In the present work, a photopolymerized urethane-based poly(ethylene glycol) hydrogel is applied as a porous scaffold material using indirect solid freeform fabrication (SFF). This approach combines the benefits of SFF with a large freedom in material selection and applicable concentration ranges. A sacrificial 3D poly(ε-caprolactone) structure is generated using fused deposition modeling and used as template to produce hydrogel scaffolds. By changing the template plotting parameters, the scaffold channel sizes vary from 280 to 360 μm, and the strut diameters from 340 to 400 μm. This enables the production of scaffolds with tunable mechanical properties, characterized by an average hardness ranging from 9 to 43 N and from 1 to 6 N for dry and hydrated scaffolds, respectively. Experiments using mouse calvaria preosteoblasts indicate that a gelatin methacrylamide coating of the scaffolds results in an increased cell adhesion and proliferation with improved cell morphology.
Novel “all-acrylate” block copolymers have been synthesized by ATRP with a simple and cost-effective one-pot-two-step process. The (A−B)
n
copolymers are composed of an elastomer segment (A = P(2EHA-co-MA) = poly(2-ethylhexyl acrylate-co-methyl acrylate)) and a thermoplastic segment (B = PMMA =
poly(methyl methacrylate)). To study the relationship between the molecular architecture and the mechanical
properties, a four-arm radial block copolymer (A−B)4 is compared to the linear diblock (A−B)1 and symmetric
triblock (A−B)2 and compounds of similar composition. Atomic force microscopy (AFM) shows that all block
copolymers present a well-defined microphase separation, which is confirmed by the observation of two glass
transitions in DSC. Thermomechanical data from viscoelastic, indentation, and tensile measurements are discussed
in terms of the structural characteristics of the copolymers. The increase in the complexity of the molecular
structure results in an enhanced elastic response, and the stress−strain curves confirm the strengthening effect
with increasing molecular connectivity (radial > linear triblock) and end-block length.
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