卟啉铝催化下二氧化碳与氧化环己烯共聚反应研究

利用四苯基卟啉氯化铝(TPPAlCl)与双三苯基膦氯化铵(PPNCl)组成的二元催化剂催化二氧化碳与氧化环己烯共聚合,80℃下反应9h,二氧化碳-氧化环己烯共聚物(PCHC)的收率为97.2％,分子量分布窄(Mw/Mn=1.12),但数均分子量仅为6.8×103.研究发现溶剂的浓度和极性变化对聚合过程中的链转移反应影响...     

胺基铪茂催化乙烯/1-辛烯无规共聚合的研究

在亚乙基双（ 茚基） 二胺化茂铪（ｒａｃ Ｃ２Ｈ４（Ｉｎｄ）２Ｈｆ（ＮＭｅ２）２ ,简称１ ,Ｉｎｄ ＝ 茚基,Ｍｅ＝ 甲基） 催化作用下,对乙烯（Ｅ） 与１ 辛烯（Ｏ） 无规共聚合进行了研究．作为比较,利用异亚丙基（ 环戊二烯基）（１ 芴基） 二甲基锆茂催化体系（（ＣＨ３）２Ｃ（Ｆｌｕｏ）（Ｃｐ）ＺｒＭｅ２ ,简称２ ,Ｆｌｕｏ ＝ 芴基,Ｃｐ ＝ 环戊二烯基） 对乙烯／１ 辛烯在相同共聚合条件下进行了共聚合．结果表明,在单体浓度比［Ｏ］／［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（ｉＢｕ）２Ｈ／［Ｐｈ３Ｃ］［Ｂ（Ｃ６Ｆ５）４］（３） 催化共聚活性比２／ ＭＡＯ高得多．共聚物中辛烯含量随反应单体１ 辛烯含量的增加而增加,两单体竞聚率乘积（ ｒＥ×ｒｏ） 小于１ ,表明聚合物为无规共聚物．相同共聚单体浓度比下１／Ａｌ（ｉＢｕ）２Ｈ／３ 催化共聚物中辛烯含量比２／ ＭＡＯ 共聚物中辛烯含量高,表明前者具有更强的共聚合能力．所得无规共聚物熔点温度、结晶度、本体粘度及密度随共聚物中辛烯含量的增加而显著降低．辛烯含量较高时共聚物呈现明显无结晶行为．差示扫描量热分析显示,同乙烯均聚?     

单茂钪催化苯乙烯衍生物与异戊二烯共聚合的研究

研究了单茂钪(C_5Me_4SiMe_3)Sc(CH_2C_6H_4NMe2-o)_2催化异戊二烯(IP)与苯乙烯衍生物对氯苯乙烯(St-Cl)、4-二甲基硅氢苯乙烯(St-Si HMe_2)共聚合的性能,通过NMR、GPC和DSC对所获共聚物的微观结构和热性能进行表征分析.结果表明,在室温氯苯溶剂中,改变IP和苯乙烯衍生物的用量,单茂钪均可以催化IP与St-Cl、St-SiHMe_2共聚合,获得了组成可控(IP含量21 mol%～95 mol%)、高分子量(M_n=3.1×10~4～15.9×10~4)、窄分布(M_w/M_n=1.21～1.92)的IP/St-Cl和IP/St-SiHMe_2两类共聚物,共聚物中IP形成1,4-和3,4-结构单元,苯乙烯衍生物形成间规聚合结构.苯乙烯衍生物取代基的电负性直接影响共聚合活性和共聚物的序列分布.IP与St-SiHMe_2共聚合活性(10~5 g聚合物molSc~(-1) h~(-1))远高于IP与St-Cl共聚合活性(10~4 g聚合物mol Sc~(-1) h~(-1));相同共聚合条件下St-SiHMe_2的插入率高于St-Cl.单茂钪催化IP与St-Cl共聚合获得了梯度共聚物,IP/St-Cl共聚物具有源自聚IP链段的玻璃化转变温度(T_g=-1～5°C)和源自间规聚St-Cl链段的熔点(T_m=314～318°C).单茂钪催化IP与St-SiHMe_2共聚合获得无规共聚物,IP/StSiHMe_2共聚物具有一个T_g,该T_g值(12～82°C)随St-SiHMe_2含量(13 mol%～79 mol%)的增加而线性增加.     

