浅谈农药悬浮剂的质量提升

阐述了我国农药悬浮剂在配方研制、生产和应用中存在的问题,重点介绍了长期物理稳定性、交叉污染和质量控制问题;建议从理论基础、物理稳定性评估、原药与相关杂质、助剂、安全化生产等方面提升悬浮剂的质量。     

纳米Al_2O_3表面接枝聚合改性的研究

为改善纳米Al2O3粒子在聚合物中的分散状况,本工作先在粒子表面引入双键,然后通过溶液自由基引发接枝单体丙烯酰胺和苯乙烯在Al2O3粒子表面的聚合,使接枝物与纳米粒子之间形成化学键合。系统研究了投料方式、引发剂浓度、单体浓度、反应时间等对接枝效果的影响,为调控纳米粒子表面的化学性质提供依据。     

基于均匀设计的苯乙烯分散聚合反应研究

本文基于均匀设计方法对苯乙烯的分散聚合反应进行了试验设计,并通过回归分析,建立了聚苯乙烯粒子相关性能参数(聚苯乙烯粒子分子量、粒径大小及分布)和各变量(单体浓度、稳定剂用量、引发剂用量和反应介质溶度参数)之间的回归方程。根据回归方程进行了分散聚合反应的配方优化,得到了约束条件下的苯乙烯分散聚合反应配方,实测值与预测值比较结果表明,回归方程的预测值与优化配方制备的PS粒子的各项性能实测值存在一定的偏差(相对偏差在15%以内),但仍对试验配方设计有一定的指导作用。     

世界丁苯系胶乳发展概况 二

3 SB系胶乳的生产方法SB系各种胶乳的生产方法大同小异,其基本工艺过程大体上与生产固体SBR的聚合、脱气(除去反应单体)工艺相同。所不同的是生产固体SBR时聚合得到的胶乳是中间产品,聚合物粒子的粒径较小,总固物浓度较低;而商品胶乳则需要粒径大、总固物浓度高的胶乳。因而,生产商品胶乳时尚需有使粒径增大和使总固物浓度提高方法。这些方法和生产胶乳所用助剂的种类及作用在专业书刊中有详     

高含量阿维菌素微囊悬浮剂的制备

为开发高含量的阿维菌素微囊悬浮剂配方,提高阿维菌素紫外光降解稳定性,采用界面聚合的方法,以聚合MDI和乙二胺为囊皮材料单体,筛选出高溶解能力的新型溶剂POWERBLOXTM SV-17及配套的乳化剂、分散剂,开发了3%～5%阿维菌素微囊悬浮剂配方。该配方包覆率大于95%,热贮稳定性、冷贮稳定性及稀释稳定性均合格。与乳油产品相比,包覆后的有效成分在紫外光照下的降解率明显降低。     

GK270N型密炼机混炼产生杂质原因及解决措施

分析GK270N型密炼机配合Φ380／450辊子机头挤出机在进行混炼胶生产，特别是生产终炼胶时易产生混炼杂质的原因，并提出相应的解决措施。杂质主要为密炼机和辊子挤出机内的积聚物，与设备状况、胶料配方和生产操作方法等因素有关。通过调整设备和生产工艺，大大减轻了杂质污染，污染率下降了50％以上。     

乙炔气和氯化氢气混合脱水后含水量的气相色谱分析法

(一)前言 我厂聚氯乙烯(PVC)车间之乙炔气和氯化氢气混合后,经冷冻脱水处理而进入转化器,以合成氯乙烯单体。混合气中若含水量高,进入转化器会腐蚀设备致漏,所生成三氯化铁堵塞管道,使触媒结块失效,缩短触媒寿命,且增加入气阻力,影响单体合成反应。含水量高产生付产物乙醛等杂质组份多,又增耗乙炔气,使精馏塔精制氯乙烯增加负担,影响单体质量。所以要严格控制混     

