用热聚法固定指示剂的光纤氧气传感器研究

采用热聚法将甲叉双丙烯酰胺（MBBA）聚合并共价交联在硅烷化的玻璃微珠上 ，同时将指示剂Ru（Ⅱ）-邻啡咯啉配合物物理包埋于聚合物中，研制了一种基于 荧光猝灭原理的光纤氧气传感器，采用NaHSO_3-O_2-MnSO_4体系引发MBBA水溶液热 聚合后应，通过确定NaHSO_3,MnSO_4,MBBA和Ru(phen)_3Cl_2的最佳反应浓度以及 玻璃微珠的尺寸，优化了聚合反应条件，改善了指示剂的固定效果，制备了性能较 好的传感器探头，该传感器的检测下限为5×10~(-6)(V/V)，响应时间为10s该传感 器连续工作50min,重复性标准偏差为±1%。     

丙烯酰胺在聚乙二醇水溶液中的聚合动力学

用改进溴法对丙烯酰胺 (AM)在聚乙二醇 (PEG)水溶液中聚合动力学进行研究 .在单一和氧化还原引发体系中分别考察了引发剂、单体和PEG用量、不同HLB值乳化剂以及聚合温度等因素对动力学的影响 .得到AM聚合速率与过硫酸铵 (APS)浓度的 0 91次方成正比 ;单一APS和APS 三乙醇胺 (TEA)氧化还原引发体系中的AM聚合表观活化能分别为 96 1和 4 2 3kJ mol.     

阳离子聚丙烯酰胺合成工艺条件及絮凝性能的研究

以丙烯酰胺(AM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)为共聚单体,采用氧化还原/偶氮化合物复合引发剂体系在水溶液中进行自由基聚合,合成了阳离子型聚丙烯酰胺聚合物(CPAM)。系统研究了反应条件对反应产物的影响,用红外光谱对CPAM的结构进行了表征。结果表明,制备较高分子量CPAM的优化工艺参数为:单体总质量分数35%(AM∶DMC=3∶1),氧化还原引发剂质量分数0.06%((NH_4)_2S_2O_8∶NaHSO_3=1∶1),偶氮类引发剂质量分数0.09%,助溶剂质量分数1.5%,络合剂质量分数1.5%。在此优化条件下,所得CPAM的分子量达1.2×10~6,对蒙脱土模拟废水的絮凝效果良好,经其处理后的模拟废水透光率达到99.3%。     

硫酸锰存在下亚硫酸氢钠引发丙烯酰胺水溶液聚合反应的研究

K₂S₂O₈-NaHSO₃是目前工业生产上广泛使用的丙烯酰胺(AM)聚合引发体系。该体系优点很多,但缺点是 O₂ 的存在会明显延长聚合诱导期和使聚合产物分子量下降,而且残存的K₂S₂O₈会导致聚合物降解。单独使用NaHSO₃也能引发AM聚合,但 O₂ 的阻聚作用仍未消除。本文通过加催化剂,组成一个有自己特色的AM聚合引发体系。     

二价锰盐存在下过硫酸钾引发丙烯酰胺聚合反应的研究

<正> 用过硫酸钾(以下用KPS表示)或三价锰盐单独作为引发剂,或者高价锰盐和过硫酸钾分别与另一还原剂组成氧化-还原引发体系,以引发单体丙烯酰胺(以下用AM表示)聚合,已有许多报道。为了弄清用KPS引发AM聚合时二价锰盐的影响,本文用膨胀计法研究了二价锰盐存在下,KPS引发AM聚合的动力学(用膨胀计毛细管内液柱     

等离子体引发聚合制备共聚醚及其锂盐配合物的离子电导性

为改善梳形聚醚-聚甲基丙烯酸甲氧基多缩乙二醇酯[P(CH_1=C(CH_3)CO(OCH_2CH_2)_nOCH_3),n=8,22,分子量分别为400,1000,简称PMEO_8,PMEO2_(22)的力学性能,作者曾用等离子体引发聚合代替自由基引发聚合制备了PMEO_8,PMEO_(22)及其与丙烯酰胺(AM),甲基丙烯酰胺(MA)的共聚物,取得了较满意的结果。为系统地研究     

