Browsing by Author "Terraza, C. A."

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    Biocompatible and bioactive PEG-Based resin development for additive manufacturing of hierarchical porous bone scaffolds
    (2023) Sarabia-Vallejos, Mauricio A.; Cerda-Iglesias, Felipe E.; Terraza, C. A.; Cohn-Inostroza, Nicolas A.; Utrera, Andres; Estrada, Manuel; Rodriguez-Hernandez, Juan; Gonzalez-Henriquez, Carmen M.
    Bone diseases can often result in patient bone fragility. Different bone problems include low bone density, osteoporosis, and other bone diseases. Such bone diseases, ailments, and malfunctions often require complex and expensive treatments. In this study, we synthesized a new type of DLP resin for 3D printing purposes based on poly(ethylene glycol diacrylate) (PEGDA) and acrylic acid (AAc). In addition, using a porogen within the photopolymerizable resin allowed us to fabricate hierarchical interconnected porous structures. These structures combine the pores resulting from the CAD design with those obtained by the lixiviation of the porogen. Finally, bioactive particles were added to the mixture to increase the material's biocompatibility, thus proving the strategy's potential to include active compounds for particular purposes. Our results demonstrate that including the photoabsorber, Orange G, considerably increases the printing precision and resolution of the synthesized resin, making it possible to obtain printed parts with intricate and complex geometries with high accuracy and definition. Nano-hydroxyapatite (nHA) inclusion significantly increases the material's biocompatibility and mechanical stiffness (similar to 47 % increase, from 5.47 MPa to 8.02 MPa).
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    Oligomeric aliphatic/aromatic poly(amides) containing silicon in the main chain and phthalimide or tetrahalophthalimide moieties as side groups
    (2014) Tagle, L. H.; Terraza, C. A.; Tundidor-Camba, A.; Soto-Salamanca, J.
    Oligomeric aliphatic poly(amides) (PAs) with phthalimide or tetrahalophthalimide were obtained from aspartic and glutamic acids which reacted previously with phthalic or tetrahalophtalic anhydrides, and the diamine bis(4-aminophenyl)-diphenylsilane, by direct polycondensation according to the Yamazaki method. PAs were characterized by IR and H-1, C-13 and Si-29 NMR, inherent viscosity measurements and optical activity. The results showed low eta (inh) values due to the insolubility of the PAs in the reaction media. All PAs were soluble in aprotic polar solvents and partially soluble in other common solvents as CHCl3 and THF. The T (g) values for the PAs derived from aspartic acid showed an increase when the size of the halogen atom is increased due to the more rigidity of the imide group. For those PAs derived from glutamic acid the influence of the side groups was less important due probably to the higher influence of the longer aliphatic main chain. The thermal degradation analysis showed that PAs have good TDT values with the exception of PA-7. The temperature for 50 % of weight loss for both PAs series was dependent on the nature of the halogen, showing an increase when the halogen was more electronegative. PAs do not showed good optical properties, with the exception of PA-1 and PA-6 without halogen atoms in the side chain, due to the increase of the volume of the side group which affects their mobility increasing their packing. It is possible to see a low increase of the transmittance when the aliphatic chain is increased from aspartic to glutamic acid due to an increase of the flexibility of the main chain.