无机盐对氟烷基封端的嵌段共聚物在水相聚集行为的影响

以含氟醇钾盐(NFHO-K )作为引发剂,通过阴离子活性聚合方法合成了氟烷基封端的聚甲基丙烯酸-2-(二甲氨基)乙酯-block-聚甲基丙烯酸-2-(二乙氨基)乙酯嵌段共聚物(NFHO-PDMA-b-PDEA).该共聚物与一般的含氟嵌段共聚物相比,既具有优良的表面活性,又具有较好的溶解性.通过对溶液表面张力的测定,荧光探针法对溶液临界聚集浓度(cac)的测定和透射电子显微镜(TEM)对共聚物在溶液中胶束形态的研究,发现无机盐对共聚物在水溶液中的聚集行为有明显的影响,并可以增强共聚物的表面活性.     

光谱法分析乙丙共聚物的序列结构及链节比

用FTIR, 1 H NMR和 13 C NMR分析乙丙共聚物的序列结构与链节比. 通过对乙丙共聚物 1 H NMR, 13 C NMR和 13 C-1 H二维核磁共振谱的综合分析, 提出了与前人不同的归属, 并提出了不同位置碳原子积分面积相关性分析方法, 该方法避免了烦琐的理论计算, 可简便地得到乙丙共聚物的主要序列结构. 通过比较 1 H NMR和 13 C NMR计算乙丙共聚物中乙烯、 丙烯链节比, 表明可以用 1 H NMR代替 13 C NMR完成对乙丙共聚物中乙烯、 丙烯链节比的定量计算.     

含氟两亲接枝共聚物的制备及其结晶行为

采用大分子单体技术合成了一系列以聚乙二醇为支链、甲基丙烯酸六氟丁酯为主链的含氟两亲接枝共聚物(PHFMA-g-PSPEG)。用1HNMR和凝胶色谱(GPC)对制备的大分子单体和两亲接枝共聚物的结构进行了表征。利用示差扫描量热法(DSC)、X射线衍射(XRD)和偏光显微镜(POM)测试技术对含氟两亲接枝共聚物的结晶行为进行了研究。DSC和XRD结果表明,随着共聚物中含氟链段质量分数的增加,其结晶温度(Tc)和结晶度(Xc)均降低,而结晶熔融温度(Tm)先减小后增加。POM发现,随着共聚物中含氟链段质量分数的增加,其结晶速度减慢,共聚物形成清晰球晶的能力减弱,当共聚物中含氟链段质量分数为57%时,含氟两亲接枝共聚物已不能形成清晰的球晶。     

MMA/MAh共聚物的合成及其凝胶聚合物电解质性能

从聚甲基丙烯酸甲酯型凝胶聚合物电解质存在的问题出发,设计制备一种甲基丙烯酸甲酯/共聚马来酸酐型凝胶聚合物电解质.采用溶液聚合法,以偶氮二异丁腈(AIBN)为引发剂,甲基丙烯酸甲酯(MMA)、顺丁烯二酸酐(MAh)为单体,其MMA与MAh单体摩尔配比为1∶1,合成了P(MMA-co-MAh)共聚物;采用凝胶色谱(GPC)、傅立叶红外光谱(FTIR)、核磁共振(MNR)、示差扫描量热法(DSC)、热失重分析(TGA)、X-射线衍射分析(XRD)对所合成共聚物的结构进行了表征.结果表明,合成的共聚物为无规非晶型聚合物,其数均分子量Mn为6.40×104,共聚物中MMA与MAh链段摩尔比大约为8∶1,热分解温度为300℃,玻璃化转变温度(Tg)为121.3℃.以P(MMA-co-MAh)共聚物为树脂基体,环状碳酸1,2-丙二酯(PC)为增塑剂,LiClO4为电解质盐,制备了凝胶聚合物电解质(GPE),当共聚物含量为45 wt%时,GPE具有好的成膜性,其室温离子电导率为3.0×10-5S/cm.     

