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- Boujemaoui, Assya, et al.
(författare)
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Preparation and characterization of functionalized cellulose nanocrystals
- 2015
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 115, s. 457-464
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Tidskriftsartikel (refereegranskat)abstract
- In this work, a series of functional nanocrystals (F-CNCs) was successfully produced by an efficient preparation method, combining acid hydrolysis and Fischer esterification with various organic acids. Functionalities such as ATRP initiators, double bonds, triple bonds, and thiols could be incorporated on CNCs. Surface modification was confirmed by FT-IR, XPS, and elemental analysis. Physical properties of FC-NCs were assessed by AFM, XRD and TGA. Moreover, ATRP initiator functionalized CNCs were utilized to graft poly(methyl methacrylate) via ATRP, thiol functionalized CNCs were reacted with Ellman's reagent to determine the thiol content and dye disperse red 13 was attached to alkyne functionalized CNCs to estimate the propiolate content. The herein presented method is a highly versatile and straightforward procedure for the preparation of F-CNCs which is believed to be a better alternative for the commonly utilized, extensive, multistep, and time consuming post functionalization methods.
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| 2. |
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| 3. |
- Larsson, Emma, et al.
(författare)
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Thermoresponsive cryogels reinforced with cellulose nanocrystals
- 2015
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Ingår i: RSC Advances. - : RSC Publishing. - 2046-2069. ; 5:95, s. 77643-77650
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report the first study of thermoresponsive cryogels with cellulose nanocrystals (CNCs) incorporated into the structure. Free radical polymerization was utilized to synthesize cryogels of poly(N-isopropylacrylamide) (PNIPAAm), resulting in thermoresponsive gels after the cryo-polymerization. Two types of CNCs were investigated: one which had reactive vinyl groups on the surface, enabling covalent incorporation and crosslinking with the cryogel network; and one which had no reactive groups on the surface, rendering it physically embedded in the network. The degree of crosslinking of the cryogels was controlled by varying the addition of N,N'-methylenebisacrylamide (MBAm). The cryogels were analyzed by FE-SEM and were all found to be macroporous. The morphology of the gels was largely dependent on the reaction conditions and the presence of CNC. The swelling properties of the freeze-dried gels were investigated and all gels exhibited a thermoresponsive behavior. Our study showed that the incorporation of CNCs is an effective method to alter both the morphologies and the mechanical properties of a cryogel, although the final properties of the cryogels depend on several different parameters. Due to the complexity of the system, a clear trend regarding the CNC incorporation is difficult to conclude, but compression testing showed that a cryogel having 1 wt% of crosslinkable CNC was far superior to the other gels in terms of mechanical properties, exhibiting that the presence of crosslinkable groups on the surface of CNCs could have a large influence over the final properties.
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| 4. |
- Mongkhontreerat, Surinthra, et al.
(författare)
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Dendritic hydrogels : From exploring various crosslinking chemistries to introducing functions and naturally abundant resources
- 2015
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Ingår i: Journal of Polymer Science Part A. - : Wiley. - 0887-624X .- 1099-0518. ; 53:21, s. 2431-2439
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Tidskriftsartikel (refereegranskat)abstract
- Dendritic hydrogels from dendritic-linear-dendritic (DLD) block copolymers based on PEG and bis-MPA dendrons were constructed via UV-initiated thiol-ene, thiol-yne, CuAAC, and amine-NHS crosslinking chemistries. Stoichiometric ratio manipulations, prior to film formation, resulted in functional hydrogels with tuneable compressive moduli. The highest gel fractions for all networks were obtained at off-stoichiometric ratios with surplus of DLDs. Finally, sustainable networks were fabricated by amalgamating DLD, naturally abundant cellulose nanocrystal, and protein-based bovine serum albumin.
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