肉鸡欧洲效益指数与有机微量元素的应用

应用有机微量元素可提高肉鸡的饲料利用率、免疫力、抗应激能力和鸡肉产品品质,有机微量元素能与微生态制剂等功能性添加剂协同作用,从而改善肉鸡肠道微生态环境,调控肠道健康,促进营养物质的吸收利用,实现健康养殖,特别是在全面禁抗的大环境下,为养殖企业提高肉鸡欧洲效益指数(EPI)提供了绿色方案.文章主要阐述了影响肉鸡欧洲效益指...     

Effect of the ethylene/vinyl acetate ratio of ethylene-vinyl acetate emulsion on the curing behavior of an emulsion polymer isocyanate adhesive for wood

We investigated the curing behavior of an emulsion polymer isocyanate adhesive for wood with different ethylene-vinyl acetate (EVA) emulsions, because it was found that the ethylene/vinyl acetate weight composition (E/VA ratio) of EVA could control the volume of gas emitted from the adhesive. EVA with higher VA content reduced the volume of gas emitted at the initial stage, which was caused by the extent of the reaction between the NCO groups and water. The reaction scheme of NCO could not be determined because the broad infrared (IR) absorptions due to CaCO3 and water masked the information of the NCO products in IR spectra. Examination of the degree of swelling suggested that the adhesive films stored for 3 weeks had the same degree of cross-linking structure in spite of the variation of EVA. This result was supported by IR spectroscopy, which showed the same amounts of NCO remained in these films. All the adhesives prepared in this study had satisfactory bond performance. The findings indicate that the E/VA ratio affects the curing behavior of the adhesive in the initial curing stage, whereas the cross-linking structure and the bond performance were independent of the E/VA ratio after storage for 3 weeks. Part of this report was presented at Wood Adhesives 2005, November 2–4 2005, San Diego, CA, USA