二过碘酸合银(Ⅲ)络离子氧化还原引发丙烯酰胺聚合反应动力学的研究

二过碘酸合银[Ag(Ⅲ)]在氧化还原反应中为双电子转移反应,没有中间自由基产生,不能引发丙烯腈聚合^[1,2].我们发现,Ag(Ⅲ)与不同还原剂组成氧化还原体系,在一定条件下,能引发烯类单体聚合.本文研究了Ag(Ⅲ)为氧化剂、丙烯酰胺(AM)为还原剂引发AM聚合反应的动力学,得到了聚合速率方程和表观活化能,测得了聚合物分子量M,探讨了引发机理.     

(N,N′—二乙基)偶氮二异丁脒盐酸盐引发下的丙烯酰胺水溶液聚合

本文研究了(N,N′—二乙基)偶氮二异丁脒盐酸盐引发下丙烯酰胺水溶液聚合的反应动力学。得出了聚合速率方程式为RP=KP[EAIBA]05[AM]。测定了聚合表观活化能。并研究了聚合条件对产物分子量及其分布的影响。利用该引发—聚合体系,获得了相对分子量上千万超高分子量聚丙烯酰胺。     

芳香叔胺引发丙烯酰胺光聚合动力学及机理研究

研究了N,N-二甲基对甲苯胺(DMT)为引发剂时丙烯酰胺(AM)的光聚合。聚合速率与AM、DMT浓度的关系为: R_p∞[DMT]~(0.35)[AM]~(1.34)(水为溶剂) R_p∞[DMT]~(0.33)[AM]~(1.32)(二甲亚砜为溶剂)二甲亚砜为溶剂时,光聚合表观活化能为4.62千卡/克分子。 从光照下DMT与AM形成激发态电荷转移复合物的机制初步讨论了引发机理。     

SET-LRP法制备星型疏水缔合水溶性聚合物

采用丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸钠(NaAMPS)以及N-叔丁基丙烯酰胺(NtBA)为共聚单体,以Cu~0粉/三(2-二甲氨基乙基)胺(Me_6-TREN)为催化体系,四氯化碳(CCl_4)为引发剂,利用单电子转移自由基聚合(SET-LRP)方法合成星型疏水缔合水溶性聚合物P(AM/NtBA/NaAMPS)。采用控制变量法分别考察了引发温度、疏水单体含量、AMPS含量、引发剂用量、催化剂铜、单体浓度等因素对聚合物相对分子质量的影响,确定了最佳聚合条件并考察了聚合物的耐温抗盐性能。结果表明,当单体浓度为35%,引发温度为25℃,AM、AMPS、NtBA分别占单体总量的93.6%、5%、1.4%(摩尔比),引发剂质量分数为0.4942%,催化剂铜的质量分数为0.0848%,钝化剂的质量分数为0.1192%时,所得星型疏水缔合水溶性聚合物P(AM/NtBA/NaAMPS)的相对分子质量出现最高值为267万,同时具有一定的耐温抗盐性,其溶液性能与线型化的P(AM/NtBA/NaAMPS)相似,且在相同浓度下CaCl_2对聚合物表观粘度的影响比NaCl大。     

