Plasma Enhanced Chemical Vapor Deposition of Poly(Cyclohexyl Methacrylate) as a Sacrificial Thin Film

Plasma Chemistry and Plasma Processing - In this study, thin films of poly(cyclohexyl methacrylate) (PCHMA) were deposited on silicon wafer using PECVD technique, in which the plasma power is...     

Fabrication of Poly(N-isopropylacrylamide) with Higher Deposition Rate and Easier Phase Transition by Initiated Plasma Enhanced Chemical Vapor Deposition

Plasma Chemistry and Plasma Processing - This study demonstrates the fabrication of thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) thin films using the initiated PECVD (i-PECVD) method, in...     

聚乙丙交酯电纺纳米纤维膜的等离子体改性及性能研究

采用等离子体表面处理的方法, 通过正交实验设计, 以纤维膜表面引入的氮含量为响应变量, 确定了NH3等离子体改性PLGA电纺纤维膜的最佳条件, 并在PLGA纤维膜表面成功地引入了功能性氨基基团. 研究结果表明, 改性后PLGA电纺纤维膜的力学性能有所降低, 但表面亲水性明显增强.     

Enhancement of Poly(vinyl chloride) Electrolyte Membrane by Its Exposure to an Atmospheric Dielectric Barrier Discharge Followed by Grafting with Polyacrylic Acid

Plasma Chemistry and Plasma Processing - A poly(vinyl chloride) (PVC) membrane was exposed to atmospheric-pressure dielectric barrier discharge and subsequently wet-chemically grafted with...     

Poly(Urethane)-Crosslinked Poly(HEMA) Hydrogels

Abstract

Hydrogels have been prepared from 2-hydroxyethyl methacrylate polymerized in the presence of isocyanate-terminated poly(ethylene glycol) (PEG) crosslinking agents. PEGS of molecular weights 200, 400, and 1000 were investigated. The crosslinked nature of the hydrogels was demonstrated by their insolubility in solvents which normally dissolve poly(HEMA). Hexamethylene diisocyanate (HDI) was mainly used as the isocyanate. The molecular weight of the PEG and the crosslinker content significantly influenced the equilibrium water sorption and mechanical properties of the saturated networks. It was observed that as the molecular weight of the PEG increased, the water sorption increased and the nominal modulus decreased. However, for higher levels of cross-linker, water sorption decreased and modulus increased at low molecular weight PEG; for PEG 1000, water absorption increased as crosslinker content increased. These results are explained by the competing effects of flexibility, crosslink density, and hydrophobicity contributed by the various constituents of the hydrogels.     

溶胶凝胶微流控酶反应器用于蛋白质肽谱分析的研究

The silica-based poly(dimethylsiloxane)(PDMS)microfluidic enzymatic reactor was reported along with itsanalytical features in coupling with MALDI TOF and ESI MS.Microfluidic chip was fabricated using PDMS cast-ing and O_2-plasma techniques,and used for the preparation of enzymatic reactor.Plasma oxidation for PDMS en-abled the channel wall of microfluidics to present a layer of silanol(SiOH)groups.These SiOH groups as anchorsonto the microchannel wall were linked covalently with the hydroxy groups of trypsin-encapsulated sol matrix.As aresult,the leakage of sol-gel matrix from the microchannel was effectively prevented.On-line protein analysis wasperformed with the microfluidic enzymatic reactor by attachment of stainless steel tubing electrode and replaceabletip.The success of trypsin encapsulation was investigated by capillary electrophoresis(CE)detection,and MALDITOF and ESI MS analysis.The lab-made device provided excellent extent of digestion even at the fast flow rate of7.0 μL/min with very short residence time of ca.2 s.In addition,the encapsulated trypsin exhibits increased stabil-ity even after continuous use.These features are the most requisite for high-throughput protein identification.     

聚癸二酸丙三醇酯对聚乳酸的改性

以丙三醇和癸二酸为单体通过熔融缩聚制得了聚癸二酸丙三醇酯(PGS),并用其预聚物(p-PGS)对聚L-丙交酯(PLLA)进行共混改性.利用傅立叶变换红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)及凝胶渗透色谱(GPC)法对P-PGS的结构进行表征,并研究了改性后材料的力学性能、两相相容性、亲水性能和细胞相容性.结果表明:P-PGS具有支化分子结构,分散系数约为2.7;共混改性后的材料弹性模量和拉伸强度均有所下降,而断裂伸长率从7 %显著提高到150%左右;PLLA/PGS属于海岛式共混结构,PGS以小于10μm的尺寸均匀分布在PLLA基体中;共混后材料的亲水性也有一定的提高,且几乎保持了PLLA原有的细胞相容性.     

Poly(dimethylsilylene-co-diphenylsilylene)

In this work several polyorganosilylenes were synthesized including homo-and copolymers containing SiMe₂ and SiPh₂ units. A Wurtz-type coupling reaction of the respective dichlorodiorganosilanes with sodium metal, varying the Ph₂SiCl₂/Me₂SiCl₂ ratio was the chosen synthesis method. Products with different characteristics for solubility, structure (cyclic or linear), composition, and molecular weight distribution could be obtained depending on the comonomer ratios employed. The polysilane derivatives were characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance (¹H-NMR), and gel permeation chromatography (GPC). Valuable information related to the comonomers' reactivities was obtained, such as molecular weight distribution, composition, and relationships between yields of soluble, insoluble, and cyclic materials of each polycondensation reaction. © 1992 John Wiley & Sons, Inc.     

