RADICAL POLYMERIZATION OF METHYL METHACRYLATE WITH DIPHENYL DISELENIDE UNDER THERMAL OR PHOTOIRRADIATIONAL CONDITIONS

Polymerization of methyl methacrylate (MMA) with diphenyl diselenide (DPDSE) in the presence of AIBN at 60°C was investigated. DPDSE was worked as a chain transfer agent (CTA). The chain transfer constant (C_tr) of DPDSE for MMA was estimated to be 1.43. On the other hand, DPDSE was functioned as a photoiniferter for the photopolymerization of MMA. In a limited range of conversion, both the polymer yield and number average of molecular weight ([Mbar]_n) increased with the reaction time, and the [Mbar]_n linearly increased with the yield. The terminal structure of poly(MMA) was investigated by the ⁷⁷Se NMR spectrum based on Methyl α-phenylseleno isobutylate (MSEPI) as model compound of the ω-chain end of poly(MMA). Further, photopolymerization of poly (MMA) containing phenylseleno group at ω-chain end as a polymeric photoiniferter with MMA effectively afforded a poly (MMA) having higher molecular weight.     

Synthesis of Telechelic Polystyrene by Radical Polymerization Using 1,4-Bis(p-tert-Butylphenylseleno-Methyl)benzene as a Photoiniferter

Abstract

1,4-Bis(p-tert-butylphenylselenomethyl) benzene was synthesized, and used as a bifunctional photoiniferter for the polymerization of styrene. Both the polymer yields and the number average of molecular weights (_n) of polymers increased with the polymerization. The polymerization of styrene by this iniferter permitted telechelic polystyrene containing arylseleno groups at both chain ends, and the degree of functionality was 1.9. The seleno groups of both chain ends of polystyrene were reduced quantitatively by tri-n-butyltin hydride. These seleno groups in polystyrene were also eliminated by treatment with hydrogen peroxide to give telechelic polystyrene with carbon-carbon double bond at both chain ends. Further, polystyrene with double bonds was converted to telechelic polystyrene carrying terminal functional groups as epoxy, hydroxy, and iodide group, respectively.

     

原子转移自由基聚合制备聚(甲基丙烯酸甲酯-b-苯乙烯)时单体聚合顺序对嵌段效率的影响

采用原子转移自由基聚合研究了聚（ 甲基丙烯酸甲酯 ｂ 苯乙烯） 嵌段共聚物的合成,实验结果表明,当先进行甲基丙烯酸甲酯的聚合,然后再进行苯乙烯的聚合时,得到了完全的嵌段共聚物;反之,如果改变单体的聚合顺序,则嵌段效率很低．用聚合物末端Ｃ—Ｘ（Ｘ＝ Ｃｌ,Ｂｒ） 键的断裂能对实验结果进行了解释．     

以1,4-二氯甲氧基丁烷为氯甲基化试剂合成线型氯甲基化聚苯乙烯

采用自制的氯甲基化试剂——1,4-二氯甲氧基丁烷(BCMB),使用Lewis酸催化剂,在均相反应体系中高效地实现了聚苯乙烯的氯甲基化.研究了反应机理,考察了各种因素对氯甲基化反应的影响规律,优化了反应条件,通过红外光谱法与Volhard分析法表征了产物的化学结构与组成.实验结果表明,反应机理可能由苯环亲电取代与伴随着醚键断裂的亲核取代两类反应构成,氯甲基化试剂用量、催化剂的酸性与用量、溶剂的性质与用量及反应温度等因素对反应都有显著的影响,其一,会影响聚苯乙烯的氯甲基化程度,其二,会导致或避免大分子链之间通过Friedel-Crafts反应而发生交联.以四氯化碳为溶剂、以SnCl4为催化剂并在较低温度(18℃)下进行反应,可制得氯甲基化程度达80%且完全线型化的氯甲基化聚苯乙烯.     

ATRP法制备两亲性嵌段共聚物的研究

以α 溴代丙酸乙酯 (EPN Br)为引发剂、氯化亚铜 (CuCl)和联二吡啶 (bpy)组成的混合体系为催化剂 ,引发苯乙烯聚合 ,得到了端基为卤原子的单分散聚苯乙烯 (PS X)预聚体 .以此PS X为大分子引发剂、CuCl和N ,N ,N′ ,N″ ,N″ 五甲基二亚乙基三胺 (PMDETA) bpy的混合体系为催化剂 ,引发N ,N 二甲基丙烯酰胺(DMAA)聚合 ,得到了分子量分布较窄的聚苯乙烯 b 聚N ,N 二甲基丙烯酰胺 (PS b PDMAA)两亲性嵌段共聚物 .考察了大分子引发剂的分子质量、聚合介质及配位剂等对聚合过程的影响 .并用GPC、IR、1 H NMR等对产物进行了表征 .研究结果表明 ,该聚合反应体系符合原子转移自由基聚合的特征 .     

