二亚胺镍配合物/烷基铝催化4-乙烯基吡啶的聚合

制备了N,N-二(2,6-二异丙基苯基)苊二亚胺氯化镍,与A lE t2C l组成催化体系,催化4-乙烯基吡啶(4-VP)的聚合。研究表明,该催化体系可以有效地催化4-乙烯基吡啶聚合,并具有较高的活性,聚合条件如单体浓度、铝镍摩尔比、聚合温度和聚合时间等对4-乙烯基吡啶的聚合反应活性有较大的影响。最佳反应条件是单体浓度为0.6 m o l/L、n(A l)/n(N i)为800、温度为30℃,这时催化活性达到47.2 kg P(4-VP)/m o l N i.h。     

桥链二胺基给茂催化乙烯／1—己烯无规共聚合的研究

分别在亚乙基双 (茚基 )二胺化铪茂 (简称 1)和异亚丙基 (环戊二烯基 ) (1-芴基 )二甲基锆茂 (简称 2 )催化作用下 ,对乙烯 (E)与 1-己烯 (H)无规共聚合进行了研究。结果表明 ,在单体浓度比 [H]/ [E]较小时共聚合速率随单体浓度比增加而增加 ,进一步增加单体浓度比则导致共聚合速率降低。催化体系 1/ Al(i Bu) 2 H/ [Ph3C][B(C6 F5 ) 4](3)催化共聚活性比 2 / MAO高得多。两单体竞聚率乘积 (r E× r H)小于 1,表明聚合物为无规共聚物。两催化体系共聚合能力相当。 DSC分析显示 ,共聚物具有较宽的熔融峰 ,甚至出现双熔点。与催化体系 2 / MAO相比 ,1 /Al(i Bu) 2 H/3催化共聚物具有更高的分子量和更宽的密度变化范围     

桥链二胺基铪茂催化乙烯/1-己烯无规共聚合的研究

分别在亚乙基双(茚基)二胺化铪茂(简称1)和异亚丙基(环戊二烯基)(1-芴基)二甲基锆茂(简称2)催化作用下,对乙烯(E)与1-己烯(H)无规共聚合进行了研究.结果表明,在单体浓度比[H]/[E]较小时共聚合速率随单体浓度比增加而增加,进一步增加单体浓度比则导致共聚合速率降低.催化体系1/Al(1Bu)2H/[Ph3C][B(C6F5)4](3)催化共聚活性比2/MAO高得多.两单体竞聚率乘积(rE×rH)小于1,表明聚合物为无规共聚物.两催化体系共聚合能力相当.DSC分析显示,共聚物具有较宽的熔融峰,甚至出现双熔点.与催化体系2/MAO相比,1/Al(iBu)2H/3催化共聚物具有更高的分子量和更宽的密度变化范围.     

聚(甲基丙烯酸丁酯+(4-乙烯基)吡啶)共聚物膜的富氧性能研究

通过自由基共聚合反应，合成了一系列不同分子量、不同乙烯基吡啶基的聚（甲基丙烯酸丁酯 （4-乙烯基）吡啶）共聚物，并以低真空度法测试了其氧氮渗透性能。结果表明，随着共聚物膜中乙烯基吡啶含量的增加，共聚物的密度、玻璃化转变温度及氧氮选择性都随之增加，但氧氮渗透率和扩散系数、溶解度系数却相应下降。     

双核水杨醛亚胺镍催化剂的制备及对降冰片烯聚合的催化性能

合成了3种5,5′-亚甲基-双-水杨醛亚胺配体,利用它们和trans-[NiCl(Ph)(PPh3)2]反应得到Cat1、Cat2和Cat3三种双核水杨醛亚胺镍催化剂,并通过红外(FT-IR)和元素分析进行了表征。研究了在甲苯为溶剂,MAO为助催化剂下,催化降冰片烯(NBE)单体聚合的催化性能,考察了聚合条件,如温度、Al/Ni物质的量比对降冰片烯的催化活性、单体转化率、聚合物分子量及分子量分布的影响。当在n(Al)/n(Ni)为1000,聚合温度为80℃的条件下,催化剂的催化活性达到最大值1.16×105g of PNB/(mol of Ni.h)。聚合产物的核磁共振(1H-NMR)和红外光谱分析结果表明,该聚合反应是以单体的乙烯基加成聚合机理进行的。     

