Microstructural Characterization of Diblock Copolymers Formed by Styrene and Different Methacrylic Units

FT-IR, DSC, and NMR techniques allowed the structural characterization of four copolymers formed by styrene and methacrylic units (methacrylic acid (MAA), dimethylamine ethyl methacrylate (DMAEMA), sodium methacrylate (MANa), and 1-hydroxyethyl methacrylate (HEMA). The copolymer composition was studied by Fourier transform-infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The thermal behavior of the block copolymers was analyzed by differential scanning calorimetry (DSC). Three of the four copolymers showed two transitions caused by changes in the polymer heat capacity (ΔCp) of each block. Diffusion-ordered spectroscopy (DOSY) experiments were used to distinguish copolymer from homopolymer mixtures. Finally, the triad-level stereosequences of styrene-methacrylic copolymers were obtained using ¹³C NMR. The results indicate that by increasing the alkyl-substituent length in the methacrylic block, the probability of syndiotactic polymerization increases.     

聚合物存在下纳米银复合材料的制备与表征

以聚丙烯腈聚乙二醇嵌段共聚物PAN-b-PEG-b-PAN为稳定剂, 在超声辐照下成功地制备了分散性较好、尺寸均匀的纳米银颗粒. 用X射线衍射(XRD)、红外光谱(FTIR)、透射电镜(TEM)、紫外-可见吸收光谱(UV-Vis)和热分析(TGA)等对制备的纳米银复合材料进行了表征. 红外结果表明超声辐照并没有破坏聚合物的链结构. 聚合物的引入, 对纳米银颗粒起到了很好的分散保护作用. 用低浓度的硝酸银溶液, 得到粒径较小的纳米银颗粒; 随着硝酸银浓度增大, 纳米银颗粒粒径也增大. 而聚合物的浓度增大时, 所得银纳米颗粒粒径减小. 对银纳米颗粒的形成机理进行了讨论.     

芳醚砜二胺、芳醚砜双马来酰亚胺的合成及共聚树脂的性能研究

通过在三种不同的溶剂一碱体系中合成芳醚砜二胺的研究，确定了最佳的合成路线。用酸碱法对产物进行了纯化，进而合成了芳醚砜双马来酰亚胺。热重分析表明，芳醚砜双马来酰亚胺／芳醚砜二胺共聚树脂具有较高的热和热氧稳定性。     

含芳酯键的双马来酰亚胺Ia／二苯醚二胺共聚物的合成与液晶行为

本文以苯甲酸对苯二酚酯双马来酰亚胺（Ｉａ）和二苯醚二胺为单体，合成了Ｉａ／二苯醚二胺的共聚物，应用ＦＴＩＲ谱、热分析ＤＴＡ和ＤＳＣ、热台偏光显微镜对共聚物的结构和液晶行为进行了研究。该类共聚物具有较好的热致液晶行为，其液晶相结构可以通过共聚物的化学交联反应而固定在交联网络中，从而形成液晶网络材料。     

Preparation and Properties of Novel Aromatic Polyamides from Diamines Containing 4,5-Imidazolediyl Structure

Novel aromatic polyamides were prepared from aromatic diamine containing 4,5-imidazolediyl unit, either by low temperature solution polycondensation or by direct polycondensation. Used diamines were 4,5-bis(4-aminophenyl)-2-phenylimidazole 1, 4,5-bis[4-(4-aminophenyl)]-2-(4-methylphenyl)imidazole 2 and 4,5-bis[4-(4-aminophenoxy)phenyl]-2-phenylimidazole 3. The obtained aromatic polyamides were produced with moderate to high inherent viscosity and soluble in polar aprotic solvents such as N,N-dimethylacetamide (DMAc), 1-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). Thermogravimetric analysis showed those polymers were stable up to 422°C in nitrogen atmosphere. The glass transition temperature (T _g)s of the polymers derived from diamine 3 were in the range between 243 and 275°C, and these values were approximately 120–160°C lower than those analogue polyamide I series containing no phenoxy units. The properties of polyamide I series are also compared with those of analogue polymers that order of aromatic nuclei and amide linkage is reversible.     

