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1.
用Fimeman-Ross法处理数据,测定了乙烯基聚硅氧烷(SV)与苯乙烯(ST)、甲基丙烯酸甲酯(MMA)和甲基丙烯酸正丁酯(n-BMA)的共聚反应的竞聚率,结果为rST=1.45和rSV=1.08,rMMA=0.78和rSV=2.01,rn-BMA=0.46和rSV=3.49.以含SV的乳液作为种子进行烯类单体的乳液聚合,单体和SV共聚反应对复合粒子的形态有很大影响。  相似文献   

2.
丙烯腈和(甲基)丙烯酸酯基团转移共聚合的竞聚率   总被引:4,自引:0,他引:4  
研究了丙烯腈(AN)和甲基丙烯酸甲酯(MMA)、乙酯(EMA)、丁酯(BMA)、丙烯酸丁酯(BA)和顺丁烯二酸二丁酯(DBM)等5种酯类单体的基团转移无规共聚.用Kelen Tudus法测定了二元共聚体系的竞聚率,分别为rAN=1022、rMMA=077、rAN=568、rEMA=016、rAN=859、rBMA=009、rAN=408、rBA=006;rAN=138,rDBM=006.发现竞聚率,单体组分对聚合速率的影响等都和阴离子共聚类似.  相似文献   

3.
核磁共振法测定苯乙烯和甲基丙烯酸正丁酯竞聚率的研究   总被引:6,自引:0,他引:6  
以苯乙烯(St)-甲基丙烯酸正丁酯(BMA)共聚体系为研究对象,在共聚单体组成敏感点附近做重复实验,进行了40、60、80、100,120、140℃下的共聚合,用NMR方法测定共聚物的组成,用Mayo-Lewis微分组成方程的误差变量法计算竞聚率,同时给出竞聚率的95%可信椭圆区间.并根据竟聚率对温度的依赖关系得到一组合理的竞聚率值.  相似文献   

4.
研究了N-乙烯基咔唑-丙烯酸共聚物(NVC-AA)和微量的钼簇合物「Mo3O2(O2CCH3)6(H2O)3」Br2.2H2O在水溶液相互作用及其溶液荧光。实验发现,体系中存在单体荧光(375nm)和二聚体激态缔合物荧光(500nm)。荧光强度分别随钼簇合物的浓度啬和pH值的提高而增强。  相似文献   

5.
报道了以Waters BondapakTM,ODS—C18为色谱柱,甲醇:四氢呋喃:水(72:6:22,V/V为 流动相,在UV254nm为测定波长的条件下,利用外标法定量,建立了反相高效液相色谱法测 定光诱导反应粗产物中N-(α-萘基)咔唑和N-(β-萘基)咔唑的方法。为光诱导自由基链式亲 核取代反应(SRN1)反应机理的探讨提供了可靠的理论依据。  相似文献   

6.
刘焕蓉  张昭 《分析化学》1998,26(7):868-871
报道了以WatersBondapak^TM,ODS-C18为色谱柱,甲醇:四氢呋喃:水(72:6:22,V/V)为流动相,在UV254nm为测定波长的条件下,利用外标法定量,建立了反相高效液相色谱法测定光诱导反应粗产物中N-(α-萘基)咔唑和N-(β-萘基)咔唑的方法,为光诱导自由基链式亲核取代反应(SRN1)反应机理的探讨提供了可靠的理论依据。  相似文献   

7.
用Fimeman-Ross法处理数据,测定了乙烯基聚硅氧烷与苯乙烯,甲基丙烯酸甲酯和甲基丙烯酸正丁酯的共聚反应的竞聚率,结果为st=1,45和rsv=1.08,rMMA=0.78和rsv=2.1,ra-BMA=0.46和rsv=3.49。以含SV的乳液作为种子进行烯类单体的乳液聚合,单体和SV共聚反应对复合粒的形态有很大影响。  相似文献   

8.
一对单体,可查到非常多数值不同的竞聚率文献值,说明无论从精度和准确性来说,竞聚率的测定和求算都可能产生很大误差。本文在单体敏感点组成进行实验,用元素分析法测定共聚物组成,用Error-in-VariableMethod(EVM)[1]法计算苯乙烯(St,M1)和丙烯酸-β-羟乙酯(HEA,M2)竞聚率,分析全过程的误差来源和大小。  相似文献   