STUDY ON THE EFFECT OF POLYSTYRENE SULFONIC ACID MACROMOLECULES ON THE POLYMERIZATION OF ACRYLAMIDE

The effect of polystyrene sulfonic acid (PSSA) macromolecules on the polymerization of acrylamide (AM) has been studied. It was found that the rates of polymerization of AM were greatly increased in the presence of PSSA in the polymerization system.The maximum value of the rate of polymerization of AM was obtained when the ratio of [—SO_3H]: [AM] reached 3:1. When the insoluble crosslinked PSSA was used instead of the soluble one, this effect decreased considerably. The interaction between molecules of PSSA and AM was determined by infrared spectroscopy, elementary analysis and X-ray photoelectron spectroscopy. The combination form, —SO_3-NH_3~ CO—, formed between sulfonic group and amide group was found to be existed since the infrared absorption band of —NH_2 shifted from 3400cm~(-1) to 3150 cm~(-1), the binding energy of electron N_(18) changed from 399.7 eV to 401.3 eV, and the atomic ratio of N to S of the products was similar to the ratio of reagents. Based on these experimental results, the mechanism of AM polymerization in the presence of PSSA is proposed. The initial step is the combination of AM with sulfonic group to form —CONH_3~ , then followed by polymerization on the PSSA macromolecule. The role of PSSA on the polymerization of AM is discussed.     

POLYMERIZATION OF OCTAMETHYLCYCLOTETRASILOXANE WITH HEXAMETHYLDISILAZYL-LITHIUM AS INITIATOR*

 This work focused on the anionic polymerization of octamethylcyclotetrasiloxane (D₄, D = Me₂SiO_2/2) initiated by a new kind of initiator hexamethyldisilazyl-lithium (MM^NLi). ²⁹Si-NMR spectroscopy and gas chromatography (GC) were used to characterize the polymerization products. The process was accelerated by adding a small amount of high activity monomer D₃ and by raising the polymerization temperature. At the end of polymerization more than 95% of the monomer was converted to polymer and only a very small amount ofD₄ and D₅ remained in the polymers.     

The kinetics of polymerization of cyclopentene by WCl6/AliBu3 catalyst

The kinetics of the polymerization of cyclopentene by WCl₆/AliBu₃ catalysts have been studied and the factors controlling the reproducibility of the rate of polymerization have been ascertained. A significant dependence of the rate of polymerization on the time between the additions of WCl₆ and AliBu₃ was observed. The dependence of the catalyst activity r,i this time delay suggested that WCl₆ reacted with cyclopentene to produce an unstable species (W₁) that could react with AliBu₃ to produce a catalytically active species (W₁¹) or that could react further with cyclopentene to produce another species W₂ that in turn would react with AliBu₃ to produce a much less active catalyst W₂¹. The detailed study of the kinetics of polymerization under controlled conditions suggested a kinetic chain mechanism initiated by two catalyst species; mechanism of polymerization based on the carbene system is suggested.     

三氟化硼引发四氢呋喃聚合的研究——以环氧氯丙烷为促进剂

<正> 四氢呋喃(THF)通过正离子开环聚合而制得的聚丁二醇(PTMG)是生产嵌段聚醚聚氨酯及嵌段聚醚聚酯弹性材料的重要原料。目前制备PTMG所采用的引发剂都是强酸型的,如高氯酸、氟磺酸或发烟硫酸等,对设备腐蚀严重。用酸性较弱的三氟化硼引发聚合在文献上也有一些研究报道,但尚难以采用,其主要困难在于实际应用的     

Effect of Cu(II)/H2 Salen complex on the non-conventional initiated emulsion polymerization of acrylonitrile

Radical polymerization of acrylonitrile was carried out in an emulsifier-free condition initiated by KHSO₅ catalyzed with Cu(II)/bis-salicylidene ethylene diamine (H₂ Salen) complex. The Cu(II) salt alone, Cu(II)/salicylaldehyde and Cu(II)/ethylene diamine have a retarding effect on the polymerization reaction, while the chelate of Cu(II) with the tetradentate Schiff base ligand, H₂ Salen has a catalytic effect. Prior to this, the catalytic effect of various bivalent transition metal salts and their couple with the Schiff base, H₂ Salen on the polymerization reaction has been examined to be not significant. The in situ developed complex produces the stable emulsion leading to high conversion. In the polymerization, the variables studied were the concentration of monomer, initiator, Cu(II), H₂ Salen and temperature. The overall activation energy was computed to be 13.1 kcal/mol. From the kinetic and spectral analyses, the mechanism of the initiator decomposition and initiation of polymerization by Cu(II)/H₂ Salen complex were suggested. The rate of polymerization (R_p) was found to be dependent on the monomer, initiator, Cu(II) ion, H₂ Salen concentrations to the 1.4, 0.3, 1.6, 1.5 power respectively. The polymers are characterized by IR and molecular weight by viscosity and GPC methods.     