含疏水链节的聚N-异丙基丙烯酰胺共聚物的温敏性

采用溶液聚合法合成了一系列N-异丙基丙烯酰胺(NIPAM)与甲基丙烯酸甲酯、丙烯酸乙酯、丙烯酸丁酯或甲基丙烯酸丁酯的无规共聚物,用浊度观测法和光散射法测定了不同共聚物水溶液的温敏相转变行为.结果表明:所得共聚物的低临界溶解温度(LCST)均低于均聚物PNIPAM的,酯类单体的结构和含量对共聚物的LCST有显著影响,其中酯基上的烷基对共聚物LCST的影响能力大于丙烯酸酯α位上的烷基,前者对增大共聚物的疏水性有更大贡献.通过NIPAM与特定丙烯酸酯单体进行无规共聚可以合成转变温度低于PNIPAM均聚物且具有预设LCST数值的水溶性温敏聚合物.     

Synthesis and Characterization of A Novel Cholesteric Liquid Crystalline Containing Carboxyl Group

A novel liquid crystal compound with a carboxyl group at one end, cholest-5-en-3-ol-(3β) hydrogen decanedioate (1) was successfuly prepared by the reaction of cholesterol with sebacoxl chloride. Its chemical structure and liquid crystalline properties were characterized by FTIR.CNMR,HNMR,POM and DSC. The compound with an active carboxyl group shows themortropic liquid crystalline behaviour.     

Synthesis and Properties of Poly （aryl ether ketone） Copolymers Containing 2,7-Naphthalene Moieties

IntroductionPoly(aryl ether ketone)s are high performance en-gineering plastics with outstanding physical,chemical,thermal and mechanical properties and have been ap-plied to the aerospace industry,the electronic industry,the automobile industry,the petro…     

Copolymers of ethyl glycolate and ω–pentadecalactone: Enzymatic synthesis and solid-state characterization

Synthesis of poly(PDL-GA) copolymers is successfully achieved via enzymatic catalysis starting from ω-pentadecalactone and ethyl glycolate. In the copolymers PDL and GA units show a significant tendency to an alternating arrangement. All copolyesters display a high degree of crystallinity (χ_c ≈ 70%) regardless of their composition (GA content: 0–27 mol%). Analysis of melting point depression by the Wendling–Suter model suggests inclusion of GA units in PPDL-type crystals. Accordingly WAXS results show that, with increasing GA unit content, the PPDL unit cell undergoes a gradual increase of c-axis (chain axis) periodicity, compatible with the insertion of GA units within the crystallizing PDL sequences. Poly(PDL-GA) copolymers combine typically hydrophobic (PDL) and hydrophilic (GA) monomers and are promising new tuneable drug-delivery systems for medical applications. In this perspective, poly(PDL-GA) nanoparticles are fabricated and characterized.     

新型含苯并二噻吩与苯并二吡咯酮基元的 D-A共聚物的合成及性质

采用苯并二吡咯酮作电子受体单元，在钯催化下，与不同取代基修饰的电子给体单元苯并二噻吩进行Stille偶联聚合反应，合成了两种新型的电子给受体（D-A）聚合物(P1和P2)，其结构和性能经UV-Vis, ¹H NMR, ¹³C NMR,元素分析，GPC, CV和TGA表征。结果表明：薄膜态P1和P2在300~800 nm表现出较强吸。P1和P2的低能端吸收峰值分别位于621 nm和616 nm。氧化峰分别位于0.41 V和0.46 V，能隙分别为1.41 eV和1.36 eV。     

含不同柔性链的(甲基)丙烯酸酯类液晶高分子的合成及其液晶行为研究

通过改变侧链中柔性间隔基的长度,合成了一系列含有两个手性中心的侧链液晶（甲基）丙烯酸酯类聚合物.红外、核磁和GPC表征各中间体、单体及聚合物的结构和分子量.通过DSC和热台偏光显微镜系统地研究了单体和聚合物的液晶态织构.结果表明,含有六个碳的柔性间隔基的丙烯酸酯类聚合物表现为近晶SA和手性近晶SC^＊液晶相.     

