超支化聚酯/聚醚聚氨酯互穿网络的力学性能研究

为了改善聚醚聚氨酯的力学性能,采用端硬脂酸酯基超支化聚酯和端乙酸酯基超支化聚酯与环氧乙烷四氢呋喃共聚醚型聚氨酯(PET-PU)形成互穿网络聚合物。结果表明,前者出现明显的相分离,而后者最大拉伸强度和最大延伸率比PET-PU提高了1.33倍和2.74倍。采用基团贡献法讨论了超支化聚合物与PET-PU的混容性。     

Synthesis and characterization of interpenetrating polymer networks with hyperbranched polymers through thermal-UV dual curing

The aim of this study was to investigate the possibility of using acrylated hyperbranched polyesters (HBP) as UV curable component in dual curing automotive applications. Dual curing is one of possible ways to obtain fast curing, scratch resistant coatings for use in OEM and car refinish applications. Dual curing systems, upon hardening, can give interpenetrating networks (IPNs).     

Morphology and thermal and dielectric behavior of cycloaliphatic epoxy/trimethacrylate interpenetrating polymer networks for vacuum‐pressure‐impregnation electrical insulation

Vacuum pressure impregnation has been known as the most advanced impregnation technology that has ever been developed for large and medium high‐voltage electric machines and apparatuses. We developed one new type of vacuum‐pressure‐impregnation resin with excellent properties by means of a novel approach based on in situ sequential interpenetrating polymer networks resulting from the curing of trimethacrylate monomer [trimethylol‐1,1,1‐propane trimethacrylate (TMPTMA)] and cycloaliphatic epoxy resin (CER). In this study, the influence of the concentrations of the components and their microstructures on their thermal and dielectric behaviors were investigated for the cured CER/TMPTMA systems via atomic force microscopy, dynamic mechanical analysis, thermogravimetric analysis, and dielectric analysis. The investigation results show that the addition of TMPTMA to the CER–anhydride system resulted in the formation of a uniform and compact microstructure in the cured epoxy system. This led the cured CER/TMPTMA systems to show much higher moduli in comparison with the pure CER–anhydride system. The thermogravimetric analysis results show that there existed a decreasing tendency in the maximum thermal decomposition rates of the cured CER/TMPTMA systems, which implies that the thermal stability properties improved to some extent. The dielectric analysis results show that the cured CER/TMPTMA systems displayed quite different dielectric behaviors in the wide frequency range 0.01 Hz–1 MHz and in the wide temperature range 27–250°C compared with the cured CER–anhydride system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

A two‐step method for the synthesis of a hydrophilic PDMS interpenetrating polymer network

A hydrophilic PDMS (polydimethylsiloxane) surface was formed by the synthesis of an interpenetrating polymer network (IPN) in a two‐step process. In the first step, PDMS was loaded with crosslinker and initiator using a solvent that swells the PDMS. In the second step, the PDMS sample was submerged into a solution containing the hydrophilic monomer followed by a UV‐polymerization step. The choice of solvent in the second step is critical to obtain a hydrophilic surface. It can be concluded that the solubility parameter of the solvent should be above a threshold value. Hence, in the second step only sufficiently polar solvents will result in hydrophilic PDMS‐IPNs. These principles are illustrated by using N‐vinyl‐2‐pyrrolidone as the hydrophilic monomer forming PVP/PDMS‐IPNs. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

聚合物合金相容性研究进展

在聚合物合金的制备过程中,主要是通过加入增容剂来改善聚合物合金相容性。早期普遍采用非反应型增容剂,而目前主要是以反应型增容剂为主。改变链结构、利用低分子量化合物、互穿网络技术等也是改善聚合物合金的常用办法。此外,无机纳米粒子对聚合物共混体系相容性也会产生一定影响。     

