Publications by authors named "Dailyn Guzman"

A series of bio-based epoxy shape-memory thermosetting polymers were synthesized starting from a triglycidyl phloroglucinol (3EPOPh) and trimethylolpropane triglycidyl ether (TPTE) as epoxy monomers and a polyetheramine (JEF) as crosslinking agent. The evolution of the curing process was studied by differential scanning calorimetry (DSC) and the materials obtained were characterized by means of DSC, thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), stress-strain tests, and microindentation. Shape-memory properties were evaluated under free and totally constrained conditions.

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The pure trifunctional glycidyl monomer from phloroglucinol (3EPO-Ph) was synthesized and used as feedstock in the preparation of novel bio-based thermosets by thiol-epoxy curing. The monomer was crosslinked with different commercially available thiols: tetrafunctional thiol (PETMP), trifunctional thiol (TTMP) and an aromatic dithiol (TBBT) as curing agents in the presence of a base. As catalyst, two different commercial catalysts: LC-80 and 4-(,-dimethylamino) pyridine (DMAP) and a synthetic catalyst, imidazolium tetraphenylborate (base generator, BG) were employed.

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New thermosets from a triglycidyl eugenol derivative (3EPOEU) as a renewable epoxy monomer were obtained by an epoxy-amine curing process. A commercially-available Jeffamine and isophorone diamine, both obtained from renewable resources, were used as crosslinking agents, and the materials obtained were compared with those obtained from a standard diglycidylether of bisphenol A (DGEBA). The evolution of the curing process was studied by differential scanning calorimetry and the materials obtained were characterized by means of calorimetry, thermogravimetry, thermodynamomechanical analysis, stress-strain tests and microindentation.

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The study of the non-isothermal crystallization behavior of polymers is of great importance due to the effect of degree of crystallinity and crystallization process on the polymer properties. The effect of aminopropylisobutyl polyhedral oligomeric silsesquioxane (APIBPOSS) and aminopropylisooctyl polyhedral oligomeric silsesquioxane (APIOPOSS) on poly(-caprolactone) (PCL) crystallization is studied by differential scanning calorimetry (DSC) under non-isothermal conditions and polarized optical microscopy (POM). The crystallization kinetics is analyzed using the Avrami and Mo models, and effective activation energies are evaluated by the Friedman isoconversional method.

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The incorporation of polyhedral oligomeric silsesquioxanes (POSS) molecules as nanoparticles into polymers can provide improved physico-chemical properties. The enhancement depends on the extent of dispersion of the nanofiller, which is determined by the compatibility with the polymer that is by the POSS type, and the processing method. In this study, poly(ε-caprolactone)/POSS derivatives nanocomposites (PCL/POSS) were obtained via solution-casting and melt compounding.

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