聚乳酸-壳聚糖接枝共聚物的制备及性能

以L-乳酸(LLA)和壳聚糖(CS)为原料,4-(二甲胺基)吡啶(DMAP)及N,N′-二环己基碳酰亚胺(DCC)为催化剂在室温下,通过直接缩合方法制备了聚乳酸-壳聚糖接枝共聚物(PLLA-CS)。采用IR、1H-NMR及薄板毛细渗透法对其结构进行了表征。探讨了原料配比、催化剂用量、LLA的二氯甲烷溶液浓度、反应时间等对共聚物收率和亲水性的影响。得到最佳工艺条件:-NH2∶LLA为1∶15,DCC∶LLA为1∶1,LLA的二氯甲烷溶液浓度为1.88 mol/L,反应时间为24 h。此方法合成路线短、反应条件温和。聚乳酸-壳聚糖接枝共聚物具有良好的细胞亲和性,有望成为一类优良的组织工程材料。     

水杨醛亚胺共价修饰碳纳米管负载镍催化剂的合成及催化乙烯齐聚性能

以1,4-丁二胺为起始剂,4-羟基水杨醛和四水合乙酸镍为原料,经亲核加成和配位反应合成具有配位能力的水杨醛亚胺配体和含有活性羟基的水杨醛亚胺镍催化剂。通过缩合反应将水杨醛亚胺镍催化剂共价接枝到碳纳米管上,合成有机配体共价修饰碳纳米管催化剂。傅里叶变换红外光谱、核磁共振氢谱、X射线衍射等表征结果证实了合成的水杨醛亚胺配体及催化剂结构与理论结构相符。经助催化剂MAO活化后,2种催化剂均表现出良好的催化乙烯齐聚性能。条件优化实验确定了2种催化剂的较佳聚合条件,Ni用量5μmol、Al/Ni为500、反应压力0.7 MPa、反应时间30 min,均相催化剂和负载催化剂最佳反应温度分别为25℃和35℃。此条件下,均相催化剂催化乙烯齐聚活性为1.99×10~5 g/(mol·Ni·h),齐聚产物C_8和C_(10+)选择性分别为30.38%和29.65%。负载催化剂催化乙烯齐聚活性为5.25×10~5 g/(mol·Ni·h),齐聚产物C_8和C_(10+)选择性分别为38.14%和15.28%。与均相催化剂相比,负载催化剂具有更好的催化活性和重复利用性。     

“扫帚型”镍系催化剂的合成及催化乙烯齐聚的性能

以直链十四胺为核的低代"扫帚型"大分子、水杨醛和Ni Cl2为原料,依次通过希夫碱反应和络合反应合成了一种新型的"扫帚型"水杨醛亚胺镍催化剂,采用傅里叶变换红外光谱、核磁共振氢谱和紫外-可见分光光度计证实其合成产品的结构与理论结构相符。在甲基铝氧烷(MAO)活化下,该催化剂具有良好催化乙烯齐聚的性能,且随着反应压力的升高和Al/Ni(摩尔比)增加,其催化活性增大;在反应温度为25℃,反应压力为0.5 MPa,Al/Ni摩尔比为1500时,该催化剂的活性可达2.33×106g/(mol Ni·h),聚合产物主要是C8以下的低碳烯烃,含量高达94%以上。相同条件下,其催化乙烯齐聚的活性高于与其具有类似结构的超支化镍系催化剂。     