9.
以1,4-双(氯甲基)-2,5一二甲基苯(BCMDMB)和1,4-双氯甲基-2-甲氧基-5-壬氧基苯(BCMMONOB)为单体,采用脱氯化氢法,合成了聚(2,5-二甲基)对亚苯基亚乙烯(PDMPV)和聚(2-甲氧基-5-壬氧基)对亚苯基亚乙烯(PMONOPV);并对BCMDMB和BCMMONOB的共聚进行了研究。结果表明,适宜的反应条件为:碱与单体的摩尔比为20∶1,在室温下聚合时间为30h,碱的pH=14时产率最高。用IR、1H-NMR、UV—Vis对聚合物进行了表征。  相似文献   

10.
ASENSITIVEPROTEINASSAYBYCo(II)-BIURETMETHOD¥YunXiangCI;XiaoTingTANGandXiaoDaYANG(DepartmentofChemistry,PekingUniversity,Beiji...  相似文献   

11.
Novel, soluble poly(9,9‐dialkylfluorene)/poly(2‐alkylaniline) block copolymers were synthesized following a three‐step synthetic procedure: (i) aryl‐aryl coupling of alkylated dibromofluorenes and fluorene diboronic esters according to Suzuki in the presence of 4‐nitrobromobenzene as a monofunctional end‐capping reagent, (ii) reduction of nitrophenyl to aminophenyl functions with H2/Pd/C and (iii) subsequent oxidative condensation with 2‐undecylaniline. The colored conjugated‐conjugated block copolymers were characterized by means of GPC, NMR and UV‐Vis spectroscopy.  相似文献   

12.
The 2-acrylamido -2-methylpropane sulfonic acid (AMPS) was used as a reactive comonomer for the methyl methacrylate (MMA), n-butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA) emulsifier-free emulsion copolymerization system to obtain latices of stable and high-solid content (50 wt%).The polymerization and storage process is very stable, and the emulsion could store at room temperature for more than six months with the addition of AMPS. Properties of the latices, such as stability, flow behavior, particles diameter and morphology were studied. In addition, physical properties of the obtained copolymers, such as water resistance, glass transition temperature (Tg) were also investigated. The final size of the latex particles is 200~300 nm in diameter. Compared with the copolymers that were prepared by surfactant emulsion polymerization water resistance is greatly improved.  相似文献   

13.
The photophysical properties of a series of pyrene-labelled styrene/divinyl benzene (St/ DVB) copolymers have been studied for the first time by steady-state fluorescence spectra. The results indicate that when pyrenyl content (mol%) in the copolymer is lower than 0. 006% , the fluorescence spectra only show the pyrenyl monomer emission, while the 0-0 transition band is much suppressed and the vibronic structure is partially lost. However, in the fluorescence spectra of the copolymers with pyrenyl content higher than 0.3%, there appear some new emission bands at ca 420 nm, 440 nm and 475 nm. These results are explained in terms of the formation of ground-state and excited-state aggregates, which reveals the heterogeneity of the crosslinked networks.  相似文献   

14.
以无水AlCl3/ClCH2CH2Cl/NMP为催化剂/溶剂体系,通过缩聚反应,由二苯醚,对苯二甲酰氯和4,4-二苯氧基二苯砜合成了聚醚酮酮和聚醚砜醚酮酮共聚物(PEKK/PESEKK).考察了单体浓度、反应时间对聚合物分子量的影响,并对其进行了IR、DSC、WAXD等分析表征.结果表明,共聚物具有优异的耐热性,随着共聚物中PESEKK单元含量的增加,其玻璃化温度逐渐升高,而熔融温度和结晶度逐渐降低.与聚醚酮酮(PEKK)相比,共聚物的断裂伸长率明显提高,而拉伸强度和拉伸模量却有所下降,但仍具有良好的力学性能.  相似文献   

15.
The dehydrohalogenation of several alternating and random vinyl chloride/acrylonitrile copolymers was characterized by thermogravimetry. The polymers were made in solution, and the conversions were kept below 5% to insure uniform sequence distributions. Hydrogen chloride was generated within a relatively narrow temperature range somewhere between 200 and 300°C depending on the sequence distribution, relative viscosity, and composition. The weight-loss during the dehydrohalogenation could be attributed completely to the hydrogen chloride available in the copolymer. Alternating copolymers were significantly more stable than random copolymers were significantly more stable than random copolymers at the same relative viscosity. For a given sequence distribution or composition, stability decreased with decreasing relative viscosity. The stability decreased as acrylonitrile content was increased from 23 to 57%.

