共查询到19条相似文献,搜索用时 46 毫秒
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对聚乙烯(PE)包膜尿素的制备工艺、氮(N)释放速度及物理机械性能进行了探讨,表明该产品可有效控制氮的释放,减少尿素流失,提高氮的利用率,有希望成为一种新型缓释尿素产品。 相似文献
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尿素氨化制备歧化松香腈的研究 总被引:3,自引:0,他引:3
以歧化松香为原料,在氯化钴和硼酸催化作用下,用尿素氨化,制得了歧化松香腈。以歧化松香计,歧化松香腈的收率为83.3%,讨论了原料比、催化剂、反应温度、反应时间等因素对反应的影响。 相似文献
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逆转喷射乳化法制备石蜡分散松香胶 总被引:3,自引:0,他引:3
研究了逆转喷射乳化法制备石蜡分散松香胶的新方法,乳化剂可选用甲磺酸钠类阴离子表面活性剂和非离子表面活性剂进行复配,乳化剂用量为6% ̄8%;水温为60 ̄70℃;油温为125 ̄135℃;抄纸时松香胶的用量为绝干浆的0.8% ̄1.0%;pH值为4.5 ̄5.5;明矾用量为石蜡松香胶的4 ̄7倍;施胶度为1.0 ̄1.2。 相似文献
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采用MDI、PAPI和大豆多元醇为原料,制备包膜尿素肥料.探索并确定了该工艺路线的可行性,研究了树脂型包膜材料,并使用包膜剂对尿素进行了包膜,开展了包膜尿素释放率试验.结果表明,包膜尿素在前15 d尿素没有释放,到30 d的时候,尿素释放率为70%.该包膜材料具有明显的缓释作用,且包膜材料对尿素的物理性能和机械性能有一... 相似文献
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用异氰酸酯与聚氧化丙烯二醇(PPG)合成聚氨酯,再以其包裹尿素制成聚氨酯包膜尿素.采用比色法绘制聚氨酯包膜尿素的缓释曲线,讨论了异氰酸酯与羟基摩尔比(NCO/OH)、包膜率、反应方式、异氰酸酯、PPG分子量对包膜尿素缓释性能的影响.结果发现,以丙酮为溶剂,NCO/OH为1.1,在50~60℃的水浴温度下,PPG-300... 相似文献
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采用回转法工艺,使松香在性能优良的表面活性剂作用下,经过乳化,固液相回转,制备出性能稳定的高分散松香胶,其主要特点为施胶效果好,能降低造纸业生产成本,制备工艺简单,操作方便。 相似文献
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Lixia Li Huaihe Song Qiang Xiao Wenping Yi Xiaohui Ni 《Polymer-Plastics Technology and Engineering》2017,56(8):866-872
Pure polyurethane (PU) and its composites with zeolite 4A prepared through the in situ reaction were used as coating materials for urea. On the basis of analyzing their morphologies and structures, the effect of zeolite 4A content on release property of coated urea was investigated. SEM images showed the formation of the good interface between microsized zeolite 4A and polyurethane. When 2% of zeolite 4A was added into PU, the N release duration of coated urea reached 70 d, implying that PU/zeolite 4A composite can be used as an alternate strategy to improve the N use efficiency in controlled release fertilizer. 相似文献
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Lixia Li Bing Cao Yumeng Sun Wenping Yi Xiaohui Ni 《Polymer-Plastics Technology and Engineering》2019,58(1):77-82
Polyurethane composite coatings on urea granules were prepared by SBA-15 mesoporous silica (in as-synthesized and calcined forms) as a pseudo-crosslinker without any other chain extenders. The calcination of mesoporous silica leaded to reduction of hydroxyl groups and increase of mesopores. The composite coating containing calcined SBA-15 showed enhanced controlled release properties compared with the other two coatings. At the loading content of 1 wt%, the initial release rate and release duration of urea coated by polyurethane/calcined SBA-15 composite were 0.08% and 83 d, respectively. It is shown that the calcination played an important role in controlling the properties of composite coating. 相似文献
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新型包膜尿素的制备及其特性的研究 总被引:2,自引:0,他引:2
以桐油为主要成膜物质制备新型包膜尿素。研究结果表明,包膜后尿素颗粒的粒径分布更加均匀,有外密封层时可在包膜尿素表面形成连续致密的包膜,包膜尿素因之获得逐步释放特性。使用溶解率和无土柱淋溶率可以评价包膜尿素的养份释放特性。 相似文献