Preparation of a new IPBC/β-cyclodextrin compound fungicide

Objective  A new IPBC/β-cyclodextrin compound fungicide was prepared and its properties were explored, aiming to improve the water solubility and photothermal stability of 3-iodo-2-propynyl-butyl-carbamate (IPBC) and broaden its application in the field of wood and bamboo fungicide.

Method Using β-cyclodextrin (β-CD) as the host and IPBC as the guest, IPBC/β-CD compound fungicide was prepared by coprecipitation method. Three factors including the molar ratio of host to guest, reaction temperature and reaction time were selected to explore the influence of different factors on the inclusion reaction and optimize the preparation process through single factor experiments. The fungicide was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), light aging resistance analysis and other methods. The solubilization characteristics of IPBC/β-CD compound fungicide were tested by phase solubility method. The anti-fungal efficacy of IPBC/β-CD compound fungicides with different mass fractions was evaluated using four fungi, namely Aspergillus niger, Botryodiplodia theobromae, Penicillium citrinum and Trichoderma viride, to obtain their comprehensive fungicide performance index.

Result (1) The crystal structure and physical properties of IPBC/β-CD compound fungicide had changed. The compound fungicide had uniform distribution and regular four sided microstructure characteristics. Taking the inclusion rate as the test index, the optimal preparation conditions of the compound fungicide were as follows: the molar ratio of β-CD to IPBC was 4:1, the reaction temperature was 50 ℃, and the reaction time was 4 h. Under these conditions, the inclusion rate of IPBC in the compound fungicide could reach 52.02%. (2) The thermal degradation temperature of the effective component IPBC in the compound fungicide was increased from 120 ℃ to 200 ℃, and only slight yellowing occurred on the surface after 60 min of UV irradiation. When the concentration of β-CD was 0.01 mol/L, the water solubility of IPBC could be increased by 1.65 times. (3) As the increase of the mass fraction of the antifungal agent, its anti-fungal efficacy against four types of fungi gradually improved. The compound fungicide with a mass fraction of 1.00% had the best anti-fungal performance. After 7 days of cultivation, the diameters of inhibition zones of Aspergillus niger, Botryodiplodia theobromae, Penicillium citrinum and Trichoderma viride were 25.47, 49.12, 52.45, and 39.93 mm, respectively.

Conclusion The IPBC/β-CD wood compound fungicide prepared in this study improve the water solubility and photothermal stability of IPBC, and show good control efficacy against four common wood and bamboo fungi. This study can enhance the application stability of IPBC, and expand its application in the field of wood and bamboo mold prevention.