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.

Graft Copolymerization of Ethyl Acrylate onto Hydroxypropyl Methylcellulose Using Potassium Persulfate as Initiator

With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration, initiator concentration, matrix concentration, and reaction temperature on the percentage of grafting (G) and grafting efficiency (G_E) were studied. The results show that G and G_E values both increase with the the increase of EA concentration and KPS concentration; when raising HPMC concentration from 0.12 mmol/L to 0.47 mmol/L, G decreases, while G_E increases;and when raising reaction temperature from 50 ℃ to 65 ℃,G increases, but G_E decreases. In addition, the graft copolymers were characterized by Fourier transform infrared (FTIR) spectra and transmission electron microscopy (TEM) methods.

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.

Studies on the Graft Copolymerization of Methyl Acrylate and Ethyl Acrylate onto Corn Starch Using Potassium Persulfate-Sodium Thiosulphatc as Initiation System

Grafting copolymerizations of methyl acrylate(MA) and ethyl acrylate(EA) onto corn starch, respectively, initiated by potassium persulfate-sodium thiosulphate (KPS-STS) redox system, were studied. The structures of poly(MA)-g-starch and poly(EA)-g-starch were characterized by IR, SEM and X-ray diffraction. Experimental results show that KPS-STS is an efficient initiation system for grafting of MA and EA onto corn starch. The maximum percent grafting was obtained at [KPS] of 6.0× 10~3 mol/L, [STS] of 1.8× 10 5 mol/L, [M] of 6. 0× 101 mol/L, S:L=4:100 at 40℃ for 6 h. The reactivity order is MA>EA.

COMPUTER SIMULATIONS ON UNPERTURBED CONFIGURATIONAL DIMENSIONS OF POLY (METHYL ACRYLATE)

A full-relaxation optimization of molecule and the popular MM2 force field are employed to obtain the geometry parameters and the conformational energy surface of a meso or a racemic dyad of poly(methyl acrylate) (PMA) with a specified carbonyl-bond orientation in side-groups. It is found that the conformational energy maps calculated here considerably differ from those calculated with the rigid molecular model as reported in the earlier studies. The g(-) state cannot be omitted in the obtained contour maps. Two important conformers tg(-) and g(-t) with energy minima were newly detected for a racemic dyad. The analysis on the conformations with energy minima confirmed that the ester groups are not always perpendicular to the plane defined by the two adjacent skeletal bonds and may change their relative orientations to meet the requirement of lower energies during the conformational state transition. Instead of the early way of adjusting the interaction energy parameters to fit the experimental data, we attempt to predict unperturbed chain dimensions via the reliable force field and the configurational statistical mechanics. The proposed scheme with three rotational states identified from the contour maps allowed us to satisfactorily reproduce the experimental dimensions of random PMA chains.

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.

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.

STRUCTURE OF 1-BROMOMETHYL-7, 7-DIMETHYLBICYCLO[2.2.1]HEPT-2-YL ACRYLATE AND THE PROPERTIES OF ITS POLYMER

In this paper, the structure of 1-bromomethyl-7,7-dimethyl btcyclo[2.2.1]hept-2-yl acrylate has been studied by X-ray diffraction, and the relation between the molecular structure and the properties of polymerization and its polymer have been discussed.

Effects of Side-Chain on Conformational Characteristics of Poly(3,5-Dimethyl-Phenyl Acrylate) in Toluene at 40℃

The intrinsic viscosity [η] of poly(3,5-dimethylphenylacrylate) (35PDMPA)solutions were evaluated throughout the measurements of the flow times of toluene and polymer solutions by classical Huggins, and Kraemer’s methods using a Cannon-Ubbelohde semi-micro-dilution capillary viscometer in a Cannon thermostated water bath at 40℃ ± 0.02℃. The values of Huggins’ constant estimated ranged from 0.2 to 0.4 which were within expectations. The intrinsic viscosities and molecular weight relationship was established with the two-parameter classical models of Staudinger-Mark-Houwink-Sakurada and Stockmayer-Fixman. Conformational parameter C∞ and σ indicated 35PDMPA be semi flexible. Also, the rigidity of 35PDMPA was confirmed by Yamakawa-Fuji wormlike theory modified by Bohdanecky. The molecular parameters were estimated and compared. The results showed that 35PDMPA behaves like a semi-rigid polymer in toluene at 40℃ rather than a random coil flexible macromolecule.

Antimicrobial Expanded Polytetrafluoroethylene Film Prepared by 3-ray Radiation Induced Grafting of Poly（acrylic acid）

The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic acid） （PAA） can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2＋]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was im- mersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag＋ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quart- titative antibacterial activity of the obtained ePTFE-g-PAA/Ag hybrid films was measured using counting plate method. It can kill all the Escherichia coli in the suspension in 1 h. Moreover, this excellent antibacterial activity can last at least for 4 h. This work provides a facile and practical way to make ePTFE meet the demanding antimicrobial requirement in more and more practical application areas.

PREPARATION OF POLY(ETHYLENEGLYCOL-co-ACRYLIC ACID) MICROSPHERES WITH DIVINYLBENZNE AS CROSSLINKER BY DISTILLATION-PRECIPITATION POLYMERIZATION

Monodisperse poly（poly（ethyleneglycol） methyl ether acrylate-co-acrylic acid） （poly（PEGMA-co-AA）） microspheres were prepared by distillation-precipitation polymerization with divinylbenzene （DVB） as crosslinker with 2,2＇- azobisisobutyronitrile （AIBN） as initiator in neat acetonitrile without stirring. Under various reaction conditions, four distinct morphologies including the sol, microemulsion, microgels and microspheres were formed during the distillation of the solvent from the reaction system. A 2D morphological map was established as a function of crosslinker concentration and the polar monomer AA concentration, in comonomer feed in the transition between the morphology domains. The effect of the covalent crosslinker DVB on the morphology of the polymer network was investigated in detail at AA fraction of 40 vol%. The ratios of acid to ethylene oxide units presenting in the comonomers dramatically affected the polymer-polymer interaction and hence the morphology of the resultant polymer network. The covalent crosslinking by DVB and the hydrogen bonding crosslinking between two acid units as well as between the acid and ethylene oxide unit played key roles in the formation of monodisperse polymer microspheres.

