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

พัฒนาการพอลิเมอร์ชีวภาพสู่นวัตกรรมพลาสติกรักษ์โลกBioplastic: From Research to Innovation and Implementation Against Global Warming

ปัญหาสิ่งแวดล้อมอันเนื่องมาจากการสะสมของขยะพลาสติกอย่างมากในขณะนี้ ทำให้นานาประเทศทั่วโลกตื่นตัวต่อการแก้ไขปัญหาดังกล่าวอย่างต่อเนื่อง นอกจากการรณรงค์ให้ลดการใช้พลาสติกที่ผลิตจากกระบวนการทางปิโตรเคมีแล้วการส่งเสริมการพัฒนาวัสดุทางเลือก ได้แก่ พลาสติกชีวภาพจึงเป็นที่สนใจอย่างยิ่งต่อทั้งนักวิจัยในแวดวงวิชาการและนักลงทุนในภาคธุรกิจและอุตสาหกรรมทั่วโลก ส่งผลต่อกระแสรักษ์สิ่งแวดล้อมในประเทศไทย โดยเฉพาะนโยบายจากภาครัฐในการลดการใช้ถุงพลาสติกจากปิโตรเคมีที่ได้เริ่มดำเนินการอย่างจริงจังนับตั้งแต่วันที่ 1 มกราคม พ.ศ. 2563 เป็นต้นมาซึ่งสามารถลดจำนวนถุงพลาสติกในท้องตลาดกว่า 20% ของทั้งประเทศ เพื่อขับเคลื่อนประเทศไทยสู่การเป็นสังคมปลอดขยะ (Zero Waste Society) ทำให้เกิดการวิเคราะห์ทิศทางและโอกาสทางธุรกิจของนวัตกรรมพลาสติกชีวภาพอย่างแพร่หลายมากขึ้น อาทิ ศูนย์วิจัยกสิกรไทยคาดการณ์ว่าความต้องการพลาสติกชีวภาพทั่วโลกจะขยายตัวอย่างรวดเร็วจาก 4% เป็น 40% ภายใน 10 ปีข้างหน้า โดยเฉพาะตลาดบรรจุภัณฑ์อาหารและเครื่องดื่มที่เป็นผลิตภัณฑ์ใช้ครั้งเดียว (Single-use Plastics

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

Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as model cases

[EN] The extended use of polymers from renewable resources such as aliphatic polyesters or polyhydroxyalkanoates boosted the necessity to understand their behaviour in an end-of-life scenario. Although they can be degraded in reasonable shorter times than traditional polymers, understanding the degradation mechanisms under dissimilar conditions will contribute to further developments in this field. This work aimed to study the effect of temperature and substrate in the degradation of polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) in a simulated laboratory scale to ascertain their contribution, separately or in combination. For this purpose, nine parallel degradation assays were performed by means of the combination of mesophilic (25 °C), thermophilic (58 °C) and hyperthermophilic (80 °C) temperatures with enriched synthetic medium, compost and standardised soil substrates. Although the analysis of the surface morphology, the thermal properties and the thermo-oxidative stability revealed changes as a function of time, the evaluation of the molar mass allowed for a more precise determination of the degradation. In general, chain scission was perceived in all cases as a function of time. The effect of temperature was critical, significantly more important than the effect of the substrate, which showed a less significant contribution, especially in terms of molar mass reduction. While for the PLA, biodegradation at 58 °C and thermal degradation at 80 °C resulted in similar consequences, for the PHBH the hyperthermophilic temperature of 80 °C was the most severe condition, regardless of the substrate. From a technological perspective, it may be highlighted that biodegradation at 58 °C may be the most cost-effective condition due to the lower energy supply required and the valuable contribution of the microorganisms.The authors would like to thank the support of the Spanish Ministry of Science, Innovation and Universities, for the POLYDECARBOCELL project (ENE2017-86711-C3-1-R) and the Chilean Economic Development Agency (CORFO) for the project 13CEI2-21839.Gil-Castell, O.; Andres-Puche, R.; Dominguez, E.; Verdejo, E.; Monreal Mengual, L.; Ribes-Greus, A. (2020). Influence of substrate and temperature on the biodegradation of polyester-based materials: Polylactide and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as model cases. Polymer Degradation and Stability. 180:1-16. https://doi.org/10.1016/j.polymdegradstab.2020.109288S11618