Candidate Monomers Research Articles

ChemInform Abstract: An Efficient Synthesis of α‐Acyloxyacrylate Esters as Candidate Monomers for Bio‐Based Polymers by Heteropolyacid‐Catalyzed Acylation of Pyruvate Esters.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: An Efficient Heteropolyacid Catalyzed Acylation of Pyruvate Esters to α‐Acyloxyacrylate Esters as Potential Candidate Monomers for Bio‐Based Polymers.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An efficient synthesis of α-acyloxyacrylate esters as candidate monomers for bio-based polymers by heteropolyacid-catalyzed acylation of pyruvate esters

A series of α-acyloxyacrylate esters are candidate monomers for bio-based polymers, converted from biomass feedstock. Polymers from these monomers are useful materials for bio-based plastics showing high heat resistance and transparency. In this paper, a new efficient method for α-acyloxyacrylate ester synthesis with a strong inorganic acid, heteropolyacid, is presented. The reaction in the presence of the heteropolyacid catalyst was carried out in liquid phase under mild conditions and showed higher productivity than that of the conventional synthesis with a typical organic acid, p-toluenesulfonic acid. Among the various heteropolyacids examined, α-Keggin-type tungsten-based phosphotungstic acid, H3PW12O40, showed the best performance, suggesting that the acid strength of the heteropolyacid is the crucial property for this reaction. We also found that pyruvate ester was consecutively converted into α-acyloxyacrylate estervia2,2-diacyloxypropionate ester.

A computational molecular design framework for crosslinked polymer networks

Crosslinked polymers are important in a very wide range of applications including dental restorative materials. However, currently used polymeric materials experience limited durability in the clinical oral environment. Researchers in the dental polymer field have generally used a time-consuming experimental trial-and-error approach to the design of new materials. The application of computational molecular design (CMD) to crosslinked polymer networks has the potential to facilitate development of improved polymethacrylate dental materials. CMD uses quantitative structure property relations (QSPRs) and optimization techniques to design molecules possessing desired properties. This paper describes a mathematical framework which provides tools necessary for the application of CMD to crosslinked polymer systems. The novel parts of the system include the data structures used, which allow for simple calculation of structural descriptors, and the formulation of the optimization problem. A heuristic optimization method, Tabu Search, is used to determine candidate monomers. Use of a heuristic optimization algorithm makes the system more independent of the types of QSPRs used, and more efficient when applied to combinatorial problems. A software package has been created which provides polymer researchers access to the design framework. A complete example of the methodology is provided for polymethacrylate dental materials.

An efficient heteropolyacid catalyzed acylation of pyruvate esters to α-acyloxyacrylate esters as potential candidate monomers for bio-based polymers

Alpha-acyloxyacrylate esters were efficiently synthesized from pyruvate esters and carboxylic anhydrides under mild conditions. These esters are potential candidate monomers for bio-based polymers with high durability and transparency. Tungsten-based Keggin type heteropolyacids, especially H(3)PW(12)O(40), worked more effectively as catalysts for this reaction than other typical acids.

Development of new bone cement utilizing low toxicity monomers.

Acrylic bone cement is self-curing cement comprising of liquid and powder component of methyl methacrylate (MMA). It has been used extensively in orthopedics; however, adverse effects were associated with its use. Hence we investigated in this paper the possibility of new cement utilizing methacrylates with lower toxicity than MMA. LD50s of candidate monomers were determined with administration to the medullary cavity of the rat's femur. 2-Ethylhexyl methacrylate (EHMA) and trimethylolpropane trimethacrylate (TMP) demonstrated greater LD50 values of 187 mg/kg and 380 mg/kg, respectively, than MMA (108 mg/kg); they were selected as the liquid components of the new cement. The copolymer of EHMA and cyclohexyl methacrylate was then selected as the powder component. With this combination, we developed the new cement (EHMA cement).Temperature rise during polymerization of EHMA cement was 9 degrees C-13 degrees C, which was significantly lower than that of conventional cement. The compression strength of the polymerized EHMA cement was 57 MPa without TMP, and 67 MPa with TMP (15 wt%). Thus we concluded that new EHMA cement was slightly inferior in the compression strength than the conventional cement. However, it was characterized by the low toxicity of utilized monomers and the low temperature rise during polymerization.

DFT study of molecular structure and electronic properties of fluoromethylpyrrole oligomers including di-, tri- and tetramer

Structural and electronic properties of oligomers including dimer, trimer and tetramer of fluoromethylpyrroles (FMPs), NC 4H 4–CH n F 3− n with n = 0, 1, 2, 3, and their radical cations have been studied using DFT-B3LYP method with 6–31G(d, p) basis set. FMPs are proposed in this research as candidate monomers for conducting polymers with modified characteristics compared to polypyrrole and polymethylpyrrole. A preliminary study using a set of ab initio computations (HF) with medium basis set was carried out on di-, tri- and tetramer in order to investigate the stability of configuration of polymer chains for FMPs. The B3LYP/6-31G** optimized geometry and stereochemistry show that the selectivity of branching of the propagating polymer chain is affected by the characteristics of the substitutions of monomer and, therefore, the growth pattern of the polymer chain can be predicted upon characterization of different centers of the monomers. Also, the results of this study, including quinoid coefficients, orbital energy spacing, charge- and spin-density distributions and electric dipole moment vectors show that conducting polymers consisted of trifluoromethyl pyrrole (Py-CF 3), compared with the other FMPs, are the most favorable to be used as monomers for conducting polymer structural and electronic properties.

Halomethylpyrroles as candidate monomers for conducting polymers: a theoretical study

Abstract Structural, electronic, thermochemical and electrical properties of mono-, di- and trihalomethylpyrroles (HMPys), NC 4 H 4 –CH n X 3 − n ; X = F, Cl, Br; n = 0, 1, 2, 3, and their radical cations have been studied using DFT-B3LYP method with 6-31G(d,p) basis set. Vibrational frequencies and NMR shielding constants of these compounds have also been calculated and analyzed. HMPys are proposed in this research as candidate monomers for conducting polymers with modified characteristics compared to polypyrrole and polymethylpyrrole. Stability of HMPy radical cations have been studied in detail and compared with available experimental data, including oxidation potentials. Results of the present study show that bromomethylpyrroles have the highest thermochemical stability and have higher characteristics for electropolymerization compared to fluoro- and chloromethylpyrroles. Stability of HMPys increases with increasing number of substituted halogen atoms.