Carbon nanotubes-graft-polyglycerol: Biocompatible hybrid materials for nanomedicine

New biocompatible and water soluble hybrid materials containing multi-wall carbon nanotubes (MWCNTs) as core and hyperbranched polyglycerol (PG) as shell were synthesized successfully. In this work, pristine MWCNTs were opened and functionalized through treatment with acid and polyglycerol was covalently grafted onto their surface by the “grafting from” approach based on in-situ ring-opening polymerization of glycidol. Some short-term In vitro cytotoxicity and hemocompatibility tests were conducted on HT1080 cell line (human Fibrosarcoma), because this epithelial cell line can be one of the first route of entry of the exogenous materials to the vascular system and therefore subsequent interactions with the whole body, in order to investigate their potential application in nanomedicine and to understand the limitation and capability of these material as nanoexcipients in biological systems.     

Automated Solvent-Free Polymerization of Hyperbranched Polyglycerol with Tailored Molecular Weight by Online Torque Detection

Polymerization processes with high reproducibility, traceability, and nontoxic compounds are required for biomedical applications. Here an automated solvent-free polymerization of hyperbranched polyglycerol has been established on a multiple-hundred gram scale. Performed is an anionic ring-opening multibranching (ROMB) polymerization with slow addition of glycidol. The solvent-free approach avoids commonly used organic solvents during the polymerization and work-up. Due to the automation of the polymerization process a high reproducibility and traceability is accomplished. The used reactor is equipped with an anchor stirrer and stirrer control, which measures the applied torque. A linear correlation of the increasing torque and the degree of polymerization is observed, which can be used to monitor the molecular weight in situ during the polymerization.     

Synthesis of fluorescent ABA triblock copolymer via click reaction

A hyperbranched–linear–hyperbranched (ABA) triblock copolymer containing poly(ethylene glycol) (PEG) as linear block and polyglycerol (hbPG) as hyperbranched blocks has been synthesized through a copper‐catalysed click reaction. In order to synthesize the hyperbranched block, propargyl alcohol‐initiated ring‐opening multibranching polymerization of glycidol was used to prepare hbPG with the propargyl segment in the focal point (CH?C? hbPG). Separately, PEG was functionalized at both ends using cyanuric chloride, and then the chloride groups of cyanuric chloride were substituted by azide groups. Finally, the azide‐functionalized PEG was conjugated to CH?C? hbPG via a click reaction. Substitution of the chlorine atoms of cyanuric chloride under different conditions together with click chemistry allows the synthesis of a variety of polymeric architectures. In the last step, fluorescein was attached to the block copolymer as a fluorescent probe in order to study the cell internalization of this copolymer. This type of triblock copolymer is a promising future nanomaterial for simultaneous drug delivery and cell imaging. © 2016 Society of Chemical Industry     

聚甘油脂肪酸酯的表面性能研究

利用甘油聚合得到聚甘油,与一系列高级脂肪酸酯化合成聚甘油脂肪酸酯。分别测试和比较了合成产品的HLB值、表面张力、乳化性能、泡沫性能及钙皂分散性能,并讨论了合成影响因素,为研究聚甘油酯类产品应用性能提供了理论基础。     

Perfluoroalkyl-Functionalized Hyperbranched Polyglycerol as Pore Forming Agents and Supramolecular Hosts in Polymer Microspheres

Perfluoroalkyl-functionalized, hyperbranched polyglycerols that produce stable microbubbles are integrated into a microfluidic emulsion to create porous microspheres. In a previously-presented work a dendrimer with a perfluorinated shell was used. By replacing this dendrimer core with a hyperbranched core and evaluating different core sizes and degrees of fluorinated shell functionalization, we optimized the process to a more convenient synthesis and higher porosities. The new hyperbranched polyglycerol porogens produced more pores and can be used to prepare microspheres with porosity up to 12% (v/v). The presented preparation forms pores with a perfluoroalkyl-functionalized surface that enables the resulting microspheres to act as supramolecular host systems. The microspheres can incorporate gases into the pores and actives in the polymer matrix, while the perfluoroalkylated pore surface can be used to immobilize perfluoro-tagged molecules onto the pores by fluorous-fluorous interaction.     