The thermogravimetric analyzer was interfaced with a digital computer. The digitized data were smoothed and differentiated by convoluted integers. The differentiated data provided rates for a qualitative discussion of dehydrohalogenation kinetics.  相似文献   

16.
The homopolymerization of a series of alkyl vinyl sulfoxides (CH2[dbnd]CHSOR; R = CH3 (MVSO), C2H5 (EVSO), t-C4H9 (BVSO)) and their copolymerization with vinyl acetate (VAc) with 2,2′-azobisisobutyronitrile (AIBN) as initiator at 60°C was attempted. MVSO was found to homopolymerize radically, but EVSO and BVSO were not. Poly-MVSO is soluble in chloroform, methanol, DMSO, and water, but insoluble in acetone and benzene. MVSO and EVSO were found to copolymerize with VAc, but BVSO was not. The copolymerization parameters obtained for both systems were as follows; r1(MVSO) = 2.23, r2 (VAc) = 0.09, and r1(EVSO) = 3.40, r2 (VAc) = 0.11, respectively. MVSO/vinyl alcohol (VA) copolymers were obtained through the saponification of MVSO/VAc copolymers by sodium hydroxide in methanol. The solubility of MVSO/VAc and of MVSO/VA copolymers toward various solvents was examined, and it was observed that the sulfoxide comonomer has a tendency to give amphiphilicit to poly(vinyl acetate) and poly(vinyl alcohol). The 24 mol% MVSO containing VAc copolymer is soluble in both benzene and water.  相似文献   

17.
吩噻嗪在十二烷基硫酸钠/苯甲醇/水微乳液中的定位   总被引:1,自引:0,他引:1  
郭霞  刘燕  郭荣 《物理化学学报》2001,17(11):982-985
采用循环伏安法和荧光猝灭法研究了吩噻嗪(PTZ)在十二烷基硫酸钠(SDS)/苯甲醇(BA )/ 水(H2O)微乳液中的定位.结果表明,吩噻嗪在十二烷基硫酸钠/苯甲醇/水体系微乳液中位于微乳液膜相中靠近表面活性剂极性头基的一侧,PTZ分子中的S原子和N原子均可朝向表面活性剂的极性头基.  相似文献   

18.
Films of aniline/metanilic acid copolymers ensure a better protection of iron against corrosion with respect to the protection given by polyaniline. Raman and optical spectroscopies are used to characterize this new material. The confrontation with the polyaniline properties allows to understand the improvement of protection.  相似文献   

19.
赵月  裴世红  王梓旭 《合成化学》2017,25(10):836-839
采用核壳乳液聚合法,制备了乙烯基三乙氧基硅烷(VTES)改性的St/BA/AA三元共聚乳液,其结构经FT IR确证。研究了VTES用量、乳化剂用量及配比和引发剂用量对单体转化率和粒径的影响。结果表明:在最优条件[48%St, 48%BA, 4%AA, 1%N-MA, 4%VTES, 8%乳化剂(OP-10/SDS=1/3), 0.8%引发剂]下,单体转化率为95.8%,平均粒径242 nm。并研究了改性St/BA/AA乳胶膜(1)的耐溶剂性和铅笔硬度。结果表明:1具有良好的耐溶剂性,铅笔硬度为2H。  相似文献   

20.
徐慧  柳全文 《化学通报》2006,69(7):524-528
用紫外-可见吸收光谱和荧光发射光谱研究了蒽在不同组成和结构的十二烷基硫酸钠(SDS)/苯甲醇(BA)/H20微乳液中的光谱特征,探讨了微乳液组成和结构对蒽光谱特征的影响,阐述了蒽在微乳液中的定位。结果表明,蒽位于O/W微乳液的膜相和油核;在SDS/BA/H2O W/O微乳液中,蒽定位于油连续相。  相似文献   

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