两性电荷型毛细管电色谱整体柱的制备及性能研究

采用原位聚合方法制备了聚(甲基丙烯酸异丁酯-乙二醇二甲基丙烯酸酯-甲基丙烯酸-N-烯丙基二甲胺) 两性电荷型整体柱.考察了pH值对电渗流的影响.结果表明该整体固定相的电渗流可以通过改变流动相的pH值来进行调控.     

结晶PMMA/SAN共混体系的相容性和PMMA结晶行为的NMR研究

我们用固体NMR方法研究了SAN与结晶PMMA的相容性,并提出了可能的相容性机理;同时我们也研究了PMMA的结晶行为,发现它不同于SMA/PMMA中只存在少量结晶区的PMMA的行为.SAN/结晶PMMA是部分相容的体系,由于PMMA中的羰基与SAN中的苯基的相互吸引才导致共混物相容,且SAN只与无定形PMMA区相容,结晶区可用NMR方法检测到,这说明SAN/PMMA的相容性比SMA/PMMA差,主要原因是SAN与PMMA的相互作用弱于SMA与PMMA的相互作用.交替共聚利于相容.     

用13CNMR研究聚甲基丙烯酸锡酯的立构序列分布

本文测定了自由基型溶液聚合的聚甲基丙烯酸三甲基锡酯(PTMTM),聚甲基丙烯酸三乙基锡酯(PTETM)和聚甲基丙烯酸三丁基锡酯(PTBTM)的¹³C-NMR谱,对其C-2谱扩展分峰,计算立构序列,从定量数据表明,聚合物样品的空间立构富于或稍富于间规立构,随取代基的体积增大而趋于无规分布,作者认为受空间位阻效应和分子内或分子间形成配位键的影响。     

Eu3+掺杂的PMMA-络合物体系的发光特性

研究了聚甲基丙烯酸甲脂PMMA-Eu(DBM)3(phen)和PMMA-辛酸铕体系的发光特性。已有的结果表明，聚甲基丙烯酸甲脂PMMA—Eu(DBM)3(phen)体系具有较高的色纯度，Eu^3 的主发射峰几乎只有613nm(Eu^3 的^5D0→^7F2)被观测到，其发射强度比PMMA-辛酸盐体系的高一个量级，是潜在的高效稀土红光材料。     

超支化高分子桥联聚倍半硅氧烷复合物的NMR研究

以三羟甲基丙烷(TMP)为内核,二羟甲基丙酸(DMP)为支化单元用准一步法合成了重均分子量为12100的第四代端羟基脂肪族超支化聚酯(HBPE-G4),用3-异氰酸酯基丙基三乙氧基硅烷(TPIC)对它进行了端基改性,并以其为桥联剂,与聚倍半硅氧烷(PMSQ)复合制备出超支化高分子桥联聚倍半硅氧烷复合物．利用固体核磁共振(NMR),傅立叶红外(FI-IR),分子纳米粒度分析等方法表征了改性超支化高分子和复合物的结构和反应程度,并通过测量¹³C T₁,¹H T₂,¹H T_1ρ研究了体系中各组分的运动性能,以及超支化高分子与聚倍半硅氧烷之间的相容性．     

泵浦光偏振态的改变对SO/PMMA薄膜光致双折射的影响

在紫外光伴随下,用偏振态分别为s和p的HeNe激光器发出的632.8nm红光(均为10mW)交替激发螺恶嗪掺杂的聚甲基丙烯酸甲脂薄膜(SO/PMMA),用532nm的绿光(0.1mW)作为探测光记录光致双折射的动力学过程.实验发现透射信号被周期性调制,而且每次调制的最大值随时间逐渐减小并最终趋于稳定.指出了泵浦过程中的异构动态平衡与取向动态平衡并存的物理机制.     

PET与SAN/PAN复合膜界面的 FTIR-ATR研究

应用傅里叶衰减全反射红外光谱(FTIR-ATR)技术对聚对苯二甲酸乙二酯(PET)表面形成不同厚度的超薄苯乙烯-丙烯腈共聚物(SAN)和聚丙烯腈(PAN)的共混物膜及其SAN/PAN共混物膜的厚度、界面层PET亚甲基的构像变化等进行研究,结果表明PET表面共混物膜的厚度随共混物混合液中SAN含量的增加而增加,界面层成膜物质与基材的分子链段间发生了相互渗透和扩散,分子链的极性越相近,越容易成膜.对PET红外光谱吸收峰的A1340/A1410进行定量研究表明,在成膜过程中,PET分子链的亚甲基构像由反式向旁式转变,引起界面层PET的结晶度降低.FTIR-ATR是分析复合膜界面层结构信息的有效方法.     