甲基丙烯酸甲酯、苯乙烯与顺丁烯二酸二丁基锡三元共聚物的合成与表征

以过氧化苯甲酰(BPO)为引发剂,将顺丁烯二酸二丁基锡(DBTM)与苯乙烯(St)、甲基丙烯酸甲酯(MMA)进行本体三元共聚反应,探讨了共聚反应条件.用液相色谱、红外光谱、核磁共振氢谱和热重分析对共聚物的结构和性能进行了表征.动态热流变性实验结果表明,在含锡量相同的情况下,共聚物对PVC的热稳定效果优于DBTM,可以作为多功能化的PVC热稳定剂.     

Nano- and micro-structured random copolymer modified cycloaliphatic epoxy resins for use as light-emitting diode encapsulation

Poly(2,2,3,4,4,4-Hexafluorobutylmethacrylate–random–glycidolmethacrylate) random copolymer (P(HFBMA-r-GMA)) was synthesized via free radical polymerization. The novel reactive random copolymer was incorporated to modify cycloaliphatic epoxy resins and obtain the nano- or micro- structured composites. The chemical structures of P(HFBMA-r-GMA) were confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The morphology and light transmittance of the cured epoxy resins were observed by scanning electron microscopy (SEM), transmission electron microscope (TEM) and ultraviolet-visible spectrophotometry (UV-vis), respectively. It is indicated that the optical transmittance of composites were basically kept although the microphase separation occurred in the curing process, which has a profound influence on the mechanical properties and refractive indexes. The thermal properties, surface dewettability and water absorbency of the cured epoxy resins were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurement and immersion test respectively. The experimental results revealed that the values of glass transition temperatures (Tg), surface dewettability and water resistance were effectively improved by the high cross-linking density and the enrichment of the fluorinated random copolymer dispersing in the composites. With respect to the corresponding properties of the neat epoxy resin, P (HFBMA-r-GMA)-0.25 hybrimer embraced the relatively good comprehensive properties, making the modified epoxy resins as good candidates for LED encapsulation.     

SAPO-5分子筛骨架结构研究

SAPO-5分子筛的骨架是由PO_4~-、AlO_4~-和SiO_4四面体构成.可以看作是硅同晶置换AlPO_4-5分子筛骨架上的磷或铝而得到,其取代方式可以通过三种可能的途径实观;(1)Si 取代Al;(2)Si 取代P;(3)两个Si 等同取代一个P 和一个Al.由于取代方式的不同,将导致骨架TO_4(T=P、Al,Si)的连接方式的不同,因此Si 在SAPO-5分子筛骨架中的存在状态是人们十分关注的问题.目前这方面的研究工作都采用固体核磁共振的方法,并且认为合成条件的不同其取代机理也不相同.本工作用~(31)P 和~(29)Si 固体高分辨核磁共振技术结合电子探针和光电子能谱方法对HF 参与下得到的SAPO-5分子筛骨架构成进行了系统的研究.     

聚肽接枝共聚物的自组装行为研究

Polymeric micelles of poly(γ-benzyl L-glutamate)(PBLG)-poly(ethylene oxide)(PEO) graft copolymer were prepared by the dialysis method in deionized water. Fluorescence spectroscopy, nuclear magnetic resonance(NMR) and transmission electron microscope(TEM) were used for the investigation of the self-assembly of PBLG-PEO graft copolymer. Fluorescence spectrosco0y measurements suggest that PBLG-PEO graft copolymer associates to form polymeric micelles in water. ^1H NMR measurements further prove that in aqueous medium PBLG-PEO graft copolymer could assemble into polymeric micelles with PBLG segments as the hydrophobic inner core and PEO segments as the hydrophilic shell. The results of the TEM observations show that the polymeric micelles of PBLG-PEO graft copolymer are almost spindly shaped, which are different from the morphology of the spherical micelles formed by PBLG-PEO block copolymer. Polymeric micelles formed by polypeptide copolymer have potential application as drug carrier in controlled-release delivery system.     

