Synthesis of Comblike Poly(methyl methacrylate) by Atom Transfer Radical Polymerization with Poly(ethyl 2-bromoacrylate) as Macroinitiator

Comblike poly(methyl methacrylate) was synthesized by atom transfer radical polymerization of methyl methacrylate with poly(ethyl 2-bromoacrylate) as a macroinitiator, which was prepared by conventional free radical polymerization of ethyl 2-bromoacrylate. The obtained comblike polymers were characterized by GPC and 1H NMR.

PREPARATION AND MECHANICAL PROPERTIES OF POLY(METHYL METHACRYLATE)/ URETHANE ACRYLATE COPOLYMERS

The urethane acrylate(UA) was made of poly(tetramethylenc oxide), 4,4’-diphenylmethane diisocyanate, and 2-hydroxyethyl methacrylate. A series of poly(methyl methacrylate) / urethane acrylate copolymers was prepared by using a redox initiating system. The copolymers had cross linked structures and two-phase morphologies as indicated by the results of the dynamic mechanical measurement and swelling test.

IONIC CONDUCTION IN BLENDS OF POLY(PYRIDINIUM ETHYL METHACRYLATE)AND COMB—LIKE COPOLYETHER

Poly(pyridinium ethyl methacrylate)was synthesized.The blends of polymeric solid anion conductor,P(PyEMAClO+4)/P(MEO_(16)—AM),were prepared. The temperature—dependence of both the conductivity and anionic mobility in the blends obey Arrhenius relationship,the transport of perchlorate anion being of thermal activation mechanism.Perchlorate anion is a free anion in the blends.

EFFECTS OF ω-ACRYLOYL POLY (ETHYLENE OXIDE) MACROMONOMER ON EMULSIFIER-FREE EMULSI0N COPOLYMERIZATION OF METHYL METHACRYLATE AND n-BUTYL ACRYLATE

Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.

CONFORMATIONAL CHARACTERISTICS OF POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID)

A full-relaxation optimization of molecule and the Dreiding force field are employed to obtain the geometry parameters and the conformational energy surfaces of meso or racemic dyad of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA). Three different carbonyl-bond orientations of side-groups resulted in the differences in depth of potential wells in their energetic contours for a meso or a racemic dyad. These discrepancies are interpreted as a result of various fine structures corresponding to grid search conformations as well as thereby different interactions. The analysis on the most stable conformations of PMAA confirmed that the ester groups are nearly perpendicular to the plane defined by the two adjacent skeletal bonds but may possibly change their relative orientations to meet the requirement of lower energy during the conformational state transition. For each polymer, two global energy maps of a meso and a racemic dyad were finally constructed from the superposition of energy data for the three kinds of side-group orientations by the Boltzmann factors. From an ensemble average, the proposed scheme with three rotational isomeric states (RIS) allowed us to access the experimentally unperturbed dimensions of PAA chain via the configurational statistical mechanics. Although the calculation was based on the short-range, local interactions, it was interested to note that the experimental characteristic ratios just fell within the range calculated for atactic chains.

OXIDATIVE ETHOXYCARBONYLATION OF ANILINE TO ETHYL PHENYLCARBAMATE CATALYZED BY SILICA- SUPPORTED POLY-γ-AMINOPROPYLSILOXANEMETAL COMPLEXES

Several silica-supported poly-γ-aminopropylsiloxane-monometal and bimetal complexes (Si-NH_2-M,M = Cu or Co ; Si-NH_2-Cu-M', M' =Co, Sn, Mn, Ni or Fe) have been prepared. Their catalytic properties for oxidative ethoxycarbonylation of aniline to ethyl phenylcarbamate have been investigated.The catalytic reaction was carried out under relatively mild conditions. The catalyst Si-NH_2-Cu-CO had high activity and selectivity, and the turn-over number (molar of aniline converted/molar of metal in Si-NH_2-Cu-CO added) could amount to 450 under the conditions: 150℃ , 4 MPa (CO/O_2 =3) and 40 hours.The results of XPS and IR indicated that the coordination bonds were formed between nitrogen and metals in Si-NH2-Cu, Si-NH_2-Co and Si-NH_2-Cu-Co, and the coordination pattern was not single. In the oxidative ethoxycarbonylation of aniline to ethyl phenylcarbamate, the catalytic property of Si-NH_2-Cu-CO bimetallic complex was better than Si-NH_2-Cu or Si-NH_2-Co monometatlic complex. This indicated that there as synergistic action between different metals in the bimetallic complex.

