衣康酸-天冬氨酸-苯乙烯磺酸钠三元共聚物的合成及阻垢性能研究

以衣康酸(IA)、天冬氨酸(ASP)及苯乙烯磺酸钠(SSS)为单体,过硫酸铵为引发剂,采用水溶液自由基聚合法合成了IA-ASP-SSS三元共聚物,并对产物结构进行红外表征。探讨单体配比、引发剂用量、聚合温度、反应时间对共聚物阻垢性能的影响,通过正交实验和单因素实验确定最佳合成条件。采用静态阻垢法考察阻垢剂用量、钙离子浓度对阻垢性能的影响。结果表明,共聚单体的摩尔比(nASP∶nIA∶nSSS)为1∶1∶0.1、引发剂用量为单体总质量的9%、反应温度85℃且反应时间3h时,合成的IA-ASP-SSS共聚物对碳酸钙、磷酸钙及硫酸钙的阻垢率皆在95%以上,且此共聚物阻垢剂适用于高硬度水环境。     

衣康酸-天冬氨酸共聚物合成及其阻垢性能的研究

针对目前国内使用的阻垢剂存在难降解、易造成水体富营养化等问题,以衣康酸(IA)、天冬氨酸(ASP)为单体,过硫酸铵为引发剂,采用水溶液自由基聚合法合成了可生物降解的IA-ASP二元共聚物,并对产物结构进行红外表征。探讨单体配比、引发剂用量、聚合温度、反应时间对共聚物阻垢性能的影响,通过正交实验和单因素实验确定最佳合成条件。采用静态阻垢法考察阻垢剂用量、阻垢实验温度对阻碳酸钙垢性能的影响,并借助扫描电镜观察碳酸钙垢的晶体形貌,探讨其阻垢机理。结果表明:共聚单体的物质的量比(n_(IA)∶n_(ASP))为4∶1,引发剂用量为单体总质量的9%,反应温度85℃,反应时间2 h时,合成的IA-ASP共聚物对碳酸钙的阻垢率可达95%以上。IA-ASP共聚物作为阻垢剂适用于中低水温环境,其阻垢率随阻垢剂用量增加逐渐提高,最终趋于平缓。IA-ASP共聚物阻垢机理主要涉及螯合、分散作用及晶格畸变。     

IA/ASP/AMPS三元共聚物合成及阻垢性能

以衣康酸(IA)、天冬氨酸(ASP)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,在过硫酸铵引发下采用水溶液自由基聚合方法制备了新型IA/ASP/AMPS三元共聚物阻垢剂,并利用红外光谱仪对其结构进行分析表征。通过正交实验和单因素实验考察单体摩尔配比、引发剂用量、反应温度及反应时间对共聚产物阻垢性能的影响,确定其最佳合成条件。实验结果表明:共聚单体的摩尔比nIA:nASP:nAMPS为3:1:0. 5,引发剂用量占单体总质量的10%,反应温度为85℃,反应时间为4 h时,合成三元共聚物对碳酸钙、硫酸钙及磷酸钙的阻垢性能最好,阻垢率分别达91%、95%及96%以上;此共聚物的固含量和黏均相对分子质量分别为30. 5%、1402。静态阻垢法评价温度对IA/ASP/AMPS共聚物阻垢性能的影响,结果表明,IA/ASP/AMPS共聚物适用于含碳酸钙、磷酸钙的高温循环冷却水体系。     

碳酸钙在St-MMA悬浮聚合中的应用研究

以碳酸钙为分散剂,过氧化二苯甲酰为引发剂,采用悬浮聚合法合成苯乙烯-甲基丙烯酸甲酯共聚物。研究了碳酸钙用量、反应温度、反应时间、引发剂用量、水与单体体积比、苯乙烯与甲基丙烯酸甲酯体积比对悬浮聚合的影响。结果表明,碳酸钙用量为2.0~3.0g,反应温度为75~80℃,反应时间为3h,引发剂用量为0.3115g,水与单体体积比为5:1~7:1,苯乙烯与甲基丙烯酸甲酯体积比为1/8.5~1:1(单体总体积为9.5m L)时,制得的共聚物颗粒大小均匀,粒径在0.31mm~0.60mm,产率在90%以上。     

