/30 ،80/20 ،90/10 ،100/0( و ﭼﺴﺐ اوره ﻓﺮمآﻟﺪﻫﯿﺪ در دو ﺳﻄﺢ )5 و 10 درﺻﺪ( ﺑﻪ ﻋﻨﻮان ﻣﺘﻐﯿﺮﻫﺎي ﻣﺴﺘﻘﻞ اﯾﻦ ﻣﻄﺎﻟﻌﻪ اﻧﺘﺨﺎب ﮔﺮدﯾﺪ. ﺑﺮاي اﻧﺠﺎم آزﻣﻮنﻫﺎي ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ از اﺳﺘﺎﻧﺪاردﻫﺎي اروﭘﺎﯾﯽ ﻣﺠﻤﻮﻋﻪ EN اﺳﺘﻔﺎده ﺷﺪ. ﺗﺄﺛﯿﺮات ﺗﯿﻤﺎر اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ ﺑﺮ روي ﺧﺮده ﭼﻮب ﺑﻪ وﺳﯿﻠﻪ FTIR آﻧﺎﻟﯿﺰ ﺷﺪ. ﻧﺘﺎﯾﺞ ﻃﯿﻒ FTIR ﻧﺸﺎن داد ﮐﻪ ﮔﺮوهﻫﺎي ﮐﺮﺑﻮﮐﺴﯿﻞ اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ ﺑﺎ ﮔﺮوهﻫﺎي ﻫﯿﺪروﮐﺴﯿﻞ ﺧﺮده ﭼﻮب واﮐﻨﺶ داده و ﺑﺎﻋﺚ ﺑﻬﺒﻮد وﯾﮋﮔﯽﻫﺎي ﻓﯿﺰﯾﮑﯽ و ﻣﮑﺎﻧﯿﮑﯽ ﺗﺨﺘﻪ ﺷﺪه اﺳﺖ. ﺑﻪ دﻟﯿﻞ ﻋﻤﻠﮑﺮد ﺧﻮب اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ در ﺑﻬﺒﻮد ﻣﻘﺎوﻣﺖﻫﺎ ﻣﯽﺗﻮان ﻣﻘﺪار ﻣﺼﺮف ﭼﺴﺐ اوره ﻓﺮمآﻟﺪﻫﯿﺪ در ﺳﺎﺧﺖ ﺗﺨﺘﻪ ﺧﺮده ﭼﻮب را ﮐﺎﻫﺶ داد. ﻃﺒﻖ ﻧﺘﺎﯾﺞ اﯾﻦ ﺗﺤﻘﯿﻖ ﻣﯽﺗﻮان ﺑﺎ اﺳﺘﻔﺎده از ﻣﯿﺰان ﭼﺴﺐ 5 درﺻﺪ و اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ 20 درﺻﺪ، ﺣﺪاﻗﻞ اﺳﺘﺎﻧﺪاردﻫﺎي EN312 ﺑﺮاي ﺗﺨﺘﻪﻫﺎﯾﯽ ﺑﺮاي اﻫﺪاف ﻋﻤﻮﻣﯽ )ﺗﯿﭗ 1( را ﺑﺮآورده ﻧﻤﻮد. ﻫﻤﭽﻨﯿﻦ ﻣﯽﺗﻮان ﺑﺎ اﺳﺘﻔﺎده از ﻣﯿﺰان ﭼﺴﺐ 10 درﺻﺪ و اﺳﯿﺪ ﺳﯿﺘﺮﯾﮏ 20 درﺻﺪ ﺗﺨﺘﻪﻫﺎﯾﯽ ﺑﺎﻻﺗﺮ از ﺣﺪ اﺳﺘﺎﻧﺪارد 312 EN ﺑﺮاي ﻟﻮازم داﺧﻠﯽ ﺗﯿﭗ 2 ﺗﻮﻟﯿﺪ ﻧﻤﻮد

In this study, the effect of the addition of citric acid on physical and mechanical properties of particleboard were investigated. The variable in this research were the ratio of citric acid to wood chips (at four levels; 0:100, 10:90, 20:80, 30:70) and urea - formaldehyde resin (in two levels of 5 and 10 percent). The physical and mechanical properties were evaluated according to European standards set of EN. The effect of citric acid treatment on the wood particles was analyzed by FTIR. Fourier transform infrared spectra analysis suggested that the carboxyl groups of citric acid had reacted with the hydroxyl groups of the wood particles to give the boards good physical and mechanical properties. The urea-formaldehyde resin content can be reduced in the particleboard as good function citric acid in improving strengths. On the basis of results of this study can be concluded that particleboard containing urea-formaldehyde resin in the level of 5 percent and citric acid in the level of 20 percent can be used for general purpose board (Type P1) for use in dry conditions. Also, there was usability of urea-formaldehyde resin in the level of 10 percent and citric acid in the level of 20 percent for interior fitments (Type P2) for use in dry conditions.