Polymeric Photoinitiators Containing Side-chain Ketoaromatic Moieties for Fast Ultraviolet Initiated Polymerisation of Acrylic Monomers

The synthesis of polymeric photoinitiators having side-chain cyclohexylphenylketone as well as benzophenone moieties at different distances from the backbone is described. Study of the activity of the former systems, in the ultraviolet initiated polymerisation of acrylic monomers, indicates that a remarkable increase in the polymerisation rate is observed when the cyclohexylphenylketone chromophore is attached to the main chain through an ethereal linkage rather than an ester group. In the case of the latter systems, considerable improvement is observed in the photoinitiating activity with respect to the corresponding low molecular weight model compounds in the polymerisation of acrylic monomers. Moreover, in general the copolymers of benzophenone-containing monomers show higher activity than the corresponding homopolymers. These results are discussed in terms of photoexcitation energy migration along the polymer chain, as well as of intramolecular hydrogen abstraction from both main and side chains. This last occurrence seems to be the main activation process, as suggested by a strict correlation between activity and hydrogen-donating properties of the co-units in the copolymers, Photophysical evidence supporting this point is also reported. Finally, the synthesis of polymeric photoinitiators, containing both benzophenone and tertiary amine groups in the same macromolecule, has been accomplished via copolymerisation of 4-acryloxybenzophenone with 4-(N,N-dimethylamino)styrene. Preliminary data concerning photoinitiating activity of these last copolymers indicate that conformational mobility affects the formation capability of exciplexes and then the activity itself.     

Structural test of precast polymer concrete

This study was performed to check the feasibility of concrete polymer manhole through a development test of high strength polymer concrete and prepare fundamental data for design to solve the problems of the existing cement concrete manhole. The lower absorption capacity (0.39%) of polymer concrete will be more advantageous in installing manhole in an area with subsurface water. Also long working‐life (63 minutes) will be enough to establish manholes. Conclusively, the high strength polymer concrete that is the most important issue in development of polymer concrete manhole could be made. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A new photopolymerization system for vinyl monomers

A mixture of Ce⁺³ salt and an aminomethylene phosphonic acid, such as amino tri(methylene phosphonic acid) (ATMP), diethylene triamine penta(methylene phosphonic acid), N,N‐di(methylene phosphonic acid) ethanol amine, N,N‐di(methylene phosphonic acid)‐N‐methylamine, N‐oxo‐N,N,N‐tri(methylene phosphonic acid), or 1‐hydroxy‐ethylidene‐1,1‐diphosphonic acid, was used for the photopolymerization of acrylonitrile, vinyl acetate, acrylic acid, and styrene in water. Molecular weights of the polymers decreased with increasing concentration of both Ce⁺³ salt and ATMP. The effect of oxygen, light, pH, and the addition order on polymerization were also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2494–2499, 2002     

Synthesis and properties of brominate bismaleimide monomers

Brominated bismaleimides were prepared by reacting 3(4)‐maleimidobenzoylchloride with various bisphenols, using chloroform as solvent and triethylamine as acid acceptor. These monomers were characterized by elemental analysis, infrared (IR), and proton nuclear resonance (¹H‐NMR) spectroscopy. Thermal properties of monomers were accomplished by differential scanning calorimetry (DSC) and dynamic thermogravimetric analysis (ATG). The properties of these compounds were compared with those of monomers derived from bisphenol A and bisphenol A chlorinated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3881–3885, 2006     

Synthesis and characterization of side‐chain liquid‐crystalline polyacrylates containing azobenzene moieties

Syntheses of novel liquid‐crystalline polymers containing azobenzene moieties were performed by a convenient route with an acrylate backbone. The azobenzenes were key intermediates of the monomers, and side‐chain liquid‐crystalline polymers were prepared, that is, poly[α‐{4‐[(4‐acetylphenyl)azo]phenoxy}alkyloxy]acrylates, for which the spacer length was 3 or 11 methylene units. In addition, poly[3‐{4‐[(3,5‐dimethylphenyl)azo]phenoxy}propyloxy]acrylate was prepared with a spacer length of 3 methylene units. The structures of the precursors, monomers, and polymers were characterized with Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR techniques. The polymers were obtained by conventional free‐radical polymerization with 2,2′‐azobisisobutyronitrile as an initiator. The phase‐transition temperatures of the polymers were studied with differential scanning calorimetry, and the phase structures were evaluated with a polarizing optical microscopy technique. The results showed that two of the monomers and their corresponding polymers exhibited nematic liquid‐crystalline behavior, and one of the monomers and its corresponding polymer showed smectic liquid‐crystalline behavior. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2653–2661, 2002     

Preparation and electro‐optical behaviors of polymer stabilized liquid crystal cells with chiral matrices derived from (−)‐camphor

