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1.
采用油酸失水山梨醇酯(SPAN)-壬基酚聚氧化乙烯醚(OP)复合乳化剂与K2S2O8-Na2SO3氧化还原引发剂,进行二烯丙基二甲基氯化铵-丙烯酰胺反相乳液共聚合,测得单体的竞聚率为γDADMAC=0.14±0.11,γAM=5.05±0.66;在单体浓度为25─45%,引发剂浓度0.06—0.1%,乳化剂浓度为5—9%,聚合温度303K条件下,得到了共聚反应动力学方程:Rp=k[M]0.68[I]1.31[E]0.73,文中对上述结果做了解释.  相似文献   

2.
STRUCTURALMODIFICATIONOF11-ISOPROPYLIDENEendo-TRICYCLO[6.2.1.0 ̄(2,7)]UNDECA-4,9-DIENE-3,6-DIONETOIMPROVETHESTABILITY¥XiaoPeiG...  相似文献   

3.
高单体浓度下反相微乳液聚合   总被引:19,自引:0,他引:19  
选择丙烯酰胺(AM)、丙烯酸胺/丙烯酸钠(AM/SA)和丙烯酰胺/(2-甲基丙烯酰氧乙基)三甲基氯化铵(AMAIM.MC)为单体(对),在相同的实验条件下进行反相微乳液(共)聚合,得到各自的动力学关系式,并对其做了解释.  相似文献   

4.
苯乙烯—甲基丙烯酸超浓乳液的制备及聚合   总被引:4,自引:0,他引:4  
超浓乳液聚合有着良好的应用前景[1,2].但文献报道的超浓乳液研究多集中于苯乙烯体系,而对于在此基础上引入功能基单体制备超浓乳液,研究得较少[3].本文研究了影响苯乙烯(St)与甲基丙烯酸(MAA)制备(St-MAA)超浓乳液稳定性的因素.探讨了其聚...  相似文献   

5.
研究了含叔胺基结构的药物奋乃静(Perphemnazinum,简称PERP)和有机过氧化物所构成的引发体系,并以此体系引发丙烯酸酯类单体聚合所得的含奋乃静缓释药膜的缓释行为.结果表明,奋乃静(PERP)和过氧化苯甲酰(BPO)引发体系引发甲基丙烯酸甲酯(MMA)聚合的动力学方程为:Rp=Kp[BPO]05[PERP]05[MMA]10,聚合表观活化能Ea=418KJ/mol,从而确定此引发体系的引发机理为氧化还原引发机理.PERP BPO体系能在40℃温度下,引发丙烯酸酯类单体共聚,而能形成含有奋乃静的缓释药膜  相似文献   

6.
用膨胀计研究了Nd(OPri)2Cl-AlEt3均相稀土催化剂异戊二烯聚合动力学.在实验条件下,本体系显示稳态聚合特征;聚合速度对单体浓度和催化剂浓度均为一级关系,即聚合速度方程为Rp=Kp[Nd][M];本体系总的活化能Ea为57.4kJ/mol.  相似文献   

7.
用膨胀计研究了Nd(OPr^i)2Cl-AlEt3均相稀土催化剂异戊二烯聚合动力学。在实验条件下,本体系显示稳态聚合特征;聚合速度对单体浓度和催化剂浓度均为一级关系,即聚合速度方程为Rp-Kp[Nd][M];本体系总的活化能Ea为57.4kJ/mol。  相似文献   

8.
基团转移嵌段共聚研究   总被引:1,自引:1,他引:0  
本文采用双官能团引发剂和负离子型催化剂进行了甲基丙烯酸甲酯和甲基丙烯酸C7~9酯的基团转移嵌段共聚.讨论了温度、单体投料方式、引发剂-催化剂浓度比及单体浓度对聚合反应的影响,认为当两段反应温度分别为85℃和25℃时,引发剂浓度[I]=1.35×10-2mol/L,催化剂引发剂浓度比[Cat]/[I]=0.126,以活性较低的C7~9MA为第一嵌段单体,有利于C7~9MA和MMA的嵌段共聚.测定了嵌段共聚物的热形变温度;用GPC对嵌段共聚物的相对分子质量及分布进行了表征,结合IR、1HNMR和热形变温度分析,证明所得到的为PMMA-PC7~9MA-PMMA均相三嵌段共聚物.  相似文献   

