Synthesis and Properties of Novel Cationic Maleic Diester Polymerizable Surfactants

Three new cationic polymerizable surfactants are synthesized by the reaction of alkylmaleic hemiester with glycidyltrimethylammonium chloride. Their structures are confirmed by H-1 NMR, IR and elements analysis. The values of CMC and gamma (CMC) of these surfactants have been measured. One can obtain nearly monodisperse polystyrene latex by emulsion polymerization using the polymerizable surfactant.

Properties of Polyacrylate Latex Prepared Under Different Emulsified Systems

The polyacrylate latexes were synthesized via pre-emulsified and semi-continuous seeded emulsion polymerization technology when conventional surfactant or polymerizable surfactant was used as emulsifiers. The resultant latexes and their films were characterized with the contact angle determinator and rheometer. Effect of the polymerizable surfactant on water resistance, stability and rheology of the latex was studied. Results show that the water resistance of film is increased first then decreased with the increase of the amount of the polymerizable surfactant. There exists the optimum value of the amount of the polymerizable surfactant for the water resistance of the film. In comparison with the latex prepared with the conventional surfactant, both the mechanical stability and the freezing-thaw stability of the latex are improved when the polymerizable surfactant is used during the course of the emulsion polymerization. The resultant latex has rheological properties of pseudo-plastic fluid and belongs to non-Newtonian fluid.

Application of Polymerizable Surfactant in the Preparation of Polystyrene/Nano-Fe_3O_4 Composite

Monooctadecyl maleate, as a polymerizable surfactant, was synthesized by the mono-esterification of maleic anhydride and octadecanol, and was utilized to surface-modify nano-Fe3O4 particles. A polymerizable magnetic fluid was obtained by directly dispersing modified nano-Fe3O4 particles into styrene monomer, and the polystyrene/nano-Fe3O4 composite was prepared through free radical polymerization of polymerizable magnetic fluid. The structure and dispersion status in different dispersion phases of modified nano-Fe3O4 particles were studied by Fourier transform infrared （FTIR） spectrometry, X-ray diffraction （XRD） and transmission electron microscopy （TEM）, respectively. The experimental results show that the nano-Fe3O4 particles modified by monooctadecyl maleate with the size of about 7-10 nm can be uniformly dispersed into styrene and fixed in the composite during the procedure of polymerization. Thermogravimetric analysis （TGA） and vibrating sample magnetometry （VSM） indicate that the thermal stability of polystyrene/nano-Fe3O4 composite is improved compared to that of pure polystyrene, and the composite is a sort of superparamagnetic materials.

Nonionic Polymerizable Emulsifier in High-Solids-Content Acrylate Emulsion Polymerization

Stable high-solids-content acrylate emulsion were obtained with a nonionic polymerizable emulsifier allyloxy nonylphenoxy poly （ethyleneoxy） （10） ether （ANPEO10）, and a conventional emulsifier OP-10 as a reference sample. 1H NMR proves that the polymerizable emulsifier ANPEO10 has been incorporated into the resulted acrylate polymers. TEM demonstrates that there are some differences in the particle morphologies. AFM proves that the polymerizable emulsifier ANPEO10 migrating to the surface of the emulsion film was much less than the conventional emulsifier OP-10. The polymerizable emulsifier ANPEO10 can enhance the adhesion with glass plate compared to the conventional emulsifier. Furthermore, with increasing amount of emulsifier, the surface free energy of the films first decreased and then increased, and the adhesion with glass plate is initially enhanced and then attenuated. The water-resistance and solvent-resistance of the films prepared by the polymerizable emulsifier ANPEO10 are superior to those prepared by the conventional emulsifier OP-10.

STUDY ON THE POLYMERIZATION KINETICS AND STABILITY OF P(UA)/MMA MICROEMULSION

Urethane acrylate anionomer (APUA) as a kind of new type polymerizable emulsifier was synthesized using 2,4-toluene diisocyanate (TDI), polypropylene glycol (PPG), 2-hydroxyethyl methacrylate (HEMA) and dimethylolpropionic acid (DMPA). The critical micelle concentration (CMC) of APUA was measured by the methods of conductance and surface tension. The comparative studies between polymerizable emulsifier AUPA and conventional emulsifier sodium dodecyl sulfate (SDS) were carried out in the emulsion polymerization of methyl methacrylate (MMA). Polymerization kinetics, stability, size and morphology of the latex particles were investigated. It was found that in APUA both water soluble initiator potassium persulfate (KPS) and oil soluble initiator 2,2'-azobisisobutyronitrile (AlBN) can start the reaction of MMA, and the polymerization rate and yield were very high. On using AlBN as an initiator, the conversion-time behavior of MMA with APUA as emulsifier was different to that of SDS as emulsifier, signifying a different nucleation mechanism of the polymer latex particle. The average size of the two kinds of particles is about 50 nm. The particle size decreases with increasing emulsifier concentration. On using KPS as the initiator, APUA as emulsifier, cross-linking hydrogel of PMMA would be formed, but SDS was used as emulsifier and the hydrogel of PMMA was not present.