TiCl_4/MgCl_2催化丙烯/1-辛烯共聚合研究

本文用TiCl_4/MgCl_2-Al(i-Bu)_3催化剂进行丙烯/1-辛烯共聚合,研究发现引入少量共聚单体1-辛烯时,能提高丙烯的聚合活性。30℃时,测得共聚合竟聚率为r_丙=5.63,r_辛=0.32。共聚物的结晶度和己烷不溶物含量随其1-辛烯含量的增加而迅速下降。X射线衍射及~(13)C-NMR测定结果表明,共聚物的己烷可溶部分为非结晶的无规共聚物,己烷不溶部分是具有镶嵌着半个1-辛烯单体单元的长嵌段聚丙烯链结构的结晶性共聚物。     

氯化铝高效催化合成1-(1-酰胺基)烷基-2-萘酚类化合物

无溶剂条件下,氯化铝可有效催化2-萘酚、醛和胺/尿素三组分"一锅法"合成1-(1-酰胺基)烷基-2-萘酚.考察了溶剂条件和催化剂用量对产率的影响.与已报道的方法相比,该方法具有反应时间短、产率高、实验操作和后处理步骤简单等优点.     

双金属氰化络合物催化环氧丙烷和邻苯二甲酸酐共聚

采用双金属氰化络合物 (DMC)催化环氧丙烷 (PO)和邻苯二甲酸酐 (PA)共聚 ,探讨了共聚合特征 ,并用IR、1 H NMR和GPC对共聚物的结构和分子量进行了表征 .发现DMC催化剂对该共聚反应速度快 ,转化率高 ,是该反应的有效催化剂 ,催化剂浓度为 6 0mg kg时 ,90℃下 ,以THF作溶剂共聚反应 3h ,转化率可达94 0 % .聚合速度甚至比DMC催化PO均聚还快 .该共聚反应可在多种溶剂中进行 ,极性溶剂更有利于共聚合 ,溶液聚合温度比本体共聚低 ,合适的溶液共聚温度在 90～ 10 0℃之间 .共聚产物的分子量受催化剂用量、反应温度和体系中水份含量的影响 ,数均分子量在数百至数千之间 .考察该共聚体系的动力学表明 ,该共聚反应速率对单体浓度呈一级关系     

苯氧基亚胺钛催化降冰片烯与1-辛烯共聚合

以3,5-二叔丁基水杨醛缩苯胺氯化钛(Ti)、三异丁基铝(Al)和四(五氟苯基)硼酸三苯基甲酯(B)组成的三元催化体系实现了降冰片烯(NBE)与1-辛烯(OC)的共聚合,得到NOC无规共聚物.探索了催化剂组成、聚合时间及聚合温度等对共聚合反应的影响.结果表明,当n(Al)/n(Ti)=5∶1,n(B)/n(Ti)=1∶1,n(Monomer)/n(Ti)=400∶1,n(NBE)/n(OC)=5∶5时,于40℃在甲苯中聚合6 h,共聚合产率达到43.7%,2种单体的竞聚率分别为rNBE=3.01;rOC=0.08.改变助催化剂三异丁基铝的用量可在一定范围内调节所得NOC无规共聚物的分子量及分子量分布(MWD),得到Mw=3.0×104~6.5×104,MWD=1.91~2.45的NOC共聚物.NOC无规共聚物具有饱和的主链结构且带有较长的侧链,其玻璃化转变温度较高(约87~174℃),并对NOC无规共聚物组成具有很强依赖性.NOC共聚物的热分解温度超过300℃,热稳定性能优异.     