9,9-二(4-羟基苯基)呫吨、1,4-二(4-氟苯甲酰基)苯和双酚A三元共聚物聚醚醚酮酮的合成与表征

通过亲核取代反应,将9,9-二(4-羟基苯基)呫吨(BHPX)、1,4-二(4-氟苯甲酰基)苯和双酚A(BPA)进行三元共缩聚反应,合成了几种主链含二甲基甲烷和呫吨结构的聚醚醚酮酮无规共聚物(PEEKK-X/PEEKK-A),并以FTIR、DSC、TG、WAXD等对其结构和性能进行了表征.结果表明,共聚物的玻璃化转变温度(Tg)为185～218℃,均为无定形结构,其数均分子量为39500～41600,多分散性指数为1.94～2.05.在氮气、空气气氛中,在430℃之前不分解,5%的热失重温度(Td5)分别为490～511℃、480～505℃,在氮气中700℃时的残炭率均在40%以上;在常温下易溶于非质子极性溶剂(如NMP和DMAc)以及极性较弱的溶剂(如THF和CHCl3)中.共聚物均可通过溶液浇铸成膜,所得到的薄膜韧性好,透明且耐折,其拉伸强度为58～75MPa,杨氏膜量为1.95～2.70GPa,断裂伸长率为8%～13%.当双酚单体BHPX和BPA摩尔比为60/40～50/50时,所得到的PEEKK-X/PEEKK-A共聚物更有潜在的应用前景.     

SYNTHESIS OF POLYPROPYLENE-POLY(METH)ACRYLATE BLOCK COPOLYMERS USING METALLOCENE CATALYZED PROCESSES AND SUBSEQUENT ATOM TRANSFER RADICAL POLYMERIZATION

ABSTRACT

The synthesis of block copolymers containing low molar mass polypropylene and poly(meth)acrylates is reported. Vinyl-terminated polypropylene (M_n SEC=3,100; M_w/M_n=1.45) was used to prepare a macroinitiator for atom transfer radical polymerization (ATRP) via hydrosilation with 1-(2-bromoisobutyryloxy)propyl-tetramethyldisiloxane. Polar segments were then incorporated to polypropylene by chain extension using either methyl methacrylate, or n-butyl acrylate. While blocking efficiency was limited in this system, well-defined PP-b-PMMA (M_n=22,220; M_w/M_n=1.14) was obtained by extraction of unreacted polypropylene with diethyl ether.     

聚(L-谷氨酸γ-苄酯)-聚四氢呋喃-聚(L-谷氨酸γ-苄酯)三嵌段共聚物的合成与表征

聚氨基酸是一类低毒性、生物相容性良好、易被机体吸收和代谢的可降解合成高分子材料，在药物控释载体、组织工程支架、生物材料表面改性方面得到了广泛应用．但其降解周期及降解速度通常难以控制，应用受到一定限制．通过共聚方法将生物相容和亲水性良好的聚乙二醇（PEG）引入聚氨基酸链段中形成两亲性嵌段共聚物旧，研究其自组装行为，及作为基因转染和药物控释载体等已成为高分子科学领域新的研究热点．     

SYNTHESIS OF POLY(SILPHENYLENE-SILOXANE) THROUGH DEHYDROCARBON POLYCONDENSATION OF 1,4-BIS(DIMETHYLSILYL)BENZENE AND DIALKOXYSILANE

Poly(silphenylene-siloxane)s had been synthesized through dehydrocarbon polycondensation of 1,4- bis(dimethylsilyl)benzene(BDSB)and dialkoxysilane.The polymer composition and structure was characterized by ~(29)Si-NMR.The influence of temperature,B(C_6F_5)_3 concentration and monomer structure on the composition and the microstructure of the copolymers were investigated.It shows that elevating reaction temperature or using substrate (R'O)_2R_2R_1Si with bulk organic group of R_1 or R_2 augments the run n...     

