Abdülkadir Kuyulu

Preparation and characterization of novel UV-curable urethane methacrylate difunctional monomers and their structure-property relationships, 1

Four new UV-curable cross-linking agents namely 2,2-bis(4-β-ethoxy urethane ethyl methacrylate phenyl)propane (HEPAIEM), 2,2-bis(4-β-ethoxy urethane ethyl methacrylate phenyl)6Fpropane (HEPFAIEM), 2,2-bis(4-β-ethoxy urethane ethyl methacrylate-3,5-dibromo phenyl)propane (TBHEPAIEM), and 5-tert-butyl-1,3-bis(4-ethoxy urethane methacrylate phenyl)benzoylbenzene (tBuHEPBIEM), which can be good candidates for UV-curable coating applications, were synthesized by reacting isocyanato ethyl methacrylate (IEM) with four different diols. The structures of the monomers thus prepared were characterized by FTIR, mass and 1 H NMR spectroscopies. Introduction of new difunctional cross-linking agents affected the mechanical and physical properties of UV-cured films. Addition of 10% cross-linking agents into the formulations caused an increase both in tensile strength and elongation, when compared with widely used di(ethylene glycol)diacrylate (DEGDA) containing films. Elongation values of TBHEPAIEM containing films were exceptions. Gel contents of the UV-cured polymeric films were found to be between 88-98%. Thermogravimetric analysis showed that there were not any noticeable changes in thermal oxidative stability of the films compared with DEGDA containing ones. On the other hand, HEPFAIEM and TBHEPAIEM containing films showed increases in char yields due to the presence of F and Br in their structures. Introduction of the new difunctional monomers lowered the water absorption values of the films somewhat proportional to the methyl group content of the x-linkers.

Effect of diluents on the porous structure of crosslinked poly(methyl methacrylate) beads

SummaryCopolymer beads based on methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM) were prepared by suspension polymerization technique. Two different solvents, namely toluene and cyclohexane, were used as the diluents in the polymerization system. It was found that toluene produces pores of radii 2 to 10 nm corresponding to the interstices between the nuclei. In the case of cyclohexane as the diluent, formation of large pores with a broad size distribution from 10 to 1000 nm were observed. These sizes correspond to the spaces between the microspheres and the aggregates forming the copolymer beads. The results indicate that, as in porous styrene-divinylbenzene copolymers, the solvating power of the diluent present during the network formation is mainly responsible for the structural characteristics of porous MMA/EGDM copolymer beads.

Kinetic Investigations of Formation of Polyimides Containing Arylene Sulfone Ether Linkages by Potentiometric Titration and Their Characterization

In this work, thermal solution imidization kinetics of two high performance polyimides, prepared from the polycondensation of pyromellitic dianhydride (PMDA) and 3,3*,4,4*-benzophenonetetracarboxylic dianhydride (BTDA) with 4,4*-bis(3- aminophenoxy)diphenylsulfone (DAPDS) were investigated using nonaqueous titra- tion technique with tetramethylammonium hydroxide. Most of the kinetic investiga- tions, found in the literature, are based on the aromatic p-diamines. 1,2 In the present work, attention was focused on imidization kinetics with m-substituted aromatic di- amines having electron donating ({O{) and electron withdrawing ({SO2{) groups in the same molecule. Kinetic parameters, namely the rate constants, activation energ- ies, entropies and enthalpies of imidization reactions were determined and compared with the literature values. It is reported in literature 3 that electron affinities of dianhy- drides and ionization potentials of diamines, have strong influence on the reaction rate and activation energies of imidization. Activation energy (Ea) values were found to be 66 and 57 kJ/mol for DAPDS/PMDA and DAPDS/BTDA respectively, and order of reaction was found to be second order. Polyimides DAPDS/PMDA and DAPDS/BTDA, subjected to kinetic investigation, showed glass transition temperatures of 2677C and 2417C, both were found to be thermally stable up to 5007C. q 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2981-2990, 1997

Preparation and Characterization of Novel UV-Curable Ester Methacrylate Crosslinking-Agents and Their Structure-Property Relationships, 2

