Synthesis of poly(methyl methacrylate-g-α-methyl-β-alanine) [poly(MMA-g-mBA)] copolymer was achie... more Synthesis of poly(methyl methacrylate-g-α-methyl-β-alanine) [poly(MMA-g-mBA)] copolymer was achieved through base-catalyzed hydrogen transfer polymerization (HTP) and free-radical polymerization (FRP), respectively. For this purpose, poly(α-methyl β-alanine) [PmBA] oligomer with olefinic end-group as a macromonomer was synthesized from methacrylamide by base-catalyzed HTP method. Poly(MMA-g-mBA) in different compositions was obtained through FRP of methyl methacrylate/the PmBA macromonomer mixtures using the "grafting through" method. The characterization of the copolymerization products was accomplished by using multi-instruments such as 1 H-NMR, FTIR, TGA, and dynamic light scattering. The spectroscopic and thermal analysis of the graft copolymer reveal that the copolymer was easily built through a combination of HTP and FRP techniques.
Synthesis of poly(methyl methacrylate-g-β-alanine) [poly(MMA-g-BA)] brush-type graft copolymer wa... more Synthesis of poly(methyl methacrylate-g-β-alanine) [poly(MMA-g-BA)] brush-type graft copolymer was carried out by free-radical polymerization (FRP) of polyβ-alanine macromonomer with vinyl end-group and methyl methacrylate, that is, "grafting through" method. For this purpose, polyβ-alanine macromonomer with vinyl end-group was synthesized by base-catalyzed hydrogen transfer polymerization (HTP) of acrylamide monomer. The spectroscopic characterization of the products was determined by 1 H-NMR and FTIR. The molecular weights of the synthesized polyβ-alanine macromonomer and the graft copolymers were defined through MALDI-TOF-MS analysis and Static Light Scattering measurement, respectively. TGA and DSC techniques were performed to reveal the thermal properties of the products. The morphological properties of the products were examined by SEM analysis. The spectroscopic and thermal analyses of poly(MMA-g-BA) brush-type graft copolymer revealed that the copolymer was easily built through a combination of HTP and FRP techniques.
ABSTRACT Novel ABA-type block copolymers were prepared using end-groups activated poly(ethylene g... more ABSTRACT Novel ABA-type block copolymers were prepared using end-groups activated poly(ethylene glycol) (PEG) as an initiator for hydrogen transfer polymerization (HTP). For this purpose, PEG with average molar mass of 1450 Da (PEG-1450) was firstly treated with the equivalent amount of sodium hydride to synthesize PEG with dialkoxide end-groups, namely PEG-dialkoxide. Using the PEG-dialkoxide as a macroinitiator, base-catalyzed HTP of acrylamide, N-methoxypropyl acrylamide, and 2-hydroxyethyl acrylate were then performed to achieve the novel ABA-type block copolymers. The copolymers were obtained with high yields of about 90%. Characterization of the ABA-type copolymers was carried out using Fourier Transform Infrared Spectroscopy (FTIR spectroscopy) and Matrix Assisted Laser Desorption Ioizaton (MALDI) mass spectrometry. FTIR spectra of the copolymers exhibited some characteristic bands assigned to the functional groups arising from the mechanism of HTP. Molar mass distributions of the copolymers from the MALDI mass study pointed out that chain extensions by mass in each copolymer were almost equal. Hence, the MALDI mass spectra of the copolymers revealed that chain extensions of telechelic PEGs by β-alanine, 2-hydroxyethyl acrylate, and N-methoxypropyl β-alanine units were successfully fulfilled.