9.
单茂钛催化剂的丙烯无规聚合反应及其动力学研究   总被引:4,自引:1,他引:4  
比较了不同钛化合物/甲基铝氧烷(MAO)催化体系的丙烯无规聚合,催化活性次序为CpTi(OR)3>CpTi(OPh)3>CpTiCl3>Cp2TiCl2>Ti(OBu)4>TiCl4>Ti(OBu)2Cl2,所得聚丙烯用沸庚烷抽提8h,溶解95%以上,可溶部分经13C NMR、WADX、FTIR等分析证明为无规聚丙烯(aPP),是没有结晶性的弹性体.GPC测出其分子量Mw=8.0~10.0×104,Mw/Mn≈2.0.探索了催化体系CpTi(O n Pr)3/MAO中钛的浓度、[Al]/[Ti]摩尔比,丙烯聚合压力,聚合温度和时间对丙烯聚合反应的影响.研究了该催化体系丙烯聚合反应动力学规律,表观聚合反应速率对催化剂浓度和单体压力(浓度)都呈一级反应关系,表观聚合速率常数KP=292×105mol/L·h(40℃).活化能ΔE=-7.88×103J·mol-1,碰撞因子A=1.41×10-4mol/L·h.  相似文献   

10.
详细讨论了[(NH4)2S2O8/NaHSO3]氧化-还原引发体系引发苯乙烯(St)丙烯酸丁酯(BuA)体系的细乳液共聚合的动力学特征及其成核机理的关系,细乳液的聚合速率比相同条件下的常规乳液聚合速率低,引发期长,随聚合温度、引发剂浓度、乳化剂浓度的增加,聚合速率增大,共乳化剂正十六烷(HDE)的浓度在一定范围内增大,反应的速率增大,然后再增加HDE,反应速率下降,建立动力学曲线数学模型,并深入讨  相似文献   

11.
微乳液结构和丙烯酰胺反相微乳液聚合   总被引:41,自引:0,他引:41  
本文对微乳液的结构及其特征作了概括性的论述,并着重总结了近年来在微乳液聚合方面的研究成果,特别是对丙烯酰胺,丙烯酸盐以及(2-甲基丙烯酰氧乙基)三甲基氯化铵等单位的反相微乳液聚合的研究工作进行了详尽论述。  相似文献   

12.
The synthesis of polyacrylamide nanoparticles by semi-continuous inverse heterophase polymerization as a function of feeding rate of monomer aqueous solution is reported here. In this process, a concentrated acrylamide aqueous solution is dosed semi-continuously at various rates over an AOT-toluene solution containing the initiator. Our results indicate that particle size and the viscosimetric molar masses diminish as the dosing rate is slowed down and that smaller particles, as well as lower molar masses, are obtained compared to those produced by batch and semi-continuous microemulsion polymerizations, employing the same concentration of surfactant. Moreover, higher polymer/surfactant ratios are higher compared to those obtained in batch microemulsion polymerization and similar or slightly higher than that in semi-continuous microemulsion polymerization.  相似文献   

13.
阳离子型微乳液聚合丙烯酰胺的表征   总被引:10,自引:0,他引:10  
自从Hoar[1]和Schulman[2]利用乳化剂、水和油制得均一透明的微乳液以来,微乳液在许多领域中得到广泛应用.Candau[3,4]通过微乳液聚合得到分子量很高(105~106)的纳米级聚合物粒子,且聚合物分子链采取紧密缠绕的构象.Antonietti[5]在对苯乙烯微乳液聚合的研究报道中认为,聚合物分子链是以一种类似于网状交联结构的形态存在的,这些结果表明,通过微乳液聚合所得聚合物可能存在着一些特殊的性质.本文采用阳离子型乳化剂十六烷基三甲基溴化铵(CTAB)和脂肪族醇助乳化剂制备的油包水(W/O)型反相微乳液体系来聚合丙烯酰胺(Am),并与使用相同乳…  相似文献   

14.
辐射引发丙烯酰胺微乳液聚合   总被引:6,自引:0,他引:6  
辐射引发丙烯酰胺微乳液聚合徐相凌,张志成,张曼维(中国科学技术大学应用化学系合肥230026)关键词丙烯酰胺,微乳液聚合,辐射引发聚合聚丙烯酸胺(PAM)及其共聚物是广泛应用的水溶性高分子.80年代中期,Candau等’‘-”首先开始研究了丙烯酸胺的...  相似文献   

15.
聚合方法对一种正离子聚丙烯酰胺结构与性能的影响   总被引:2,自引:0,他引:2  
对相同进料比下,以过硫酸胺/亚硫酸氢钠为氧化还原引发剂,分别用溶液法和反相微乳液法合成的丙烯酰胺(AM)与2-甲基丙烯酰氧乙基三甲基氯化胺(MADQUAT)的共聚物P(AM-MADQUAT),根据单体竞聚率计算了两种共聚物的序列分布和组成分布.考察了两种聚合物结构对高岭土絮体尺寸、zeta电位降以及絮体压缩屈服应力的影响,初步建立了不同聚合方法合成的阳离子聚丙烯酰胺结构与絮凝性能之间的相关性.  相似文献   