SYNTHESIS OF POLY(METHYL METHACRYLATE)-graft-POLYSTYRENE BY ATOM TRANSFER RADICAL POLYMERIZATION

The radical copolymerization of methyl methacrylate and 2-hydroxyethyl methacrylate was carried out via atomtransfer radical polymerization (ATRP) initiated by ethyl 2-bromoisobutyrate and catalyzed by CuBr/2,2'-bipyridinecomplex. This polymerization proceeds in a living fashion with controlled molecular weight and low polydispersity. Theobtained copolymer was esterified with 2-bromoisobutylryl bromide yielding a macroinitiator, poly(methyl methacrylate-co-2-hydroxyethyl methacrylate-co-2-(2-bromoisobutyryloxy)ethyl methacrylate), and its structure was characterized by ~1H-NMR. This macroinitiator was used for ATRP of styrene to synthesize poly(methyl methacrylate)-graft-polystyrene. Themolecular weight of graft copolymer increased with the monomer conversion, and the polydispersity remained relatively low.The individual grafted polystyrene chains were cleaved from the macroinitiator backbone by hydrolysis and the hydrolyzed product was characterized by ~1H-NMR and GPC.     

乙醇-水介质中单分散聚甲基丙烯酸甲酯微球的制备

与一般的以非极性脂肪烃或甲醇 水作为分散介质不同 ,采用乙醇 水混合溶剂作为分散介质进行了聚甲基丙烯酸甲酯的分散聚合 ,讨论了醇 水比例对聚合的影响 .在反应中 ,采用了一种新的加热反应方式 ,先高温反应一段时间以利于成核 ,然后降温到一较低温度反应至结束 .这种反应方式取得了明显的效果 ,大大降低了粒度分布 .此外 ,还研究了引发剂种类对粒径大小及分布的影响 ,发现混合引发剂偶氮二异丁腈 (AIBN)和过硫酸钾 (KPS)中即使只含有少量的KPS ,也会明显使粒径减小 ,分布变宽     

SYNTHESIS OF A COMB GRAFT COPOLYMER VIA RING OPENING METATHESIS POLYMERIZATION CATALYZED BY SUPPORTED RHUTHENIUM CARBENE COMPLEX

5－Chloromethyl-2-norbornene was synthesized via Diels-alder reaction of cyclopentadiene and allyl chloride using a polymer supported boron trifluoride as the catalyst,and was then lithiated and used to initiate a livcing anionic polymerization of styrene to prepare a macromonome,5-polystryl-2-norbornene NB-PS,Comb graft copolymer PNB-g-PS was synthesized via ring opening metathesis polymerization of the macromonomer under the catalysis of ruthenium carbene complex RuCl2(PPh3)2(=CCHtBu)and its polymer supported correspondent.Experimetal results showed that the behavior of both the supported boron and supported ruthenium catalysts are superior to their unsupported counterparts.The possible promotion mechanism of the tailor-made supports is discussed.     

PREPARATION OF POLY（ETHYLENEGLYCOL-co-ACRYLIC ACID） MICROSPHERES WITH DIVINYLBENZNE AS CROSSLINKER BY DISTILLATION-PRECIPITATION POLYMERIZATION

Monodisperse poly（poly（ethyleneglycol） methyl ether acrylate-co-acrylic acid） （poly（PEGMA-co-AA）） microspheres were prepared by distillation-precipitation polymerization with divinylbenzene （DVB） as crosslinker with 2,2＇- azobisisobutyronitrile （AIBN） as initiator in neat acetonitrile without stirring. Under various reaction conditions, four distinct morphologies including the sol, microemulsion, microgels and microspheres were formed during the distillation of the solvent from the reaction system. A 2D morphological map was established as a function of crosslinker concentration and the polar monomer AA concentration, in comonomer feed in the transition between the morphology domains. The effect of the covalent crosslinker DVB on the morphology of the polymer network was investigated in detail at AA fraction of 40 vol%. The ratios of acid to ethylene oxide units presenting in the comonomers dramatically affected the polymer-polymer interaction and hence the morphology of the resultant polymer network. The covalent crosslinking by DVB and the hydrogen bonding crosslinking between two acid units as well as between the acid and ethylene oxide unit played key roles in the formation of monodisperse polymer microspheres.     

过渡金属盐催化甲基丙烯酸2-(N,N-二乙氨基)乙酯的自引发自由基聚合

研究了高氧化态过渡金属盐(CuX2/L、FeX3/L,X=C1或Br;L =2,2′-联吡啶、N,N'-四甲基乙二胺、N,N,N′,N″,N″-五甲基二亚乙基三胺;CuSO4)催化甲基丙烯酸2-(N,N-二乙氨基)乙酯(DEAEMA)的自引发氧化聚合,利用气相色谱跟踪单体转化率、利用凝胶渗透色谱和多角激光光散射跟踪聚合...     