激光在线监测无皂乳液聚合

当激光束通过乳液时其吸光度与乳液浊度有关，而浊度又与乳液粒子直径、浓度相关，在无皂乳液聚合过程中，由于体系的稳定性较差，若加料速度不适当，很容易在聚合初期出现乳液浊度陡增甚至凝胶。本研究利用氦氖激光器分别对苯乙烯、丙烯酸酯、醋酸乙烯酯等单体的无皂乳液聚合实施监测，即通过吸光度变化来控制加料速度，使乳液吸光度保持平缓变化，也就是在聚合初期使乳液粒子浓度保持在适当水平，从而避免因小粒子溶胀聚并产生凝胶，制得了具有良好稳定性的无皂聚合乳液。     

均匀设计的甲基丙烯酸甲酯分散聚合反应研究

基于均匀设计方法对甲基丙烯酸甲酯（MMA）的分散聚合反应进行了试验设计，并通过回归分析，建立了聚甲基丙烯酸甲酯（PMMA）粒子相关性能参数（PMMA相对分子质量、粒径大小及分布）和各变量（单体质量分数、稳定剂用量、引发剂用量和反应介质溶度参数）之间的回归方程。根据回归方程进行了分散聚合反应的配方优化，得到了约束条件下的MMA分散聚合反应配方，实测值与预测值比较结果表明，回归方程的预测值与优化配方制备的PMMA粒子的各项性能实测值之间的相对偏差在10％以内，对试验配方设计有指导作用。     

12000 IU/μl B.t.超低容量喷雾水悬浮剂的研制

通过对十多种农药中常用助剂的筛选，研制了一种高浓度的B．t．超低容量喷雾水悬浮剂(B．t．-ULV制剂)。配方优化试验表明，在B．t．发酵浓缩液中加入1％润湿剂X，15％的悬浮剂ZY，在0．05％的浓度下对石蜡表面仍有较好的润湿性，有效成分悬浮率为90．8%，粘度为7．1mPa．s挥发率为21．16％。激光粒度分析和电镜照片表明，该制剂的粒子平均直径为8，46μm，低于B．t．-80水悬浮剂的平均粒径，粒径分布较窄，适合进行超低容量喷雾。     

Effects of poly(vinyl acetate) suspending agents on suspension polymerisation of vinyl chloride monomer

Abstract

When partially hydrolysed poly(vinyl acetate) (PVAc) is used as a suspending agent in the suspension polymerisation of vinyl chloride monomer, it has significant effects on the morphology of the resulting poly(vinyl chloride) (PVC) particles. At the initial step of polymerisation, PVC molecules are grafted onto the molecules of the suspending agent forming a PVC–PVAc membrane. The properties of this membrane depend on the type of suspending agent, the polymerisation temperature, the mixing efficiency, and other factors. The morphology of the growing PVC particles and the properties of the PVC resin obtained depend in turn on the characteristics of the membrane. A model has been developed relating to the connection between the polymerisation conditions and the characteristics of the suspending agent on one hand, and on the PVC properties on the other hand. The model is based on an analysis of the characteristics of the PVC–PVAc membrane and their effect on PVC properties.     

碳酸钙晶须的除杂工艺研究

以氯化铵为除杂剂,针对碳酸钙晶须中镁杂质进行除杂研究,考察了工艺条件对除杂效果的影响。采用化学分析和X射线衍射分析（XRD）对除杂前后样品进行分析,得出最佳工艺条件。结果表明：在氯化铵浓度为 3 mol/L,除杂温度为100 ℃,反应时间为6 h的条件下,样品中镁方解石的去除率达62.5%,碳酸钙晶须纯度达97%。利用扫描电镜对产品进行表征,结果显示碳酸钙晶须表面附着的杂质颗粒明显减少。     

光电比色法测定水样中的氯化物含量

以硫氰酸汞作为沉淀剂,硫酸铁铵作为显色剂,采用光电计比色,通过水样对光的吸收程度来确定氯化物的浓度,并与硝酸银滴定法进行对比。实验结果表明,水中氯化物在10~300 mg/L时,光电比色法测定氯化物的结果与硝酸银滴定法测定结果较为接近。采用光电计比色测定氯化物的方法快捷、准确且重复性好。     