生物降解高分子--聚己内酯/聚氧乙烯/聚丙交酯三元共聚物水解行为的研究

以异辛酸亚锡为催化剂,通过聚乙二醇醚(PEG)引发ε-己内酯和L-丙交酯开环聚合,制备了PCL/PEO/PLA三元共聚物.研究了聚合物在pH7.4磷酸缓冲溶液、37℃条件下的体外降解行为.采用GPC、1H-NMR、DSC和XRD技术研究了聚合物在水解降解过程中分子量、分子量分布、组成、吸水率、结晶性等的变化.结果表明共聚物的吸水率随聚醚组分含量而增大;随水解材料的失重率增大,聚醚组分含量下降程度也加大.此外研究还表明:聚合物中丙交酯组分含量高时,聚合物的结晶结构主要由PLLA形成.由于聚合物的水解降解首先发生在无定形区和结晶区边缘,随着共聚物的降解、结晶性的PLLA低聚物的生成,导致了共聚物的分子量呈双峰分布.     

Fe(acac)3-Al(i-Bu)3-α,α''-联吡啶催化丙烯腈与苯乙烯共聚合

研究了Fe(acac)3-Al(I-Bu)3-α,α'-联吡啶(acac=乙酰丙酮)催化体系催化丙烯腈(AN)与苯乙烯共聚合, 用元素分析和核磁共振研究了共聚物的结构, 在单体比为1:1时共聚物中丙烯腈/苯乙烯含量分别为49.3%和50.7%. 用凝胶渗透色谱研究了聚合物分子量和分子量分布, 共聚物分子量分布较窄. 动力学研究表明共聚合反应对单体浓度呈一级关系,表观活化能为57.8 kJ/mol.     

Fe(acac)_3-Al(i-Bu)_3-α,α′-联吡啶催化丙烯腈与苯乙烯共聚合

研究了Fe(acac)3-A l(i-Bu)3-α,α′-联吡啶(acac=乙酰丙酮)催化体系催化丙烯腈(AN)与苯乙烯共聚合,用元素分析和核磁共振研究了共聚物的结构,在单体比为1∶1时共聚物中丙烯腈/苯乙烯含量分别为49.3%和50.7%.用凝胶渗透色谱研究了聚合物分子量和分子量分布,共聚物分子量分布较窄.动力学研究表明共聚合反应对单体浓度呈一级关系,表观活化能为57.8 kJ/mol.     

COPOLYMERIZATION OF ETHYLENE WITH 1-OCTENE USING Et(Ind)2ZrCl2/MAO CATALYST

Copolymerization of ethylene/1-octene was carried out in toluene withvarious concentrations of comonomer in the feed using Et(Ind)_2ZrCl_2/MAO (methyl alu-minoxane) as catalyst. It was found that with the increase of 1-octene concentration in thefeed the content of 1-octene in the copolymer increases, while the density, melting point,crystallinity and intrinsic viscosity of copolymer decrease. A copolymer with very lowdensity, containing 11.5 mol% of 1-octene (VLLDPE) can be produced with this catalystsystem. The effect of temperature and zirconium aluminum mole ratio of the catalyst onthe copolymerization was also investigated. The results of ~(13)C NMR determination of thecopolymer showed that the 1-octene units in the copolymer are principally isolated.     

Fe-Al络合催化苯乙烯-马来酸酐交替共聚

应用Ｆｅ（ａｃａｃ）３ Ａｌ（ｉ Ｂｕ）３（ａｃａｃ＝乙酰丙酮）催化苯乙烯 马来酸酐共聚,制得富于交替的白色粉末共聚物．共聚反应动力学研究表明,共聚反应与单体浓度呈一级关系,表观活化能为４８６ｋＪ／ｍｏｌ．     

耐热性星形甲基丙烯酸甲酯共聚物的合成

195 6年 ,Swarzc等 [1,2 ] 报道了一种没有链转移和链终止的阴离子聚合技术 ,提出了“活性”聚合的概念 . 1 995年王锦山等 [3]发现和提出原子转移自由基聚合 ( ATRP)以来 ,活性自由基聚合就成了高分子合成领域的研究热点 ,并合成出各类指定结构的聚合物 [4～ 12 ] .具有环状结构的 N -环己基马来酰亚胺 ( NCMI)被广泛地用于与甲基丙烯酸甲酯 ( MMA)自由基共聚合制备耐热性有机透明材料 [13,14 ] ,但NCMI的引入将降低聚合物的加工流动性 ,若能利用多官能团引发剂如四溴甲基苯实现含 NCMI单体结构的可控 ATRP共聚合 ,合成出星形耐…     