Rapid Expansion of Supercritical Solution of Poly (1,1,2,2- Tetrahy-droperfluorodecyl Acrylate)

Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At apre - expansion temperature of 45℃), amorphous polymer was formed. At temperature around 60 ℃ to 80 ℃ , fibers were formed. Increase of temperature increasesparticle size slightly. At temperature of 105℃ , most of particles are spheres. The RESS is an attractive process. To apply the polymers desired for coating applications in an organic solvent - free process that is economically viable , and it will have implications for pollution prevention during polymer film

Synthesis and evaluation of poly(N-vinyl caprolactam)-co-tert-butyl acrylate as kinetic hydrate inhibitor

Low dosage kinetic hydrate inhibitors(KHIs)are a kind of alternative chemical additives to high dosage thermodynamic inhibitors for preventing gas hydrate formation in oil&gas production wells and transportation pipelines.In this paper,a new KHI,poly(N-vinyl caprolactam)-co-tert-butyl acrylate(PVCapco-TBA),was successfully synthesized with N-vinyl caprolactam(NVCap)and tert-butyl acrylate.The kinetic inhibition performances of PVCap-co-TBA on the formations of both structureⅠmethane hydrate and structureⅡnatural gas hydrate were investigated by measuring the onset times of hydrate formation under different conditions and compared with commercial KHIs such as PVP,PVCap and inhibex 501.The results indicated that PVCap-co-TBA outperformed these widely applied inhibitors for both structureⅠand structureⅡhydrates.At the same dosage of KHI,the maximum tolerable degree of subcooling under which the onset time of hydrate formation exceeded 24 hours for structureⅠhydrate was much lower than that for structureⅡhydrate.The inhibition strength increased with the increasing dosage of PVCap-co-TBA;The maximum tolerable degree of subcooling for the natural gas hydrate is more than10 K when the dosage was higher than 0.5%(mass)while it achieved 12 K when that dosage rose to0.75%(mass).Additionally,we found polypropylene glycol could be used as synergist at the dosage of 1.0%(mass)or so,under which the kinetic inhibition performance of PVCap-co-TBA could be improved significantly.All evaluation results demonstrated that PVCap-co-TBA was a very promising KHI and a competitive alternative to the existing commercial KHIs.

Synthesis of Ethyl 3-Fluoroalkyl-3-Halo Acrylate With CH_2N_2

When ethyl 3-fluoroalkyl-3-haloacrylate was treated with excess CH2N2,1-methyl-3-ethoxycarbonyl-4-fluoroalkylpyr azoles(3)and 1-methyl-5-ethoxycarbonyl-4-fluoroalkylpyrazoles(4)were obtained with a ratio of 90-95:10-5 in good yield.

Swelling Properties of New Hydrogels Based on the Dimethyl Amino Ethyl Acrylate Methyl Chloride Quaternary Salt with Acrylic Acid and 2-Methylene Butane-1,4-Dioic Acid Monomers in Aqueous Solutions

Hydrogels of dimethylaminoethyl acrylate methyl chloride quaternary salt (Q9) have been synthesized with different monomer ratio by copolymerization of this poorly studied monomer either with acrylic acid or with 2-methylene bu-tane-1,4-dioic acid. Hydrogel swelling was measured as a function of the composition of the hydrogel and of the crosslinking agent ratio. High values of swelling have been obtained at very high crosslinking values (【14 wt %) and the equilibrium swelling was reached at very low time (less than 15 minutes). The swelling isotherms consisted of a steep initial portion and then levelled off as asymptotically to the equilibrium swelling limit. The experimental data suggest clearly that the swelling process obeys second-order kinetics. According to this, the kinetics rate constant and the equilibrium water content were determined at different comonomer composition and crosslinker concentration. The calculated kinetic constants ranged from 0.48 to 3.76 ×10-2 min-1 for poly (acrylic acid-co-Q9) hydrogels and from 0.68 to 4.0 ×10-2 min-1 for poly (2-methylene butane-1,4-dioic acid-co-Q9) hydrogels depending on the hydrogels composition. The diffusion process was evaluated for each hydrogel showing a non-Fickian type diffusion. In all cases was observed a considerable increase in diffusion coefficient as Q9 content increases.

Studies on interacting Blends of Acrylated Epoxy resin based Poly(Ester-Amide)s and Vinyl EsterResin

Epoxy resin based Unsaturated poly(ester-amide) resins (UPEAs) can be prepared by many methods but here these were prepared by reported method [1]. These UPEAs were then treated with acrylotl chloride to afford acrylated UPEAs resin (i.e. AUPEAs). Interacting blends of equal proportional AUPEAs and vinyl ester epoxy (VE) resin were prepared. APEAs and AUPEAs were characterized by elemental analysis, molecular weight determined by vapour pressure osmometer and by IR spectral study and by thermogravimetry. The curing of interacting blends was monitored on differential scanning calorimeter (DSC). Based on DSC data in situ glass reinforced composites of the resultant blends have been prepared and characterized for mechanical, electrical and chemical properties. Unreinforced blends were characterized by thermogravimetry (TGA).

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%.

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。