低相对分子质量苯乙烯-马来酸酐交替共聚物的合成

将引发剂偶氮二异丁腈(AIBN)、共聚单体苯乙烯(St)和马来酸酐(MA)溶解于甲苯中,采用沉淀聚合法合成苯乙烯-马来酸酐共聚物(SMA).分别研究了反应温度、引发剂用量、反应时间、单体配比和单体浓度对聚合物得率和酸酐含量的影响.采用正交实验确定最优反应条件为:单体浓度20%,单体物质的量比为1∶1,引发剂用量为0.60%,反应温度为86℃,反应时间2h,产物得率为86.86%,酸酐含量为50.28%.并利用傅里叶变换红外光谱(FTIR)、核磁共振碳谱(~(13)C NMR)、凝胶渗透色谱(GPC)和热分析法分别研究聚合物的分子结构、相对分子质量及相对分子质量分布和热稳定性.结果表明产物是苯乙烯-马来酸酐交替共聚物,相对分子质量分布较窄,具有良好的热稳定性.     

松香丙烯酸基二元单体与苯乙烯的共聚反应

以丙烯酸松香加成物(RA)与甲基丙烯酸-2-羟乙酯的酯化物(RAH)为二元单体,采用溶液聚合法制备了苯乙烯与RAH的共聚物.通过正交实验法研究了反应条件对RAH与苯乙烯共聚反应的影响.对正交实验的结果分析得出:在反应温度为105℃下,RAH与苯乙烯的质量比为1:2,引发剂的用量为单体质量的1.5%,反应时间为8小时,单体转化率最高,为85%;原料配比对共聚反应的影响最为显著,其次是反应温度和引发剂用量,反应时间的影响最小.通过红外光谱分析和核磁共振图谱分析表明成功合成了RAH与苯乙烯的共聚物,热重分析表明产物的热稳定性随单体中RAH比例的增加而增加.     

(丙烯酰胺-丙烯酸十六酯)共聚物的合成及其增稠性能研究

采用沉淀聚合法合成丙烯酰胺 -丙烯酸十六酯共聚物。重点讨论了合成条件如单体配比、引发剂用量、温度等对共聚反应的影响以及共聚物对苯丙乳胶的增稠性能的影响。并用DMTA和凯达尔定氮法表征了共聚物组成 ,结果表明 :所合成的共聚物可以作为疏水缔合型增稠剂使用     

阳离子淀粉-壳聚糖-丙烯酰胺的接枝共聚研究

以硝酸铈铵为引发剂,合成阳离子淀粉(CS)-壳聚糖(CTS)-丙烯酰胺(AM)接枝共聚物,讨论了反应温度、引发剂浓度、单体用量、反应时间以及壳聚糖用量对接枝共聚反应的影响。结果表明:淀粉中葡萄糖环浓度(cAGU)为0.20 mol/L,mCTS/mCS=1/6,cAM=1.0mol/L,cCe4 =5 mmol/L,反应温度60℃,反应时间3 h时,转化率和接枝效率可分别达到88%和92%以上;转化率随mCTS/mCS增大而增大,接枝效率则随着CTS用量增大降低,CTS的存在使AM均聚的几率增大。     

正交实验法优化氟硅丙乳液的制备工艺

利用L25(56)正交实验设计方法,研究了引发剂,乳化剂,有机硅、氟的用量以及聚合温度,单体配比等因素对乳液单体转化率的影响.在本实验条件下,得出制备氟硅丙乳液的最佳工艺条件为:乳化剂用量为4%,引发剂用量为ω=0.6%,单体配比为n(BA):n(MMA)=44:54,有机硅用量ω=10%,有机氟用量ω=4%,聚合温度...     

季铵盐高分子抗菌剂的工艺优化与抗菌性能研究

采用正交实验设计,进行公斤级批量制备DMAEMA-DB季铵盐单体和抗菌聚合物的研究,对影响单体合成的关键因素以及聚合的条件进行优化,并采用FT-IR和NMR等方法对所合成的单体和聚合物分别进行了结构表征,通过平板活菌计数法测定了单体以及聚合物的抗菌性能.结果表明,DMAEMA-DB单体的优化合成条件为:反应温度55℃,反应时间30h,反应物浓度为V<,s>:V<,l>=1:1,反应物配比为DMAEMA:DB=1:1.1.Poly(AAm/DMAEMA-DB)的最佳合成工艺条件为:聚合温度70℃,聚合时间8h,单体浓度为0.4mol/L,引发剂用量为单体用量的0.4mol%,在该条件下合成的聚合物平均得率达89%.将它们用于杀灭大肠杆菌时,接触时间5min对大肠杆菌的抑菌率可达99%,接触时间30min抑菌率达到100%.     