Delivery of docetaxel using pH-sensitive liposomes based on D-α-tocopheryl poly(2-ethyl-2-oxazoline) succinate:Comparison with PEGylated liposomes

This study aimed to investigate the ability of the novel materials D-α-tocopheryl poly(2-ethyl-2-oxazoline) succinate(TPOS) to construct pH-sensitive liposomes. TPOS was initially synthesized and characterized by TLC, FTIR, and ~1H-NMR. The buffering capacity of polyethylene glycol-distearoyl phosphatidylethanolamine(PEG-DSPE) and TPOS was determined by acid-base titration, and TPOS displayed a slower downtrend and gentler slope of titration curve than PEG-DSPE within pH 7.4–5.0. Studies on the in vitro drug release demonstrated that TPOS modified docetaxel(DOC) liposomes(TPOS-DOC-L) had a slower drugrelease rate at pH 7.4 similar to PEGylated-DOC liposomes(PEG-DOC-L), whereas the release rate reached approximately 86.92% ± 1.69% at pH 6.4. In vitro cellular uptake assays by microplate reader, and flow cytometry revealed that TPOS modified coumarin 6 liposomes(TPOS-C6-L) had stronger cellular uptake at pH 6.4 than that at pH 7.4( P < 0.01). Conversely, for PEGylated C6 liposomes(PEG-C6-L) and conventional C6 liposomes(C6-L), very similar cellular uptakes were exhibited at different pH values. Confocal laser scanning microscopy images showed that PEG-C6-L and C6-L were mainly located in lysosomes. By contrast, TPOS-C6-L showed broader cytoplasmic release and distribution at 4 h. MTT assay showed that the cytotoxicity of TPOS-DOC-L was similar to that of PEG-DOC-L and conventional DOC liposomes(DOC-L) at the same DOC concentration and at pH 7.4, but was much lower than those at pH 6.4 after 48 h of incubation. The apoptosis of PEG-DOC-L and DOC-L had no remarkable improvement with decreased pH from 7.4 to 6.4. Meanwhile, TPOS-DOC-Lsignificantly induced the apoptosis of HeLa cells with decreased pH. Therefore, TPOS can be a biomaterial for the construction of a pH-sensitive drug delivery system.

Dosimeter Film Based on Ethyl Violet-Bromophenol Blue Dyed Poly(Vinyl Alcohol)

Dyed poly(vinyl alcohol) (PVA) films, prepared by a simple technique of casting aqueous solutions of PVA containing a mixture of Ethyl violet and bromophenol blue (EV-BPB) on a horizontal glass plate, are useful as routine high-dose dosimeter in the 1 - 30 kGy range. The color of films changes from violet to yellow when exposed to gamma radiation. The response of this dosimeter depends up on the concentration of chloral hydrate (CH) in the polymer material. The radiation chemical yield (G-value) of PVA dyed film was calculated and found to increase by increasing concentration of chloral hydrate. Post-irradiation storage on the response of the films are discussed. The overall combined uncertainty (at 2σ) associated with measurement of response (ΔA mm-1) at 600 nm for dose range 1 - 15 kGy is 5.6%.

The Amperometric Glucose Enzyme Electrode by Immobilized Glucose Oxidase in Glucose Oxidase/N-ethyl-Poly (4-vinyl)pyridine Multilayer

Multilayers of glucose oxidase(GOD)/N-ethyl-poly (4-vinyl) pyridine (EPVP) have been assembled on thiol self-assembled monolayers on gold electrode.This electrode can be used as an amperometric enzyme elcctrode for glucose. Fe (CN)63-/4- incorporated in EPVP layer acts as the electron mediator, the linear range was 0.1 to 6 mmol/L when the number of GOD layers was 5.

