添加纳米TiO_(2)改善淀粉基聚酯聚氨酯复合材料的膜层质量和养分控释特性  

Nano TiO_(2) addition improves the coating quality of starch based/polyester polyurethane and nutrient release characteristics of the coated urea

作　　者：董晶晶 田虹雨 石若琳 杨云博 武良 房福力 张民[1] 刘之广[1] DONG Jing-jing;TIAN Hong-yu;SHI Ruo-lin;YANG Yun-bo;WU Liang;FANG Fu-li;ZHANG Min;LIU Zhi-guang(National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources/College of Resources and Environment,Shandong Agricultural University,Tai’an,Shandong 271018,China;Key Laboratory of Crop Fertilizer,Ministry of Agriculture and Rural Affairs/Xinyangfeng Agricultural Technology Co.,LTD,Jingmen,Hubei 448000,China)

机构地区：[1]土肥高效利用国家工程研究中心/山东农业大学资源与环境学院,山东泰安271018 [2]农业农村部作物专用肥料重点实验室/湖北新洋丰肥业股份有限公司,湖北省荆门448000

出　　处：《植物营养与肥料学报》2023年第7期1367-1378,共12页Journal of Plant Nutrition and Fertilizers

基　　金：国家重点研发计划项目(2022YFD1700603);山东省重点研发计划项目(2022SFGC0301);辽宁省2021年揭榜挂帅课题黑土地旱田地力提升关键技术示范与推广项目(2021JH1/10400039-2)。

摘　　要：【目的】淀粉基聚氨酯包膜缓控释肥施入土壤后,膜壳降解时间短,环境风险低,但因亲水性强、杂质多、致密性差等特点也降低了养分的控释性能,无法满足作物全生育期养分需求。我们优化了淀粉基聚氨酯膜材构成比例,并从膜材化学结构和膜壳物理性状角度,研究了该包膜工艺改善复合包膜尿素养分控释性能的机理。【方法】本研究设计了以聚烯烃蜡为底涂层,淀粉基聚氨酯(BPU)为内涂层,纳米TiO_(2)改性聚酯聚氨酯(PPU)为外涂层制备复合包膜尿素的工艺流程。采用响应曲面法设计了BPU、PPU、TiO_(2)添加量三因素组合的20个处理,建立了养分初期释放率、释放期对BPU、PPU、TiO_(2)添加量的响应模型;利用电镜扫描、原子力显微镜、傅里叶红外光谱、气相色谱/质谱,探究复合膜材形态与结构特征;通过热失重、Zeta电位、静水浸提方法,评价了膜材稳定性与养分释放动力学特征;利用土壤埋袋试验,研究了膜壳降解性能。【结果】1)较BPU膜材,复合膜材(NBPU)在中性条件下Zeta电位绝对值提高34.8%,添加纳米TiO_(2)后进一步提高了26.5%~64.6%,提升了其物理稳定性;膜壳在土壤中自然降解365天后,添加1.00%纳米TiO_(2)的聚酯聚氨酯失重率为4.92%,与未添加TiO_(2)的相比显著提高了3.3倍。2)复合膜材表面孔隙少、光滑平整,切面致密均匀;颗粒硬度为85.2 N,较BPU膜材提高了37.0%,膜表粗糙度降低了71.3%,肥料力学与耐磨性能均有所改善;BPU对前期养分释放具有显著调节作用,PPU添加量3%以内时添加量与养分释放期成正比,纳米TiO_(2)则对3~28天的养分释放速度有显著影响。3)通过响应曲面法分别建立养分释放期、初期释放率与BPU、PPU、TiO_(2)添加量的二次多项式数学模型(P<0.01),可用该模型对相应的指标进行分析和预测;明确设计变量对养分释放期的贡献度为PPU>BPU>TiO_(2),对初期释放率的贡献度为Ti【Objectives】Starch based polyurethane,a type of coating materials for controlled-release fertilizer production,is easy to degradation after entering soil,so results in low environmental risk.However,its strong hydrophilicity,high impurities and poor densification reduce the controlled release performance of nutrients.We optimized the composition ratio of starch based polyurethane with other additives from the chemical structure and physical properties of the coating materials.【Methods】The composite coating materials(NBPU)were composed of starch-based polyurethane(BPU)and nano-TiO_(2)-modified polyester polyurethane(PPU).The coating procession included three steps,i.e.polyolefin wax as the base coating,BPU as the internal control layer,and PPU as the external control layer.Total 20 combination schemes of BPU,PPU and TiO_(2) were designed using the response surface method,and the response models of initial nutrient release rate and release period to the BPU,PPU and TiO_(2) ratio were established.Electron microscope scanning,atomic force microscopy,Fourier infrared spectroscopy,and GCMS were used to investigate the morphology and chemical structures of the composite coating materials.Thermogravimetric,Zeta potential and hydrostatic extraction method were used to evaluate the stability and nutrient release kinetics.Soil embedding bag test was used to evaluate the degradation performance of coating materials.【Results】1)Compared with BPU,the absolute Zeta potential of designed NBPU increased by 34.8%under neutral condition,and that was further increased by 26.5%−64.6%through addition of nano-TiO_(2),indicating the improvement in physical stability of the NBPU After 365 days of natural degradation in soil,the weight loss rate of polyester polyurethane with 1.00%TiO_(2) increased to 4.92%,which was 3.3 times higher than that without 1.00%TiO_(2).2)The surface of the composite coating layer was smooth and flat,with few pores,and the section surface was compact and uniform.The particle hardness of PPU was 85.

关 键 词：淀粉基聚氨酯 生物基聚氨酯 纳米TiO_(2) 复合包衣 响应曲面法 养分初期释放率 养分释放期 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TQ450.6[化学工程—农药化工]