Influences of initiator addition methods in suspension polymerization of vinyl chloride on poly(vinyl chloride) particles properties

Vinyl chloride suspension polymerization was carried out in a pilot‐scale reactor to study the effects of different methods of initiator addition on poly(vinyl chloride) (PVC) resin properties. The experiments used different arrangements for adding the initiator to the reactor, whereas other reaction conditions were the same: (i) initiator was added to the continuous aqueous phase and then monomer was dispersed in it (conventional method); (ii) initiator was predissolved in monomer before dispersing in the continuous aqueous phase; and (iii) suspending agents along with initiator were added to the monomer before polymerization. The PVC resin prepared by method of (i) had a higher monomer conversion and a higher Sauter mean diameter of grains with a narrow particle size distribution comparable to that of PVC resins by other methods. Scanning electron microscopy showed more uniform particles and fused primary particles in the grains, which confirms lower porosity and lower cold plasticizer absorption (CPA) for PVC grains produced by procedure of (ii). The results showed that when the suspending agents were also predispersed in monomer along with initiator (iii), CPA increases dramatically due to internal porosity of the grains. Simultaneously, a marked decrease in Sauter mean diameter was apparent. Scanning electron microscopy micrographs show that primary particles in the interior of PVC grains prepared by the latter method are looser, and there is more free volume between primary particles resulting the high internal porosity and consequently higher CPA. Mercury porosimetry analysis also confirms these results. K value as a molecular weight characteristic for all methods was the same . J. VINYL ADDIT. TECHNOL., 24:116–123, 2018. © 2016 Society of Plastics Engineers     

Fe3+浸提剩余污泥中重金属试验

在室温下,污泥固液比例1∶20的条件下,以氯化铁为萃取剂对污泥进行重金属浸提的研究试验。分别进行了不同浓度的氯化铁溶液、pH值、振速及浸提时间对污泥浸提的效果影响试验。结果表明:当FeCl3溶液浓度小于48 mmol/L时,Zn和Cu的去除率随着浓度的增加而升高,当FeCl3溶液浓度大于48 mmol/L时,浓度增大对去除率的贡献降低;在相同的pH值下,氯化铁溶液比盐酸溶液更能有效的浸出污泥中的重金属;浸提的较佳振速为150 r/min,浸提的最佳时间为24 h。     

Radiation grafting of acrylic and methacrylic acids onto poly(tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) TFB films

A study has been made for the preparation of membranes by the direct radiation grafting of acrylic and methacrylic acids onto poly(tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) TFB films. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. In this grafting system, ammonium ferrous sulfate (Mohr's salt), ferric chloride, and cuppric chloride were used as inhibitors to minimize the homopolymerization of acrylic acid and methacrylic acid. Also, the effect of monomer concentration on the rate of grafting was investigated. The dependence of the grafting rate on monomer concentration was found to be of the order of 1.1 and 1.0 for acrylic acid and methacrylic acid, respectively. This grafting system was proceeded by a front mechanism. Some selected properties of the grafted films such as swelling behavior, dimensional change, and mechanical and electrical properties were investigated. It was found that the grafted membranes possess good hydrophilic properties that may make them promising in some practical applications. © 1993 John Wiley & Sons, Inc.     

无机盐对三甘醇脱水及发泡性能影响研究

在天然气净化工艺过程中,三甘醇会受到天然气所携带高矿化度地层水的污染,影响生产。因此,通过实验分析了氯化钠、碳酸氢钠、氯化钙以及氯化铁等无机盐对三甘醇富液脱水和发泡、消泡的影响。研究结果表明,三甘醇富液含水量越大,脱水需要的时间越长,且不易脱除;三甘醇富液脱水率随氯化钠、氯化钙和碳酸氢钠浓度的增大而下降。钙离子对三甘醇富液脱水影响要大于钠离子,碳酸根离子的影响大于氯离子;对于发泡来说,氯化钙影响最小,但氯化钠、氯化钙和碳酸氢钠都存在一个引起三甘醇富液(含有十二烷基磺酸钠)发泡高度最大的浓度,碳酸氢钠的最大,氯化钙的最小;消泡方面,三种盐存在一个消泡最大时间对应的浓度范围,这个浓度范围氯化钙最小,碳酸氢钠最大。氯化铁浓度增大使三甘醇富液脱水率缓慢下降,在研究范围内,总体变化不大;三甘醇富液发泡高度及消泡时间随氯化铁加入浓度的增大而增大,在氯化铁浓度达到0.12%(重量浓度)趋于平缓。     

Drop coalescence processes in suspension polymerization of vinyl chloride

A tracer dye technique was used to investigate the effect of turbulence intensity, stirring time, and the type and concentration of the suspending agent, partially hydrolyzed poly(vinyl acetate) (PVA), on the coalescence rate of vinyl chloride monomer (VCM) droplets in an agitated liquid–liquid dispersion. It was found that the extent of coalescence rises slowly with mixing time, is roughly proportional to the agitation speed, and decreases sharply when the concentration of stabilizer is increased. Coalescence rate depended on the degree of hydrolysis of the stabilizer. The method of addition of initiator during VC suspension polymerization was also studied and its effects on the polymerization conversion and final PVC particles' properties were determined. It was found that the polymerization reaction occurs more uniformly in all the VCM droplets when the initiator was predissolved in the VCM prior to reaction compared with the case when the initiator was predispersed in the continuous water phase. Also, for the same reaction time, the conversion was higher in the former case. During polymerization, the concentration of PVA in the aqueous phase decreased substantially and the porosity of the polymer particles was reduced. © 1996 John Wiley & Sons, Inc.     

悬浮凝胶颗粒调驱剂研究与现场试验

针对辽河油田注水区块现有颗粒类深部调驱堵剂耐温、抗剪切性能差,成胶强度低,有效期短,压力提升幅度有限等问题,采用丙烯酰胺与天然橡胶胶乳、乙烯基吡咯烷酮通过自由基共聚,经胶体干燥、造粒得到具有良好柔韧性和粘弹性能的柔性凝胶颗粒,并确定了最佳聚合反应条件:单体浓度30%,丙烯酰胺:天然橡胶胶乳:乙烯基吡咯烷酮质量比为1:0.8:0.3,交联剂浓度0.05%,引发剂(甲醛合次硫酸氢钠与过硫酸铵质量比为1:2)浓度0.6%,聚合反应温度65℃。同时确定了用于悬浮凝胶颗粒的凝胶配方体系:聚合物800 mg/L、交联剂400 mg/L、稳定剂80 mg/L,得到了凝胶颗粒现场应用的合理粒径中值为2 mm,最佳使用浓度范围1%~3%。现场试验结果表明:凝胶颗粒对调驱压力提升作用明显,具有很高的可行性和实用性,为注水区块稳油控水提供了有力的技术保障。     

海上油田专用浮选剂的合成及应用

采用水溶液自由基聚合方法开发合成了一种油田专用浮选剂。综合考察了物料质量分数、引发剂质量分数、反应温度对产品性能的影响,结果表明,最佳的实验条件:单体质量分数5%(AM、MD、高阳离子单体的摩尔比为10∶3∶1),介质质量分数20%,引发剂质量分数0.4%,乙二醇的质量分数13.5%,氯化钠质量分数3.5%,其余为去离子水,反应温度45℃。南堡35-2油点现场应用表明,合成浮选剂的加入浓度相比于在用浮选剂BHFX-01的80 mg/L降为40 mg/L时,其清水除油效果更加明显,污水含油量由加入合成浮选剂前的480 mg/L左右降为加药后的110 mg/L左右,其平均除油率为68.3%,最大除油率为78.6%。