【作者】 尚纪兵；

【导师】 庞煜霞；

【作者基本信息】 华南理工大学 ， 化学工程， 2011， 硕士

【摘要】 可湿性粉剂(WP)是一种能在水中分散形成稳定的、可供喷雾使用的农药制剂,其成本低,加工包装运输方便,且无溶剂污染,应用非常广泛。但WP也存在一定问题,其浓度低、悬浮率低,对于低熔点原药(如腈菌唑)热贮后性能差。随着新剂型(WG、SC)等的涌现和应用,WP未来的发展必须朝高质量、高性能方面发展,优秀的分散剂可以提升WP的质量和性能,因此分散剂的研究是WP能否保持国内第二农药剂型地位的关键。本文首先研究了不同种类分散剂(特别是木质素磺酸盐系分散剂)对40%腈菌唑WP性能的影响,进一步筛选出几种WP优选配方;其次,研究了分散剂的分子量和磺化度对WP性能的影响;最后,就农药助剂对腈菌唑WP的增效作用和分散稳定机理进行了初步研究。通过测定聚羧酸系、脂肪族系、氨基磺酸系、木质素磺酸盐类等不同品种共13个分散剂对40%腈菌唑WP应用性能的影响,发现木盐做分散剂的腈菌唑WP润湿性能较好。WP热贮前的悬浮率以GCL4-A和Borresperse Na作分散剂时的最好,热贮后,悬浮率基本都有下降,其中GCL4-A为分散剂时下降得较少。分别测定了GCL4-1、GCL4-A、Borresperse Na、石岘木钠四种木质素磺酸钠(简称木钠)的分子结构特征。以四种木钠为分散剂制备40%腈菌唑WP并测试其性能。结果显示,GCL4-A和GCL4-1的性能较好,这与GCL4-A的高纯度、高磺化度及GCL4-1的高磺化度、高分子量密切相关。GCL4-A做分散剂时,WP热贮前后的悬浮率分别为84.47%和81.89%,悬浮液2 h的分散稳定指数都是最小分别为2.6和4.03。对40%腈菌唑WP的新配方进行了研究。结果表明,润湿剂选用1%掺量的K12时,WP的润湿时间最短为52 s;分散剂选用5%掺量的GCL4-A性价比较好,热贮前后的悬浮率分别为80.07%和78.19%。GCL4-A与GCL4-1、PC2700、六偏磷酸钠的复配效果较好。在此基础上筛选了四种WP配方,综合性能好于深圳某农化公司实际产品。采用超滤的手段对石岘木钠、SAF、GCL4-1进行分级。石岘木钠超滤实验表明,随着截留分子量由小变大,超滤级分分子量依次增大,重均分子量从2360增加到19852;磺酸根含量依次减小,从2.66 mmol/g降低到0.98 mmol/g。以三种分散剂的不同分子量级分制备WP,性能测试表明,WP热贮前后的悬浮率随分散剂分子量的增大基本上依次增大,热贮前的润湿时间随分子量的增大而依次减小,悬浮液2 h的分散稳定指数及沉淀层厚度随分子量的增大基本上依次减小。测试了一组分子量相近,不同磺化剂用量的改性木盐GCL3S样品对40%腈菌唑WP性能的影响。结果表明,WP热贮后的悬浮率随磺化剂用量的增加先增后降,磺化剂用量为57.2 g时制备的GCL3S-9对应WP悬浮率最大,为81.34%,说明适度磺化剂用量的改性产品对应的WP性能较优。考察了GCL4-1、GCL4-A、Borresperse Na、石岘木钠对40%腈菌唑WP的增效作用。水溶液表面张力测试表明,GCL4-1降低表面张力的能力最强,最低降至22.4 mN/m,其次为GCL4-A的32.2 mN/m。四种木钠降低WP药液在基材表面接触角的能力依次为:GCL4-A>GCL4-1> Borresperse Na >石岘木钠。GCL4-A制备的WP其药液在香蕉叶表面持液量最大为3.6 mg/cm~2。初步研究了GCL4-1、GCL4-A、Borresperse Na、石岘木钠对40%腈菌唑WP的分散稳定作用机理。GCL4-A在腈菌唑颗粒表面的吸附能力最强,吸附量最大为7.2 mg/g,石岘木钠的吸附能力最弱,吸附量最大仅为3.9 mg/g;GCL4-A、GCL4-1为分散剂时对腈菌唑颗粒表面的Zeta电位影响较大且非常相近,1.5 g/L时达到绝对值最大的31.7 mV和32.4 mV,远高于另外两种木钠。对照应用性能可知,通过在腈菌唑上的大量吸附并提高颗粒的静电排斥作用,是两种分散剂具有较好的分散性能的原因。更多还原