SYNTHESIS AND CHARACTERIZATION OF A SERIES OF LIPOPHILIC CISPLATIN ANALOGS WITH CIS-1,4-DIAMINOCYCLOHEXANE AS NONLEAVING AMINE LIGAND

Abstract

A series of lipophilic platinum(II) complexes of the type [Pt(cis-1,4-DACH)L₂] (where cis-1,4-DACH = cis-1,4-diaminocyclohexane and L = acetate, propionate, butyrate, valerate, hexanoate, heptanoate, octanoate, 2,2′-dimethyloctanoate, nonanoate, decanoate, undecanoate, laureate, tridecanoate, myristate, pentadecanoate, palmitate, heptadecanoate, stearate, nonadecanoate, or eicosanoate) has been synthesized and characterized by elemental analysis and by infrared, ¹³C, and ¹⁹⁵Pt nuclear magnetic resonance spectroscopic techniques.     

二维核磁共振法研究线型聚乙二醇与树枝状聚苄醚形成的三嵌段共聚物

嵌段共聚物是由几个不同的高分子链段通过化学键相连所构成的 .在合成方法上一般是通过几类不同的活性聚合 ,调控单体的加料次序或者通过不同的大分子链段末端的反应活性点偶联而成[1～ 3 ] .所形成的化学键将嵌段共聚物中不相溶的几段相连 ,于是在特定的条件下就产生了微相分离的现象 ,继而可以在 1 0～ 1 0 0nm尺度范围内形成各种各样的微区结构[4,5] .在过去的几十年里 ,研究的重点是认定嵌段共聚物的微区结构和研究微相分离的动力学 ,已发表了大量重要的结果 ,至今仍然是高分子科学中的热门课题 .非常重要的一点是 ,正是由于不同的高分…     

甲基丙烯酸N,N-二甲氨基乙酯的CuX/PMDETA催化氧化聚合

在添加一定浓度的CuX(X=C l/B r)/五甲基二亚乙基三胺(PMDETA)后,甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)于室温下只需暴露于空气中即可聚合形成PDMAEMA.通过一系列对比试验验证了该过程的催化氧化聚合特征,通过改变催化剂浓度与反应温度等反应条件,利用气相色谱、核磁共振和凝胶渗透色谱研究了该聚合过程的动力学和所得PDMAEMA的结构.结果表明,单体转化率与所得聚合物分子量均随反应时间的延长而逐渐增加,过高或者过低浓度的CuX/PMDETA均无法催化该聚合过程,所得聚合物具有与普通线型PDMAEMA类似的化学结构.我们提出了一个假设性的机理以解释此现象.     

SYNTHESIS OF POLY(METHYLENE TEREPHTHALATE) AND COPOLYMERS WITH POLY(ETHYLENE TEREPHTHALATE)

Poly(methylene terephthalate) (PMT) and poly(ethylene terephthalate) (PET) were synthesized by triethylamine-mediated reactions of terephthalic acid and dihalomethanes or 1,2-dihaloethanes, respectively. Reactions with chloro compounds required longer reaction times and higher temper-atures than those with bromo. Copolymers were synthesized by using proportionate amounts of dihalomethane/1,2-dihaloethane mixtures. Copolymer compositions were determined by inte-grations of relative areas of methylene and ethylene ¹H NMR peaks. Mn values were determined from ¹H NMR end group signals. Mole fraction feed is linearly related to CH₂/CH₂CH₂ incorporation into copolymer products. Mechanisms are proposed to explain results.     

SINGLE LANTHANUM TRIS(N-PHENYLETHYL-3,5-DI-t-BUTYLSALICYLALDIMINATO)S INITIATOR FOR RING-OPENING POLYMERIZATION OF 1,4-DIOXAN-2-ONE IN BULK

A rare earth Schiff base complex:lanthanum tris(N-phenylethyl-3,5-di-t-butylsalicylaldiminato)s [La(OPEBS)_3] was successfully applied as single component initiator for the ring-opening polymerization of 1,4-dioxan-2-one (PDO) in bulk.The influence of reaction conditions,such as polymerization temperature,the molar ratio of the monomer to initiator (M/I) on the monomer conversion and molecular weight of the polymer has been investigated.Poly(1,4-dioxan-2-one) with a viscosity-average molecular weight (My...     

Synthesis of star polystyrene by radical polymerization with 1,2,4,5-tetrakis(p-tert-butylphenyl selenomethyl)benzene as a novel photoiniferter

1,2,4,5-Tetrakis(p-tert-butylphenylselenomethyl)benzene was synthesized and used as a tetrafunctional photoiniferter for the polymerization of styrene. Both the yield and the number average molecular weight () of polymers increased with reaction time and linearly increased with yield of polymer. The polymerization of styrene using this novel photoiniferter permitted formation of star-shaped polystyrene containing arylseleno groups at the chain ends, and the average degree of functionality was 3.2. Photopolymerization of styrene with end-functional star polystyrene as polymeric photoiniferter afforded polystyrene having high molecular weight.