Synthesis and Surface-Active Behavior of New Fluorinated Hyperbranched Polymer

In this article, a series of novel hyperbranched fluorinated polymer with polyglycerol (PG) as the hydrophilic core and poly(2,2,2‐trifluoroethyl methacrylate) (PTFEMA) as solvophobic arms were synthesized. When the atom transfer radical polymerization was carried out using N,N‐dimethylformamide (DMF) as the solvent, [M]/[I] ratio of 200, and [CuBr]/[N_Br] ratio of 0.1 at 30 °C, controlled polymerization was achieved. The surface active properties of the polymer at the dimethyl sulfoxide (DMSO)/air and chloroform/water interface were studied by pendant drop measurements. The results showed that the copolymers could reduce surface tension (interfacial tension) in a manner analogous to the conventional surfactant in aqueous solutions. Thermodynamic analysis suggested that the solvophobic PTFEMA chains play an important role in determining the driving force of the aggregate formation in DMSO.     

Fabrication and microstructural characterization of the diamond@amorphous carbon nanocomposite core/shell structure via in-situ polymerization

A novel diamond@carbon core/shell structure, constituting diamond as a hard core and carbon as a soft shell, was synthesized from resole resin and nanodiamond as the starting materials via in-situ polymerization and subsequently high-temperature carbonization. The diamond@carbon nanocomposite was characterized using field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and Fourier transform infrared spectroscopy (FT-IR). The results indicated that the shell material are comprised of amorphous carbon. The thickness of carbon shell was controlled from 502.5 nm to 27 nm by adjusting the concentration of the nanodiamond. As confirmed by TEM, FT-IR and XPS, the diamond@carbon nanocomposite revealed a stable structure, due to the formation of the chemical bonding between diamond and carbon shell after calcination process. Overall, the diamond@carbon nanocomposite abrasives could lead to a reducted surface roughness and damage of SiC wafer comparing with the nanodiamond abrasives, due to the spring-like effect coming from the elastic component of the amorphous carbon shell. Moreover, the as-prepared nanoparticles exhibited better dispersion stability than the pure diamond in the pH range from 8 to 11.     

Complex aggregates formed with a hyperbranched polyglycerol derivative for drug delivery

An amphiphilic hyperbranched polyglycerol derivative (HPG‐C18) was synthesized by the anionic ring‐opening copolymerization with glycidol and 1,2‐epoxyloctadecane as the monomers. This hyperbranched polymer formed large complex aggregates as confirmed by dynamic light scattering and transmission electron microscopy tests. Because of its amphiphilic properties, HPG‐C18 was explored to load hydrophobic docetaxel, a clinical antitumor drug, and deliver it into breast cancer cell line (MCF‐7) cells. To investigate the application of the aggregates in drug delivery, blood compatibility was studied by hemolysis analysis, red blood cell observation, and thromboelastography assay. These results indicate that HPG‐C18 inhibited MCF‐7 proliferation effectively with good blood compatibility, and this suggested a potential application in tumor therapy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42895.     

Synthesis of amphiphilic hyperbranched polyglycerol polymers and their application as template for size control of gold nanoparticles

Amphiphilic thioether‐containing core‐shell polymers were synthesized by two‐step reaction of hyperbranched polyglycerol (PG): first the hydroxyls of PG were O‐alkylated with 1‐bromo‐3‐chloropropane by improved Williamson reaction, and 31.6% of the hydroxyls were transformed to allyl groups and 22.4% of hydroxyls to 3‐chloropropyl; then the residual 3‐chloropropyl groups were efficiently S‐alkylated with 1‐dodecanethiol. Thus the amphiphilic polymers composed of hydrophobic thioether‐containing shell and hydrophilic PG core were formed and could be used as template for the synthesis of zero‐valent gold nanoparticles by the coordination interaction between gold species and thioether. The resulting colloids were stable and the size of the encapsulated gold nanoparticles could be adjusted by changing the molecular weight/size of the PG core of the amphiphilic derivatives. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 509–514, 2006     