【Abstract】 Wettable powder (WP) is composed of drug, fillers and additives and crushed into very fine particles, which can form a stable dispersion in water for spraying pesticide use. It is widely used because of its low cost, convenient packaging and transportation process and without solvent pollution. However, WP also has some problems such as low concentration, suspension rate and the performance of after accelerated aging is poor for some low melting point drugs (such as myclobutanil),Excellent dispersant can enhance the quality and performance.The effect of different dispersants especially lignosulfonates on 40% myclobutanil WP’s performance was tested firstly and several WP formulations were choosed. Then, the effect of pesticide dispersants’molecular weight and sulfuric group content on WP was studied. Finally, the mechanism of pesticides additives on the suspension dispersion and drug-efficiency were studied.The applied performance of WPs, which used 13 different dispersants of PC, SAF, ASP, and LS were tested. According to the effect, LS has better wettability, WP’s suspension rate was best when use GCL4-A and Borresperse Na as dispersant before accelerated aging.The structural features of 4 kinds of LS were investigated. Using this four LSs as dispersants to prepare 40% myclobutanil WPs and tested their performances, the results showed that GCL4-A and GCL4-1 were better, when using GCL4-A as dispersant, WP’s suspension rates before and after accelerated aging were 84.47% and 81.89%, the 2 h suspension stability index were 2.6 and 4.03.New formulation of 40% myclobutanil WP was studied.The results showed wettability of WP with K12 as wetting agent was best and the dosage was 1%; when using 5% GCL4-A as dispersant, the performance of WP was good, the suspension rates before accelerated aging were 80.07% and 78.19%. GCL4-A mixed with GCL4-1、PC2700、hexametaphosphate were good. Four formulas of WP were prepared and the comprehensive performance was better than the actual product.of shenzhen chemical company.Using the ultrafiltration method to divide SXMN、SAF、GCL4-1 into different molecular weight range Fractions. The gel permeation chromatography and potentiometric titration testing showed the relative molecular weight of SXMN was increased with the Fraction, from 2360 to 19852; the sulfonic acid content of SXMN was decreased with the Fraction, which was decreased from 2.66 mmol /g to 0.98 mmol /g. Using the different molecular weight range Fractions of the three dispersants to prepare WPs and tested their performances, the results showed that with the increasing of molecular weight range Fractions, WP’s suspension rates before and after accelerated aging increased, the wetting time before accelerated aging decreased, the 2 h suspension stability index and thickness of sediment layer decreased.Using a group of GCL3S with similar molecular weight and different sulfonic content as dispersants to prepare WPs and tested their performances, the results showed that WP’s suspension rate after accelerated aging increased with the sulfonating agent firstly and then dropped. when sulfonation agent was 57.2 g, the corresponding GCL3S-9’s suspension rate was the highest for 81.34%, it indicated moderate amount of sulfonating agent was good.It investigated GCL4-1、GCL4-A、Borresperse Na、SXMN on the performance of WP efficiency. The results showed GCL4-1 had the strongest ability to reduce surface tension, it can drop to 22.4 mN / m, followed by GCL4-A of 32.2 mN / m. The ability of reducing contact angle of WP suspension on substrate were GCL4-A>GCL4-1>Borresperse Na >SXMN. When using GCL4-A as dispersant, retention of the WP suspension on the banana Leave surface was biggest of 3.6 mg/cm~2.It investigated GCL4-1、GCL4-A、Borresperse Na、SXMN on the mechanism of WP dispersion. The results showed GCL4-A had the highest adsorption amount of 7.2 mg/g and SXMN had the lowest adsorption amount of 3.9 mg/g. The Zeta potential of GCL4-A、GCL4-1 on Myclobutanil were very similar, they were 31.7 mV and 32.4 mV when the concentration was 1.5 g/L, much higher than Borresperse Na and SXMN. Combined the application performance We can see that GCL4-A and GCL4-1 were better because they had the high adsorption amount on Myclobutanil and increased the electrostatic repulsion of particles.更多还原