Glenn Gregory M, Klamczynski Artur P, Ludvik Charles, Shey Justin, Imam Syed H, Chiou Bor-Sen, McHugh Tara, DeGrandi-Hoffman Gloria, Orts William, Wood Delilah, Offeman Rick
Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA.
J Agric Food Chem. 2006 May 3;54(9):3297-304. doi: 10.1021/jf053262z.
Volatile agrochemicals such as 2-heptanone have potential in safely and effectively controlling important agricultural pests provided that they are properly delivered. The present study reports the permeability of starch gel matrices and various coatings, some of which are agricultural-based, that could be used in controlled release devices. Low-density, microcellular starch foam was made from wheat, Dent corn, and high amylose corn starches. The foam density ranged from 0.14 to 0.34 g/cm3, the pore volume ranged from 74 to 89%, and the loading capacity ranged from 2.3 to 7.2 times the foam weight. The compressive properties of the foam were not markedly affected by saturating the pore volume with silicone oil. The vapor transmission rate (VTR) and vapor permeability (VP) were measured in dry, porous starch foam and silicone-saturated starch gels. VTR values were highest in foam samples containing solvents with high vapor pressures. Silicone oil-saturated gels had lower VTR and VP values as compared to the dry foam. However, the silicone oil gel did not markedly reduce the VP for 2-heptanone and an additional vapor barrier or coating was needed to adequately reduce the evaporation rate. The VP of films of beeswax, paraffin, ethylene vinyl alcohol, a fruit film, and a laminate comprised of beeswax and fruit film was measured. The fruit film had a relatively high VP for polar solvents and a very low VP for nonpolar solvents. The laminate film provided a low VP for polar and nonpolar solvents. Perforating the fruit film portion of the laminate provided a method of attaining the target flux rate of 2-heptanone. The results demonstrate that the vapor flux rate of biologically active solvents can be controlled using agricultural materials.
挥发性农用化学品如2-庚酮，只要能恰当释放，就有安全有效地控制重要农业害虫的潜力。本研究报告了淀粉凝胶基质和各种涂层（其中一些是基于农业的）的渗透性，这些可用于控释装置。低密度微孔淀粉泡沫由小麦淀粉、马齿玉米淀粉和高直链玉米淀粉制成。泡沫密度范围为0.14至0.34克/立方厘米，孔隙率范围为74%至89%，负载能力范围为泡沫重量的2.3至7.2倍。用硅油充满孔隙体积对泡沫的压缩性能没有显著影响。在干燥的多孔淀粉泡沫和硅油饱和的淀粉凝胶中测量了蒸汽透过率（VTR）和蒸汽渗透率（VP）。在含有高蒸汽压溶剂的泡沫样品中，VTR值最高。与干燥泡沫相比，硅油饱和凝胶的VTR和VP值较低。然而，硅油凝胶并没有显著降低2-庚酮的VP，需要额外的蒸汽屏障或涂层来充分降低蒸发速率。测量了蜂蜡、石蜡、乙烯-乙烯醇、一种水果薄膜以及由蜂蜡和水果薄膜组成的层压材料薄膜的VP。水果薄膜对极性溶剂具有相对较高的VP，对非极性溶剂具有非常低的VP。层压薄膜对极性和非极性溶剂都提供了较低的VP。在层压材料的水果薄膜部分打孔提供了一种达到2-庚酮目标通量率的方法。结果表明，使用农业材料可以控制生物活性溶剂的蒸汽通量率。
