| 1. |
- Andronova, Natalia, et al.
(författare)
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Potential tissue implants from the networks based on 1,5-dioxepan-2-one and epsilon-caprolactone
- 2005
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Ingår i: Polymer journal. - : Elsevier BV. - 0032-3896 .- 1349-0540. ; 46:18, s. 6746-6755
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and characterization of degradable polymeric networks for biomedical applications was performed. Cross-linked films of poly(epsilon-caprolactone) (PCL) and poly(1,5-dioxepan-2-one) (PDXO) having various mole fractions of monomers and different cross-link densities were successfully prepared using 2,2'-bis-(epsilon-caprolactone-4-yl) propane (BCP) as cross-linking agent. Reaction parameters were carefully examined to optimise, the film-formin.,, conditions. Networks obtained were elastomeric materials. easy to cast and remove from the mould. Effect of CL content and cross-link density on the final properties of the polymer network was evaluated. High CL content or degree of cross-linking led to increase in Young's modulus and decrease in elongation at break. An increase in crystalline domains in films having a higher CL content was observed by optical microscopy. A greater thermal stability was observed in films having a high CL content. The hydrophilicity of the materials could be tailored by changing the CL content. The surface of the films became rougher with higher CL content.
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| 2. |
- Li, Zhenguang, et al.
(författare)
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A concentrated poly(ethylene carbonate)/poly(trimethylene carbonate) blend electrolyte for all-solid-state Li battery
- 2019
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Ingår i: Polymer journal. - : NATURE PUBLISHING GROUP. - 0032-3896 .- 1349-0540. ; 51:8, s. 753-760
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical and ion-transport properties of polymer blend electrolytes comprising poly(ethylene carbonate) (PEC), poly (trimethylene carbonate) (PTMC) and lithium bis(fluorosulfonyl) imide (LiFSI) were studied in this work, and the electrolyte with the best blend composition was applied in all-solid-state Li batteries. The ionic conductivity of both PEC and PTMC single-polymer electrolytes increased with increasing Li salt concentration. All PEC and PTMC blend electrolytes show ionic conductivities on the order of 10(-5) S cm(-1) at 50 degrees C, and the ionic conductivities increase slightly with increasing PEC contents. The PEC6PTMC4-LiFSI 150 mol% electrolyte demonstrated better Li/electrolyte electrochemical and interfacial stability than that of PEC and PTMC single-polymer electrolytes and maintained a polarization as low as 5 mV for up to 200 h during Li metal plating and stripping. A Li vertical bar SPE vertical bar LFP cell with the PEC6PTMC4-LiFSI 150 mol% electrolyte exhibited reversible charge/discharge capacities close to 150 mAh g(-1) at 50 degrees C and a C/10 rate, which is 88% of the theoretical value (170 mAh g(-1)).
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| 3. |
- Olsson, Gustaf D., et al.
(författare)
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Simulation of imprinted emulsion prepolymerization mixtures
- 2015
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Ingår i: Polymer journal. - : Springer Science and Business Media LLC. - 0032-3896 .- 1349-0540. ; 47:12, s. 827-830
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop protocols for and evaluate the use of all-atom full system molecular dynamic (MD) simulations of emulsion systems in the development of molecularly imprinted polymers (MIPs). Here, we report on the first, to the best of our knowledge, use of all-component MD studies to simulate and evaluate MIP miniemulsion prepolymerization mixtures; in this case, the mixtures used in the synthesis of a series of MIP-nanoparticles (MIP-NPs).
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| 4. |
- Tunell, Helena, et al.
(författare)
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Synthesis and Characterization of Main Chain Polyimides Containing Chalcone Derivatives for LC Alignment
- 2006
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Ingår i: Polymer Journal. - 0032-3896 .- 1349-0540. ; 38:7, s. 716-723
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Tidskriftsartikel (refereegranskat)abstract
- Two soluble polyimides containing chalcone derivatives in the main chains were successfully prepared using the Mitsunobu reaction at room temperature, reacting diols with diimides. With this reaction procedure the high temperature imidization step normally needed for the synthesis of polyimides is avoided and the polymers can be used for temperature sensitive applications. The main chain polyimides were characterized with FT-IR, NMR and DSC and the extent of the photoreaction was measured with FT-IR and UV-vis spectroscopy. Isobestic points were observed in the absorption spectral changes at the early stage of UV irradiation as a result of a single photochemical process. Further photoirradiation is accompanied by deviation from the isobestic points, implying that another photochemical process has started. With FT-IR investigations it was concluded that photodimerization is the process occurring at low UV exposure doses and that trans-cis isomerization is starting simultaneously at higher doses. The optical anisotropic properties were investigated upon exposure of the polymers as thin films to linearly polarized UV (LPUV) light of different doses. Selected crosslinking in the parallel direction relative to the direction of the LPUV light and subsequent optical anisotropy in the film were achieved.
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| 5. |
- Yamaguchi, Syuhei, et al.
