Home About us Contact
|
Home About us Contact | ||
|
|
||
Reactive Monomer (reactive + monomer)
Selected AbstractsMultifunctional Polymethacrylates Obtained Via ATRP of Functional and Reactive Monomers Followed by Polymer Analogous Reaction with Functional AminesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 19 2008Dragos Popescu Abstract Starting from methyl methacrylate (MMA), butyl methacrylate (BMA), allyl methacrylate (AMA), phenoxycarbonyloxy ethyl methacrylate (PCEMA), and functional amines different multifunctional polymethacrylates are accessible. The reactive monomer PCEMA was synthesized starting from 2-hydroxyethyl methacrylate, and then copolymerized via ATRP with other methacrylates in order to obtain reactive copolymers which were subjected to polymer analogous reactions with different functional amines leading to multifunctional polymethacrylates. These can be used for the preparation of multifunctional surfaces. [source] Theoretical Modeling of the Phase Separation Dynamics in Blends of Reactive MonomersMACROMOLECULAR THEORY AND SIMULATIONS, Issue 5 2005Gregory R. Yandek Abstract Summary: Experimental observations of the dynamics of phase behavior for blends of reactive constituents, i.e. diglycidyl ether of bisphenol A (DGEBA), curing agent methylene dianiline (MDA), and a reactive liquid rubber (R45EPI), have been theoretically modeled by coupling system thermodynamics governed by a summation of the free energies of mixing and network elasticity with reaction kinetics and diffusion equations. Snap-shots of the temporal evolution of ternary phase diagrams have been established based on the self-condensation reactions of DGEBA-MDA and R45EPI as well as a cross-reaction between the two constituents forming a copolymer. Numerical solution of the proposed mean-field model provides good qualitative agreement with experimental results, namely, the observance of phase separation followed by a phase dissolution and subsequent secondary segregation in a 50/25.4/50 DGEBA/MDA/R45EPI mixture, as well as a single gradual phase separation in a 70/25.4/30 mixture. The phase separation dynamics are explained by a competition between the growth in molecular weights of the reactive species rendering the systems towards instability, and the formation of copolymer acting to compatibilize the mixtures. Theoretical phase diagram for a DGEBA/MDA/R45EPI system. [source] Influence of the copolymer architecture and composition on the response and mechanical properties of pH-sensitive fibersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Anasuya Sahoo Abstract A series of copolymers based on acrylonitrile (AN) and acrylic acid (AA) with varying architecture and composition were synthesized using free radical polymerization. The distribution of monomers in the copolymer chains could be successfully controlled by regulating the addition of more reactive monomer (AA). Copolymers having nearly random distribution of comonomer moieties to block type distribution with different composition (10,50 mol % AA) were synthesized to investigate the effect of polymer architecture and composition on pH response and mechanical properties of resultant structures. These copolymers were solution spun from dimethylformamide-water system, drawn in coagulation bath, and annealed at 120°C for 2 h to make pH-sensitive fibers which were structurally stable without the need of chemical crosslinking. The fibers from block copolymers showed significantly better tensile strength (34.3 MPa), higher retractive forces (0.26 MPa), and enhanced pH response (swelling 3890%) in comparison with fibers from random copolymer (13.55 MPa, 0.058 MPa, and 1723%, respectively). The tensile strength and retractive forces could be further improved to a value of 72 MPa and 0.36 MPa, respectively, by changing the composition of the block copolymer while retaining the swelling percentage similar to the random copolymer mentioned above. It is proposed that on processing to fibers, the block copolymers could form a segregated domain structure with separate domains of AA and AN, where AN domains were responsible for high structural integrity by providing connectivity among polymer chains, while AA domains showed improved response to changing pH of the environment. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Development of the powder reaction moulding processJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2009Lei Zhao Abstract BACKGROUND: The powder reaction moulding process uses a reactive monomer as carrier and binder for the moulding of metal or ceramic powders. De-binding is achieved using thermal depolymerisation which is followed by sintering to give the finished component. Binder can be recovered for re-use. RESULTS: Moulding compounds, with various powder volume fractions, have been prepared using stainless steel, silicon nitride and alumina with n-butyl cyanoacrylate as binder, and the stability of the compounds established. Rheological properties of the compounds have been measured using both pressure flow and drag flow methods. Compounds are strongly pseudoplastic. Comparison of experimental results with theoretical models, describing suspension flow behaviour shows that experimental maximum volume fractions are close to the theoretical volume fraction of 0.42 for silicon nitride, 0.68 for alumina and 0.7 for stainless steel. Differential scanning calorimetry and thermogravimetry have been used to simulate de-binding and show a rapid loss of binder through depolymerisation. Post-sintering