Dissertation
Dissertation > Industrial Technology > Chemical Industry > Pesticide Industry > Pesticides > Botanical insecticide

The Study of Controlled-release Microcapsules on Botanical Insect Behavior Interference Agent

Author WangDan
Tutor ChiDeFu
School Northeast Forestry University
Course Forest Biological Engineering
Keywords α-pinene Black pepper essential oil Leaf alcohol Lure Repellent Slow release
CLC TQ453.3
Type PhD thesis
Year 2012
Downloads 115
Quotes 0
Download Dissertation

This study has successfully prepared slow-release microcapsule of a-pinene, black pepper oil, and leaf alcohol micro sizing agents with the method of complex coacervation.1) First of all, the study had performed the orthogonal experiment after exploring various factors of the influence on the microcapsule capsule and embedding rate, and found a preferred preparation process of the microcapsules.(1) Two better preparation technologies to prepare α-pinene microcapsuleComplex coacervation method with chitosan-gum arabic as wall materials can be effective for micro-encapsulation of core material a-pinene. The optimum conditions of preparation of α-pinene microcapsules are:concentration of0.2%chitosan, gum arabic concentration of3.5%,2.5%emulsifier content the core wall than1:1, the reaction temperature is45℃, pH=4.5, reaction time60min, stirring speed770r/min. Under the best preparation conditions, the microcapsule cladding and drug loading rate reach up to61.70±2.5%and52.11±2.3%, and the microcapsule were capsule-shaped, round, and well-dispersed; the particle size is concentrated in about8μm.Optimum conditions for preparation of a-pinene microcapsules with gelatin-gum arabic as wall material are as follows:complex cohesion solution pH=3.4, wall material concentration of2.0%, the core wall ratio1:1, reaction temperature45℃, complex coacervation reaction time50min, stirring speed660r/min. Under the best preparation condition, the microcapsules are capsule-shaped, rounded, and well-dispersed; encapsulation efficiency reach up to71.70±1.09%and56.70±0.09%drug loading; the particle size of the microcapsules is concentrated in the distribution21μm.(2) Two better preparation technologies to prepare black pepper essential oil microcapsuleThe optimum conditions of preparation of black pepper essential oil by using the Chitosan-Arabia gum as wall material was:Concentration of0.2%chitosan, gum arabic concentration of3.0%,2.0%emulsifier content the core wall than1:1, the reaction temperature is45℃, pH=4.5, reaction time60min, and stirring speed770r/min. Under the best preparation conditions, the microcapsule cladding and drug loading rate reach up to51.70±2.5%and42.11±2.3%, and the microcapsule were capsule-shaped, round and well-dispersed; the particle size is concentrated in about7μm.Optimum conditions for preparation of black pepper essential oil microcapsule with gelatin-Arabia gum as wall material are:complex cohesion solution pH=3.4, wall material concentration of2.0%, the core wall ratio1:1, reaction temperature45℃, complex coacervation reaction time50min, stirring speed660r/min. Under the best preparation conditions, the microcapsules are capsule-shaped, rounded, and well-dispersed; encapsulation efficiency reached69.26%; the particle size of the microcapsules is concentrated in the distribution13p.m.(3) Two better preparation technologies to prepare geranial microcapsule The optimum conditions of preparation of black pepper essential oil by using the Chitosan-Arabia gum as wall material are:concentration of0.2%chitosan, gum arabic concentration of3.0%,2.5%emulsifier content the core wall than1:1, the reaction temperature is45℃, pH=4.5, reaction time30min, and stirring speed770r/min. Under the best preparation conditions, the microcapsule cladding and drug loading rate reach up to73.56%±1.69; drug loading is49.7%+2.49, and the microcapsules are capsule-shaped, round and well-dispersed; the particle size is concentrated in about12μm.Optimum conditions for preparation of geranial microcapsule with gelatin-Arabia gum as wall material: complex cohesion solution pH=3.4, wall material concentration of2.0%, the core wall ratio1:1, reaction temperature45℃, complex coacervation reaction time50min, stirring speed660r/min. The microcapsules capsule-shaped rounded, well dispersed, encapsulation efficiency reached83.01%±2.67, the particle size of the microcapsules is concentrated in the distribution19μm about the best preparation conditions.2) Infrared analysis of the results of the two methods for preparing microcapsule:the chitosan and Arabia gum, gelatin and Arabia formed condensed mixture, and the core material of a-pinene, black pepper essential oil, and cis-3-hexen-l-ol exist in the preparation of microcapsules.3) The results of suspending capsule prepared by the a-pinene, black pepper oil, and leaf alcohol micro sizing agents(1) Suspending formula of microcapsules prepared by the two methods is:4%polyvinyl pyrrolidone and0.1%sodium chloride,0.1%of the thickening/anti-settling agent is xanthan gum,5%of the anti-freezing agent propylene glycol, and0.05%fungicides sodium benzoate. The suspension rate of the microcapsules prepared in the above reaches90%, which is in line with the requirements of the suspension rate of pesticide formulations.(2) Through hot and cold storage stability test, the appearance and fluidity of the microcapsules prepared suspensions almost did not change, and the scanning electron microscope microcapsules morphology did not, either. The change in content of the active ingredients by the UV spectrophotometer microcapsule suspensions also comply with the FAO prescribed standards(3) B-type (NDJ-1) measurement of microcapsule suspensions prepared by chitosan-gum arabic as wall material and gelatin-gum arabic as wall material separately show that the viscosity of the a-pinene is121mpa.s and158mpa.s separately; black pepper oil,129mpa.s and167mpa.s; leaf alcohol microcapsules,114mpa.s and143mpa.s. All of these comply with the viscosity of pesticide suspension requirements of the agent.4) Efficacy and slow-release capsule suspension results(1) Indoor testing prepared by the two methods are a-pinene, black pepper essential oils, the sustained release effect of phytol microcapsule suspensions manefested:encapsulating the a-pinene, black pepper oil, leaf alcohol microcapsule suspensions, the core material is released by the dialysis bag to a medium rate was significantly inhibited and their microcapsules prepared sustained-release effect of the suspending agent of up to11days or more. (2) microcapsule suspensions of α-pinene, black pepper oil, leaf alcohol prepared by two methods, if placed for some time, the morphological changes of the microcapsules of the scanning electron microscope show that:If gelatin-gum arabic as wall material prepared in black microcapsules is placed for3days, the wall will show depression, and with the growth of the storage time, the depression degree as well as the depth of the recess and recessed areas are also increasing. This phenomenon indicates that using complex coacervation of gelatin-gum arabic as wall material can successfully entrapped volatiles alpha-pinene, the essential oils of black pepper, leaf alcohol, and the microcapsules can effectively control the core material volatile; If chitosan-Gum Arabic as the wall material of microcapsules prepared suspensions are placed for some time, the shape of the microcapsules do not change, and its internal is cut to be of cryptand structure, which is left after evaporation of the core material. The same goes to chitosan-gum arabic as wall material, which successfully entrapped volatiles alpha-pinene, the essential oils of black pepper, leaf alcohol.5) The field bioassay pharmacodynamic results show that:the efficacy of microcapsule suspensions prepared by α-pinene, black pepper oil, and leaf alcohol is not affected, and it is possible to effectively reduce the volatilization of the core material, and to extend the efficacy time.

Related Dissertations
More Dissertations