Superabsorbent Polymers:From long-established, microplastics generating systems, to sustainable, biodegradable and future proof alternatives

Superabsorbent polymers (SAPs) play important roles in our daily life, as they are applied in products for hygiene, agriculture, construction, etc. The most successful commercially used types of SAPs are acrylate-based, which include poly(acrylic acid)s, poly(acrylamide)s, poly(acrylonitrile)s and their salts. The acrylate-based SAPs have superior water-absorbent properties, but they have high molecular weight and in addition an entirely carbon atom-based and cross-linked backbone. These factors endow them with poor (bio)degradability, which has a devastating impact on the environment where such SAP-containing materials may end up at the end of their lifetime. Furthermore, the raw materials for production of acrylate-based SAPs are mostly petroleum-based. From the viewpoint of sustainability, a bio-based resource would be the ideal candidate to replace the fossil-based ones. To overcome the shortcomings of the existing SAPs, bio-based and degradable SAPs are required. This review will then cover the following topics: (1) the technology development history and state-of-the-art of current SAPs; (2) the product designing principles of SAPs; (3) an in-depth introduction and discussion of the structural characteristics and properties of different kinds of SAPs derived from both fossil or renewable resources and (4) novel polycondensate-based, potentially biodegradable SAPs with promising industrial applicability

Fully renewable limonene-derived polycarbonate as a high-performance alkyd resin

Limonene-derived polycarbonate-based alkyd resins (ARs) have been prepared by copolymerization of limonene dioxide with CO2, catalysed by a β-diiminate zinc–bis(trimethylsilyl)amido complex, and subsequent chemical modification with soybean oil fatty acids using triphenylethylphosphonium bromide as the catalyst. This quantitative partial modification was realized via epoxy–carboxylic acid chemistry, affording ARs with higher oil lengths, lower polydispersities and higher glass transition temperatures (Tg) in comparison to a conventional polyester AR based on phthalic acid, multifunctional polyol pentaerythritol and soybean fatty acid. The novel limonene polycarbonate AR and the conventional polyester AR were evaluated as coatings and both the physical drying (without the presence of the oxidative drying accelerator Borchi® Oxy Coat) and chemical curing (with Borchi® Oxy Coat) processes of these coatings were monitored by measuring the König hardness and complex modulus development with time. A better performance was obtained for the alkyd paint containing polycarbonates modified with fatty acids (FA-PCs), which showed a faster chemical drying, a higher König hardness and a higher Tg in coating evaluation, demonstrating that the fully renewable FA-PCs are promising resins for alkyd paint applications

Low-crystallinity to highly amorphous copolyesters with high glass transition temperatures based on rigid carbohydrate-derived building blocks

The current trend of developing novel biobased polymeric materials is focused more on utilizing the unique structural/physical properties of renewable building blocks towards niche market applications. In this work, with the aim of developing low-crystallinity to amorphous polyesters with enhanced thermal properties, a series of copolyesters based on rigid and structurally asymmetric carbohydrate-derived building blocks, namely furan-2,5-dicarboxylic acid and isosorbide, and 1,4-butanediol were successfully synthesized using melt polycondensation. The copolyesters were obtained with varied chemical compositions and rather high molecular weights (Mn = 24 000–31 000 g mol−1) and intrinsic viscosities ([η] = 0.56–0.72 dL g−1). Incorporation of both building blocks significantly enhances the glass transition temperatures (Tg = 38–107 °C) of polyesters, and also efficiently inhibits the crystallization of the copolyesters. A low content of isosorbide (ca 10 mol%) leads to complete transition of the homopolyester to nearly fully amorphous materials. Detailed characterizations of the chemical structures and thermal properties of the synthesized copolyesters were conducted using various analytical techniques. In addition, hydrolytic and enzymatic degradations of the copolymers in the presence of porcine pancreatic lipase and cutinase were also investigated

Is a preoperative multidisciplinary team meeting (cost)effective to improve outcome for high-risk adult patients undergoing noncardiac surgery:the PREPARATION study-a multicenter stepped-wedge cluster randomized trial

BACKGROUND: As a result of increased life expectancy and improved care for patients suffering from chronic disease, the number of patients with multimorbidity requiring surgical intervention is increasing. For complex surgical patients, it is essential to balance the potential benefits of surgical treatment against the risk of permanent loss of functional capacity and quality of life due to complications. European and US guidelines on perioperative care recommend preoperative multidisciplinary team (MDT) discussions for high-risk noncardiac surgical patients. However, the evidence underlying benefits from preoperative MDT meetings with all relevant perioperative specialties present is limited. The current study aims to investigate the effect of implementation of preoperative MDT discussions for high-risk patients undergoing noncardiac surgery on serious adverse events.METHODS/DESIGN: PREPARATION is a stepped-wedge cluster randomized trial in 14 Dutch hospitals without currently established preoperative MDT meeting. The intervention, preoperative MDT meetings, will be implemented sequentially with seven blocks of 2 hospitals switching from control (preoperative screening as usual) to the intervention every 3 months. Each hospital will be randomized to one of seven blocks. We aim to include 1200 patients. The primary outcome is the incidence of serious adverse events at 6 months. Secondary outcomes include (cost)effectiveness, functional outcome, and quality of life for up to 12 months.DISCUSSION: PREPARATION is the first study to assess the effectiveness of a preoperative MDT meeting for high-risk noncardiac surgical patients in the presence of an anesthesiologist. If the results suggest that preoperative MDT discussions for high-risk patients are (cost)-effective, the current study facilitates implementation of preoperative MDT meetings in clinical practice.TRIAL REGISTRATION: ClinicalTrials.gov NCT05703230. Registered on 11/09/2022.</p

Carbohydrate-based PBT copolyesters from a cyclic diol derived from naturally occurring tartaric acid: a comparative study regarding melt polycondensation and solid-state modification

2,3-O-Methylene-L-threitol (Thx) is a cyclic carbohydrate-based diol prepared by acetalization and subsequent reduction of the naturally occurring tartaric acid. The structure of Thx consists of a 1,3-dioxolane ring with two attached primary hydroxyl groups. Two series of partially bio-based poly(butylene terephthalate) (PBT) copolyesters were prepared using Thx as a comonomer by melt polycondensation (MP) and solid-state modification (SSM). Fully random copolyesters were obtained after MP using mixtures of Thx and 1,4-butanediol in combination with dimethyl terephthalate. Copolyesters with a unique block-like chemical microstructure were prepared by the incorporation of Thx into the amorphous phase of PBT by SSM. The partial replacement of the 1,4-butanediol units by Thx resulted in satisfactory thermal stabilities and gave rise to an increase of the Tg values, this effect was comparable for copolyesters prepared by MP and SSM. The partially bio-based materials prepared by SSM displayed higher melting points and easier crystallization from the melt, due to the presence of long PBT sequences in the backbone of the copolyester. The incorporation of Thx in the copolyester backbone enhanced the hydrolytic degradation of the materials with respect to the degradation of pure PBT.Peer ReviewedPostprint (published version