微流体技术在农药制剂加工中的应用

概述了微流体技术发展的必要性,详细阐述了微流体技术在农药制剂加工中的实践,介绍了微囊悬浮制剂的加工现状,展望了微流体技术发展前景。

5%己唑醇微乳剂配方的研究开发

针对己唑醇现有微乳剂配方中乳化剂种类多、用量大易导致成本高、环境污染等问题,研究开发了乳化剂种类少、用量小的5%己唑醇微乳剂。通过外观变化情况筛选乳化剂种类和用量,对微乳剂的质量指标、应用性能进行表征。结果表明,5%己唑醇微乳剂较佳配方为5%己唑醇原药;18%溶剂(N-N-二甲基甲酰胺∶环己酮=1∶8);15%乳化剂(EL-40∶农乳500#=5∶1),水补足余量。制备的5%己唑醇微乳剂对水稻纹枯病菌的抑制活性优于市售的10%己唑醇乳油,与10%己唑醇微乳剂抑制效果相当。该研究获得了配方组成简单,乳化剂用量低,性能优异的己唑醇微乳剂,对农药微乳剂配方开发具有借鉴作用。

Preparation and Mechanical Properties of PAN/HNTs Composite Nanofibers

The enhanced composite nanofibers have attracted great attention for application in recent years. The electrospinning technique was considered to be a prospective production pattern for them. This paper provided a promising technique to prepare the polyacrylonitrile(PAN)/halloysite nanotube(HNT) composite nanofibers by using the electrospinning method. The PAN/HNTs composite nanofibers with well enhanced performance were successfully fabricated from a mixture of PAN/DMF/HNTs dispersion solution processed by the electrospinning technique. For achieving good dispersion in PAN polymer, the highly dispersed HNTs were obtained by using polycarboxylate modification employing the in-situ spray-drying method. The structure and properties of the composite nanofibers were characterized by TEM, XRD, EDX, IR, and DSC techniques. The obtained PAN/HNTs composite nanofibers with different HNTs contents were about 300—500nm in diameter. In addition, the mechanical properties of PAN/HNTs composite nanofibers were tested, which exhibited an excellently enhanced performance.

Electrospinning Preparation and Mechanical Properties of Polymethyl Methacrylate (PMMA)/Halloysite Nanotubes (HNTs) Composite Nanofibers

The paper was aimed at the PMMA/HNTs composite nanofibers with well enhanced mechanical properties prepared by electrospinning technique for the first time. A series of characterizations were used to illustrate the structure and properties of the composite nanofibers by SEM, XRD, FTIR and DSC techniques. The effect of the PMMA/HNTs composite nanofibers in relationship to the mass percentage of HNTs was investigated. The results indicated that HNTs wrapped in polymer matrix were highly oriented and dispersed by the electrospinning technique, resulting in improved thermal stability of the polymer. Moreover, the mechanical properties of the PMMA/HNTs composite nanofibers which were dependent on HNTs mass content were measured, and good enhanced mechanical properties were obtained.

A Study on Tribological Properties of Polypropylene Nanocomposites Reinforced with Pretreated HNTs

The polypropylene(PP) nanocomposites filled with pretreated halloysite nanotubes(HNTs) were prepared by the melt-blending method. Before filling, the as-received HNTs powder was at first purified and then modified. The characterization tests showed that the purified HNTs had less impurity and more uniform pore size distribution and the surface hydrophobicity of the modified HNTs was obviously improved. The mechanical and tribological properties of the PP/HNTs nanocomposites were extensively investigated. The results showed that the tensile, bending and notched impact strength of the PP/HNTs nanocomposites was somewhat improved, but the wear resistance of the PP/HNTs nanocomposites was obviously enhanced.

An Approach for Preparation of Excellent Antiwear PTFE Nanocomposites by Filling As-prepared Carbon Nanotubes/Nanorods(CNT/CNR)Mixed Nano-Carbon Material

The one-dimensional carbon nanotubes/nanorods(CNT/CNR)mixed nano-carbon material was successfully prepared by halloysite nanotubes(HNTs)as the template for the first time,in which CNT was formed through PVA modification in internal surface of HNTs and CNR was obtained by nanocasting PVA in hollow nanostructure of HNTs.The CNT of the mixture with flexible structure has ca.20 nm in pore diameter and ca.500 nm in length,whereas the CNR with hard and solid structure shows ca.30 nm in diameter and ca.2μm in length.For application as fillers,the CNT/CNR mixed nano-material is used to reinforce the properties of polytetrafluoroethylene(PTFE).The mechanical and tribological properties of PTFE nanocomposites were intensively examined by a series of testing.The ring-on-ring counterface was used to evaluate the tribological behavior of the nanocomposites.The results showed that the volume wear rate of the CNT/CNR-reinforced PTFE nanocomposite after being filled with 0.3%of CNT/CNR was only 1/700 of that of the pure PTFE under a load of 200 N and a rotary speed of 200 r/min,while other mechanical and tribological performance was comparable to the performance of pure PTFE,which exhibited a desirable application prospect.