Synthesis of amphiphilic tri-block copolymerpoly(vinylpyrrolidone)-b-poly(methyl methacrylate)-b-poly(vinylpyrrolidone) for the modification of polyethersulfone membrane

Well-defined amphiphilic tri-block copolymer PVP-b-PMMA-b-PVP was prepared for the first time via successive reversible addition fragmentation chain transfer(RAFT) polymerization using carboxyl-terminated trithiocarbonate as the RAFT agent.The structure of the copolymer was characterized using FTIR,GPC and ~1H NMR.The block copolymer could be directly blended with polyethersulfone(PES) as a macromolecule additive using N-methyl-2-pyrrolidone(NMP) as the solvent to prepare membranes. The water contact angles for the modified membranes decreased obviously,and therefore,the protein adsorption amount on the membrane surface decreased.     

Synthesis of poly(N-isopropylacrylamide)-b-poly(2-vinylpyridine) block copolymers via RAFT polymerization and micellization behavior in aqueous solution

Poly(N-isopropylacrylamide)-b-poly(2-vinylpyridine) (PNIPAM-b-P2VP) block copolymers were synthesized for the first time via reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of S-1-dodecyl-S(')-(a,a(')-dimethyl-a(')-acetic acid)trithiocarbonate as chain transfer agent (CTA) and 2,2(')-azobis(isobutyronitrile) as initiator. Both pH- and thermo-induced micellization behavior of the PNIPAM(59)-b-P2VP(102) block copolymer in dilute aqueous solution was investigated by pyrene fluorescence, dynamic and static light scattering, transmission electron microscopy and (1)H NMR. The results show that the critical aggregation pH value of the block copolymer is around 5 and the critical aggregation temperature of the block copolymer is around 42 degrees C. A reversible transition between P2VP-core and PNIPAM-core micelles can be observed through an intermediate unimer state in aqueous solution.     

SYNTHESES OF STYRENE-METHYL METHACRYLATE BLOCK COPOLYMER BY POLYAZOAMIDE AS INITIATOR

Polyazoamide(PAA) was used as initiator to prepare block copolymer P(MMA-b-St) byfree radical polymerization. The fraction of block copolymer was about 50%. The structureof the block-copolymer was characterized by IR and the results of ~1H-NMR and GPCshowed that the content of the block and the molecular weight (M_w) of the prepolymerand block copolymer could be controlled by varying the mol ratio of styrene/PAA andMMA/prepolymer. DSC and TEM results revealed that the block copolymer has twoseparated glass transition temperatures and phase separation within the domain structure.     

Synthesis,micellization and gelation of temperature‐responsive star‐shaped block copolymers

A series of amphiphilic temperature‐responsive star‐shaped poly(D,L‐lactic‐co‐glycolic acid)‐b‐methoxy poly(ethylene glycol) (PLGA‐mPEG) block copolymers with different arm numbers were synthesized via the arm‐first method. Gel permeation chromatography data confirmed that star‐shaped PLGA‐mPEG copolymers had narrow polydispersity index, indicating the successful formation of star‐shaped block copolymers. Indirectly, the ¹H NMR spectra in two kinds of solvents and dye solubilization method had confirmed the formation of core‐shell micelles. Further, core‐shell micelles with sizes of about 30–50 nm were directly observed by transmission electron microscopy. Subsequently, the micellar sizes and distributions as a function of concentrations and temperature were measured. At various copolymer concentrations, individual micelles with size of 20–40 nm and grouped micelles with size of 600–700 nm were found. Micellar mechanism of star‐shaped block copolymers in aqueous solution was simultaneously discussed. In addition, sol–gel transition of star‐shaped block copolymers in water was also investigated via the inverting test method. The critical gel temperature (CGT) and critical gel concentration (CGC) values of two‐arm, three‐arm and four‐arm copolymer solutions were markedly higher than ones of one‐arm copolymer. Moreover, the same CGC values of copolymer solution with different molecular weight and the same arm composition were ~15 wt %, and CGT values increased from ~38 to ~47°C with increasing arm numbers. Finally, the temperature‐dependent micellar packing gelation mechanism of star‐shaped block copolymer was schematically illustrated. Copyright © 2013 John Wiley & Sons, Ltd.     