金属苯并卟啉液晶的合成与表征

金属苯并卟啉液晶的合成与表征王杏乔，曹昌盛，高爽，师同顺，于连香，曹锡章（吉林大学化学系，长春，１３００２３）关键词苯并卟啉，卟啉液晶，液晶卟啉用作有机半导体薄膜时，它的光电性质引起了科学家的极大关注［１～４］．特别引人注意的是卟啉的结构和电性可以利...     

含咪唑酮结构聚芳醚砜共聚物的制备与表征

通过共聚的方法在酚酞聚芳醚砜(PES-C)的主链上引入苯并咪唑酮和5,6-二甲基苯并咪唑酮结构,制备了一系列苯并咪唑酮和5,6-二甲基苯并咪唑酮结构含量不同的高玻璃化转变温度(T_g)聚芳醚砜共聚物。利用核磁共振谱(NMR)、傅里叶变换红外光谱仪(FTIR)、热重分析仪(TGA)等技术手段表征了三元共聚物的结构和性能。结果表明,聚芳醚砜共聚物为无定型结构。聚合物具有优异的热性能,并且均呈现出单一的T_g(T_g271℃);随着苯并咪唑酮和5,6-二甲基苯并咪唑酮的摩尔分数的增加,聚合物T_g呈现规律性升高,分别从270℃升高到340和344℃。两种共聚物均能够溶于极性非质子N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAc)、二甲基亚砜(DMSO)、N-甲基吡咯烷酮(NMP)及氯仿(CHCl_3)等溶剂中。具有很好的溶解加工性和成膜性,可以进行溶液加工制备韧性的薄膜。     

新型苯并二吡咯酮与苯并二噻吩衍生物的共聚及性能研究

以苯并二吡咯酮（BDP）类衍生物为电子受体单元,噻（硒）吩修饰的苯并二噻吩（BDT）类作为电子给体单元,通过钯催化Stille缩聚反应合成了3种新型的给体-受体（D-A）共聚物PBDP-BDT(T), PBDP-BDT(Se), PBDP-BDTT(T),并采用核磁共振、凝胶渗透色谱、紫外-可见分光光度计、循环伏安法,热重分析对3种聚合物的结构和性能进行了表征。结果表明：3种聚合物紫外可见吸收范围为250～1200 nm,其能量最低的吸收峰分别位于680 nm, 722nm, 744 nm;起始氧化电位分别为0.90 eV, 0.73 eV, 0.75 eV,由此估算出其电化学能隙分别为1.72eV,1.47 eV,1.40 eV,显示出较窄的能隙特征。此外,聚合物还具有较好的热稳定性。      

胆甾相液晶微胶囊制备与表征

为了实现液晶的分散和保护,开展了胆甾相液晶的包覆研究。通过扫描电镜和激光粒度仪等分析手段探究了液晶微胶囊的形貌及粒径分布范围,利用傅里叶变换红外光谱确认了液晶微胶囊的组成,通过偏光显微镜研究液晶微胶囊在加热前后的光学特性。当原料投入比为5∶4、剪切速率为7000r/min、剪切时间为10min、乳化剂HSMA用量为5mL时,所制备胆甾相液晶微胶囊具有单分散性好、显色性优、耐高温能力强等优点,可以制成热致变色液晶膜。     

含有联苯和肉桂酸酯基团的侧链液晶共聚物的合成与表征

合成了两种含有联苯刚性基元的甲基丙烯酸酯单体M1和M2,其中M1为含有可光交联的肉桂酸酯端基的单体.通过溶液自由基聚合,得到一系列含不同比例M1和M2单体单元的聚丙烯酸酯类侧链液晶共聚物.采用1H-NMR、FT-IR等方法对单体和聚合物的结构进行了详细表征.用示差扫描量热法、偏光显微镜以及广角和小角X-射线衍射对单体和聚合物的液晶性进行了研究.结果表明,末端为肉桂酸酯基团的单体M1无液晶性,其均聚物P1有微弱的液晶性,而端基为正丁基的单体M2及其均聚物P9则表现出近晶相液晶行为.共聚物P2~P5均为向列型液晶,P6~P9则为近晶型液晶.随在聚合物中M2单体含量的增加,共聚物的玻璃化转变温度、熔点及清亮点温度均呈现增加趋势.     