POSS纳米复合物链运动的固体NMR研究

利用固体NMR技术、并结合TEM技术研究了POSS掺杂到不同聚合物体系后POSS复合物的链段运动及结构特点,其中聚合物包括聚甲基丙烯酸正丁酯（PBMA）和聚甲基丙烯酸甲酯（PMMA）. 实验结果表明：POSS能很好的分散在这2种聚合物中,形成纳米结构的复合物;其中POSS在PBMA中形成的复合物表现出较强的链段运动性,而在PMMA中则表现出较低的运动性;同时,2D HETCOR的结果表明这2种聚合物本身结构特点不同,POSS/PBMA复合物中聚合物部分与POSS部分间的距离较近,而在POSS/PMMA中则较远.     

塑料光纤拉曼散射的研究

给出了聚甲基丙烯酸甲脂(PMMA)塑料光纤(POF)的一级受激拉曼散射光谱,研究了一级斯托克斯光谱特点,测试了它的阈值,带宽,分析了拉曼光谱的形成机制,并将塑料光纤的拉曼光谱和石英光纤的拉曼光谱进行了比较。     

固溶态染料激光物质的研究

本文从不同改进的掺Rh6G聚甲基丙烯酸甲脂(PMMA)固溶态物质获得了有效的激光.热稳定性得到改善以及工作寿命得到延长.研究了它们的激射和光谱特性.     

Unusual Phase Separation Kinetics in Poly(Methyl Methacrylate)/Poly(Styrene-co-Acrylonitrile) (PMMA/SAN) Blends with PMMA of Different Molecular Weights

The influence of molecular weight of poly (methyl methacrylate) (PMMA) on the thermodynamics and dynamics of phase separation in PMMA/poly (styrene-co-acrylonitrile) (SAN) blends was investigated via optical microscopy, time-resolved small-angle light scattering (SALS), and dynamic rheological measurements. It was found that the cloud point temperature of the blends decreased with an increase in the molecular weight of the PMMA. The phase separation rates of PMMA 48K/SAN and PMMA 85K/SAN blends with the near-critical composition were almost the same at small quench depths due to the limited mobility of molecular chains at low temperatures. However, an unexpected phase separation dynamics was observed at larger quench depths. Not only the morphology evolution but also the apparent diffusion coefficient D_app calculated from SALS revealed that the phase separation rate was faster in the PMMA 85K/SAN blend than in the PMMA 48K/SAN blend. The possible reasons for this unusual rapid kinetics of phase separation observed in the higher molecular weight blend were discussed in terms of molecular mobility and viscoelasticity.     

Toughening Effect of Poly(ethene-co-1-butene)-graft-methyl Methacrylate and Acrylonitrile on Styrene-acrylonitrile Copolymer (SAN)

Poly(ethene-co-1-butene)-graft-methyl methacrylate-acrylonitrile (PEB-g-MAN), synthesized by suspension grafting copolymerization of methyl methacrylate and acrylonitrile onto PEB, was blended with styrene-acrylonitrile copolymer (SAN). The mechanical properties, phase structure, toughening mechanism, miscibility, and thermal stability of the SAN/PEB-g-MAN blends were studied using a pendulum impact tester, tension tester, scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TG). The results showed that PEB-g-MAN has an excellent toughening effect on SAN resin. The notched impact strength of the blends (containing 25 wt% PEB) was 63.3 kJ/m², which was nearly 60 times that of SAN resin. The brittle-ductile transition of SAN/PEB-g-MAN blends occurred when the weight percentage of PEB was between 17.5 and ～20 wt%. SAN and PEB-g-MAN were partially miscible. The toughening mechanism of the blends changed with the PEB content. When the PEB content was low, the toughening mechanism of the blends was branching and termination of cracks with slight cavitation. As the content of PEB increased, the toughing mechanism gradually changed from branching and termination of crack with slight cavitation to both branching and termination of crack and cavitation, to extensive cavitation, and finally to shear yielding accompanied by cavitation. The phase structure of the blends changed from a “sea-island’’ structure to a cocontinuous structure as the PEB content increased. ATG analysis showed that the thermal properties of the SAN resin in the blends were enhanced by adding the PEB-g-MAN.     

