Benzaldehyde-mediated selective aerobic polyethylene functionalisation with isolated backbone ketones

Abstract

Post-synthetic functionalization of commodity polymers such as polyethylene (PE) is an increasingly-important strategy for giving waste plastics new ‘lease-of-lives’ as functional polymers. In particular, installing oxygenated functional groups such as...

Transforming Polyethylene into Water-Soluble Antifungal Polymers

“…The absence of signals at ∼2.7 ppm, which are diagnostic of methylene proton environments between closely spaced carbonyl groups (i.e., [e.g., −C 40 indicates that the carbonyl groups present on the oxidized PE were not clustered closely on the alkyl backbone. 13 C NMR of the polymer provided further evidence of carbonyl installation on the PE polymer, with resonances at 211 and 43 ppm (Figure S12A) characteristic of C�O and its α-methylene unit, 30 respectively, which were absent in the 13 C spectrum of the PE starting material (Figure S12B). Meanwhile, resonances observed at 178 and 65 ppm may be attributed to carboxylic acid (−COOH) and the α-carbon of alcohols [−CH(OH)−], respectively.…”

“…Considering that abundantly available PE has an identical saturated C−C backbone, we decided to repurpose it by first installing reactive functional groups (e.g., carbonyls, hydroxyls) along the chain by aerobic oxidation. 30 These serve as attachment points for subsequent covalent grafting of bioactive functionalities which can confer antimicrobial properties and water solubility to these polymers (Figure 1). Unlike many end-use cases (e.g., polymer blend compatibilizers), 13,31 post-synthetic modification of commodity polymers into antimicrobial polymers removes the common limiting constraint of preserving the original polymer chains' structural integrity and mechanical properties.…”

“…In addition, many of these polymers contain saturated C–C backbones, such as poly­(meth)­acrylates and poly­(vinyl pyridiniums), − all of which are derived from non-renewable petrochemical feedstock (Figure ). Considering that abundantly available PE has an identical saturated C–C backbone, we decided to repurpose it by first installing reactive functional groups (e.g., carbonyls, hydroxyls) along the chain by aerobic oxidation . These serve as attachment points for subsequent covalent grafting of bioactive functionalities which can confer antimicrobial properties and water solubility to these polymers (Figure ).…”

“Functional upcycling” of polymer waste towards the design of new materials

“…6b). 191 Note that functional upcycling methods involve the best practice from classic synthetic procedures including the utilisation of transition metal-based catalysts for transforming PE chains. The Hartwig group has contributed significantly to this area by utilising Ni, Rh, or Ru catalysts for directly introducing reactive groups such as hydroxyl, amino, borane or carbonyl groups to the PE chain (Fig.…”

Upcycling waste poly(ethylene terephthalate) into polymer electrolytes

“…In contrast, plastic upcycling transforms low-value waste polymers into chemicals and materials of higher value. [10][11][12][13][14][15] PET has been upcycled into small molecules which can be used as solvents and reagents for the chemical industry, 16 including the production of new polymers such as polyhydroxyalkanoates (PHA), 17 as well as porous materials for carbon dioxide (CO 2 ) capture 18 and utilisation. 19 Recently, with growing interest in developing sustainable materials for energy storage applications to meet ever-increasing global energy demands, 20 upcycling of post-consumer plastics into energy storage materials is expected to be of growing importance.…”