Synthesis and Characterization of Water-Soluble Starch-Acrylamide Graft Copolymers

A series of water-soluble starch-polyacrylamide graft copolymers (ST-g-PAM) were prepared by Ce⁴⁺-initiated graft copolym-erizations of acrylamide (AM) onto starch (ST) dissolved in water at 30°C. The copolymers were found to contain 3-33% (wt) of ST. The structure of the copolymers, including the average number of grafts per chain and the efficiency of the initiator, was determined by acid-catalyzed degradation of the ST followed by size exclusion chromatography (SEC) analysis of the PAM chains and was found to be consistent with the presence or absence of free ST in the polymerization product prior to hydrolysis. The average number of grafts per starch molecule was found to be three or less, depending on conditions. The initiator efficiency (6–43%) was shown to decrease with increasing [Ce⁴⁺] and decreasing [AM], and this was found to be qualitatively in accord with the proposed mechanism of initiation and polymerization. The low efficiency was shown to be due, in part, to the low rate of reaction of Ce⁴⁺ compared to the polymerization rate. The copolymers were characterized by ultra-centrifugation, SEC, and viscometry.     

液晶性芳香酰胺化合物的合成

合成了一系列炖粹以酰胺基为中心桥键的刚性芳香酰胺小分子化合物，并对其作了表征，发现其中有些化合物具有液晶性。酰胺键之间能形成很强的分子间氢键，使芳香酰胺小分子化合物的熔点很高，难于形成液成液晶态。研究发现，如果在这类化合物的中心苯环上引入合适的取代基以减弱分子间氢键，同时引入合适的末端基时，则可使芳香酰胺化合物生成液晶相的能力增强。     

新型侧链液晶M5MPP/MMEANB高聚物的合成与表征

以4,4'-二羟基联苯、4-硝基苯胺、二溴己烷、甲基丙烯酸、氯代乙醇为原料合成了单体甲基丙烯酸[5(4'-甲氧基联苯4氧基)戊基]酯(M5MPP)、4-硝基偶氮苯基甲基-2-甲基丙烯酸酯基乙胺(MMEANB),并完成了单体的聚合和共聚,得到了含有非线性光学活性基团(NLO)的侧链液晶高分子,对其结构进行了表征.结果表明,均聚物PM5MPP及共聚物(M5MPP/MMEANB)属双向液晶高分子;PMMEANB属于非晶性高分子.证实了分子间吸电子与给电子基团相互作用有利于提高液晶高分子热稳定性,共聚物(M5MPP/MMEANB)具有较宽的液晶相温度范围.     

In situ Nucleation-Growth Strategy for Controllable Heterogeneous Supramolecular Polymerization of Liquid Crystalline Block Copolymers and Their Hierarchical Assembly

The self-assembly morphologies of subunits are largely governed by thermodynamics, which plays a less important role in dimensional control. Particularly for one-dimensional assemblies from block copolymers (BCPs), the negligible energy difference between short and long ones imposes great challenges in length control. Herein, we report that by incorporating additional polymers to induce in situ nucleation and trigger the subsequent growth, controllable supramolecular polymerization driven by mesogenic ordering effect could be realized from liquid crystalline BCPs. The length of the resultant fibrillar supramolecular polymers (SP) is controlled by tuning the ratio between nucleating and growing components. Depending on the choice of BCPs, the SPs can be homopolymer-like, heterogeneous triblock, and even pentablock copolymer-like. More interestingly, with insoluble BCP as a nucleating component, amphiphilic SPs are fabricated, which can undergo spontaneous hierarchical assembly.