| 1. |
- Lüchow, Mads, et al.
(författare)
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Modular, synthetic, thiol-ene mediated hydrogel networks as potential scaffolds for 3D cell cultures and tissue regeneration
- 2020
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Ingår i: Journal of Polymer Science. - : John Wiley and Sons Inc. - 2642-4150 .- 2642-4169. ; 58:22, s. 3153-3164
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Tidskriftsartikel (refereegranskat)abstract
- Natural polymers such as collagen are popular materials for tissue engineering scaffolds due to their innate bioactivity and biocompatibility. Being derived from animal sources, however, means that batch-to-batch consistency is often low and the extraction of collagen is costly. This conundrum facilitates the need for synthetic alternatives as scaffolding materials. In this study, a system of poly(ethylene glycol) (PEG)-based thiol-ene coupled (TEC) hydrogel scaffolds is presented for tissue engineering purposes. The platform includes several necessary features, namely cytocompatibility, high swelling ability, biodegradability, tunable stiffness, and fast, straightforward fabrication. The swelling ability is provided by the hydrophilicity of the ether-links of PEG, which facilitated the formation of high water content hydrogels that match the water content of soft tissues for the proper diffusion of nutrients and waste compounds. TEC ensures fast and facile fabrication, with cross-linking moieties that allow for the biodegradation of the hydrogel network through hydrolytic cleavage. The mechanical properties of the scaffolds are made tunable in the range of storage moduli spanning <1 kPa to >100 kPa. It is also shown that despite the synthetic nature of the hydrogels, human dermal fibroblasts and murine macrophages, Raw 264.7, were able to survive and produce extracellular protein excretions while embedded in the 3D hydrogels.
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| 2. |
- Ouyang, Yingwei, 1995, et al.
(författare)
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High-temperature creep resistant ternary blends based on polyethylene and polypropylene for thermoplastic power cable insulation
- 2021
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Ingår i: Journal of Polymer Science. - : Wiley. - 2642-4150 .- 2642-4169. ; 59:11, s. 1084-1094
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Tidskriftsartikel (refereegranskat)abstract
- The impact of a small amount of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) on the thermomechanical and electrical properties of blends comprising low-density polyethylene (LDPE) and isotactic polypropylene (PP) is investigated. SEBS is found to assemble at the PP:LDPE interface as well as within isolated PP domains. The addition of 10 wt% SEBS significantly increases the storage modulus between the melting temperatures of the two polyolefins, 110 and 160°C, and results in improved resistance to creep during both tensile deformation as well as compression. Furthermore, the ternary blends display a very low direct-current (DC) conductivity as low as 3.4 × 10 S m at 70°C and 30 kV mm , which is considerably lower than values measured for neat LDPE. The here presented type of ternary blend shows potential as an insulation material for high-voltage direct current power cables.
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| 3. |
- Reiter, Manuel, et al.
(författare)
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Tuning the glass transition of siloxane-based poly(ionic liquid)s towards high ion conductivity
- 2021
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Ingår i: Journal of Polymer Science. - : Wiley. - 2642-4150 .- 2642-4169. ; 59:14, s. 1518-1527
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report a simple and versatile synthetic approach towards siloxane-based poly(ionic liquid)s (PILs) with unusually low glass transition temperatures (Tg) down to −73°C, and thus “liquid-like” behavior at room temperature. We designed a polydimethylsiloxane-derived copolymer carrying dialkylimidazolium moieties, and by careful selection of the side-chain length and the type of anions we were able to manipulate its Tg over a wide range and reach high ionic conductivities (σDC) up to 4.8 × 10−5 S/cm at 300 K. The ionized species make up only a minor fraction (<25 mol%) of the overall repeating units and are supposedly randomly distributed: Yet our results indicate dramatic effects on the thermal properties due to repulsive interactions between ionic and non-ionic segments.
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| 4. |
- Sandberg, Olov, et al.