Functionalization of Conductive Poly(thiophenes) and Poly(pyrroles)

New methods for functionalization of conductive poly(thiophenes) and poly(pyrroles) using fused aromatics or crown ethers are discussed.     

Poly (dodecacarborane-siloxanes)

The need for elastomeric polymers which will maintain their elastic properties at high temperatures has led to a wide interest in inorganic-based polymers [l]. The development of carborane-siloxane polymers in the early 1960s was a breakthrough in the search for a high-temperature elastomer. Incorporation of a carborane moiety into the siloxane backbone significantly enhanced the overall thermal stability [2].     

Dilute Solution Properties of Poly(methacrylonitrile-co-styrene) and Poly(acrylonitrile-co-styrene)

Poly(methacrylonitrile-co-styrene) (PMANS) and Poly(acrylo-nitrile- co- styrene) (PANS) having 1:1 composition were prepared with free-radical initiators. The polymers were fractionated into fractions having narrow molecular weight distribution. The dilute solution properties of the fractionated copolymers were studied by light scattering, viscometry, and osmometry in solvents (methyl ethyl ketone, dimethylformamide, and acetone), [n]-M _w and(r²)_w ^l/2?M _w relationships have been established. The validity of the various graphical methods for the determination of Flory′s constant, K _θ were observed.

From the values of the steric factors it was noticed that the copolymer coil of PANS is stiffer than that of PMANS.     

高分子量聚对二氧环己酮改进聚DL-乳酸柔韧性的研究

为了提高DL-聚乳酸(PDLLA)的柔韧性,将10～20wt%不同比例的由本课题组自主合成的高分子量聚对二氧环己酮(PPDO)加入到PDLLA基体中,对共混物的微观两相形态、力学性能、热学性能和表面性质、降解性能等物化性质进行了研究.实验结果表明,PPDO加入后,在PDLLA/PPDO共混物的柔韧性得到显著提高的同时,共混物表面亲水性相应提高,降解速率也随之加快.     

Micellization and Thermogelation of Poly(ether urethane)s Comprising Poly(ethylene glycol) and Poly(propylene glycol)

A series of multiblock poly(ether urethane)s comprising poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized. Their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 8 to 12 wt%. The composition and structural information of the copolymers were studied by GPC and ¹H NMR. The critical micellization concentration (CMC) and thermodynamic parameters for micelle formation were determined at different temperatures. The temperature response of the copolymer solutions were studied and found to be associated with the composition of the copolymers.     

Metallkomplexe von alkylsubstituierten Poly(vinylpyridin-l-oxiden) und von Poly(dimethylaminostyrol-N-oxiden)

Ohne Zusammenfassung     

Compatibility of Poly(vinyl chloride) with Polyalkyleneoxides. I. Poly(methylene oxide) and Poly(ethylene oxide)

The compatibility of poly(vinyl chloride) (PVC) with linear polyethers is examined over the entire composition range. This study examines blends with poly(methylene oxide) (PMO) and poly(ethylene oxide) (PEO) of medium (MMW) and high (HMW) molecular weight. The techniques used are dynamic mechanical analysis, DSC, and optical microscopy (phase contrast and polarizing). The results indicate that all polyethers show limited miscibility in the melt at high PVC contents. Proper analysis of the T_m data using the Kwei-Frisch and Hoffman-Weeks procedures allows the determination of the thermodynamic interaction parameter, which is found to be close to zero for all pairs of blends.     

Metallkomplexe von alkylsubstituierten Poly(vinylpyridin-l-oxiden) und von Poly(dimethylaminostyrol-N-oxiden)

Ohne Zusammenfassung     

Poly(thioester)s

Syntheses and properties of aliphatic and aromatic polythioesters (PTEs) were reviewed including polythiocarbonates and polythiourethanes. The content is subdivided into the following sections: PTEs of aliphatic α‐mercapto carboxylic acid, PTEs of ω‐mercapto carboxylic acids, PTEs derived from α,ω‐dimercapto alkanes, aromatic poly(thioester)s, aliphatic poly(thiocarbonate)s, aliphatic poly(thiourethane)s and aromatic polythiocarbonates. The synthetic strategies reviewed in this article include anionic and cationic ring‐opening polymerizations, polycondensations in bulk, polycondensations in solutions, interfacial polycondensations and in vitro enzymatic polycondensations.     

Poly(3,4-ethylenedioxyselenophene)

The first highly conductive polyselenophene, namely, poly(3,4-ethylenedioxyselenophene) (PEDOS), was synthesized by taking advantage of a novel method for efficiently contracting the selenophene ring. PEDOS shows a relatively low band gap (1.4 eV), very high stability in the oxidized state, and a well-defined spectroelectrochemistry.