Glass Transition Behavior and Dynamic Fragility of PMMA-SAN Miscible Blend-Clay Nanocomposites

An investigation of the segmental dynamics and glass transition behavior of a miscible polymer blend composed of poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN) and its melt intercalated nanocomposite by dynamic mechanical analysis is presented. The principle goal was to address the effect of intercalation on local molecular structure and dynamics. The results showed that the intercalation of polymer chains in the galleries of organoclay (Cloisite 30B) led to a lower temperature dependence of the relaxation time (fragility) and activation energy of α-relaxation. Moreover, calculation of the distribution of the segmental dispersion showed a narrower dispersion in the glass transition region so that the Kohlrausch-Williams-Watts (KWW) distribution parameter (β_KWW) increased from 0.21 for neat PMMA to 0.34 for the 50/50 PMMA/SAN blend nanocomposite containing 3 wt% organoclay. Furthermore, the relaxation behavior of the blends showed a negative deviation from mixture law predictions based on the responses of the neat PMMA and SAN. These behaviors were attributed to the lack of specific interactions between the blend components (PMMA, SAN, and nanoclay layers) and the less cooperative behavior, i.e., less constraint for segmental relaxation, of the intercalated chains.     

Preferential surface segregation of homopolymer and copolymer blend films

Surface film properties of the homopolymers polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA) and the copolymer poly(methyl methacrylate)-co-poly(butyl methacrylate) (PMMA-co-PBMA) and their blends with PS have been examined by atomic force microscopy (AFM) and contact angle measurements. The total and the Lifshitz-van der Waals, acid and base components of the surface free energy together with the work of adhesion and its components, the cohesive energy density and the solubility parameters of the homopolymer, copolymer and blend films were determined. Films of about 3 μm were considered. The results are discussed in terms of surface migration mechanisms based on surface free energy and solubilities of the polymers in the solvent, toluene in this paper. AFM imaging and contact angles revealed surface enrichment at the air polymer interface of PBMA for both the PS/PBMA blend and the copolymer PMMA-co-PBMA, whereas the PS/PMMA and PS/PMMA-co-PBMA blend film surfaces show island-like phase-separated structure of typical size 27.4-86.5 nm in diameter and 6.9-15.6 nm in height for PS/PMMA, while for PS/ PMMA-co-PBMA film surface the typical size is 49.6-153.3 nm in diameter and 1.6-14.2 nm in height.     

Structure and Properties of In-Situ Reactive Compatibilized Polypropylene/Poly (Butyl Methacrylate-Co-Hydroxyethyl Methacrylate) Blend Fibers

In this study, in-situ compatibilized polymer blends of polypropylene (PP) and poly (butyl methacrylate-co-hydroxyethyl methacrylate) P(BMA-co-HEMA) were prepared in a corotating twin screw extruder through the reactive extrusion of mixtures of PP, P(BMA-co-HEMA), butyl methacrylate, and benzoyl peroxide. In the process of reactive extrusion, butyl methacrylate and benzoyl peroxide were used as the monomer and the initiator, respectively. Thereafter the polymer blend was made into fibers via melt spinning. The miscibility of PP and P(BMA-co-HEMA) in the blend fibers was investigated using field emission scanning electron microscopy. The absorption percentage of the blend fibers for organic liquids and their remaining ratios after the absorption tests were also determined and used to prove the generation of the third phase. The changes in the fiber morphology during organic liquid absorption were observed using polarized light microscopy. In addition, the effect of the miscibility on the crystal structure and melting characteristic of the blend fibers were analyzed using wide-angle X-ray diffractometry and differential scanning calorimetry. Finally, the thermal stability of the blend fibers that was associated with the miscibility of PP and P(BMA-co-HEMA) in the blend fibers were characterized by using thermogravimetry and dynamic thermomechanical analysis.     

衰减全反射傅里叶红外光谱在聚丙烯的表面改性的应用

应用衰减全反射傅里叶变换红外光谱法(ATR-FTIR)对聚丙烯共混薄膜的表面组成进行了测试.通过比尔定律的验证,确认1 103和1 733 cm-1可以分别用于含聚乙二醇和含羰基结构单元的改性剂共混体系的定量计算.利用ATR校正程序,以相应的特征峰峰面积比作为定量测定的基准,可以减少测试误差.通过工作曲线法,定量地分析了聚丙烯共混物薄膜表层中改性剂的含量.此外,利用变角全反射,通过改变入射光线的角度,可以测定不同深度的改性剂含量,剖析改性剂在PP共混薄膜的表层分布.     