Experimental study on scale inhibition performance of a green scale inhibitor polyaspartic acid

Static and dynamic experiments were carried out to validate scale inhibition performance of a green scale inhibitor-polyaspartic acid (PASP). From the static experiment, it was shown that below 60℃, polyaspartic acid is very effective in scale inhibition, with the scale inhibition ratio exceeding 90% with only 3 mg/L PASP for the 600 mg/L hardness solution. For a higher hardness solution of 800 mg/L, the scale inhibition ratio can also reach 90% with 6 and 12 mg/L PASP at 30 and 60℃respectively. The SEM photographs of CaCO3 crystals indicate that the crystal structure transforms from a compact stick-shape to a loose shape so that the scale can be washed away easily instead of being deposited on the heat transfer surface. The dynamic experimental results show that almost no scales formed on the heat trans- fer surface and the fouling thermal resistance decreases extraordinarily if PASP is added in the solution.     

两种聚天冬氨酸接枝共聚物的制备及其阻垢性能

以马来酸酐、尿素、二乙烯三胺、1-氨基-2-萘酚-4-磺酸等为原料,合成了聚天冬氨酸/二乙烯三胺(PASP/DETA)和聚天冬氨酸/1-氨基-2-萘酚-4-磺酸接枝共聚物(PASP/1,2,4);采用红外光谱仪分析了产物的化学结构,并测定了其对工业用水的阻垢性能.结果表明,PASP/DETA对Ca3(PO4)2具有很好的阻垢性能,PASP/1,2,4对CaCO3具有很好的阻垢性能;当二者按PASP/DETA浓度5mg/L、PASP/1,2,4浓度1.5mg/L复配使用时,对CaCO3的阻垢率可达95.4%,对Ca3(PO4)2的阻垢率可达95.2%.     

聚天冬氨酸与木质素磺酸钠复配物对碳酸钙阻垢性能的研究

通过静态阻垢法研究了国产聚天冬氨酸(PASP)、木质素磺酸钠(SLS)添加量对碳酸钙的阻垢性能.结果表明:PASP在5.0mg/L时阻垢率接近100%,SLS达300mg/L以上时阻垢率趋于平缓,浓度为600mg/L时,其阻垢率仍不足70%.PASP与SLS复合配方及在不同影响因素条件下阻垢性能的研究表明:复合配方(PASP 2.0mg/L SLS 5.0mg/L)的阻垢率接近100%,且适用于高钙、高pH值、高温的水系统中,并可在水系统中长时间停留.     

Preparation of fluorescent polyaspartic acid and evaluation of its scale inhibition for CaCO3 and CaSO4

Polysuccinimide was synthesized from maleic anhydride and urea. A polyaspartic acid derivative (PASP‐Try‐SEA) was synthesized from the polysuccinimide with 2 ‐aminoethanesulfonic acid and tryptophan. The products were characterized by UV, FTIR,¹H NMR, TGA and PL, respectively. The results showed that the fluorescent chromophore‐indolyl groups were successfully incorporated into PASP. The relationship between the fluorescence intensity and the concentration of fluorescent polyaspartic acid (FPASP) is linear with the excitation wavelength of 366 nm and 422 nm. FPASP also showed excellent scale inhibition properties with a scale inhibition rate of 78% achieved for CaCO₃ with a dosage of 9 mg/L and a significantly enhanced scale inhibition effect for CaSO₄, achieving an inhibition rate of 98%, which were determined using the static scale inhibition method. When FPASP was added to the solution, CaCO₃ and CaSO₄ deposits showed flower patterns with floppy accumulation by scanning electron microscopy. Copyright © 2016 John Wiley & Sons, Ltd.     