Chitosan—A versatile semi-synthetic polymer in biomedical applications

This review outlines the new developments on chitosan-based bioapplications. Over the last decade, functional biomaterials research has developed new drug delivery systems and improved scaffolds for regenerative medicine that is currently one of the most rapidly growing fields in the life sciences. The aim is to restore or replace damaged body parts or lost organs by transplanting supportive scaffolds with appropriate cells that in combination with biomolecules generate new tissue. This is a highly interdisciplinary field that encompasses polymer synthesis and modification, cell culturing, gene therapy, stem cell research, therapeutic cloning and tissue engineering. In this regard, chitosan, as a biopolymer derived macromolecular compound, has a major involvement. Chitosan is a polyelectrolyte with reactive functional groups, gel-forming capability, high adsorption capacity and biodegradability. In addition, it is innately biocompatible and non-toxic to living tissues as well as having antibacterial, antifungal and antitumor activity. These features highlight the suitability and extensive applications that chitosan has in medicine. Micro/nanoparticles and hydrogels are widely used in the design of chitosan-based therapeuticsystems. The chemical structure and relevant biological properties of chitosan for regenerative medicine have been summarized as well as the methods for the preparation of controlled drug release devices and their applications.     

聚氨酯/丁腈橡胶互穿网络型吸水膨胀橡胶的性能研究

将丁腈橡胶与高吸水树脂（SAP）、增强剂、聚乙二醇（PEG）和二苯基甲烷二异氰酸酯（MDI）等在开炼机上充分混合,在高温下PEG和MDI发生逐步聚合反应,与丁腈橡胶原位互穿,得到互穿网络型吸水膨胀橡胶（IPN-SWR）。研究了聚氨酯（PU）用量对互穿网络型吸水膨胀橡胶的机械性能和吸水膨胀性能的影响。结果表明,随着PU含量升高,橡胶的机械性能下降,吸水速率加快,最大质量膨胀倍率（ΔWe）先升高后降低,质量损失率降低,循环测试次数越高,膨胀性能下降,质量损失率变小。同种材料的胶筒制品的膨胀速率远远小于试片的膨胀速率。     

Synthesis and Characterization of Poly(acrylic acid)/Poly(vinyl alcohol)-xanthan Gum Interpenetrating Network (IPN) Superabsorbent Polymeric Composites

Initially interpenetrating network (IPN) hydrogel was prepared by dispersing xanthan gum (XG) into poly(vinyl alcohol) (PVA) backbone in an aqueous medium. Polyacrylic acid (PAA)/Poly (vinyl alcohol)-Xanthan gum IPN superabsorbent composite were fabricated well by dispersing the prepared IPN hydrogel in acrylic acid and polymerized in a complete aqueous environment through chemical cross-linking method. These superabsorbent polymeric composites were analytically evaluated by scanning electron microscopy (SEM), Fourier Transform Infrared Spectra (FTIR), Thermal analysis (DSC) and X-ray diffraction (XRD) analysis. Simultaneously water absorbency, swelling kinetics and water retention abilities of this prepared superabsorbent polymeric composites were also investigated systematically.     

Performance Analysis of a Disk-Type Viscous Pump with Radial Pumping Grooves

A new disk-type viscous pump, with radial pumping grooves on its stator, is described and its performance analyzed. Its flow rate and discharge pressure relationship is found to be linear. Two proposed viscous pumps of this new design having slightly different dimensions are considered and compared to the recently reported design utilizing multilobes. Analyses on these two proposed pumps show that this new design exhibits higher flow rate characteristics than the recent multilobe design for the same pump size and rotor–stator clearances.     

硅烷膜对有机硅涂料性能的影响

    采用红外反射吸收光谱、热失重分析、电化学交流阻抗谱等方法研究了巯丙基三乙氧基硅烷膜对有机硅涂层的附着力、耐热性以及耐蚀性的影响.结果表明,MPTES硅烷膜与金属基体发生了化学反应,界面互穿网络的形成增强了涂层与基体的结合力,提高了涂层的热分解温度,改善了涂层耐蚀性.