Application of Et3NHCl-AlCl3 ionic liquid as an initiator in cationic copolymerization of 1,3-pentadiene with styrene

Cationic copolymerization of 1,3-pentadiene (PD) with styrene (St) using the triethylamine hydrochloride-aluminium chloride (Et₃NHCl-AlCl₃) room temperature ionic liquid as an initiator in toluene has been investigated. The polymerization proceeds to high conversions, indicating high initiating reactivity of Et₃NHCl-AlCl₃ in these copolymerization systems, although molecular weights of the polymers are limited which are similar to polymerization initiated by Lewis acids such as TiCl₄, BF₃, BF₃·OEt₂. The polymers were analyzed using IR spectra in conjunction with gel permeation chromatography (GPC).     

Alkylidenic polymerization of alkynes from w-based initiators: Kinetics and mechanism of activation by lewis acids

The polymerization of alkynes initiated by metathesis catalysts proceeds via a mechanism similar to that of the ring-opening metathesis polymerization of cycloalkenes. Various polymerizing systems have been claimed by several authors as bringing about living character; they point out the strong influence of the substituents carried by the monomer which have been shown to hinder transfer and termination processes. Whatever the initiator used, the activity of the polymerizing system is low; this paper deals with the activation of Rudler type initiator by Lewis acids. The effect of AlR₃, AlR₂Cl, AlRCl₂, BR₃ and B(OR)₃ is presented and discussed.     

THE EFFECT OF SINGLE MICELLES OF SURFACTANTS ON POLYMERIZATION OF ACRYLAMIDE

The polymerization of acrylamide in micellar solutions of cationic, anionic, zwitterionic and nonionic surfactants, initiated by NaHSO₃, has been studied at 20 and 30° C with time variable method of thermokinetics for the 1. 5-order reaction in this paper. Reaction mechanism has been suggested and rate equations have been derived. The results indicate that ionic (CTAB, TTABDTAB, SDS) and zwitterionic (SLS) surfactants catalyze the polymerization in the order SDS>SLS>DTAB ≈ TTA≈ CTAB, and nonionic surfactant (Brij35) has slight inhibition effect. These effects are mainly caused by the effect of the formation of micelle- HSO₃ complex on the step of initiator to form free radical.     

Effects of acids on vinyl polymerization initiated by chromous acetate-alkyl halide

Effects of various acids, i.e., acetic, chloroacetic, hydrochloric, and sulfuric acids on the polymerization of styrene initiated by Cr²⁺–CHCl₃ in DMF was studied. These acids reduced the rates of polymerization by Cr²⁺–CHCl₃ initiator systems. This phenomenon could be explained by a decrease of the reducing power of Cr²⁺ for alkyl halide. On the other hand, chloroacetic acids could initiate the polymerization of styrene without CHCl₃ because these acids have active chlorine in the molecule for Cr²⁺. It was found that the polymer obtained by this initiator system had an endgroup containing chromium carboxylate, therefore this polymer was green in color and insoluble in benzene.     

The effect of solvents on the homopolymerization of 4-dimethylaminostyrene initiated with CCl3COOH

In the polymerization of 4-dimethylaminostyrene (DMAS) initiated with CCl₃COOH in solvents possessing different electron-donor and electron-acceptor properties and relative permittivity (c_r), the c_r value of the solvent correlates well with the polymerization rate. The greatest increase of rate of polymerization in the homogeneous system was observed in nitrobenzene. In this solvent, characteristics of the polymerization of DMAS initiated with CCl₃COOH were determined; differences between these characteristics and the rate equation for a similarly initiated polymerization of DMAS in benzene have been elucidated.