Self-assembly of a diblock copolymer with pendant disulfide bonds and chromophore groups: a new platform for fast release

An amphiphilic block copolymer comprising poly(ethylene glycol) (PEG) and poly(2-(methacryloyl)oxyethyl-2'-hydroxyethyl disulfide) (PMAOHD) blocks was synthesized by atom transfer radical polymerization (ATRP). Pyrenebutyric acid was conjugated to the block copolymer by esterification, and a block copolymer with pendant disulfide bonds and pyrenyl groups (PEG-b-P(MAOHD-g-Py)) was obtained. (1)H NMR and gel permeation chromatography (GPC) results demonstrated the successful synthesis of the block copolymer. The cleavage of the disulfide bonds and the degrafting of the pyrenyl groups were investigated in THF and a THF/methanol mixture. Fluorescence spectroscopy, GPC, and (1)H NMR results demonstrated fast cleavage of the disulfide bonds by Bu(3)P in THF. Fluorescence results showed the ratio of the intensity of the excimer peak to the monomer peak decreased rapidly within 20 min. GPC traces of the block copolymer moved to a long retention time region after addition of Bu(3)P, indicating the cleavage of the disulfide bonds and the degrafting of the pyrenyl groups. PEG-b-P(MAOHD-g-Py) can self-assemble into micelles with poly(MAOHD-g-Py) cores and PEG coronae in a mixture of methanol and THF (9:1 by volume). The dissociation of the micelles in the presence of Bu(3)P was investigated. After cleavage of the disulfide bonds in the micellar cores, a pyrene-containing small molecular compound and a block copolymer with pendant thiol groups were produced. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and (1)H NMR were employed to track the dissociation of the polymeric micelles. All the techniques demonstrated the dissociation of the micelles and the fast release of pyrenyl groups from the micelles.     

The synthesis of biodegradable graft copolymer cellulose-graft-poly(L-lactide) and the study of its controlled drug release

According to the concept of green chemistry and sustainable development, a new biodegradable copolymer comprised of hydrophobic poly(l-lactide) (PLLA) segments and hydrophilic cellulose segment (cellulose-g-PLLA) was designed and synthesized. The structure of the copolymer was characterized by (1)H NMR, FT-IR, (13)C NMR, DSC and WAXD. The cytotoxicity study shows that cellulose-g-PLLA exhibits good biocompatibility. The copolymer can self-assemble into micelles in water with the hydrophobic PLLA segments at the cores of micelles and the hydrophilic cellulose segments as the outer shells. Transmission electron microscopy (TEM) shows that the micelles exhibit nanospheric morphology within a size range of 30-80nm. The drug loaded micelles formed by the copolymer in aqueous media show sustained drug release which indicates their potential applicability in drug carrier.     

1-甲基-3-(2-甲基丙烯酰乙基)-咪唑氯离子液体/ 苯乙烯无规共聚物及其CdTe量子点复合物的合成

以偶氮二异丁腈(AIBN)为引发剂, 通过自由基聚合制备了1-甲基-3-(2-甲基丙烯酰乙基)-咪唑氯离子液体和苯乙烯的无规共聚物P(MMEIM⁺Cl^--co-St). 用红外光谱、核磁共振氢谱和凝胶渗透色谱表征了共聚物的结构. 共聚物的氯仿溶液与巯基乙酸稳定的CdTe量子点水溶液混合, 通过静电相互作用复合组装, 得到澄清透明且稳定的CdTe/P(MMEIM⁺Cl^--co-St)纳米复合物的氯仿溶液. 复合物的紫外吸收光谱、荧光发射光谱和透射电子显微镜的表征结果表明, 量子点均匀分散于共聚物中, 无团聚, 且保持了量子点的荧光性能.     

