Three series hydrophobic association hydrogels (HA-gels) with different concentration of sodium dodecyl sulfate (SDS) were prepared by free radical micellar copolymerization. The backbone of HA-gels was based on the copolymer of acrylamide and a little octylphenol polyoxyethylene ether acrylate with 10 ethoxyl units (OP10∼AC). Their mechanical properties were determined by tension tests. It was found that the properties of all three series HA-gels presented a very similar variation tendency with increasing R, the molar ratio of SDS to OP10∼AC. In the medium region of R (around 1.23), higher effective crosslinked density and proper match between shorter and longer chains were achieved, so that the HA-gels exhibited better mechanical strengths. In lower R region, it is prone to form the unstable aggregation of OP10∼AC with little SDS, while in higher R region some of co-micelles could not act as crosslinkers. Both would reduce the effective crosslinked density and the mechanical strength of HA-gel. In the condition of fixed R, the change of OP10∼AC content would remodel the topological structure of network. The HA-gels with better properties could be obtained as the OP10∼AC content was varied from 1 to 2% at the proper R. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41222.

Octylphenol polyoxyethylene acrylate (OP-10-AC) was synthesized, and then OP-10-AC was copolymerized with acrylamide (AM) to form hydrophobically modified polyacrylamide P(AM/OP-10-AC) through micellar copolymerization. OP-10-AC content and rheology behavior of P(AM/OP-10-AC) were investigated in detail. Especially, under the conditions of different test methods, P(AM/OP-10-AC) showed interesting shear responsive behavior. The results of rheology study show that OP-10-AC content, polymer solution concentration, salt solution concentration, and different test methods powerfully influenced shear viscosity of aqueous solutions of P(AM/OP-10-AC). In addition, according to the dynamic shear experimental results, the critical hydrogel concentration range (CHCR) could be confirmed for aqueous solutions of P(AM/OP-10-AC). Above CHCR, these polymer solutions were essentially a kind of microhydrogels, which could explain the effect of concentration and hydrophobe content on their shear viscosity and viscoelasticity from the microstructure's point of view. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Five kinds of polyepichlorohydrin (PECH) of different molecular weights were synthesized and characterized by gel permeation chromatography (GPC). Mechanical blending was used to mix PECH and poly(vinyl chloride) (PVC) together. The blends of different PVC/PECH ratios were characterized by thermogravimetric analysis (TGA), tensile tests, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). TGA results show the thermal stability of PVC/PECH blends is desirable. Tensile tests indicate elongation at break is raised by increasing both the amount and the molecular weight of PECH. DSC is used to determine the glass transition temperature of PECH, and a quite low T_g is obtained. DMA results indicate that PECH has a perfect compatibility with PVC, when PECH concentration is below 20 wt %. There is only one peak in each tan δ curve, and the corresponding T_g decreases as PECH amount increases. However, above 20 wt %, phase separation takes place. The molecular weight of PECH also has a great influence on the glass transition temperature of the blends. This study shows that PECH is an excellent plasticizer for PVC, and one can tailor the glass transition temperature and tensile properties by changing the amount and the molecular weight of PECH. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Amphiphilic random copolymer consisting of monomeric units of poly (butyl acrylate) and poly (maleic acid salt) was synthesized and characterized. The emulsion polymerization kinetics of styrene stabilized by this copolymer was investigated. The influencing factors, including polymeric surfactant concentration, initiator concentration and polymerization temperature, were systematically studied. The kinetic data show that the polymerization rate (R_P) increased with the increase of the polymeric surfactant concentration ([S]) and polymerization temperature (T). At the higher [S], droplets nucleation and micelle nucleation coexisted in the polymerization system; at the lower [S], only the droplets nucleation process existed. The polymerization did not follow Smith-Ewart Case II kinetics. Dynamic light scatter and transmission electron microscope were utilized to measure the sizes and shapes of the particles, respectively. It would be speculated that a kind of large heterogeneous particles with multiple-active-sites was formed in the polymerization system. The increasing of R_P with increasing initiator concentration ([KPS]) was rapid at a medium [KPS], but the slowly increasing was observed at a lower or higher [KPS]. It was attributed to the barrier effect of the polymeric surfactant around the monomer droplets. The polymerization activation energy was 60.29 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Hybrid microspheres with a polystyrene core coated with magnetite nanoparticles were prepared by miniemulsion polymerization. Acrylic acid was used as a comonomer to promote the anchoring of the magnetite nanoparticles onto the polymeric surface. The addition of a hydrophobic agent prevents effectively the monomer from diffusing into the aqueous phase. Magnetite was treated with a silane coupling agent in order to introduce some interactions with the polymers. The morphology and the structure of the hybrid microspheres were characterized using X-ray diffraction, infrared spectroscopy, transmission electron microscopy and thermogravimetric analysis. The results show that the morphology of the hybrid microspheres was influenced by the concentrations of acrylic acid, hydrophobic agent and surfactant, and that the degree of coating can be tuned by changing these parameters. The miniemulsion polymerization technique is adaptable to the synthesis of magnetite-coated polymer particles, and the synthesis can be scaled up. Copyright © 2008 Society of Chemical Industry

BACKGROUND: The HOMO–LUMO energy level width of conjugated polymers can be manipulated by controlling the conjugation length of the polymeric materials in order to adjust their properties in terms of emission of different colors and realize polychromatic displays. In the work reported in this paper azobisisobutyronitrile (AIBN) was used to control the conjugation length of poly[2-methoxy-5-(2′-ethylhexyloxy)-co-(1,4-phenylene vinylene)] (MEH-PPV) by free radical addition. In this way a series of MEH-PPV with various conjugation lengths was obtained.

RESULTS: Characterization of MEH-PPV using ¹H NMR and Fourier transform infrared spectroscopy demonstrated that the cyano groups of AIBN hydrolyzed into carboxyls. The carboxyl free radicals attacked the conjugated double bonds of MEH-PPV, resulting in a decrease of trans-vinylenes and in an increase of cis-vinylenes as well as tert-methyls on the backbone. Changing the conjugated structure of the polymer caused the peaks of UV and fluorescence spectra to shift to the blue.

CONCLUSION: The resulting MEH-PPV derivatives can emit orange-red, green and blue light. It is expected that they could be used to prepare PPV-based materials that could modulate white light emission, by simply blending the PPV derivatives emitting different colors. Copyright © 2008 Society of Chemical Industry