Four, new difunctional monomers namely 2,2-bis(4-ethoxyacrylatephenyl)propane (HEPAAC), 2,2-bis(4-ethoxyacrylatephenyl)6Fpropane (HEPFAAC), 2,2-bis(4-ethoxyacrylate-3,5-dibromphenyl)propane (TB-HEPAAC) and 5-tert-butyl-1,3-bis(4-ethoxyacrylate benzoyl)benzene (tBuHEPBAC) containing acrylic moiety, which can be good candidates as x-linking agents for UV curable coating applications, were synthesized by reacting acryloyl chloride with four different diols. The structures of the monomers thus prepared were characterized by FTIR, mass and 1 H NMR spectroscopies. Introduction of 10% of these new monomers into the UV-curable formulations, caused different behaviors in tensile strengths and elongations, when compared with diethylene glycol diacrylate (DEGDA) containing films. Both elongation and tensile strength values were decreased for TBHEPAAC and tBuHEPBAC containing films, while the same values of the films containing HEPAAC and HEPFAACs increased. Gel contents of the UV-cured polymeric films were found to be between 88-98%. Thermogravimetric analysis showed that there were not appreciable changes in thermal stability of the films compared to DEGDA containing ones. On the other hand, HEPFAAC and tBuHEPAAC containing films showed increased in char yields due to the presence of F and Br in their structures. Introduction of the new difunctional monomers lowered the water absorption values of the films somewhat proportional to the methyl group content of the x-linkers.

Effects of nonreactive resins on the properties of a UV-curable methacrylated urethane resin

The effects of two nonreactive conventional-type resins, a bisphenol-A-based phenoxy resin PAPHEN-301 and aromatic-based PETROLEUM RESIN, on the mechanical, thermal, and physical properties of methacrylated urethane resin-based UV-curable formulations were studied. A methacrylated urethane prepolymer was synthesized from isocyanatoethyl methacrylate (IEM) and polytetrahydrofurandiol (PTHF) via a one-step reaction. An increase in PAPHEN-301 content caused an increase both in tensile strength and elongation values of UV-cured polymeric films. On the other hand, an increase in PETROLEUM RESIN content caused a decrease both in tensile strength and elongation values of the polymeric films. However, thermooxidative properties were not affected by the introduction of either resin. It was also found that the water-absorption capacities of the UV-cured methacrylated urethane films depended on the type and amount of the nonreactive resins.

Novel poly(arylene ether ketone ketone)s synthesized by Friedel- Crafts acylation

SUMMARY: A series of novel poly(arylene ether ketone ketone)s were prepared from two novel oligomers and three different diacid chlorides via Friedel-Crafts polymerization. The oligomers 2,6-bis(4-phenoxybenzoyl)naphthalene and 5-tert-butyl-1,3-bis(4-phenoxybenzoyl)benzene were synthesized by Friedel-Crafts acylation of diphenyl ether with 2,6-naphthalenedicarbonyl dichloride and 5-tert-butylisophthaloyl dichloride, respectively, in the presence of AlCl 3 as catalyst. Friedel-Crafts polymerization of either of these two novel oligomers with tert-butylisophthaloyl dichloride, isophthaloyl dichloride or 1,6-hexanedioyl dichloride gave six novel PEKK’s, having Tg’s in the range of 135 ‐ 180 8C, but only the naphthalene-based PEKKs displayed Tm’s between 130 and 345 8C. PEKK’s containing the 5- tert-butylisophthaloyl group are soluble in polar solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-dimethylformamide, THF, chloroform etc. Polymer PA1, which has a fully unsubstituted aromatic chain structure, is insoluble in common organic solvents and, moreover, shows polymorphism. Intrinsic viscosities and adhesion behavior of soluble PEKKs were also determined.

Thermal and Mechanical Properties of Poly(arylene ether ketone)s Based on 5-tert-Butyl-1,3-bis(4- fluorobenzoyl)benzene

An aromatic bishalide, 5-tert-butyl-1,3-bis(4-fluorobenzoyl)benzene (2) was synthesized in high yield and purity by the reaction of 5-tert-butylisophthaloyl chloride (1) and fluorobenzene and polymerized by nucleophilic substitution reaction with commercially available aromatic bisphenols to prepare a series of high molecular weight poly(arylene ether ketone)s containing pendant tertiary butyl groups. The effect of molecular structure on the physical, thermal, mechanical and adhesion properties of the polymers was investigated.