Effects of ceramic filler in poly(vinyl chloride)/poly(ethyl methacrylate) based polymer blend electrolytes

Effects of nano-ceramic filler titanium oxide（TiO2） have been investigated on the ionic conductance of polymeric complexes consisting of polyvinyl chloride）（PVC）/poly（ethyl methacrylate）（PEMA）,and lithium perchlorate（LiClO4）.The composite polymer blend electrolytes were prepared by solvent casting technique.The TiO2 nanofillers were homogeneously dispersed in the polymer electrolyte matrix and exhibited excellent interconnection with PVC/PEMA/PC/UCIO4 polymer electrolyte.The addition of TiO2nanofillers improved the ionic conductivity of the polymer electrolyte to some extent when the content of TiO2 is 15 wt%.The addition of TiO2 also enhanced the thermal stability of the electrolyte.The changes in the structural and complex formation properties of the materials are studied by X-ray diffraction（XRD） and Fourier transform infrared spectroscopy（FTIR） techniques.The scanning electron microscope image of nano-composite polymer electrolyte membrane confirms that the TiO2 nanoparticles were distributed uniformly in the polymer matrix.

Methoxy poly(ethylene glycol)-b-poly(ethyl cyanoacrylate) copolymer nanoparticles as delivery vehicles for dexamethasone

Methoxy poly(ethylene oxide)-b-poly(ethyl cyanoacrylate) (mPEG-b-PECA), amphiphilic block copolymer, was synthesized via oxyanion-initiated polymerization with a sodium alcoholate-terminated monomethoxy poly(ethylene glycol) as the macroinitiator. mPEG-b-PECA was characterized by GPC, 1H-NMR and FTIR. The results indicate that the structure of mPEG-b-PECA is well controlled with narrow molecular weight distribution. The dexamethasone (DXM)-loaded mPEG-b-PECA nanoparticles (NPs) were prepared by the nanoprecipitation technique and characterized by LPSA, 1H-NMR and TEM. The DXM-loaded mPEG-b-PECA NPs are of spherical shape with the size of less than 100 nm. The drug-loaded amount (DL) and encapsulation efficiency (EE) of DXM-loaded NPs were investigated by HPLC. The results show that DXM can be effectively incorporated into mPEG-b-PECA NPs, which provides a potential delivery system for DXM and other hydrophobic drugs.

NANOSTRUCTURES OF FUNCTIONAL BLOCK COPOLYMERS

Nanostructure fabrication from block copolymers in my group normally involves polymer design, synthesis, self-assembly, selective domain crosslinking, and sometimes selective domain removal. Preparation of thin films withnanochannels was used to illustrate the strategy we took. In this particular case, a linear triblock copolymer polyisoprenc-block-poly(2-cinnamoylethyl methacrylate)-block-poly(t-butyl acrylate), PI-b-PCEMA-b-PtBA, was used. Films, 25 to50 μm thick, were prepared from casting on glass slides a toluene solution of PI-b-PCEMA-b-PtBA and PtBA homopolymer,hPtBA, where hPtBA is shorter than the PtBA block. At the hPtBA mass faction of 20% relative to the triblock or the totalPtBA (hPtBA and PtBA block) volume fraction of 0.44, hPtBA and PtBA formed a seemingly continuous phase in the matrixof PCEMA and Pl. Such a block segregation pattern was locked in by photocrosslinking the PCEMA domain. Nanochannelswere formed by extracting out hPtBA with solvent. Alternatively. larger channels were obtained from extracting out hPtBAand hydrolyzing the t-butyl groups of the PtBA block. Such membranes were not liquid permeable but had gas permeabilityconstants ～6 orders of magnitude higher than that of low-density polyethylene films.

Inhibition of EGFR Suppresses Ethyl Alcohol and Tobacco Cell Effects on Growth of Human Oral Keratinocytes and Human Papillomavirus 16 Entry as a Function of Furin

