Studies On The Preparation And Properties Of Control-released Bark Beetle Attractants

Recently, bark beetle becomes one of the pests that seriously jeopardize the forest ecological system all over the world. With the increasing of imported wood, large numbers of bark beetle come into our country, which lead to tremendous loss in economy, forest and negative effect in ecological environment. Bark beetle are trapped and killed by all kinds of ways in order to decrease the damage to minimum degree. Moreover, the quarantine efficiency is improved to prevent entrance of the bark beetle. Now, new attractants have already been developed, which can ensnare the bark beetle effectively and their cost is relatively cheap. Unfortunately, they are prone to volatilize, and the insufflation burden is excessive when used. It is well known, in different cases need different slow-release effect of those attractants. So it's urgent to develop convenience, economical and manifold control-released attractants. In this paper, the forest odor perfume whose volatility is similar to bark beetle attractants was been adopted as a simulacrum. Based on studies on preparation and property of control-released forest odor perfume products, the suitable methods were chosen to use on the bark beetle attractants. The property of different control-released bark beetle attractants was investigated respectively. According to different control-released properties, they can be used in different cases where need long or short term releasing effect.Different control-released forest odor perfume microcapsules were prepared by in-situ polymerization. Different control-released porous starch and bolus double-control-released products with perfume were carried out by porous starch absorption method. Furthermore, bark beetle attractants were prepared into microcapsules and porous starch bolus control-released products by above methods.In this paper, the surface morphology of forest odor perfume microcapsule and porous starch were observed by Scanning Electron microscope. The particle size and distribution of perfume microcapsules were measured by Laser Particle Size Analyzer. The control-released properties of different samples with perfume and bark beetle attractant were analyzed by thermogravimetry analyses. The properties of control-released perfume products were measured quantitatively by ultraviolet spectrophotometry. According to the releasing curves , the release kinetics of perfume from different samples were been analyzed elementarily. Finally, the application effects of control-released bark beetle attractant products were tested in wood laydown area.Results are as following described:The shape of perfume microcapsules show spheroidal. The particle size is larger with increasing in wall quantity, and the distribution of perfume microcapsules prepared with m(wall):m(core)=0.25:l is the most concentrated. The weight loss rates of single-wall microcapsules are in constant speed up to 90℃, then accelerate between 90 and 140℃, finally kept a very low rate from 170℃on. The weight loss rates of double-wall microcapsules are lower than those of single-wall ones. In natural environment, release rates of double-wall microcapsules are lower than those of single-wall ones, and oil content still remain high level after 30d later. There are two stages in release process of single wall perfume microcapsules, and these two stages meet with class I and class II kinetic process respectively. Double wall perfume microcapsules, however, their two stages all meet with class II kinetic process.The weight loss rates of different porous starches control-released perfume materials accelerate before 150℃, then weight loss becomes very little after 170℃because of exhausting of the oil. In natural environment, the release rates of different porous starches control-released materials reduce with the time passed. There are two stages in release of perfume in porous starch, and these two stages meet with class I and class II kinetic process respectively. Additionally, the larger of the bolus double-control-released product with perfume and the higher concentration of polymer solution are, the better control-released property will be.During the application trails, the entrapping effect of the microcapsules with bark beetle attractant can last 5d, which suitable for the application in forest where need long term release. Porous starch bolus double-control-released product with bark beetle attractant is of outstanding entrapping effect. But it can only last 2d, and then have little entrapping effect. As a results, this sample is suitable for the application in quarantine where need short term release.