| Eucalyptus,as one of the three fast-growing forest species,is widely used in wood furniture and decoration,but its large amount of starch makes it prone to mildew and blueness.With the improvement of people’s living standards and the strengthening of health awareness,the bacteriostatic demand for wood has gradually become clear,and bacteriostatic furniture has entered the market.Triazole fungicides are widely used in wood preservation but have no bacterial resistance.In this paper,based on the reactivity of the triazole ring in tebuconazole and propiconazole structure,a series of quaternary ammonium triazolium salts with broad-spectrum antibacterial activity and polymerization activity were synthesized through substitution reaction.Non-decaying fungi(Aspergillus niger,Botryodiplodia theobromae)and bacteria(Staphylococcus aureus,Escherichia coli)were selected as the test strains,and the antibacterial activity of triazolium salts was detected by the inhibition ring method and agar dilution method,then prepare it into a solution and impregnate the eucalyptus wood for modification,the performance of modified eucalyptus wood in resisting non-decaying fungi and bacteria was evaluated.The main research content and results of this paper are as follows:(1)A series of triazolium salts with molecular weights ranging from 400 to 600 were synthesized using 3-bromo-1-propene,5-bromo-1-pentene,and 10-bromo-1-decene with double bonds at the end as substituent reagent,respectively,and reacting with tebuconazole and propiconazole to synthesize T-C3,T-C5,T-C10,P-C3,P-C5,and P-C10(T,P represent tebuconazole and propiconazole,respectively,and 3,5,10 represent the length of carbon chains introduced into the modified product).The reaction product was characterized by FTIR,XPS,and NMR,and it was proved that the substituent reagent substituted the hydrogen on the triazole ring,and the carbon-carbon double bond(-C=C-)and bromine ion(Br~-)were successfully introduced into tebuconazole and propiconazole to become triazolium salts.The effect of synthesis conditions on product yield showed that the shorter the carbon chain length in the modified reagent,the higher the reaction activity and the higher the yield.(2)The antifungal activity of triazolium salts against Aspergillus niger and Botryodiplodia theobromae was tested by the bacteriostatic ring method and agar dilution method.The results showed that when the concentration of triazolium salts in agar medium was400μg/m L,the order of antifungal activity against Aspergillus niger was P-C10>T-C5>T-C10>T-C3>P-C5>P-C3;The antibacterial activity against Botryodiplodia theobromae is in the order of T-C5>T-C3>P-C5>P-C3>P-C10>T-C10,among which T-C5 can completely inhibit the growth of Botryodiplodia theobromae.Through the observation of the morphology of the mycelium using a super depth of field microscope,it was found that triazolium salts have a strong inhibitory effect on the growth of the mycelium,so they have a stronger inhibitory effect on Botryodiplodia theobromaewith extremely fast mycelium growth rate.Through SEM-EDS,it was observed that the bromine element in the triazolium salts was uniformly distributed in the cell wall of the modified eucalyptus.The antifungal and discoloring properties of modified eucalyptus wood were evaluated with reference to the standard"Test Method for the Efficacy of Fungicides against Wood Mold and Stain Fungi".The results showed that the control performance of triazolium salts modified eucalyptus was positively correlated with the impregnation concentration.Triazolium salts modified eucalyptus has a higher control effect on Botryodiplodia theobromae.When the concentration of triazolium salts impregnation solution is2.5%,the control effect on Botryodiplodia theobromae is more than 70%.The quaternary ammonium modified products of tebuconazole-based triazolium salts showed better overall control efficacy,and the control effect of the T-C3 and T-C5 treatment groups after washing the modified eucalyptus wood exceeds 75%.Triazolium salts modified eucalyptus can inhibit surface mildew and blue stain.(3)Antibacterial activity of triazolium salts against Staphylococcus aureus and Escherichia coli were detected by the inhibition zone method and agar dilution method.The results showed that the antibacterial activity of triazolium salts against Staphylococcus aureus was better than that against Escherichia coli.The longer the carbon chain in the triazolium structure,the better the bacteriostatic effect.When the concentration of triazolium salts in agar medium is 100μg/m L,the inhibition rate of T-C10 and P-C10 against Staphylococcus aureus is more than 99%,and the inhibition rate against Escherichia coli is more than 97%.The antibacterial performance of modified eucalyptus wood impregnated with triazolium salts was evaluated with reference to the standard"Antibacterial Activity and Efficacy Test of Antibacterial Products".When the concentration of the impregnation solution is 2.5%,the activity value of the triazolium salts modified eucalyptus against Staphylococcus aureus exceeds2,and the antibacterial rate exceeds 99%.Except for P-C10-modified eucalyptus,the activity value of other triazolium salts modified eucalyptus against Escherichia coli exceeds 1,and the antibacterial rate exceeds 90%.The growth of gram-positive and gram-negative bacteria on the surface of eucalyptus modified with triazolium salts was significantly inhibited,and the inhibition effect on gram-positive bacteria was better. |
PDF Full Text Request