Synthesis of Novel Monomeric Dyes with Anthraquinone Residue

Two novel polymerizable dyes with anthraquinone residue have been prepared, and their structures were characterized by FTIR, HNMR and EA. 1

VINYL MONOMERS BEARING CHROMOPHORE MOIETIES AND THEIR POLYMERS——Ⅹ.INITIATION AND PHOTOCHEMICAL PROPERTIES OF p-(N,N-DIMETHYLAMINO)STYRENE AND ITS POLYMERS

A vinyl monomer having an electron-donating moiety, p-(N,N-dimethylamino)styrenc (DMAS),was synthesized. It was combined with benzoyl peroxide (BPO) to form a redox initiation system to initiatethe polymerization of methyl methacrylate (MMA). UV spectra measurements show that DMAS enters thePMMA chain as well. Both DMAS and its polymer P(DMAS) display strong fluorescence, and thefluorescence can be quenched by electron-deficient compounds such as methacrylonitrile, fumaronitrile andmethyl methacrylate etc. Moreover, DMAS can also form charge transfer complex (CTC) with strongelectron acceptors such as tetracyanoethylene (TCNE). The difference between the photochemical propertiesof DMAS and P(DMAS) were explained in terms of molecular structure change and polymer conformationeffect in solution. In addition, the CTC and exciplex formation of DMAS or P(DMAS) with C_(60) were alsostudied.

PREPARATION OF POLYSTYRENE/SiO_2 COMPOSITE NANOPARTICLES BEARING SULFONIC GROUPS ON THE SURFACE VIA EMULSION COPOLYMERIZATION USING A POLYMERIZABLE EMULSIFIER

Functionalized PS/SiO_2 composite nanoparticles bearing sulfonic groups on the surface were successfully synthesized via emulsion copolymerization using a polymerizable emulsifierαolefin solfonate(AOS).As demonstrated by transmission electron microscopy and atomic force microscopy,well-defined core-shell PS/SiO_2 composite nanoparticles with a diameter of 50 nm were obtained.Sulfonic groups introduced onto the surface of the composite nanoparticles were quantified by FTIR,and can be controlled to some exten...

Photorheologically reversible micelle composed of polymerizable cationic surfactant and 4-phenylazo benzoic acid

A photorheologically reversible micelle composed of polymerizable cationic surfactant n-cetyl dimethylallyl am- monium chloride （CDAAC） and trans-4-phenylazo benzoic acid （trans-ACA） was prepared. The effects of molar ratio of CDAAC/trans-ACA, time of UV and visible light irradiation and temperature on the rheological properties of micellar system were investigated. The results show that before UV irradiation the system with an optimum CDAAC/trans-ACA molar ratio of 1.4 forms viscoelastic micelles at 45 ℃. After 365 nm UV irradiation, the viscos- ities of micelle systems with different concentrations at fixed molar ratio of 1.4 are decreased by 85%-95%. The CDAAC/trans-ACA （14 mmol. L- 1/10 mmol. L- 1 ） micelle system exhibits shear thinning property and its viscos- ity is decreased obviously with the increases of UV irradiation time less than I h. The rheological process during LIV irradiation for CDAAC/trans-ACA （14 mmol- L- 1/10 mmol. L 1） micelle proves that viscosity, elastic modulus G＇ and viscous modulus G＂ will reduce quickly with the UV light. Furthermore, the micelle system after 1 h UV- irradiation is able to revert to its initial high viscosity with 460 nm visible light irradiation for 4 h, and the micelle can be cycled between low and high viscosity states by repetitive UV and visible light irradiations. The LIV-Vis spectra of CDAAC/trans-ACA micelle indicate that its photosensitive theological properties are related closely to photoisomerization of trans-ACA to c/s-ACA.

Comparison of Chromatographic Performance for L-Phenylalanine-Derived Organic Phases on Silica by “Grafting from” and “Grafting to” Strategies

L-phenylalanine-derived polymerizable organogel, N’-octadecyl-Nα-(4-vinyl)-benzoyl-L-phenylalanineami- de (4) has been prepared according to the procedure described elsewhere. Compound 4 was successfully polymerized by surface initiated atom transfer radical polymerization (ATRP) from the initiator grafted silica particles (sil-poly4). It was also telomerized with 3-mercaptopropyltrimethoxysilane (MPS) and the telomer (T4) was grafted on to silica (sil-T4). TGA and elemental analysis measurement revealed that higher amount of polymer can graft by ATRP process than that of “grafting to” strategy. The results of 13C CP/MAS NMR measurement showed that the N-alkyl chain of the grafted polymers for both sil-poly4 and sil-T4 remained as less ordered gauche conformational form on silica surface and no inversion to trans form was occurred until temperature is increased up to 50?C. The retention of alkylbenzene samples showed that sil-poly4 prepared by “grafting from” method yielded extremely higher retention than conventional C18 phase however, sil-T4 prepared by conventional “grafting to” method showed lower retention than C18 phase. Aspects of molecular recognition were evaluated by the retention studies of a series of polycyclic aromatic hydrocarbons (PAHs) and aromatic positional isomers. We have observed sil-T4 yielded slightly higher selectivity for PAHs than sil-poly4 regardless the fact that it has low surface coverage and lower hydrophobic interactions. The enhanced selectivity observed for sil-T4 than C18 phases and sil-poly4 can be explained by the π - π interactions between the guest PAHs and carbonyl groups present in the polymer chain. In addition the aromatic moieties of compound 4 that aggregates through π - π interactions also contribute to the separation of PAHs for both sil-poly4 and sil-T4. The minimal π - π interactions between the carbonyl groups and guest molecules for sil-poly4 probably due to the presence of long chain initiator which restrict the polymer to form order thin layer over silica surface.