20%异丙甲•苄泡腾片剂的研制及其对稻田杂草的防治效果

为了提高稻田杂草化学防除的省力化程度,降低防治成本,通过单一变量法筛选配方中的助剂种类和用量,采用干法压片工艺制备了20%异丙甲•苄泡腾片剂(有效成分异丙甲草胺+苄嘧磺隆),同时进行了田间药效评价。结果表明:20%异丙甲•苄泡腾片剂的优化配方(质量分数)为:16%异丙甲草胺,4%苄嘧磺隆,18%有机膨润土,9%白炭黑,20%酒石酸,20%碳酸氢钠,6%润湿剂EFW,4%分散剂G202和3%润滑剂硬脂酸镁。该泡腾片剂在有效成分120~180 g/hm^(2)的用量范围内能有效防除稻田杂草,防效明显优于其单剂,与已登记的20%异丙甲•苄(有效成分质量比17:3)可湿性粉剂相当,持效期达40 d以上。所研制的20%异丙甲•苄泡腾片剂表面光滑,无粉尘,使用方便,省时省工,对稻田常见杂草均有良好防效,持效期长,具有推广价值。

Study on Mechanical Performance and Wear Resistance of Halloysite Nanotubes/PTFE Nanocomposites Prepared by Employing Solution Mixing Method

Improving the mixing way of fillers and polymer before molding was demonstrated to be a promising approach in the past. In this study, we investigated the effects of the mixing method and the dispersed solvent on the mechanical and friction performance of halloysite nanotubes (HNTs)-filled polytetrafluoroethylene (PTFE) (HNTs/PTFE). After evenly mixing in solution, the HNTs/PTFE mixtures were formed into disc-like nanocomposites by the cold compression molding method. The mechanical performance showed that the tensile strength of the HNTs/PTFE nanocomposites prepared by employing the solution mixing method was about 3—5 MPa more and the Young’s modulus was increased by about 1.2 times greater than those prepared by employing the drying mixing method, but unfortunately they had a poorer elongation at break. Alternatively, it was noteworthy that the wear resistance of the nanocomposites prepared by employing the solution mixing method was improved by 5—10 times and 11—20 times as compared to those formed via the drying mixing method and pure PTFE, respectively. The results showed that the PTFE nanocomposites filled with HNTs by using the solution mixing method exhibited an excellent antiwear performance and had a desirable processability.

吡唑醚菌酯悬浮剂流变性与稳定性的关系研究

吡唑醚菌酯因其熔点低、晶型多,其悬浮剂在贮存过程中易出现膏化、析晶的现象。本文通过使用4种原药产品、3种助剂产品制备得到12个25%吡唑醚菌酯SC样品,在25℃下,测试其基本理化性能,并通过高级流变仪测定其流变曲线、屈服应力、触变性、G′/G"-γ曲线、G′/G"-ω曲线、|η*|/tanδ-ω曲线、η-T曲线等。试验结果表明,流变曲线、触变性测试结果可以反映吡唑醚菌酯SC的部分物理特性;G′/G"-γ曲线反映出吡唑醚菌酯SC的常温物理稳定性;G′/G"-ω曲线、|η*|/tanδ-ω曲线反映了吡唑醚菌酯SC倾倒、灌装过程中的流动性。由于吡唑醚菌酯低熔点的性质,η-T曲线可以更快、更直接地反映出吡唑醚菌酯SC在热贮后是否粒径增长、膏化变稠。本研究结果对吡唑醚菌酯SC的研发生产过程具有一定的指导意义。

面向纳米农药粒径调控的表面活性剂研究进展

纳米农药相较于传统农药具有微粒尺寸小、分散性能优异、对靶传输效率高、可控释放、易吸收等特点,可显著减少农药用量,成为当下研究热点。综述了国内外纳米农药及易于产业化的纳米悬浮剂和纳米乳剂粒径调控用表面活性剂研究进展,指出了表面活性剂与纳米颗粒间作用力的主要表征方式,提出分子结构可设计性强的乙烯基聚合物表活性剂在纳米农药研发中具有良好应用前景,为纳米农药落地提供助力。