Background: Reported are increased risks for malignant transformation in human oral keratinocytes (HOK) from ethyl alcohol (ETOH), tobacco products or human papilloma virus oncogenic subtype 16 (HPV 16) infections. We examined various HOK cell responses to these factors to show inhibitors of epidermal growth factor receptor (EGFR) also inhibits furin;proprotein convertase (FC) and HPV 16 entry in HOK. Methods: Immortalized HOK by HPV 16 (HPV 16B) or human telomerase (hTERT);primary foreskin keratinocytes (NHFK), primary HOK, buccal keratinocytes (NHBK) and oral SCC-25 were treated with dibenz[a,l]pyrene (DBP), anthraquinone;nitrosamine (NNAL) or ethyl alcohol (ETOH) and acetaldehyde (AA). ETOH was tested for synthesis of malondialdehyde (MDA) and alcohol dehydrogenase expression (ADH). ETOH, and PAH were evaluated by Western immunoblot for oncogene changes, and phosphorylated EGFR expression. Inhibition of EGFR by WZ4002 and Erlotinib and/or carcinogens effect on HPV 16 entry were studied. A green fluorescent pseudovirus (PsV);chloromethylketone (CMK) an inhibitor of furin activity and Western immunoblot of furin cell distribution further characterized HPV 16 entry. Results: ETOH (10 μM) increased expression of phosphorylated EGFR and HPV 16 entry through furin activity, and membrane, nuclear and cytoskeletal accumulations. CMK suppressed HPV 16 entry and blockage of ADH while aldehyde dehydrogenase (ALDH) enhanced HPV 16 entry. Similarly PAH, DBP (4-8 nM), anthraquinone (98 nM) and NNAL (6.9 μM) enhanced HPV 16 entry through furin activity and membrane, nuclear and cytoskeletal accumulations. Furthermore, WZ4002 and Erlotinib suppressed expressions of phosphorylated EGFR, FC activity, and HPV 16 entry. ETOH and DBP treatments also enhanced expressions of protease activated receptor-1 (PAR-1), and p21waf1 while depressed p16 and p27KIP1 expressions in HOK/HPV 16B cells. Conclusion: EGFR inhibitors are candidates for suppression of alcohol and tobacco effects on EGFR phosphorylated expression;keratinocyte growth, and HPV 16 entry and prevention treatment for HPV related diseases.

3D打印工艺参数对PLA/PTW共混物力学性能影响的研究

采用3D打印中的熔融沉积成型(FDM)工艺制备了聚乳酸/乙烯-丙烯酸丁酯-甲基丙烯酸缩水甘油酯共聚物(PLA/PTW),通过单因素实验探究了3D打印工艺参数(喷头温度、打印平台温度和打印速度)对PLA/PTW共混物力学性能的影响,并在此基础上设计了三因素三水平正交实验,优化了3D打印的工艺参数。结果表明,共混物的冲击强度和拉伸强度均随喷头温度的增加呈现先上升后下降、均随打印平台温度的增加而增加、均随打印速度的增加出现下降的趋势。各工艺参数对PLA/PTW共混物综合力学性能的影响从大到小依次为:喷头温度、打印速度、打印平台温度,且当喷头温度为210℃、打印平台温度为80℃以及打印速度为40 mm/s时,打印出的PLA/PTW共混物的综合力学性能最佳。

超韧聚乳酸/乙烯丙烯酸丁酯甲基丙烯酸缩水甘油酯共混物的制备与性能

向聚乳酸(PLA)和乙烯丙烯酸丁酯甲基丙烯酸缩水甘油酯(EBA-GMA)接枝共聚物的共混物PLA/EBA-GMA(质量比,70/30)中引入催化剂(N,N-二甲基十八胺,DMSA),通过促进PLA与EBA-GMA的原位反应增容来提高共混体系的冲击韧性,并研究了DMSA质量分数对共混体系力学性能的影响。结果显示,未添加DMSA时,PLA/EBA-GMA(70/30)共混物的冲击强度仅为10.9 kJ/m^(2)。当DMSA质量分数为0.5%时,PLA/EBA-GMA(70/30)共混物的冲击强度高达63.1 kJ/m^(2)。共混物结构与形态表征结果表明,添加少量DMSA就能有效促进EBA-GMA上环氧基团与聚乳酸端基的反应活性,提高PLA/EBA-GMA共混物的冲击韧性。

Synthesis and Surface Tension Properties of Polyethyleneimine-Polyethylene Oxide Block Copolymers

This paper describes the synthesis, surface tension and dispersancy properties of block copolymer nonionic surfactants comprised of polyethyleneimine (PEI) and polyethylene oxide (PEO) blocks of selected lengths. These block copolymers were prepared by a three step synthetic sequence. Firstly, PEO glycol was converted to its dimethanesulphonylester (dimesyl) derivative by reacting with methanesulphonyl chloride. Then a tri block polymer was prepared by the ring opening polymerization of 2 methyl 2 oxazoline (MeOZO) with the dimesyl PEO derivative. Lastly, linear PEI blocks were obtained by subsequent hydrolysis and purification. 1H NMR spectra confirmed the structures of the intermediate, final products and their purities (>99%). The utility of these block copolymers is described in terms of their surface tension and clay dispersancy measurements as a function of copolymer chain and block length.

