超高分子量聚丙烯酰胺的合成研究

本文研究了用含叔胺基单体同过硫酸钾组成的引发体系引发丙烯酰胺（AM）的聚合，得到分子量为2×107的超高分子量聚丙烯酰胺（PAM），也研究了某些杂质对AM聚合的影响．     

超高分子量聚丙烯酰胺

采用加碱大块均聚后水解工艺合成超高分子量聚丙烯酰胺,产品可用于石油开采、水处理、造纸和污泥脱水等。本项目研制的新型水溶性引发剂可用于各类水溶性单体聚合,可大幅度提高产品分子量,改善产品的水溶性。     

新型氧化还原引发体系合成超高分子量聚丙烯酰胺的研究

开发出一种新型氧化还原引发体系 ,以丙烯酰胺和丙烯酸钠为单体 ,进行水溶液自由基共聚合反应 ,生成聚丙烯酰胺。研究了引发剂用量对聚丙烯酰胺分子量的影响。合成了分子量高达 1 8× 10 7,过滤比为 1 2 4的超高分子量聚丙烯酰胺。     

复合引发体系制备磺化聚丙烯酰胺的研究

以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和丙烯酰胺（AM）为原料,采用复合引发体系和绝热聚合相结合的方法在水溶液体系中合成磺化聚丙烯酰胺（SPAM）,考察了单体质量分数、引发剂质量分数、单体配比、引发剂配比、pH值、聚合起始反应温度对聚合反应的影响。确定SPAM的最佳合成条件为：单体质量分数10％、引发剂质量分数0,15％、AMPS与AM质量比1．0：1、偶氮二异丁腈（AIBN）与氧化还原引发剂质量比4：1、pH值6、聚合起始反应温度40℃,在此条件下,制得的SPAM的分子量为6．13×10^6,其耐温抗盐性能明显优于采用单-氧化还原引发剂制备的SPAM及工业部分水解聚丙烯酰胺（分子量7×10^6）。     

超高分子量聚丙烯酰胺的合成研究

以丙烯酰胺(AM)单体为原料,采用复合引发体系,通过水溶液聚合,制备出了超高分子量聚丙烯酰胺。研究了聚合体系的pH值,单体浓度,温度等因素对聚丙烯酰胺分子量的影响,并确定了最佳工艺条件。     

高分子量两性聚丙烯酰胺的研究进展

综述了单体纯度、引发体系、合成途径和聚合方法对两性聚丙烯酰胺的合成及聚合物分子量的影响,并对高分子量两性聚丙烯酰胺的发展方向及应用前景进行了展望。     

高分子量聚丙烯酰胺的合成与应用进展

对高分子量聚丙烯酰胺的应用现状、合成条件等进行了综合评述。概括了单体纯度、引发剂和引发方式、聚合工艺对分子量的影响,并对高分子量聚丙烯酰胺的发展方向进行了展望。     

超低分子量聚丙烯酰胺的水溶液聚合

本文从丙烯酰胺单体出发,以过硫酸铵为引发剂,甲酸钠为链转移剂,采用水溶液聚合法合成了分子量在(2.6～10)×104范围内的聚丙烯酰胺,探讨了反应温度、单体浓度、分子量调节剂、引发剂等因素对聚合物分子量的影响.     

阳离子聚丙烯酰胺的研制

阳离子聚丙烯酰胺是一种用途广泛的有机高分子聚合物,其分子量和阳离子度是决定其性能的重要指标。在氧化-还原引发体系中,以丙烯酰胺(AM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)为单体共聚合成了阳离子型聚丙烯酰胺聚合物(CPAM),考察了反应温度、酸碱度、引发剂、单体及阳离子单体浓度等因素对CPAM分子量和阳离子度的影响。结果表明,较高分子量和阳离子度CPAM的最佳聚合条件为:聚合单体浓度为35%,阳离子单体的含量约15%,引发剂0.4%,反应体系温度35℃,pH值为6左右。     

一类新型聚丙烯酰胺的合成与絮凝性能研究

以高价铈盐（硝酸铈铵）和多羟基化合物季戊四醇组成的氧化还原引发体系引发丙烯酰胺自由基聚合合成了一类新型多支状非离子型水溶性聚丙烯酰胺。确定了最佳合成工艺条件为：单体质量分数为15％、引发剂用量1mmol·L^-1、反应时间12h、反应温度47℃,此条件下合成得到的新型聚丙烯酰胺相对分子量达400万以上。研究了新型聚丙烯酰胺的絮凝性能,结果表明,当其与无机絮凝剂聚铝复配时絮凝效果较好,模拟污水的透光率由原来的30％提高至90％以上。     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。