(författare)
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Thermal conductivity and heat capacity of liquid and glassy poly(vinyl acetate) under pressure
- 1980
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Ingår i: Journal of Polymer Science. - : John Wiley & Sons. - 2642-4150 .- 2642-4169. ; 18:10, s. 2123-2133
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Tidskriftsartikel (refereegranskat)abstract
- The dependence of thermal conductivity λ and heat capacity per unit volume pcp on temperature and pressure for poly(vinyl acetate) has been measured by a transient hot-wire probe technique. The measurements were made under pressures up to 0.5 GPa over a temperature range of 270–470 K. The temperature coefficient of thermal conductivity (∂ lnλ/∂T)p was found to increase with pressure for both the liquid and the glassy state. The change in heat capacity per unit volume in the region of the glass-transition temperature was found to decrease with increasing pressure. The Ehrenfest relation does not explain the variation of the pressure coefficient of the glass-transition temperature.
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| 5. |
- Schraff, Sandra, et al.
(författare)
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Asymmetric chain-growth synthesis of polyisocyanide with chiral nickel precatalysts
- 2020
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Ingår i: Journal of Polymer Science. - : WILEY. - 2642-4150 .- 2642-4169. ; 58:16, s. 2221-2233
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Tidskriftsartikel (refereegranskat)abstract
- Nickel(II)-aryl complexes [(L-2)Ni(Ar)Br] bearing either chiral phosphine ligands (L-2=RR- orSS-DIPAMP, Ar =ortho-anisyl), or a chiral aryl-group have been prepared, and their structural optical an chiroptical properties have been characterized. Enantiomeric pairs of both catalysts have been used for the asymmetric polymerization of different isocyanides (M1,M2,M3), to give well defined polyisocyanides (P1,P2,P3). Their polymerization behavior has been studied, which confirmed chain-growth polymerization in all cases. The asymmetric induction has been verified by circular dichroism spectroscopy on enantiomeric pairs of all three polymers.
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| 6. |
- Shi, Tianhui, et al.
(författare)
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Postsynthetic amine modification of porous organic polymers for CO2 capture and separation
- 2024
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Ingår i: Journal of Polymer Science. - : John Wiley & Sons. - 2642-4150 .- 2642-4169. ; 62:8, s. 1554-1568
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Tidskriftsartikel (refereegranskat)abstract
- Porous organic polymers (POPs) constitute an important class of sorbents studied in various adsorption and separation processes. Their unique properties, including high surface areas, adjustable pore sizes, and surface chemistries make them ideal candidates for CO2 capture. To achieve a high CO2 adsorption capacity and selectivity, particularly at the low partition pressures required for post-combustion CO2 capture or direct capture of CO2 from the atmosphere, incorporating amines onto the polymer frameworks or within the pores has shown much promise. This review provides a comprehensive summary of recent studies on the synthesis and CO2 capture performance of amine-functionalized POPs. The review also provides a detailed discussion of structure-performance relationships, focusing on how the loading amount and amine type influence CO2 capture capacity, CO2/N2 selectivity, heat of adsorption, sorption kinetics, and recyclability of POPs. Additionally, the authors offer their perspective on the challenges associated with the practical implementation of amine-modified POPs for CO2 capture.
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| 7. |
- Liu, Jiayin, et al.
(författare)
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Pressurised hot water extraction in continuous flow mode for thermolabile compounds : extraction of polyphenols in red onions
- 2014
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 406:2, s. 441-445
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Tidskriftsartikel (refereegranskat)abstract
- Extraction and analysis of labile compounds in complex sample matrices, such as plants, is often a big analytical challenge. In this work, the use of a "green and clean" pressurised hot water extraction (PHWE) approach performed in continuous flow mode is explored. Experimental data for extraction and degradation kinetics of selected compounds were utilised to develop a continuous flow extraction (CFE) method targeting thermolabile polyphenols in red onions, with detection by high-performance liquid chromatography (HPLC)-diode array detection (DAD)-mass spectrometry (MS). Water containing ethanol and formic acid was used as extraction solvent. Method performance was focused on extraction yield with minimal analyte degradation. By adjusting the flow rate of the extraction solvent, degradation effects were minimised, and complete extraction could be achieved within 60 min. The CFE extraction yields of the polyphenols investigated were 80-90 % of the theoretically calculated quantitative yields and were significantly higher than the yields obtained by conventional methanol extraction and static batch extraction (70-79 and 58-67% of the theoretical yields, respectively). The precision of the developed method was lower than 8 % expressed as relative standard deviation.
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