Hyperbranched polyglycerol/poly(acrylic acid) hydrogel for the efficient removal of methyl violet from aqueous solutions

Hydrogels were synthesized from hyperbranched polyglycerol (HPG) and acrylic acid through free‐radical polymerization with HPG as the crosslinker. The HPG/poly(acrylic acid) (PAA) hydrogel could absorb cationic dyes in aqueous solutions because of the existence of a porous structure and the large numbers of hydroxyl and carboxylic groups. With methyl violet chosen as a model compound, the HPG/PAA hydrogel reached a maximum adsorption of 394.12 mg/g at a feed concentration of 1 g/L. The highest removal ratio of 98.33% was observed at a feed concentration of 50 mg/L. The effects of the pH, contact time, and feed concentration on the dye adsorption were investigated. The dye adsorption data fit well with the pseudo‐second‐order and Langmuir models. We believe that the HPG/PAA hydrogels could perform well in appropriate applications in the removal of cationic dyes from aqueous solutions because of their high adsorption capacity and environmental friendliness. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42951.     

Preparation and characterization of stable dispersions of carbon black and nanodiamond in culture medium for in vitro toxicity assessment

Stable dispersions of carbon black and nanodiamond in culture medium were prepared by adding a pre-mixed dispersion of commercial carbon black or nanodiamond in aqueous bovine serum albumin (BSA) solution to culture medium. Dynamic light scattering revealed that carbon black and nanodiamond dispersions prepared in both NaCl solution and culture medium were highly stable. From DLVO theory and the results of zeta potential measurements, the theoretical effect of the electrostatic interactions between adsorbed BSA molecules was found to be minimal. The asymmetric flow field-flow fractionation measurements revealed that 0.05 or 0.56 mg/mL of BSA molecules were adsorbed on 0.11 or 1.09 mg/mL of carbon black, respectively, indicating 1:2 complexation of BSA with the colloidal particles. In the case of nanodiamond, 0.06 or 0.60 mg/mL of BSA molecules were adsorbed on 0.10 or 1.05 mg/mL of nanodiamond, respectively, indicating 1:2 complexation of BSA, which is the same ratio as in the case of carbon black. The adsorbed BSA molecules served as an effective stabilizing agent for the carbon black and nanodiamond, ensuring dispersion stability for at least 1 week. The preparation of the dispersions can be easily carried out by other researchers for toxicity studies.     

水相介质中纳米TiO_2粒子软团聚体的解团聚

纳米TiO_2等无机粒子在水相介质中极易发生团聚,进而会严重影响其功效的充分发挥.本文考察了TiO_2水分散液体系中TiO_2粒子的团聚形式,比较了几种常规分散技术以及表面锚固改性技术对这些团聚体的解团聚效果.结果发现:大部分TiO_2粒子在水相介质中以软团聚体形式存在,高速剪切和添加分散剂对这些软团聚体的解团聚作用有限,超声分散可产生暂时性的解团聚效应,但随着超声场的去除,被分散的TiO_2粒子又会再次逐渐聚集.TiO_2粒子表面的聚合物原位锚固改性可改变其表面性质,因而对软团聚体具有更为高效稳定的解团聚作用,从而可明显提高复合粒子中的TiO_2粒子在水相介质和目标织物表面的分散性和分散稳定性.     

超支化环氧树脂的研究进展及应用前景

综述了各类超支化环氧树脂的合成工艺,主要包括聚酯型、聚醚型、聚酯聚醚型和聚烷烃超支化环氧树脂.超支化环氧树脂的合成工艺主要有缩水甘油直接法、环氧氯丙烷间接法、原子基团转移聚合法、双键加成法.对每种超支化环氧树脂的合成工艺、产品特征进行分析.提出了超支化环氧树脂在热固性材料、胶粘剂和作为无溶剂树脂等领域的应用前景.     