Oligomers of poly(3-hydroxypropionate) (P3HP) were synthesized via hydrogen transfer polymerizati... more Oligomers of poly(3-hydroxypropionate) (P3HP) were synthesized via hydrogen transfer polymerization of acrylic acid. Olefinic end-group of the oligomers were modified through epoxidation and bromination to obtain activated oligomers with epoxy and bromide end-groups, respectively. Terminally hydroxyl oligomeric poly(ethylene glycol) (PEG-1450) was also converted to sodium alkoxide of PEG-1450 through reaction with sodium hydride. Novel ABA type P3HP-b-PEG-b-P3HP triblock copolymers were successfully obtained through simple nucleophilic addition reactions between alkoxy and epoxy/alkyl bromide. Water uptake measurements of the triblock copolymers were calculated. Characterization of the modified oligomers and the triblock copolymers was performed by using FT-IR, 1H-NMR and MALDI-MS analyses. Thermal transitions and degradation features of the copolymers were investigated by using DSC and TGA methods. Spectroscopic and thermal analyses revealed that both end-group modifications and coupling reactions were successfully achieved.
Synthesis of poly(α-methyl β-alanine)-poly(ε-caprolactone) [PmBA-(PCL)2] tri arm star polymer was... more Synthesis of poly(α-methyl β-alanine)-poly(ε-caprolactone) [PmBA-(PCL)2] tri arm star polymer was accomplished by "click" chemistry. For this purpose, poly(α-methyl β-alanine) (PmBA) was synthesized from methacrylamide by hydrogen transfer polymerization (HTP). Terminally dibromo PmBA (PmBA-2Br) was obtained by using the end-group modification method. Terminally diazido poly(α-methyl β-alanine) [PmBA-2N3] was synthesized by the reaction of PmBA-2Br and sodium azide. Terminally propargyl poly(ε-caprolactone) [PCL-propargyl] was obtained using ε-caprolactone and propargyl alcohol by ring-opening polymerization. By the reaction of PCL-propargyl and PmBA-2N3, PmBA-(PCL)2 tri arm star polymer was synthesized via "click" chemistry. The characterizations of products were performed by using multi instruments including 1H-NMR, FT-IR, MALDI-MS, GPC, and SEM. Degradation features of the tri arm star polymer was investigated by using TGA technique. Water uptake measurement of the tri arm star polymer was performed. The multi instruments studies of the tri arm star polymer monitor that the polymer easily formed as a result of "click" chemistry.
ABSTRACT Gamma radiation-induced radicals of 2-methyl nylon3 (2mN3) have been investigated by ele... more ABSTRACT Gamma radiation-induced radicals of 2-methyl nylon3 (2mN3) have been investigated by electron spin resonance spectrometry. The type of radicals generated, conversion into other radicalic species and their room temperature stability were evaluated. Two types of radicals have been detected. Two different formation mechanisms have been proposed for each radical. As suggested in literature for commercial polyamides, in our system we also observed two different radicals (R1 and R2). Among these radicals, R1 is expected to convert to R2, which is a chemically favorable process.
3‐hydroxypropionate moieties grafted polystyrene [poly(S‐g‐3HP)] was prepared by sequentially app... more 3‐hydroxypropionate moieties grafted polystyrene [poly(S‐g‐3HP)] was prepared by sequentially applying the hydrogen‐transfer polymerization (HTP) and the free‐radical polymerization (FRP) via “grafting through” strategy. For this purpose, oligomeric poly(3‐hydroxypropionate) with vinyl end‐group (P3HP) was prepared via HTP of acrylic acid in the presence of tNaBuO as an alkaline catalyst. Then, the oligomeric P3HP was used as a comonomer in the FRP of styrene yielding the poly(S‐g‐3HP) copolymer, namely chemically modified polystyrene. 1H‐NMR, FTIR, DSC, TGA, GPC, and MALDI MS techniques were applied to confirm the structures of both the oligomer and modified polystyrene. Glass transition temperatures of the modified polystyrene samples were found to be decreased from 103 to 84 °C depending upon the amount of 3‐hydroxypropionate (3HP) moieties. Solution‐cast films were prepared by the polystyrene homopolymer and modified polystyrenes. The contact angle values were determined to decrease gradually from 87.5 to 53.7° with increasing the amount of the 3HP moiety grafted polystyrene.