Novel chiral monomers derived from (?)‐camphor and difunctional monomers with biphenyl segments were synthesized. The molecular structures were identified using FTIR, NMR, and elemental analyses. Surface pretreated polymer stabilized cholesteric texture (PSCT) cells with various chiral nematic components were prepared. According to theory, they are kind of reversed mode PSCT cells. The helical twisting power (HTP) and pitches of the PSCT cells were evaluated. The polarized optical microscopic (POM) textures and the dependence of the optical properties on the applied voltage of the PSCT cells were investigated. The reflection band of the PSCT cells before and after UV irradiation were estimated. A blue shift of selective reflection of the PSCT cells was obtained after UV irradiation. PSCT cells with various reflecting colors and the dependence of the transmittance of the cells on applied voltage were investigated. Real image recording through a mask as well as the transmittance of PSCT cells controlled by applied voltage were also confirmed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 88–96, 2005     

Effect of the monomer ratio on the properties of poly(methyl methacrylate butyl acrylate) latex‐modified mortars

This article deals with the effect of the monomer ratio on the typical properties of polymer‐modified mortars with poly(methyl methacrylate butyl acrylate) latices. Polymer‐modified mortars, with methyl methacrylate/butyl acrylate copolymer latices of various methyl methacrylate/butyl acrylate ratios, were prepared with different polymer/cement ratios and were tested for their workability, air content, compressive strength, flexural strength, and water absorption. On the basis of the test results, the effects of the monomer ratio and polymer/cement ratio on the typical properties were examined. The properties of the latex‐modified mortars were affected to a great extent by both the monomer ratio and polymer/cement ratio. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2403–2409, 2004     

Free radical polymerization kinetics of monomers functionalized with ?AsO(OH)2 in aqueous media

The free radical polymerization kinetics of the isomer sodium salts of o‐ and p‐methacryloylaminophenylarsonate in aqueous solution have been studied using a dilatometric method. The polymerizations, initiated with potassium persulfate, were carried out at a constant monomer initial concentration of 0.50 mol/L and the initiator initial concentration was fixed at one of the following: 1.00, 2.00, 5.00, 8.00, or 10.00 (× 10^?3 mol/L). Another set of polymerizations were carried out at a constant initiator initial concentration of 2 × 10^?3 mol/L and the monomer initial concentration was fixed at one of the following: 0.20, 0.30, 0.50, 0.70, or 1.00 (mol/L). The polymerization reactions were conducted isothermally at 70°C. The order with respect to initiator was consistent with the classical kinetic rate equation, while the order with respect to monomer was greater that unity. The effects of temperature on the polymerization rate were also investigated and the activation energy gave values of 20.66, 22.68, and 23.22 kcal mol^?1 K^?1 over a temperature range of 50–70°C. For the case of o‐methacryloylaminophenylarsonic acid monomer, its kinetic study was carried out in DMF as solvent and AIBN initiator. p‐Methacryloylaminophenylarsonic acid was too insoluble in DMF to be studied. The polymers obtained were characterized by H‐NMR, IR, and viscosity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1662–1669, 2004     

Coating formation by spontaneous polymerization on aluminum: Various monomers

Spontaneous polymerization to give conformal, uniform coatings on metals has been expanded to a series of different monomers. The monomer 4‐fluoro maleimide, when copolymerized with styrene, a coupling agent, and a bis‐maleimide crosslinker, imparts very low dielectric constant (2.4) to the coating while retaining high temperature resistance. Diethyl fumarate, with the same comonomers, enhances ductility and provides an adjustable glass transition temperature. Addition of glycidyl acrylate to the monomer system provides reactivity of the coating to epoxy resins. Kinetic studies using these monomers were consistent with the free radical polymerization mechanism. The rate of reaction seemed limited by the diffusion of species to the reaction site. Extent of incorporation of the new monomers into the chain backbone was verified, and adhesion and corrosion resistance properties examined. The data illustrate the versatility of the conformal, chrome free spontaneous polymerization process. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 875–885, 2000     

New monomers and polymers derived from α‐hydroxymethyl methyl vinyl ketone

2‐Hydroxymethyl‐but‐1‐ene‐3‐one [α‐hydroxymethyl methyl vinyl ketone (HMVK)] was synthesized from methyl vinyl ketone using paraformaldehyde and a tertiary amine catalyst. Free‐radical polymerization of this monomer created transparent, tough polymers that were insoluble in organic solvents. HMVK was converted to trimethylsilyl, acetate, and chloride derivatives. When the hydroxyl group was thus protected or removed, all these monomers could be free radically polymerized in bulk to make soluble polymers. The chlorination reaction is complicated by the formation of 1,1‐bischloromethylacetone, which dehydrohalogenated unexpectedly to the desired α‐chloromethyl methyl vinyl ketone. HMVK will self‐condense to an ether dimer in the presence of a catalytic acid. This reagent is capable of crosslinking many alkene monomers through hydrolytically stable ether bonds. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 509–516, 2000