SalenAl(O~iPr)催化CO_2与氧化环己烯共聚及影响因素研究

以SalenAl(OiPr)为催化剂,分别加入各种路易斯碱作为共催化剂催化二氧化碳与氧化环己烯共聚,发现共聚催化效率与共催化剂的供电子能力有关.分别研究催化剂浓度、共催化剂的用量、反应时间、反应温度、CO2压力等各种因素对该共聚反应的影响,发现SalenAl(OiPr)浓度为2 g/L时,以等摩尔量的二甲氨基吡啶(DMAP)作为共催化剂,在4 MPa的CO2和80℃下反应32 h,可得到碳酸酯键含量>99%的共聚产物,其催化效率高达495 g/g,13C-NMR检测表明共聚物为无规立构聚合物,GPC测得分子量Mn为55900,分子量分布比较窄(PDI=1.32).DSC得到共聚物的玻璃化转变温度为136℃,热重分析(TGA)可以看出共聚物在350℃可完全分解,具有优良的热分解性.     

铁系催化剂催化降冰片烯与丙烯酸甲酯共聚合

研究了Fe(acac)3-Al(i-Bu)3(acac=乙酰丙酮)催化降冰片烯(NB)与丙烯酸甲酯(MA)共聚反应条件影响、第三组份影响及催化剂铁铝比影响.并用核磁共振、红外光谱和元素分析方法研究了共聚物的组成,用热分析方法研究了共聚物的分解温度,并用电镜分析了共聚物的膜结构.结果表明,铁系催化剂在温和的反应条件下有较好的催化性能,并可获得能够形成有序多孔膜的共聚物.     

Kinetic study of the alternating copolymerization of butadiene and methyl methacrylate

A kinetic investigation of the alternating copolymerization of butadiene and methyl methacrylate with the use of a system of ethylaluminum dichloride and vanadyl chloride as a catalyst was undertaken. The relation between the polymer yield and the molar fraction of methyl methacrylate in the feed was examined by continuous variation of butadiene and methyl methacrylate, the concentrations of total monomer, ethylaluminum dichloride, and vanadyl chloride being kept constant. This continuous variation method revealed that the polymer yield attains its maximum value with a monomer feed containing less than the 0.5 molar fraction of methyl methacrylate. This value of the molar fraction of methyl methacrylate affording the maximum polymer yield decreased on increasing the total monomer concentration but was not changed on varying the concentration of ethylaluminum dichloride. The number of active species estimated from the relation between yield and molecular weight of the polymer was almost constant, regardless of the molar fraction of methyl methacrylate in the feed. Consequently, it can be said that the maximum polymer yield depends mainly on the propagation reaction, not on the initiation reaction or the termination reaction. Three types of the mechanism have been discussed for this alternating copolymerization: polymerization via alternating addition of butadiene and methyl methacrylate complexed with ethylaluminum dichloride by the Lewis-Mayo scheme; polymerization via the ternary intermediate of butadiene, methyl methacrylate, and ethylaluminum dichloride; polymerization via the complex formation of butadiene and methyl methacrylate complexed with ethylaluminum dichloride occurring only at the growing polymer radical. From the kinetic results obtained, it was shown that the first and third schemes are excluded, and polymerization by way of the ternary intermediate is compatible with the data.     