Phase Structure of Polyamide 6/Poly(styrene-co-acrylonitrile) and Poly(styrene-b-(ethylene-co-butylene)-b-styrene) or Poly(maleated Styrene/Ethylene-co-Butylene/Styrene) Ternary Blends

Two sets of ternary blends; polyamide 6/poly(styrene-co-acrylonitrile)/poly(styrene-b-(ethylene-co-butylene)-b-styrene) (PA6/SAN/SEBS) and polyamide 6/poly(styrene-co-acrylonitrile)/poly(maleated styrene/ethylene-co-butylene/styrene) (PA6/SAN/SEBS-g-MA), based on 70 wt% of matrix and 30 wt% of the dispersed phases at various concentrations of the minor components, were prepared via melt blending. Morphologies of the ternary systems were studied using scanning electron microscopy (SEM) and compared with the predictions of the spreading coefficient (SC), minimum relative interfacial energy (RIE), and dynamic interfacial energy (DIE) phenomenological models. The effects of different reported surface tensions of the used polymers and different protocols of the core-shell ratio calculation on the prediction of the models were investigated. The core-shell structure for PA6/SAN/SEBS system and two separate minor phases for PA6/SAN/SEBS-g-MA were observed at all of the compositions. The results indicated that the most important parameter for the accurate prediction of the models is the accurate calculation of the interfacial tension of the used polymers, in both the static and dynamic conditions.     

Effect of Maleated Styrene/Ethylene-co-Butylene/Styrene on the Dispersed Particles Size and Mechanical Properties of Polyamide 6/Poly(styrene-co-acrylonitrile)/Poly(styrene-b-(ethylene-co-butylene)-b-styrene) Ternary Blends

In this study, the effect of several parameters, including composition, order of mixing, viscosity, and interfacial tension, on the phase structure and size of dispersed particles of polyamide 6 (PA6)/poly(styrene-co-acrylonitrile) SAN/poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) ternary blends was investigated. Moreover, the effect of addition of different ratios of reactive SEBS (maleic anhydride grafted-SEBS) and non-reactive SEBS at a fixed order of mixing and composition of 70/15/15 (PA6/SAN/SEBS + SEBS-g-MAH) on the mechanical properties of ternary blends was examined. Scanning electron microscopy (SEM) micrographs showed that among the studied parameters, interfacial tension and viscosity of dispersed phases were the leading factors in the formation of morphology and size of dispersed droplets. Mechanical results revealed that in contrast to the expectation, formation of core/shell structure of PA6/SAN/SEBS ternary blends did not result in a significant increasing of impact strength. The highest impact strength was achieved when a 50/50 weight ratio of SEBS/SEBS-g-MAH was used.     

The Mechanical Properties,Compatibility, and Thermal Stabilities of POE-Graft-Methyl Methacrylate and Acrylonitrile(POE-g-MAN)/ Styrene-Acrylonitrile Copolymer (SAN Resin) Blends

POE-graft-methyl methacrylate and acrylonitrile (POE-g-MAN) was prepared by graft copolymerization of methyl methacrylate (MMA) and acrylonitrile (AN) onto polyethylene-octene copolymers (POE) with suspension polymerization. POE-g-MAN/SAN resin blends (AOMS) were prepared by blending POE-g-MAN with styrene-acrylonitrile copolymer (SAN resin). The mechanical properties, compatibility, and thermal stabilities of AOMS were studied. The notched impact strength of the blends reached 54.0 kJ/m² when the AN/(MMA + AN) ratio (f_AN) of POE-g-MAN, benzoyl peroxide dosage, and POE content in AOMS were 15 wt%, 1.0 wt%, and 25 wt%, respectively. Transmission electron microscopy analysis showed that the highest toughness occurred when the size of POE-g-MAN particles and the surface-to-surface inter-particle distance were proper. Scanning electron microscopy analysis indicated that the AOMS fracture surface had plastic flow visible, which looked like a fibril morphology when the AN/(MMA + AN) ratio (f_AN) of POE-g-MAN was 15 wt%. The toughening mechanism of AOMS was shear yielding of the matrix, which endowed AOMS with remarkable toughness. Dynamic mechanical thermal analysis showed that the compatibility of the POE phase and SAN phase improved after graft copolymerization of MMA and AN onto POE. When the grafting chain polarity was appropriate, the miscibility between POE-g-MAN and SAN resin was the best. Thermogravimetry analysis showed that thermal stability of AOMS increased with increasing AN units in POE-g-MAN.