NKC-9催化D4、D3 F开环共聚制备高分子量端乙烯基含氟硅油

采用高活性、易分离、低腐蚀性的强酸性阳离子交换树脂(NKC-9)催化八甲基环四硅氧烷(D_4)与三氟丙基甲基环三硅氧烷(D_3F)开环共聚,四甲基二乙烯基二硅氧烷(V)封端,制备高分子量端乙烯基含氟硅油的方法。探讨了聚合温度、聚合时间、单体比例、催化剂量、封端剂用量等因素对开环共聚反应的影响。通过核磁、红外测试分析共聚物的分子结构;通过凝胶渗透色谱测试共聚物的平均分子量与分子量分布;通过热分析法测试共聚物热分解温度;通过差示扫描量热法测试共聚物的玻璃化转变温度。研究结果表明n(D_4)∶n(D_3F)=7∶3、n(D_4)∶n(V)=75、催化剂量为7%(质量分数)、聚合温度80℃、聚合时间8 h时,开环共聚反应达到最佳,获得的端乙烯基含氟硅油产率为80.27%,平均分子量高达64 064 g/mol。     

茂金属催化5-亚乙烯基-2-降冰片烯与乙烯的共聚

研究了茂金属催化体系[2-C5Me4-6-tBuC6H3O]TiCl2/Al(iBu)3/Ph3CB(C6F5)4催化5-亚乙烯基-2-降冰片烯(ENB)与乙烯(E)的共聚反应。考察了聚合条件对催化活性、共聚物中ENB的含量和共聚物分子量的影响。利用氢核磁共振谱(1H-NMR)、差示扫描量热仪(DSC)和凝胶渗透色谱仪(GPC)对合成的共聚物进行表征。结果表明,在ENB/E共聚反应中,ENB环内双键参与聚合,ENB环外双键(亚乙烯基)保留。合成了ENB物质的量分数高达50.1%和玻璃化转变温度高达170.5℃的共聚物。合成的共聚物分子量分布较窄(PDI=1.93～2.11),最高分子量达到193 kg/mol。     

茶碱-铜(Ⅱ)离子配位分子印迹膜的制备及表征

以茶碱为模板分子,铜离子为配体、4-乙烯吡啶(4-VP)为功能单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂,在聚偏氟乙烯(PVDF)基膜上采用表面涂覆热聚合的方法制备了金属配位分子印迹膜,通过平衡结合实验研究了印迹膜对茶碱的结合性能和结合选择性。结果表明,铜离子的配位作用能提高印迹膜的结合性,在茶碱浓度为0.2 mmol/L时结合量从1.61μmol/g提高到了2.69μmol/g。在铜离子配位的作用下印迹膜对茶碱的结合能力高于同样化学组成的非印迹膜。相比于可可碱印迹膜对茶碱有较好的选择性,在浓度为0.05 mmol/L时选择性达到了2.39。     

聚4-乙烯基吡啶微凝胶的绿色合成

以4-乙烯基吡啶为单体,N,N’-亚甲基双丙烯酰胺为交联剂,在超临界二氧化碳(scCO2)中,通过沉淀聚合方法制备了交联聚(4-乙烯基吡啶)的干燥粉末。考察了反应体系的引发剂浓度、交联剂浓度、反应压力、反应时间等因素对聚合反应的影响。通过红外光谱(FT-IR)和扫描电镜(SEM)对聚合物组成及形貌进行了表征。实验表明,反应压力为14MPa,温度为70℃时,在适当交联剂用量下,可获得粒径约为0.5μm-1μm的干燥粉末,所得聚合物的产率大于90%。     

玻璃表面PS-r-P4-VP共聚物“刷子”的制备与表征

采用原位活性聚合法在玻璃表面接枝聚苯乙烯与聚4-乙烯吡啶无规共聚物(PS-r-P4-VP)"刷子",并对其进行表征。X射线光电子能谱(XPS)结果表明,玻璃表面接枝共聚物后,Si(1s/2p)、O(1s)的吸收峰强度降低,C(1s)吸收峰强度增强并出现了N(1s)(吡啶环)的特征吸收峰;椭圆偏振仪测试结果表明,接枝PS-r-P4-VP的厚度随聚合时间延长而增加,表面均方粗糙度则减小;原子力显微镜(AFM)观察结果表明,随着St配比的增加,玻璃表面聚合物"刷子"粗糙度降低;红外光谱(FT-IR)表明,玻璃表面的聚合物为PS-r-P4-VP;透光率测试表明,在玻璃表面接枝PS-r-P4-VP并不影响玻璃的透光率;接触角测试结果表明,接枝共聚物的玻璃表面接触角随着St比例的增加而显著增大。     

4-(5-氯-2-吡啶)-偶氮-1,3-二氨基苯光度法测定电镀废水中的微量镍(Ⅱ)

4-(5-氯-2-吡啶)-偶氮-1,3-二氨基苯(5-Cl-PADAB)可与镍发生灵敏的显色反应,生成稳定的配位化合物。基于此建立了一种测定电镀废水中微量镍的光度法。结果表明:在2.0 mol/L HCl介质中,5-Cl-PADAB与Ni(Ⅱ)反应生成摩尔比2∶1的稳定配位化合物,其最大吸收波长为565 nm,表观摩尔吸光系数为6.42×104 L/(mol.cm),Ni(Ⅱ)含量在0～1.0 mg/L内符合比尔定律;该方法用于测定电镀废水中微量镍,结果与催化-分光光度法相符,相对标准偏差小于4.0%,加标回收率为98.5%～101.8%。     

Application of novel copolymer-TiO(2) membranes for some textile dyes adsorptive removal from aqueous solution and photocatalytic decolorization

Novel low density polyethylene-grafted-poly(4-vinylpyridine-co-acrylamide) (LDPE-g-P(4-VP/AAm)) films were prepared by means of gamma-radiation-induced graft copolymerization as support for photocatalytic application. Nanometer-sized TiO(2) particles were immobilized to the grafted LDPE via dip coating technique. The efficiency of immobilized photocatalyst is tested on two target pollutants (textile azo dyes: Remazol red RB-133 (RR RB 133) and reactive blue 2 (RB2)). The efficient photocatalytic ability as reflected in determined photobleaching rate of both dyes was observed and is comparable to that for the non-supported TiO(2) used in a typical slurry photoreactor. The LDPE-g-(4-VP/AAm) copolymers supported TiO(2) photocatalyst has the practical advantages of easy separation and removal from the polluted environment. It could be a viable technique for the safe disposal of textile wastewater into the water streams.     

PSS-VS共聚物掺杂PEDOT的合成与表征

以苯乙烯磺酸钠(SSS)和乙烯磺酸钠(SVS)的共聚物PSS-VS为掺杂剂,过硫酸铵(APS)为氧化剂,采用化学氧化法制备了PEDOT/PSS-VS分散体,研究了PSS-VS的共聚比、分子量和用量等因素对PEDOT/PSS-VS导电性能及平均粒径的影响,分析了PEDOT/PSS-VS粒子形成过程。结果表明,SSS/SVS共聚摩尔比为5/5,单体与APS摩尔比为60时制得的PSS-VS掺杂PEDOT具有较好的导电性和分散稳定性,SO3-/EDOT=2,APS/EDOT=1.5,PEDOT/PSS-VS固含量为2.8%时制得的PEDOT/PSS-VS电导率可达11.74S/cm,分散体平均粒径为447nm。     

Dinickel Bisphenoxyiminato Complexes for the Polymerization of Ethylene and α-Olefins

Dinuclear nickelphenoxyiminato olefin polymerization catalysts based on rigid p-terphenyl frameworks are reported. Permethylation of the central arene of the terphenyl unit and oxygen substitution of the peripheral rings ortho to the aryl-aryl linkages blocks rotation around these linkages allowing atropisomers of the ligand to be isolated. The corresponding syn and anti dinickel complexes (25-s and 25-a) were synthesized and characterized by single crystal X-ray diffraction. These frameworks limit the relative movement of the metal centers restricting the metal-metal distance. Kinetics studies of isomerization of a ligand precursor (7-a) allowed the calculation of the activation parameters for the isomerization process (ΔH(?) = 28.0 ± 0.4 kcal×mol(-1) and ΔS(?) = -12.3 ± 0.4 cal×mol(-1)×K(-1)). The reported nickel complexes are active for ethylene polymerization [TOF up to 3700 (mol C(2)H(4))×(mol Ni)(-1)×h(-1)] and ethylene/α-olefin copolymerization. Only methyl branches are observed in the polymerization of ethylene, while α-olefins are incorporated without apparent chain walking. These catalysts are active in the presence of polar additives and in neat tetrahydrofuran. The syn and anti isomers differ in polymerization activity and polymer degree of branching and molecular weight. For comparison, a series of mononuclear nickel complexes (26, 27-s, 27-a, 28, 30) was prepared and studied. The effects of structure and catalyst nuclearity on reactivity are discussed.     

SiO_2空心纳米微球的合成

为了改善聚合物粒子与SiO2粒子之间的亲和力及SiO2粒子在聚合物粒子表面的吸附,首先使用共单体4-乙烯基吡啶(4VP)功能化苯乙烯(PS)粒子,合成了聚(苯乙烯-共-4-乙烯基吡啶)(P(St-4VP))粒子。然后在NH4OH/乙醇介质中,将溶胶-凝胶法生成的SiO2粒子包覆在P(St-4VP)粒子表面,聚合物核被溶解得到SiO2空心纳米微球。随着P(St-4VP)粒子中共单体4VP含量以及正硅酸乙酯(TEOS)用量增加,SiO2空心纳米微球的壳层厚度增加,且壳层表面变得粗糙。随着PVP用量增加,SiO2空心纳米微球的平均尺寸下降,其壳层从松散粗糙变得致密光滑。NH4OH用量增加对SiO2空心纳米微球尺寸和形态的影响不大。     

Graft copolymerization of 2-vinyl pyridine and styrene onto isotactic polypropylene powder by the preirradiation method

Preirradiated isotactic polypropylene (IPP) powder has been modified by grafting 2-vinyl pyridine (2-VP) and styrene (Sty) in an aqueous medium. The graft copolymerization reaction was studied under different experimental conditions such as total dose, monomer concentration, amount of the solvent, time of reaction and temperature to determine the optimum conditions for affording maximum percentage of grafting (P_g). Maximum grafting percent of 2-VP (180%) and styrene (117%) was obtained under optimum conditions. The rate of grafting (R_g) of 2-VP and styrene has also been determined as a function of total dose, initial monomer concentration and the reaction temperature. From maximum P_g and different R_g values of 2-VP and Sty, 2-VP is more reactive towards grafting as compared to styrene under optimum conditions. Characterization of the graft copolymers is based on differential scanning calorimetric (DSC) analysis. Isolation of the grafted poly(2-VP) and poly(styrene) chains from the grafted samples provides an additional evidence of formation of the graft copolymer.     

Swelling behavior and drug release of NIPAAm/PEGMEA copolymeric hydrogels with different crosslinkers

Poly(ethylene glycol) methylether acrylate (PEGMEA) and tetraethylene glycol diacrylate (TEGDA) were first synthesized. The thermosensitive hydrogels were then prepared from N-isopropylacrylamide (NIPAAm), PEGMEA, and three crosslinkers with different structures such as N, N′-methylene-bis-acrylamide (NMBA), TEGDA, and poly(ethylene glycol) dimethacrylate (EGDMA). The influence of polymerization factors such as the kind and amount of crosslinker and initial total monomer concentration on the swelling behavior, gel strength, effective crosslinking densities, and number-average molecular weight between crosslink points ( ) for the present copolymeric hydrogels was investigated. The results indicate that the swelling ratios for the present copolymeric gels decrease with increase in temperature. In addition, the results also showed that the higher swelling ratios for the present gels prepared from TEGDA were obtained due to the larger space between the gel networks. The crosslinking density depends on the swelling ratio and the kind and extent of crosslinker. In addition, the drug release behavior for the present copolymeric gels was investigated.