Metallocene-catalyzed ethene/styrene co- and terpolymerization with olefinic termonomers

Ethene was co- and terpolymerized with 1-octene and styrene using the methylalumoxane (MAO) activated halfsandwich metallocene Me₂Si(Me₄Cp)(N-t.-butyl)TiCl₂(Cp = cyclopentadienyl, Me = methyl) as catalyst. At temperatures of 40 and 60°C styrene concentration was varied in order to investigate the influence of the comonomers. Despite decreasing the overall activity with respect to ethene/1-octene copolymerization, polymerization activity was found to exibit a relative maximum with increasing styrene concentration. An explanation is given taking two different comonomer effects into account. Low styrene concentration promoted higher 1-octene incorporation compared to ethene/1-octene copolymerization but significantly lowered the molecular weight of the terpolymers. With constant ethene and 1-octene concentration it was possible to produce ethene/1-octene/styrene terpolymers with styrene content varying from 0 to 25 mol % and 1-octene content varying from 8 to 21 mol %. All terpolymers were amorphous. With constant ethene content it was found possible to vary their glass transition temperature with 1-octene/styrene molar ratio incorporated in the terpolymer. ¹³C-NMR spectroscopic microstructure analysis showed that no styrene/1-octene sequences were found in the terpolymer backbone. Furthermore terpolymerizations were conducted successfully incorporating norbornene, 1,5-hexadiene and propene as monomers in terpolymertization with ethene and styrene. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2549–2560, 1997     

Enzymatic ring-opening copolymerization of trimethylene carbonate and ethylene ethyl phosphate

A growing interest in biodegradable polymers and their biomedical and pharmaceutical applications has developed since the past decade. Ring-opening polymerization has been regarded as an efficient route for the synthesis of the biodegradable polymers, such as polyester, polycar- bonates and polyphosphates[1—6]. However, chemical methods for the ring-opening polymerization of biodegradable polymers need extremely pure monomers and anhydrous conditions as well as metallic catalysts, which must …     

PEB/MMA-AN悬浮接枝共聚反应机理

研究了乙烯-1-丁烯共聚物(PEB)弹性体与甲基丙烯酸甲酯(MMA)-丙烯腈(AN)悬浮接枝共聚反应行为及接枝共聚产物对SAN树脂增韧作用随反应时间的变化规律, 用凝胶渗透色谱法和傅里叶变换红外光谱法对接枝共聚产物进行了表征, 分析了接枝共聚反应机理, 推算了接枝链分子量. 结果表明, 体系首先发生链增长自由基向PEB转移终止形成非接枝共聚物(MAN_L)和PEB大分子自由基引发单体共聚形成接枝链(g-MAN)的反应, 接枝反应结束后体系发生明显的非接枝共聚形成非接枝共聚物(MAN_H)的反应; MAN_L的分子量低于g-MAN的分子量, 而g-MAN的分子量明显低于MAN_H的分子量; 在接枝共聚过程中发生已接枝和未接枝PEB断链并随机再接生成多嵌段共聚物的副反应; 在反应初期, 接枝链的AN单元含量接近于非接枝共聚物的AN单元含量, 在反应中后期前者远低于后者.     

Grafting of polymers onto a carbon‐fiber surface by ligand‐exchange reaction of poly(vinyl ferrocene‐co‐vinyl monomer) with polycondensed aromatic rings of the surface

To improve the surface of carbon fiber, the grafting reaction of copolymer containing vinyl ferrocene (VFE) onto a carbon‐fiber surface by a ligand‐exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of carbon fiber was investigated. The copolymer containing VFE was prepared by the radical copolymerization of VFE with vinyl monomers, such as methyl methacrylate (MMA) and styrene, using 2,2′‐azobisisobutyronitrile as an initiator. By heating the carbon fiber with poly(VFE‐co‐MMA) (number‐average molecular weight: 2.1 × 10⁴) in the presence of aluminum chloride and aluminum powder, the copolymer was grafted onto the surface. The percentage of grafting reached 46.1%. On the contrary, in the absence of aluminum chloride, no grafting of the copolymer was observed. Therefore, it is considered that the copolymer was grafted onto the carbon‐fiber surface by a ligand‐exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of carbon fiber. The molar number of grafted polymer chain on the carbon‐fiber surface decreased with increasing molecular weight of poly(VFE‐co‐MMA) because the steric hindrance of grafted copolymer on the carbon‐fiber surface increases with increasing molecular weight of poly(VFE‐co‐MMA). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1868–1875, 2002