Synthesis of poly(methyl methacrylate-g-α-methyl-β-alanine) [poly(MMA-g-mBA)] copolymer was achie... more Synthesis of poly(methyl methacrylate-g-α-methyl-β-alanine) [poly(MMA-g-mBA)] copolymer was achieved through base-catalyzed hydrogen transfer polymerization (HTP) and free-radical polymerization (FRP), respectively. For this purpose, poly(α-methyl β-alanine) [PmBA] oligomer with olefinic end-group as a macromonomer was synthesized from methacrylamide by base-catalyzed HTP method. Poly(MMA-g-mBA) in different compositions was obtained through FRP of methyl methacrylate/the PmBA macromonomer mixtures using the "grafting through" method. The characterization of the copolymerization products was accomplished by using multi-instruments such as 1 H-NMR, FTIR, TGA, and dynamic light scattering. The spectroscopic and thermal analysis of the graft copolymer reveal that the copolymer was easily built through a combination of HTP and FRP techniques.
Synthesis of poly(methyl methacrylate-g-β-alanine) [poly(MMA-g-BA)] brush-type graft copolymer wa... more Synthesis of poly(methyl methacrylate-g-β-alanine) [poly(MMA-g-BA)] brush-type graft copolymer was carried out by free-radical polymerization (FRP) of polyβ-alanine macromonomer with vinyl end-group and methyl methacrylate, that is, "grafting through" method. For this purpose, polyβ-alanine macromonomer with vinyl end-group was synthesized by base-catalyzed hydrogen transfer polymerization (HTP) of acrylamide monomer. The spectroscopic characterization of the products was determined by 1 H-NMR and FTIR. The molecular weights of the synthesized polyβ-alanine macromonomer and the graft copolymers were defined through MALDI-TOF-MS analysis and Static Light Scattering measurement, respectively. TGA and DSC techniques were performed to reveal the thermal properties of the products. The morphological properties of the products were examined by SEM analysis. The spectroscopic and thermal analyses of poly(MMA-g-BA) brush-type graft copolymer revealed that the copolymer was easily built through a combination of HTP and FRP techniques.
ABSTRACT Novel ABA-type block copolymers were prepared using end-groups activated poly(ethylene g... more ABSTRACT Novel ABA-type block copolymers were prepared using end-groups activated poly(ethylene glycol) (PEG) as an initiator for hydrogen transfer polymerization (HTP). For this purpose, PEG with average molar mass of 1450 Da (PEG-1450) was firstly treated with the equivalent amount of sodium hydride to synthesize PEG with dialkoxide end-groups, namely PEG-dialkoxide. Using the PEG-dialkoxide as a macroinitiator, base-catalyzed HTP of acrylamide, N-methoxypropyl acrylamide, and 2-hydroxyethyl acrylate were then performed to achieve the novel ABA-type block copolymers. The copolymers were obtained with high yields of about 90%. Characterization of the ABA-type copolymers was carried out using Fourier Transform Infrared Spectroscopy (FTIR spectroscopy) and Matrix Assisted Laser Desorption Ioizaton (MALDI) mass spectrometry. FTIR spectra of the copolymers exhibited some characteristic bands assigned to the functional groups arising from the mechanism of HTP. Molar mass distributions of the copolymers from the MALDI mass study pointed out that chain extensions by mass in each copolymer were almost equal. Hence, the MALDI mass spectra of the copolymers revealed that chain extensions of telechelic PEGs by β-alanine, 2-hydroxyethyl acrylate, and N-methoxypropyl β-alanine units were successfully fulfilled.
