Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options

[EN] Poly(hydroxy acids) have been gaining increasing attention in the search for novel sustainable materials to replace petrochemical polymers in packaging applications. Poly(hydroxy acids) are polyesters that are obtained using hydroxy acids as the starting materials, which are derived from renewable resources and biowaste. These biopolymers have attracted a lot of attention since some of them will be in the near future competitive in price to polyolefins, show excellent mechanical and barrier properties, and can be potentially recycled by physical and chemical routes. Most of the current poly(hydroxy acids) are mainly prepared by ring-opening polymerization (ROP) of cyclic monomers derived from hydroxy acids. However, their direct polymerization has received much less attention, while one of the advantages of hydroxy acids resides in the presence of an electrophile and a nucleophile in a single molecule that makes them ideal A-B type monomers for self-condensation. This review focuses on the preparation of poly(hydroxy acids) by the self-condensation polymerization of hydroxy acids. Moreover, their end-of-life options are also evaluated considering not only their biodegradability but also their potential to be chemically recycledThe authors thank the European Commission (EC) for financial support through the project SUSPOL-EJDH2020-ITN-2014-642671 and the Spanish Ministry of Science and Innovation (MICI) through the projects RTI2018-097249-B-C21, MAT2017-83373-R, and MAT-2016-78527-P. S. Torres-Giner also acknowledges MICI for his Juan de la Cierva-Incorporacion contract (IJCI-2016-29675) and the financial support received during his stay at the Institute for Polymer Materials (POLYMAT)Gabirondo, E.; Sangroniz, A.; Etxeberria, A.; Torres-Giner, S.; Sardon, H. (2020). Poly(hydroxy acids) derived from the self-condensation of hydroxy acids: from polymerization to end-of-life options. Polymer Chemistry. 11(30):4861-4874. https://doi.org/10.1039/D0PY00088DS48614874113

Unexplored capabilities of chemiluminescence and thermoanalytical methods in characterization of intact and degraded hyaluronans. Polym Degrad Stabil 91

Abstract Three intact and four degraded hyaluronans were investigated by using chemiluminometry, differential scanning calorimetry, and thermogravimetry. Degradation of hyaluronan was induced by a system containing H 2 O 2 alone (882 mM); 55 mM H 2 O 2 plus 1.25 mM CuCl 2 ; NaOCl alone (10 mM); and NaOCl plus CuCl 2 and ascorbic acid (10 mM, 0.1 mM, and 100 mM, respectively). The four different oxidative systems yielded biopolymer fragments represented by similar viscosity characteristics. The results obtained by using chemiluminescence and thermoanalytical methods indicate that hyaluronans of similar rheological properties could be distinguished from each other

Dissimilar tendencies of innovative green clay organo-modifier on the final properties of poly(ε-caprolactone) based nanocomposites

Composites based on poly(ε-caprolactone) (PCL) were prepared by melt blending the polymer with natural and modified bentonite. Soy lecithin (SL), a natural and nontoxic biosurfactant, was used as modifier agent. Three organoclays with different SL contents were employed as fillers and composites containing 1 and 2 wt% of each clay, were prepared. Thermal (by thermogravimetric analysis, and differential scanning calorimetry), morphological (by X-ray diffraction (XRD) and melt rheology), mechanical (by tensile tests) and barrier properties (by means of water vapor permeability tests) of matrix and composites were studied as a function of clay type and content. Morphological analysis by XRD showed nanocomposites with intercalated-exfoliated structures while melt rheology suggests thermal degradation of PCL matrix catalyzed by SL bentonite modifier. Thermal and mechanical properties were consistent with this assumption, due to the slight increment in crystallinity percentage and detriment in the Young?s modulus of the nanocomposites in comparison with the neat matrix. On the other hand, water vapor permeability of PCL significantly decreased in composites, as is expected for polymer/clay nanocomposites, favoring its potential application as food packaging. Thus, dissimilar tendencies were found in the final properties of the nanocomposites that were attributed to the matrix molecular weight degradation catalyzed by the novel green clay organo-modifier.Fil: Merino, Danila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ludueña, Leandro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Alvarez, Vera Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin