MSA与PSA体系电镀锡工艺对比

对比了苯酚磺酸(PSA)体系和甲基磺酸(MSA)体系电镀锡液的抗氧化能力和环保性,以及两种体系所得镀锡板的锡层均匀性、黑灰程度和铁溶出值。结果表明,MSA体系镀液的化学需氧量、总有机碳量和锡泥产生率远远低于PSA体系镀液。与PSA体系镀锡板相比,MSA体系镀锡板的锡镀层更均匀、致密,黑灰程度和铁溶出值都更低。     

助熔剂在甲基磺酸电镀锡生产中的应用

先分析了助熔剂在镀锡板软熔中的作用机制,接着对比了采用不同助熔剂和脱盐水助熔对镀锡板性能的影响.结果表明,目前没有一款助熔剂能够兼顾镀锡板的外观和耐蚀性,因此对实际生产中的机组进行改进,以适应镀锡板的差异化助熔工艺,效果良好.     

电偶电流法研究置换镀锡工艺

采用电偶电流法研究了甲基磺酸锡镀液中,锡离子质量浓度、甲基磺酸体积分数、硫脲质量浓度、温度等参数对镀覆效果的影响,得出了优化工艺参数如下:40 g/L甲基磺酸锡,150 mL/L甲基磺酸,100 g/L硫脲,温度70℃,采用优化工艺在铜基体上得到的锡镀层致密、光亮,晶粒尺寸小于20nm.     

甲基磺酸盐高速电镀锡工艺仿真研究

为了更为真实地模拟高速电镀锡试验过程,开发了一种高速电镀锡仿真系统。研究了奎克添加剂体积分数、电流密度和温度对甲基磺酸(MSA)体系电镀锡板表面形貌和耐蚀性的影响,得到较佳工艺参数为:游离酸(35±5) mL/L,抗氧化剂(20±5) mL/L,Sn²⁺(20±5) g/L,奎克添加剂(45±5) mL/L,温度(40±5)℃,电流密度(25±5) A/dm²。该条件下所得镀锡板镀层均匀,耐蚀性好。     

PSA电镀锡可溶性阳极系统的研究

采用对比法研究了PSA镀锡中工艺参数变化对阳极锡板溶解质量和研究锡板溶出电位的影响,并在实验中初步探讨了一种复合阳极形式下对可溶性阳极的影响。通过改变时间、温度2个因素,来研究其对镀液中锡离子浓度的影响。实验结果表明,反应时间为5 s,温度为40℃时,电流效率最佳。     

添加剂对甲基磺酸盐镀锡液性能的影响

甲基磺酸盐镀锡液是一种环保、稳定、性能优良的新型镀锡体系,选择适宜的添加剂并确定其质量浓度是保证镀锡层质量的关键.借助于电化学测试、赫尔槽实验、远近阴极法、内孔法和扫描电镜等方法,考察了几种添加剂单独和复合使用时对镀液性能和镀层表面质量的影响.结果表明:OP乳化剂和试剂A可显著提高Sn2+还原时的阴极过电位,试剂B对获...     

间苯二甲醛对MSA体系中锡电沉积行为和镀层性能的影响

通过循环伏安分析、极化曲线测试、扫描电镜(SEM)和X射线衍射(XRD)研究了间苯二甲醛质量浓度对甲基磺酸(MSA)体系电镀锡过程中锡电沉积行为及镀层性能的影响。结果表明,间苯二甲醛能够提高电镀锡的阴极极化能力,有助于获得致密、光亮的镀层。间苯二甲醛质量浓度为0.10 g/L时,电流效率高达99.23%,电沉积速率为57.977μm/h,所得镀层在(220)晶面呈现强织构,表面均匀致密。     

轴瓦电镀锡线的设计

介绍了轴瓦电镀锡主要工序(包括除油、酸洗、活化、电镀锡、回收、中和、水洗等)的溶液组成和注意事项,设计了相应的自动生产线。全线采用PLC(可编程逻辑控制器)控制,自动化程度较高,生产效率得到提高。     

甲基磺酸盐电镀锡及锡合金的研究进展

介绍了甲基磺酸盐镀锡的工艺优点,综述了甲基磺酸盐镀锡的发展现状及历史.列出了电镀锡及锡基合金的工艺配方,对比了甲基磺酸盐镀锡和锡基合金镀液及镀层的性能.展望了甲基磺酸盐镀锡的发展前景.     

硫酸对甲基磺酸体系高速镀锡液清洁度的影响

研究了硫酸对甲基磺酸(MSA)体系镀液组分、浊度、锡泥粒度及镀锡板表面涂饰性的影响。结果表明,MSA体系镀液中加入1～5 g/L硫酸时,镀液中各组分的含量不受影响,镀锡板表面涂层的抗硫性、抗酸性和附着力也不受影响。MSA镀锡液中添加硫酸能够促进锡泥胶粒的聚沉,提升镀液的清洁度。当硫酸的质量浓度为2～4 g/L时,镀液中锡泥的平均粒径最大,镀液澄清得最快。     

Comparison of chitins produced by chemical and bioprocessing methods

Lactic acid fermentation was used to extract chitin from prawn shell (Nephrops norvegicus) at two different scales of operation. The fermentation products were characterized and compared with chitin extracted from the same source by a chemical method. Chitosans produced from the obtained chitins were evaluated in terms of their intrinsic viscosity, molecular weight and degree of acetylation (DA). The fermentation removed 690 g kg^?1 and 770 g kg^?1 of inorganic matter, 490 and 440 g kg^?1 of protein and 540 and 770 g kg^?1 of lipids from the shells at laboratory and pilot plant scales, respectively. However, the functional properties such as the DA of the chitin, the molecular weight and the DA of the chitosans were similar to those obtained for the chemically‐obtained chitin and its chitosan. Despite the incomplete extraction of chitin this biological process could be useful to produce chitin and chitosan in a more environment‐friendly approach. Copyright © 2004 Society of Chemical Industry     

Comparison of UF synthesis by alkaline‐acid and strongly acid processes

This work discusses two processes for producing urea‐formaldehyde (UF) resins. One is the alkaline‐acid process, which has three steps: usually an alkaline methylolation followed by an acid condensation and finally the addition of a final amount of urea. The other process, the strongly acid process, consists of four steps, in which the first step involves a strongly acid condensation followed by an alkaline methylolation, a second condensation under a moderately acid pH and finally, methylolation and neutralization under a slight alkaline pH. Two resins were produced using the two above described processes. The molecular weight distribution (MWD) of the resins was monitored off‐line by GPC/SEC and the final resins were characterized by GPC/SEC and HPLC. These studies showed that the two resins differ greatly in chemical structure, composition, viscosity, and reactivity. The monitoring of MWD indicated that the first condensation under a strongly acid environment leads to the production of a polymer with a distinctly different chemical structure, therefore increasing the flexibility of polymer synthesis and opening the way to the improvement of end‐use properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

对电镀清洁生产验收中定性指标的看法与建议

讨论了《电镀行业清洁生产评价指标体系(试行)》中定性指标所存在的问题,对个别条款提出了修改建议。     

Variations in macronutrients and nutritive value of the protein of canned tuna stored for 3 years after its preparation

The composition in macronutrients and available lysine of canned tuna stored for three years at room temperature, was analyzed. Digestibility (DC), biological value (BV) and net protein utilization (NPU) were determined with Wistar rats tests. The results were then compared to those obtained three years ago, when the canned food was prepared with casein standard protein plus DL-methionine, in order to control any variation that might had occurred in animal behaviour. No variation was found, either in macronutrient composition or in digestibility. However, BV and NPU decreased significantly. Highly significant, and somewhat surprising, was the finding that the amount of available lysine, which had diminished as the can was prepared with respect to the amount found in raw tuna, increased during the storage period.     

Effect of solution concentration in microfiltration properties of PLA mats produced by solution blow spinning

In order to remediate the difficulty of access to safe drinking water by 1/3 of the world population, mats produced by solution blow spinning (SBS) have a great potential for use in liquid filtration due to their small pores and high porosity, being capable of filtrating water by retaining particles and even microorganisms. In this context, this work aims the production and characterization of poly (lactic acid) mat obtained by SBS to be morphologically, thermally, and mechanically evaluated, as well as to observe water flux properties. The correlation between structure-processing-properties is an important part of the work, which shows that lower concentration of polymeric solution leads to mats with smaller average fiber diameter, greater crystallinity, impacting on their greater tensile strength. The water flux performance shows that mats obtained from higher polymer concentration solutions present less resistance to the water flow, which indicates larger pore diameters.     

粗氯乙烯气体中HCl吸收工艺比较

介绍了转化后粗氯乙烯气体中HCl的3种吸收工艺,并对这3种工艺在设备、材质、吸收温度、盐酸浓度、碱耗、检修频次及是否适宜使用常规解吸、深解吸酸循环吸收工艺等方面进行了比较。结果表明:采用组合塔→(水洗塔)→碱洗塔(配套常规解吸或深解吸)工艺的效果最好。     

冰胶印迹聚合物固定化脂肪酶的制备及催化性能

利用冰冻凝胶(cryogel,简称冰胶)印迹聚合物实现了脂肪酶的固定化.在脂肪酶存在的条件下,以过硫酸铵/亚硫酸氢钠为引发剂,由丙烯酰胺、N,N-亚甲基双丙烯酰胺、丙烯酸、烯丙胺共聚而得到印迹聚合物固定化酶.通过催化三油酸甘油酯与甲醇的酯交换反应,发现冰胶固定化脂肪酶、常规凝胶固定化脂肪酶、游离脂肪酶具有相似的催化性能.冰胶固定化酶与相应的凝胶固定化酶显示出类似的稳定性,而传质方面则优于常规凝胶固定化酶,因此冰胶印迹聚合物固定化有望成为一种具有吸引力的酶固定化方法.     

土工膜专用气相法聚乙烯DQTG3912的结构与性能

利用旋转流变仪、核磁共振仪等研究了采用Unipol气相工艺生产的聚乙烯DQTG3912的结构与性能,并与同类产品进行了对比.结果表明:DQTG3912为乙烯与1-己烯共聚的中密度聚乙烯,相对分子质量较高,相对分子质量分布较宽,并有较多的长支链;DQTG3912的加工性能优异,可生产双糙面土工膜,制品各项性能符合GB/T...     

熔体造粒法生产尿基复合(混)肥工艺技术的比较

对我国开发应用的塔式造粒、冷冻结晶造粒、油冷造粒、钢带冷却造粒等熔体法生产尿基复合(混)肥造粒工艺技术特点进行了比较,为国内各复合(混)肥厂家新建生产装置或技术改造提供参考.     

Comparison of thermal properties of ethylene‐norbornene copolymers prepared by batch and semi‐batch processes

Ethylene‐norbornene copolymers (ENCs) with various norbornene (NB) fractions could be synthesized by metallocene catalyst in both batch and semi‐batch processes. The batch process with long reaction time produced the ENC samples having considerable copolymer composition drift (CCD) while the semi‐batch process yielded narrow CCD. Furthermore, the effects of CCD on the resultant ENC's thermal properties were discussed. It was found that the thermal properties were dependent on both the NB fraction in obtained ENC and its CCD. The work demonstrated the importance of controlling CCD in the production of ENCs for superior materials properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009