含铕荧光两亲接枝共聚物的制备及胶束化行为

以丙烯酸(AA)、 苯甲酸(BA)和邻菲啰啉(Phen)为配体, Eu³⁺为中心离子, 制备了可聚合荧光配合物单体, 并以此单体为功能单体, 聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)和甲基丙烯酸六氟丁酯(HFMA)为共聚单体, 通过溶液聚合制备出含铕两亲荧光接枝共聚物P-[HFMA-co-Eu(AA)(BA)₂Phen]g-PEG. 利用红外光谱(FTIR)和核磁共振波谱(¹H NMR和¹⁹F NMR)对共聚物的结构进行表征; 采用表面张力法测定共聚物的临界胶束浓度(cmc)为0.20 g/L; 通过透射电子显微镜(TEM)和动态光散射仪(DLS)观察胶束的形貌及其胶束化行为, 发现该共聚物可以形成大小均一的球形胶束, 且随着共聚物浓度的提高, 胶束粒径相应增大; 在溶液浓度达到临界胶束浓度时, 溶液荧光出现强度突变.     

异戊二烯/甲基丙烯酸甲酯嵌段共聚物的合成与微结构研究

用稀土催化剂ＲＥ（Ｐ２０４）３ （ｉ Ｂｕ）３Ａｌ ＢｒＣＨ２ＣＨ２Ｂｒ（ＲＥ＝Ｎｄ,Ｐｒ,Ｙ等）合成嵌段共聚物Ｐ（ＩＰ ｂ ＭＭＡ）．系统考察了共聚合反应特征,以ＤＳＣ,１Ｈ ＮＭＲ,１３Ｃ ＮＭＲ技术研究了该嵌段共聚物的微结构．发现以二溴乙烷为添加剂的稀土催化体系是制备Ｐ（ＩＰ ｂ ＭＭＡ）的良好催化剂,共聚物含２个玻璃化转变温度,分别为－７５６℃和１２９℃,嵌段共聚物的结构规整,（ＩＰ）ｍ段以ｃｉｓ １,４结构为主,其含量为９７％左右,３,４ 结构为３％左右,链节间以头 尾方式连接．（ＭＭＡ）ｎ段以间同立构为主,其含量达７４％．     

溶聚丁苯链化学结构的NMR研究

溶聚丁苯链化学结构的NMR研究;溶聚丁苯; 链化学结构; 相容性     

Metal-free synthesis of amphiphilic functional polycarbonates

Amphiphilic block copolymers of poly(5-benzyloxy trimethylene carbonate)(PBTMC) and poly(ethylene glycol)(PEG) were synthesized through enzymatic polymerization using immobilized porcine pancreas lipase(IPPL).The obtained copolymers with different compositions were characterized by GPC and ~1H NMR.The copolymer composition was in agreement with the feed ratio. The molecular weight of the copolymers showed an increasing trend with the decrease of PEG contents.Micelles of the copolymers were formed by dialysis procedure,and characterized by transmission electron microscopy (TEM).     

温敏性含氟两亲接枝共聚物的制备及胶束化行为

以聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)为大分子单体, 甲基丙烯酸六氟丁酯(HFMA)为含氟单体, N-异丙基丙烯酰胺(NIPAAm)为功能性单体, 采用大分子单体接枝共聚法, 制备了一种温敏性含氟两亲接枝共聚物P(NIPAAm-co-HFMA)-g-PEG. 利用FTIR, ¹H NMR, ¹⁹F NMR和GPC对共聚物的结构进行表征; 采用紫外-可见分光光度计测定了共聚物的低临界溶解温度(LCST)约为38.9 ℃, 高于人体正常的生理温度; 利用荧光探针技术测定了共聚物的临界胶束浓度(cmc), 结果表明, 当共聚物溶液温度高于LCST时, 其cmc明显变小; 利用激光光散射粒度仪(LLS)测定了共聚物胶束的水合粒径及其分布, 当温度达到LCST时, 胶束粒径明显变小, 温度过高时, 粒径又有所增大; 利用透射电子显微镜(TEM)研究了共聚物胶束的形貌, 结果表明, P(NIPAAm-co-HFMA)-g-PEG在水溶液中可自组装成球状胶束粒子, 随着温度的升高, 共聚物胶束由松散的核壳结构转变成更加紧凑的球状结构, 且粒径明显变小.