Oligomers of poly(3-hydroxypropionate) (P3HP) were synthesized via hydrogen transfer polymerizati... more Oligomers of poly(3-hydroxypropionate) (P3HP) were synthesized via hydrogen transfer polymerization of acrylic acid. Olefinic end-group of the oligomers were modified through epoxidation and bromination to obtain activated oligomers with epoxy and bromide end-groups, respectively. Terminally hydroxyl oligomeric poly(ethylene glycol) (PEG-1450) was also converted to sodium alkoxide of PEG-1450 through reaction with sodium hydride. Novel ABA type P3HP-b-PEG-b-P3HP triblock copolymers were successfully obtained through simple nucleophilic addition reactions between alkoxy and epoxy/alkyl bromide. Water uptake measurements of the triblock copolymers were calculated. Characterization of the modified oligomers and the triblock copolymers was performed by using FT-IR, 1H-NMR and MALDI-MS analyses. Thermal transitions and degradation features of the copolymers were investigated by using DSC and TGA methods. Spectroscopic and thermal analyses revealed that both end-group modifications and coupling reactions were successfully achieved.
Synthesis of poly(α-methyl β-alanine)-poly(ε-caprolactone) [PmBA-(PCL)2] tri arm star polymer was... more Synthesis of poly(α-methyl β-alanine)-poly(ε-caprolactone) [PmBA-(PCL)2] tri arm star polymer was accomplished by "click" chemistry. For this purpose, poly(α-methyl β-alanine) (PmBA) was synthesized from methacrylamide by hydrogen transfer polymerization (HTP). Terminally dibromo PmBA (PmBA-2Br) was obtained by using the end-group modification method. Terminally diazido poly(α-methyl β-alanine) [PmBA-2N3] was synthesized by the reaction of PmBA-2Br and sodium azide. Terminally propargyl poly(ε-caprolactone) [PCL-propargyl] was obtained using ε-caprolactone and propargyl alcohol by ring-opening polymerization. By the reaction of PCL-propargyl and PmBA-2N3, PmBA-(PCL)2 tri arm star polymer was synthesized via "click" chemistry. The characterizations of products were performed by using multi instruments including 1H-NMR, FT-IR, MALDI-MS, GPC, and SEM. Degradation features of the tri arm star polymer was investigated by using TGA technique. Water uptake measurement of the tri arm star polymer was performed. The multi instruments studies of the tri arm star polymer monitor that the polymer easily formed as a result of "click" chemistry.
ABSTRACT Gamma radiation-induced radicals of 2-methyl nylon3 (2mN3) have been investigated by ele... more ABSTRACT Gamma radiation-induced radicals of 2-methyl nylon3 (2mN3) have been investigated by electron spin resonance spectrometry. The type of radicals generated, conversion into other radicalic species and their room temperature stability were evaluated. Two types of radicals have been detected. Two different formation mechanisms have been proposed for each radical. As suggested in literature for commercial polyamides, in our system we also observed two different radicals (R1 and R2). Among these radicals, R1 is expected to convert to R2, which is a chemically favorable process.
3‐hydroxypropionate moieties grafted polystyrene [poly(S‐g‐3HP)] was prepared by sequentially app... more 3‐hydroxypropionate moieties grafted polystyrene [poly(S‐g‐3HP)] was prepared by sequentially applying the hydrogen‐transfer polymerization (HTP) and the free‐radical polymerization (FRP) via “grafting through” strategy. For this purpose, oligomeric poly(3‐hydroxypropionate) with vinyl end‐group (P3HP) was prepared via HTP of acrylic acid in the presence of tNaBuO as an alkaline catalyst. Then, the oligomeric P3HP was used as a comonomer in the FRP of styrene yielding the poly(S‐g‐3HP) copolymer, namely chemically modified polystyrene. 1H‐NMR, FTIR, DSC, TGA, GPC, and MALDI MS techniques were applied to confirm the structures of both the oligomer and modified polystyrene. Glass transition temperatures of the modified polystyrene samples were found to be decreased from 103 to 84 °C depending upon the amount of 3‐hydroxypropionate (3HP) moieties. Solution‐cast films were prepared by the polystyrene homopolymer and modified polystyrenes. The contact angle values were determined to decrease gradually from 87.5 to 53.7° with increasing the amount of the 3HP moiety grafted polystyrene.
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