(författare)
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Green polymer chemistry : lipase-catalyzed synthesis of bio-based reactive polyesters employing itaconic anhydride as a renewable monomer
- 2014
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Ingår i: Polymer journal. - : Springer Science and Business Media LLC. - 0032-3896 .- 1349-0540. ; 46:1, s. 2-13
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Tidskriftsartikel (refereegranskat)abstract
- Itaconic acid is a platform compound for bio-based renewable materials. This study employs itaconic anhydride (IAn) as a novel monomer for lipase-catalyzed ring-opening addition condensation polymerization (ROACP) involving dehydration to produce reactive polyesters. ROACP reactions were conducted by combining a cyclic anhydride and a diol. IAn, succinic anhydride (SAn) and glutaric anhydride (GAn) were used as the cyclic anhydrides, and 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol and 1,10-decanediol were used as the diols. ROACP between two monomers, IAn and a diol, did not occur. Model reactions using IAn and n-octyl alcohol provided useful information about the regioselectivity and substrate selectivity of IAn. ROACP using three monomer components, IAn, SAn or GAn, and a diol, produced polyesters in good-to-high yields. From the SAn reactions, polyesters with M-n values of 650-3510 with 1.3-2.6 IAn units per molecule were obtained. From the GAn reactions, these values were 560-3690 and 1.2-3.1, respectively. The crosslinking reaction of a product polyester showed its reactive nature, giving a crosslinked hard solid polyester. The present polyesters derived from renewable starting materials have potential applications as macromonomers, telechelics, or crosslinking reagents, and the benign character of the ROACP reaction makes it appropriate for green polymer chemistry.
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| 6. |
- Zhang, L. N., et al.
(författare)
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Triple helix of beta-D-glucan from Lentinus Edodes in 0.5 M NaCl aqueous solution characterized by light scattering
- 2001
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Ingår i: Polymer journal. - : Springer Science and Business Media LLC. - 0032-3896 .- 1349-0540. ; 33:4, s. 317-321
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Tidskriftsartikel (refereegranskat)abstract
- beta-(1 -->3)-D-glucan with (1 -->6) branching (L-FV-I) from Lentinus edodes in water was degraded into seven fractions of different molecular weights by ultrasonic irradiation. Weight-average molecular weight M,, radius of gyration (1/2)(5) and intrinsic viscosity [eta] of the beta -D-glucan and its fractions in 0.5 M NaCl aqueous solution and dimethylsulfoxide (DMSO) were studied by multi-angle laser light scattering (MALLS), GPC combined with MALLS, and viscometry. M, dependence of [eta] for the glucan in 0.5 M NaCl aqueous solution was represented approximately by [eta] =7.69 x 10(-6) M-w(1.32) (cm(3) g(-1)) at M-w from 1.87 X 10(5) to 1.20 X 10(6) at 25 degreesC. GPC chromatograms of the glucans in aqueous solution contained two peaks, a main peak corresponding to triple-stranded chains with molecular weight M-w,M-m, and small second peak corresponding to fragments of single chains with M-w,M-s (about 20 +/-5% content). Analysis of M-w,M-m and (1/2)(z,m) in term of the known theory for wormlike chains yielded 2180 +/- 100 nm(-1), 120 +/- 10 nm and 0.31 nm for molar mass per unit contour length M-L, persistence length q, and contour length h per main-chain glucose residue, respectively, which agree closely with theory data of triple-helical chains and reported parameters for triple-helix schizophyllan in 0.01 M NaOH aqueous solution. The ratios of M-w,M-m, in 0.5 M NaCl to M, in DMSO were calculated to be roughly 3. The predominant species of the glucan in 0.5 M NaCl aqueous solution exist as triple-helical chains with high rigidity, and in DMSO as single-flexible chains.
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| 7. |
- Zhang, L., et al.
(författare)
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Transition from triple helix to coil of Lentinan in solution measured by SEC, viscometry, and C-13 NMR
- 2002
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Ingår i: Polymer journal. - : Springer Science and Business Media LLC. - 0032-3896 .- 1349-0540. ; 34:6, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- Lentinan, beta-(1 --> 3)-D-glucan with (1 --> 6) branching, was isolated from Lentinus edodes. Weight-average molecular weight M-w radius of gyration < s(2) > (1/2) and intrinsic viscosity [eta] of Lentinan in 0.2 M NaCl aqueous solution, dimethylsulfoxide (DMSO) and water/DMSO mixtures were measured by light scattering (LS), size exclusion chromatography (SEC) combined with LS, and viscometry. The results indicated that the glucan exists mainly as triple-helical chains in 0.2 M NaCl aqueous solution and water/DMSO mixtures with over 20 wt% water content, and as single-flexible chain in DMSO. The data from SEC-LS, viscosity and C-13 NMR measurements proved strongly that the helix-coil conformation transition occurred in a narrow range from 80 to 85 wt% DMSO aqueous solution, accompanying with obvious changes of M-w, < s(2) >(1/2)(z), [eta] as well as signals of C6 and C6(s). The transition of Lentinan in water/DMSO mixture was irreversible. The difference in C-13 NMR spectra for the triple-helical and coil conformations was the disappearance of the signals of C3 in beta-(1 --> 3)- linked backbone and the enhancement in relative intensities of glucose substituted C6s in the helix state, as well as the appearance of an asymmetric and broad peak of C6 in the intermediate of the conformation change. This suggests that the immobilization of the backbone by binding with intra and intermolecular hydrogen bonds resulted in the loss of the signals of its carbon atoms in the triple helix state. An overcoating cylinder model composed of the beta-(1 --> 3)- linked backbone as helix core and the side chains as rotatable overcoat was proposed to illustrate the triple-helical conformation and its transition in the solution.
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