16.
Isothermal phase diagrams of the system cetyltrimethylammonium bromide (CTAB)/n‐butanol/n‐octane/water were constructed, and the effect of the oil (n‐octane) contents on the microemulsions was studied at 40 °C. We determined the microemulsion structures of two systems, CTAB/n‐butanol/10% n‐octane/water and sodium dodecyl sulfonate (As)/n‐butanol/20% styrene/water, by conductivity measurements to investigate the polymerization of acrylamide and styrene in the two microemulsion systems. The polymerization kinetics of the water‐soluble monomer acrylamide in CTAB micelles and the different CTAB/n‐butanol/10% n‐octane/water microemulsion media [water‐in‐oil (W/O), bicontinuous (BC), and oil‐in‐water (O/W)] were studied with water‐soluble sodium bisulfite as the initiator. The maximum polymerization rate in CTAB micelles was found at the second critical micelle concentration. A mechanism of polyacrylamide formation and growth was proposed. A connection between the structures of the microemulsions and the polymerization rates was observed; the maximum polymerization rate occurred at two transition points, from W/O to BC and from BC to O/W, and the polyacrylamide molecular weights, which depended on the structures of the microemulsions, were also found. A square‐root dependence of the polymerization rates on the initiator concentrations was obtained in CTAB micelles and O/W microemulsion media. The polymerization of the oil‐soluble monomer styrene in different As/n‐butanol/20% styrene/water microemulsion media (W/O, BC, and O/W) was also investigated with different initiators: water‐soluble potassium persulfate and oil‐soluble azobisisobutyronitrile. A similar connection between the structures of the microemulsions and the conversions of styrene in CTAB/n‐butanol/10% n‐octane/water for the polymerization of acrylamide was observed again. The structures of the microemulsions had an important role in the molecular weights and sizes of polystyrene. The polystyrene particles were 10–20 nm in diameter in BC microemulsion media and 30–60 nm in diameter in O/W microemulsion media according to transmission electron microscopy. We determined the solubilization site of styrene in O/W microemulsion drops by 1H NMR spectra to analyze the results of the microemulsion polymerization of styrene. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3320–3334, 2001  相似文献   

17.
通过实验绘制了失水山梨醇单月桂酸酯(Span20)-聚氧乙烯山梨醇酐单脂酸酯(Tween80)复配乳化剂、丙烯酰胺、(2-甲基丙烯酰氧乙基)三甲基氯化铵、2-丙烯酰胺基-2-甲基丙基磺酸钠和环己烷的拟三元相图.采用过硫酸铵-亚硫酸氢钠氧化还原引发剂,通过动力学研究,得到了聚合反应的表观活化能为68.10 kJ/mol,并分别得到了聚合速率与产物特性粘数的动力学关系式Rp∝[M]1.74[APS]0.60[E]-1.28,[η]∝[M]0.78[APS]-0.23[E]-0.71,分析了单体浓度、引发剂浓度、乳化剂浓度对共聚合反应速率Rp和共聚物特性粘数[η]作用及影响的原因,在动力学研究的基础上初步探讨了聚合机理.  相似文献   

18.
微乳液聚合研究进展   总被引:51,自引:0,他引:51  
从聚合机理和所得聚合物性能两个方面,分析总结了微乳液聚合与乳液聚合的差别.并介绍了微乳液聚合研究的国内外研究动态.  相似文献   

19.
The seeded microemulsion polymerization of butyl acrylate was studied with γ-rays. The hydrodynamic diameter and its distribution of polymer particles in the seeded microemulsion before and after polymerization were determined with photon correlation spectroscopy (PCS). Though there were micelles in the microemulsion, it was found that new particle formation could be ignored during polymerization. The polymerization kinetics of the seeded microemulsion was investigated. The polymerization rate increases with the dose rate and added monomer content and decreases with the seed fraction. It was completely different from that for seeded emulsion polymerization. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2631–2635, 1998  相似文献   

20.
丙烯酰胺微乳液聚合   总被引:12,自引:1,他引:12  
由乳化剂聚乙二醇壬基苯基醚OP、聚乙二醇壬基苯基醚(TX—4)、丙烯酸胺、水和煤油组成微乳液时,体系中水相丙烯酸胶浓度及体系温度对乳化剂最小量有明显的影响;而OP、TX—4比例及油水比例的影响不大.本文研究了辐射引发微乳液聚合的动力学,得到如下表达式:聚合速率及聚合物特性粘数的表观活化能分别为53.2KJ/mol,-33.2KJ/mol.聚丙烯酸胺微乳液具有特殊的增稠性能,与聚电解质增稠剂相比,电解质对增稠效果的影响不大,而其他表面活性剂的影响较大.  相似文献   

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