porosity of the ceramic materials is high but this is thought to arise from the low pressure moulding techniques used. Porosity of the stainless steel mouldings is much lower. CONCLUSIONS: The results validate the powder reaction moulding idea and demonstrate applicability to three widely different powder materials. Copyright © 2008 Society of Chemical Industry [source] Free-radical copolymerization of 2,2,2-trifluoroethyl methacrylate and 2,2,2-trichloroethyl ,-fluoroacrylate: Synthesis, kinetics of copolymerization, and characterizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2010Jean-Marc Cracowski Abstract Copolymers based on 2,2,2-trifluoroethyl methacrylate (MATRIFE) and 2,2,2-trichlororoethyl ,-fluoroacrylate (FATRICE) were synthesized in good yields by radical process initiated by tert -butyl 2,2-dimethylperoxypropanoate. Molar composition of the obtained poly(MATRIFE- co -FATRICE) copolymers were assessed by means of 1H and 19F nuclear magnetic resonance spectroscopy and by elemental analysis. The reactivity ratios, ri, of both comonomers were determined from the Kelen-Tüdos and Finneman-Ross methods (rMATRIFE = 1.52 ± 0.03 and rFATRICE = 0.61 ± 0.03 at 74 °C) showing unexpectedly that MATRIFE is the more reactive monomer in copolymerization. Molecular weights and polydispersity indexes of poly(MATRIFE- co -FATRICE) copolymers were ranging between 1.47 and 2.68 × 104 g·mol,1 and from 1.44 to 2.21, respectively. Thermal properties of the resulting polymers were examined and thermogravimetric analyses showed a satisfactory thermal stability, a thermal decomposition occurring from 220 to 295 °C as the molar ratio of FATRICE increased in the copolymer. Moreover, the glass transition temperatures of copolymers varied from 66 to 108 °C and also increased with FATRICE molar ratio in the copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2154,2161, 2010 [source] Aryl acrylate based high-internal-phase emulsions as precursors for reactive monolithic polymer supportsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2005Peter Krajnc Abstract Water-in-oil high-internal-phase emulsions (HIPEs), containing 4-nitrophenyl acrylate and 2,4,6-trichlorophenyl acrylate as reactive monomers, were prepared and polymerized, and highly porous monolithic materials resulted. The novel materials were studied by combustion analysis, Fourier transform infrared spectroscopy scanning electron microscopy, mercury porosimetry, and N2 adsorption/desorption analysis. With both esters, cellular macroporous monolithic polymers were obtained; the use of 4-nitrophenyl acrylate resulted in a cellular material with void diameters between 3 and 7 ,m and approximately 3-,m interconnects, whereas the use of 2,4,6-trichlorophenyl acrylate yielded a foam with void diameters between 2 and 5 ,m, most interconnects being around 1 ,m. The resulting monoliths proved to be very reactive toward nucleophiles, and possibilities of functionalizing the novel polymer supports were demonstrated via reactions with amines bearing additional functional groups and via the synthesis of an acid chloride derivative. Tris(hydroxymethyl)aminomethane and tris(2-aminoethyl)amine derivatives were obtained. The hydrolysis of 4-nitrophenylacrylate removed the nitrophenyl group, yielding a monolithic acrylic acid polymer. Furthermore, functionalization to immobilized acid chloride was performed very efficiently, with more than 95% of the acid groups reacting. The measurement of the nitrogen content in 4-nitrophenyl acrylate poly(HIPE)s after various times of hydrolysis showed the influence of the total pore volume of the monolithic polymers on the velocity of the reaction, which was faster with the more porous polymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 296,303, 2005 [source] Bicyclobutanes and cyclobutenes: Unusual carbocyclic monomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2003H. K. Hall Jr. Abstract Bicyclobutanes and cyclobutenes substituted with electron-attracting groups represent novel classes of reactive monomers. They readily undergo free-radical and anionic polymerizations to give high polymers consisting of 1,3- and 1,2-enchained cyclobutane rings, respectively. They also copolymerize readily with conventional vinyl monomers. These polymers display numerous attractive properties in comparison with their vinyl counterparts, including enhanced thermal stability, superior optical properties, and higher glass-transition temperatures. The syntheses of these monomers are reviewed, and suggestions toward future larger scale production are made. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 625,635, 2003 [source] Monte Carlo Simulation of Polymer Reactions at InterfacesMACROMOLECULAR THEORY AND SIMULATIONS, Issue 4 2007Andreas John Abstract Adhesion of immiscible polymers during two-component injection moulding may be improved by transreactions of properly functionalised components. We performed MC simulations based on the three-dimensional coarse-grained bond fluctuation model (BFM) including a thermal interaction potential in with energy to characterise the behaviour of several selected types of chemical reactions, which are governed by activation energies of EA,=,0, 1, 3 and 5 kBT. The consumption of reactive monomers for all the reactions in the time interval below the Rouse time ,R exhibits a typical crossover from a kinetic-controlled to a diffusion-controlled behaviour and can be described by a bimolecular kinetic ansatz. [source] | ||||||||||