Ascorbate oxidase electrochemical biosensor based on the biocompatible poly(3,4-ethylenedioxythiophene) matrices for agricultural application in crops

The vitamin C（VC） in crops was successfully determined using ascorbate oxidase（AO） electrochemical biosensor based on the biocompatible poly（3,4-ethylenedioxythiophene）（PEDOT） matrices,which was easily prepared by one-step electrodeposition technique in ionic liquid microemulsions.The fabricated biosensor displayed excellent bioelectrocatalytic performance to the oxidation of VC,wide linear range,low detection limit,fast response time,good operational and storage stability,the good results of the determination of VC in vegetable crops indicated that the fabricated biosensor will be a good candidate for the physiological and biochemical studies of crops in near future.

Enzymatic ring-opening copolymerization of trimethylene carbonate and ethylene ethyl phosphate

Enzymatic ring-opening copolymerization of trimethylene carbonate (TMC) and ethylene ethyl phosphate (EEP) are performed in bulk at 100℃ using porcine pancreas lipase (PPL) or candida rugosa lipase (CL) as catalyst. The factors affecting the yield and molecular weights such as catalyst concentration, polymerization time and monomer feed ratio are investigated. The ran-dom copolymers obtained have molecular weight ranging from 3200 to 10200. The glass transition temperature (Tg) of the copolymers decreases from -28 to -41.7℃, with the increase of the EEP content in the feed from zero to 5∶10. Degradation tests show that the degradability of the co-polymers is improved by introduction of the EEP unit into the copolymer chain.

Synthesis and Characterization of p-[Perfluoro-1-(2-fluorosulfonylethoxy)]ethylated Polystyrene

A new fluorinated polystyrene bearing a p substituted perfluoro[1 (2 fluorosulfonylethoxy)]ethyl group was synthesized via one electron oxidation of polystyrene by perfluoro[2 (2 fluorosulfonyl ethoxy)]propionyl peroxide at different peroxide to polystyrene molar ratios. The yield of perfluoroalkylation decreases with the increase of the reactant molar ratio. The modified polymer has been characterized by various techniques: the ring pefluoro[1 (2 fluorosulfonylethoxy)]ethylation has been proved by FT IR and 19 F NMR; the X ray photoelectron spectra (XPS) show the maximum binding energy of F 1s , O 1s , C 1s (two kinds of carbon atoms, namely C H and C F) and S 2p , respectively; desulfonylation of the fluorinated polystyrene appearing at 217 ℃ has been found by its thermogravimetric analysis (TGA). The determinations of contact angle, refractive index and glass transition temperature of the modified polymer have disclosed that when the contact angle increases with the increase of the molar ratio, the refractive index and glass transition temperature decrease. The polydispersity values indicate that the degradation of the polymer chains did not occur during the reaction.

增韧聚氯乙烯电工套管复合材料的制备与性能研究

采用丙烯酸酯橡胶(ACM)、刚性体纳米碳酸钙(nano-CaCO_(3))、弹性体丙烯酸丁酯/甲基丙烯酸甲酯/丁二烯三元共聚物(AMB)作为增韧剂,对聚氯乙烯(PVC)进行复合增韧改性,并对复合材料的冲击性能、拉伸性能、加工流变性、动态热力学性能等进行了表征。结果表明,当PVC/ACM/nano-CaCO_(3)/AMB质量比为100/10/3/9时,复合材料的常温冲击强度为27.64 kJ/m^(2),比纯PVC提升5倍;低温冲击强度为14.91 kJ/m^(2),比纯PVC提升4.1倍。加入AMB能使体系的玻璃化转变温度(Tg)下降,由93.71℃下降到86.36℃。