Piecing together the puzzle: understanding a mild, metal free reduction method for the large scale synthesis of hydrazines

A key intermediate for the synthesis of hydrazines via a mild, metal free reduction of diazonium salts has been isolated and characterized by X-ray analysis. The presence of this intermediate is general, as demonstrated by the preparation of a number of analogues. A discussion of the mechanism and potential benefits of such a process are also described.     

Molecular scale bioelectrochemistry

Our ability to interface with biological macromolecules continues to advance at a significant pace and brings with it potential applications that are as broad as they are powerful. Running alongside this evolution has been the refinement of methods by which interfaces can be probed at scales approaching (or being at) the molecular. Through combinations of experimental design, proximal probe technology and high sensitivity optical imaging, one can truly probe the bioelectronic interface at levels that are both startling and associated with unprecedented levels of detail.     

Acidity function scale for H2SO4 solutions in phenol-acetone solvents with low water content at 25°C

The indicator method was employed to measure the acidity function H ₀ ^S of H₂SO₄ solutions in solvents consisting of an equimolar mixture of phenol and acetone with 0.8% water (from 3.6·10^–4 to 2.6·10^–2 M H₂SO₄) and 2.5% water (from 4.3·10^–4 to 0.32 M H₂SO₄) and of phenol and acetone in a molar ratio of 1:1.5 with 0.67% water (from 1.63·10^–4 to 7.77·10^–2 M H₂SO₄) and 2.09% water (from 4.49·10^–4 to 0.35 M H₂SO₄) at 25°C. The indicators employed were 4- and 2-nitroaniline.Deceased.N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Lenneftekhim Scientific-Commercial Association, St. Petersburg. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 72–78, January, 1992.     

The diiodine basicity scale: toward a general halogen-bond basicity scale

The new diiodine basicity scale pK_BI2 is quasi‐orthogonal to most known Lewis basicity scales (hydrogen‐bond, dative‐bond and cation basicity scales). The diiodine basicity falls in the sequence N>P≈Se>S>I≈O>Br>Cl>F for the iodine‐bond acceptor atomic site and SbO≈NO≈AsO>SeO>PO>SO>C?O>? O? >SO₂ or PS?? S? >C?S?N?C?S for the functionality of oxygen or sulfur bases. Substituent effects are quantified through linear free energy relationships, which allow the calculation of individual complexation constants for each site of polybases and thus the classification of aromatic ethers as carbon π bases and of aromatic amines, thioethers and selenoethers as N, S and Se bases, respectively. The pK_BI2 values of nBu₃N⁺‐N^?C≡N, 2‐aminopyridine and 1,10‐phenanthroline reveal a superbasic nitrile, a hydrogen‐bond‐assisted iodine bond and a two‐centre iodine bond, respectively. The diiodine basicity scale is a general inorganic but family‐dependent organic halogen‐bond basicity scale because organic halogen‐bond donors such as IC≡N and ICF₃ have a stronger electrostatic character than I₂. The family independence can be restored by the addition of an electrostatic parameter, either the experimental pK_BHX hydrogen‐bond basicity scale or the computed minimum electrostatic potential.     

分子尺度电致发光器件

近年来,有机单分子电致发光研究在材料和器件方面取得了突破,是分子电子学新兴的研究方向之一。本文综述了扫描隧道显微镜法、纳米间隙电极法等测量单分子尺度电致发光的研究进展。根据电致发光谱图,可以确定分子器件的发光类型,并得到单个分子的指纹信息。     

Micrometer scale gel patterns

A novel method for fabricating micrometer sized gel patterns is described. The presented method involves spin-coating a pre-gel solution on a surface that was chemically treated to modulate its surface energy, creating highly hydrophobic areas on a hydrophilic substrate. Following spin-coating, the gel solution self organizes on the hydrophilic sites. This method offers the advantages of high resolution, self-alignment to pre-patterned electrodes, and a simple straightforward fabrication process. Minimum feature size achieved was approximately 20 μm. The characteristic shrinking and swelling times of gel patterns were measured and found to be around 0.6 s for swelling and 2 s for shrinking (for a 60 μm diameter gel) in agreement with the reduced response time expected for scaled down gel patterns. These results suggest the suitability of these gel patterns as valves or actuators in microfluidic devices. Micron-size gel patterns were also incorporated into microfluidic channels thus demonstrating a new approach to create simple, affordable, microfluidic devices, which incorporate “smart” hydrogels as building elements in a simple fashion.