Hyperbranched polyglycerols,obtained from environmentally benign monomer,as reactive clays inhibitors for water‐based drilling fluids

To prevent the degradation of the borehole and also the disintegration and dispersion of drilled cuttings, different shale stabilizing additives are used in water‐based drilling fluids (WBFs). Glycols, poly(ethylene glycol), glycerols, and polyglycerol derivatives, also called polyols, have been used to inhibit shales containing reactive clays in WBF. These additives are normally used in conjunction with KCl to reduce clay swelling and dispersion of drilled cuttings. Highly branched polymers have become an important field in current polymer science. Such materials typically exhibit compact, globular structures in combination with an exceptionally high number of sites with functional groups. They have unique properties that differ significantly from their linear counterparts, and the hyperbranched polyglycerol (hPG) is an important hyperbranched polymer that can be produced from an environmentally benign monomer, the glycerol carbonate. In this article, the clay inhibitive properties of hPG were evaluated by different test methods including bentonite inhibition test, cuttings recovery, and X‐ray diffraction measurements. The results show that the hPG has a great potential to be used as an environmental friendly inhibitor additive in WBFs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40384.     

Superparamagnetic latex synthesized by a new route of emulsifier‐free emulsion polymerization

The aim of this study was to design polymeric nanospheres containing magnetic nanoparticle which could display superparamagnetic behavior and thus find application in allied fields. First magnetite nanoparticles were synthesized with coprecipitation method and then their stable acidic dispersion was prepared without surfactant and dropped into the polymerization system during a certain time interval after the polymerization started. The effects of time at which the magnetic sol was added into polymerization system on latex size and stability, average molecular weight of polymer were examined in the case of two different monomer concentrations. Extensive characterization by transmission electron microscopy, dynamic light scattering, thermal gravimetric analysis and magnetic measurements shows that when the magnetic sol was dropped during earlier time of polymerization at stage 1, the latex size, average molecular weight of polymer, thermal stability of polymeric composite, and saturation magnetization reduced, whereas polydispersity of size and molecular weight increased because of the reaction between persulfate and naked surface of magnetite at the aqueous phase. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

超支化聚缩水甘油甲基丙烯酸酯作为O/W型乳状液的破乳剂

以超支化聚缩水甘油（HPG）和甲基丙烯酸缩水甘油酯（GMA）进行酯交换反应,得到一系列超支化聚缩水甘油甲基丙烯酸酯（HPG-MA）破乳剂,考察了添加量、破乳温度、沉降时间及相对分子质量对破乳性能的影响,并探究动态界面张力和破乳过程中油滴的破裂速率常数的变化,分析其破乳机理。结果表明,在60℃、沉降时间为40min、破乳剂的添加量为2000mg/L时,其脱油率达到90%。与商用破乳剂相比,超支化聚缩水甘油甲基丙烯酸酯因具有独特的超支化多位点结构,用作破乳剂时界面活性高、沉降时间短。     

Thixotropic interparticle interaction between silica and nonionic polymer particles prepared by static dispersion polymerization

Static dispersion polymerization of styrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate and benzyl methacrylate, initiated by a lipophilic initiator in an aqueous dispersion with unmodified silica particles was investigated. Polymerization of styrene gave a mixed dispersion of silica and monodisperse polystyrene (PS) particles, which was extremely stable compared with the aqueous dispersion of silica particles. The enhanced dispersion stability is due to a thixotropic effect based on weak attractive interparticle interactions between silica and PS particles in aqueous dispersion. An aggregate in which silica particles are surrounded by the smaller PS particles is formed and inhibits flocculation of silica particles, thus giving enhanced dispersion stability. The results of similar static polymerization reactions with methacrylate analogs indicate that hydrogen bonds between benzene ring and hydroxy groups on the silica surface, and not electrostatic interaction derived from initiator residues, are the origin of weak interaction for thixotropic aggregation.     

Different dispersion polymerization strategies influence the quality of fluorescent poly (St‐co‐GMA) microspheres

The polymerization strategy plays a vital role in the preparation of functional microspheres. In this work, fluorescent poly (styrene‐co‐glycidyl methacrylate) (PSt‐GMA) microspheres were synthesized via one‐stage and two‐stage dispersion polymerization with 4‐Bis(5‐phenyl‐1,3‐oxazol‐2‐yl)benzene (POPOP) as fluorescence agent. SEM and DLS were adopted to characterize the properties of prepared microspheres. The UV‐vis and fluorescence spectroscopy were used to analyze the mechanisms of two‐stage dispersion polymerization. The experimental results showed that the size distribution and fluorescence intensity of prepared microspheres could be improved by two‐stage dispersion polymerization compared to one‐stage dispersion polymerization. In addition, according to UV‐vis, the interactions between POPOP and Poly (N‐vinyl pyrrolidone) (PVP) as well as POPOP and Glycidyl methacrylate (GMA) could affect the particle size and its distribution. UV‐vis and fluorescence spectra implied that the POPOP existed outside of the particle's core via two‐stage strategy. The monomer conversion of styrene was similar at the beginning of reaction; however, the monomer conversion of styrene by two‐stage strategy was higher than that of by one‐stage strategy. In a word, two‐stage dispersion polymerization could prepare fluorescent microspheres with the monodispersion micrometer‐size and high quality. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41927.     

Preparation and Characterization of Poly L-Lactide/Triclosan Nanoparticles for Specific Antibacterial and Medical Applications

This work aims at preparation of poly-L-lactide (PLLA)/triclosan nanoparticles as antibacterial products used in some specific medical applications. PLLA was synthesized by the reaction extrusion via the ring opening polymerization of L-lactide using a continuous single-stage process, which is a fast and easy method. The PLLA triclosan nanoparticles were prepared by the emulsification–diffusion process with few modifications. Chloroform was used for the surface reaction of triclosan without any chemical shifts. The resulting nanoparticles with various triclosan quantities were fully characterized. The release as well as its kinetics was studied using the UV-visible spectroscopy. All the results confirmed the high stability and process efficiency of molecular dispersion and attachment of triclosan to PLLA. The sample containing 30% triclosan showed the best form among the others with the highest encapsulation efficiency. The synthesized nanoparticles with the controlled antibacterial activity could be considered as an appropriate alternative for application as antibacterial agent in the implantable surgical products as well as the drug delivery and wound-dressing applications.     

Inhibition of influenza virus activity by multivalent glycoarchitectures with matched sizes

We describe the synthesis of a series of sialic acid‐conjugated, polyglycerol‐based nanoparticles with diameters in the range of 1–100 nm. Particle sizes were varied along with the degree of functionalization to match the corresponding virus size and receptor multiplicity in order to achieve maximum efficiency. To build up these architectures, we used biocompatible, hyperbranched polyglycerols as scaffolds and recently developed polyglycerol‐based nanogels, the sizes of which can be varied between 2–4 nm and 40–100 nm, respectively. We demonstrate here that such multivalent nanoparticles inhibit influenza A virus cell binding and fusion and consequently infectivity. The potential of multivalency is evident from larger particles showing very efficient inhibition of viral infection up to 80 %. Indeed, both the size of the nanoparticle and the amount of ligand density are important determinants of inhibition efficiency. The inhibitory activity of the tested polymeric nanoparticles drastically increased with size. Particles with similar dimensions to the virus (50–100 nm) are exceedingly effective. We also observed a saturation point in degree of surface functionalization (i.e. ligand density), above which inhibition was not significantly improved. Our study emphasizes the importance of matching particle sizes and ligand densities to mimic biological surfaces and improve interactions; this is a vital concept underlying multivalent interactions.