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

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Use of waste mushroom beds for the production of value-added biodegradable fiber sheet

This research focused on the utilization of waste mushroom beds (WMB) after the harvesting of oyster (WMB-O) and lingzhi mushrooms (WMB-L) for the preparation of eco-friendly materials, fiber sheets. The WMB were sterilized and determined for their chemical compositions. The dry fiber of the sterilized WMB were pretreated by a steam explosion, comparing with alkaline pretreatment before the fiber sheet forming process. The results showed that f-cellulose contents of the WMB were in the range of 27-35% by dry weight basis. The fiber from WMB-L treated by alkaline at 13.5% w/w of NaOH for 120 min showed better fiber sheet appearance, compared to the steam explosion. Afterward, tapioca starch was added as a natural binder during the fiber sheet forming and their physical properties were determined. The analytical results indicated that an increase of NaOH concentration in the pretreatment led to an increase in the toughness and water absorption of the fiber sheet. The additional tapioca starch promoted the interaction between cellulose fiber networks, corresponding to the decrease of water absorption and a compressed appearance after water immersion. These finding results disclosed a potential use of the WMB as ecofriendly materials, e.g. biodegradable packaging, packing materials, cultivation vase in the future.</jats:p