Product development of fully recyclable single-use coffee cups

Disposable cups are typically made from PE-lined paper. They are recyclable at specialist sites where their components are separated, however the cups must be isolated from all other waste prior to collection by recycling companies. PE is obtained from fossil fuels, although it can be acquired from crops such as sugarcane. To derive PE solely from crops, a lot of land would be needed to grow them, which is unrealistic. Regardless of the source, PE is non-biodegradable. This project aimed to develop a polymer that is from a renewable source, biodegradable, and/or easier to recycle. PLA and PHB were investigated as copolymers of varying compositions for their suitability to line cups. The 8 copolymers made all had melting points and thermal degradation temperatures significantly higher than the boiling point of water. All the copolymers were all melted onto uncoated cup paper and some tests were performed to assess their water permeability. The polymers with a higher percentage of BL in their composition (75% or higher) demonstrated better water resistance, when exposed to room temperature DI. Further testing is required using hot water

Data to support study of Di-Iron(II) [2+2] Helicates of Bis-(Dipyrazolylpyridine) Ligands – the Influence of the Ligand Linker Group on Spin State Properties

A diiron(II) complex has been crystallised in three different helicate conformations, which differ in the torsions of the butane-1,4-diyl ligand linker groups. The crystals exhibit a range of spin state properties, including stepwise spin-crossover of the two iron atoms. A related ligand with a rigid pyrid-2,6-diyl spacer forms more a distorted, high-spin diiron(II) helicate structure

Copolymerisation of cyclic esters by yttrium initiators for increasingly sustainable applications

In chapter 1, the use and dependence on single-use plastics is explored using big picture thinking. Single-use coffee cups are used as a case study, and their invention and acceptance into society is discussed. Issues with the polyethylene plastic used to line paper to make these cups are explored, and potential alternatives are evaluated. Chapter 2 focuses on polymers and their properties. Methods used to alter polymer properties and how polymer microstructure influences these properties are discussed. Poly(3-hydroxybutyrate) is introduced as a potentially renewable polymer that could replace some polyolefins in current applications. The formation of poly(3-hydroxybutyrate) from β-butyrolactone by ring-opening polymerisation facilitated by metal catalysts is described. In chapter 3, the yttrium complexes that are used as catalysts for ring-opening polymerisation throughout chapters 4 and 5 are introduced and their synthesis is described. The complexes are all characterised by 1H and 13C NMR spectroscopy and, in some cases, solid-state structures of the complexes were obtained. In chapter 4, β-butyrolactone and γ-butyrolactone are polymerised and copolymerised. Various reaction conditions are explored to determine their influence on polymer microstructure and properties. In particular, the molecular weights, compositions, and thermal properties of the polymers are explored. In this work, incorporation of 87% γ-butyrolactone into poly(3-hydroxybutyrate) was achieved, which was the highest reported at the time of writing. In chapter 5, β-butyrolactone and ε-decalactone are polymerised and copolymerised, and characterised in a similar manner to the polymers produced in chapter 4. Monomer sequences were determined for a selection of copolymers, which suggested block copolymers could be synthesised in a one-pot synthesis under the reaction conditions used. In chapter 6, the conclusions and outlook from the findings in chapters 3-5 are discussed. Chapter 7 contains the experimental details

Copolymerisation of β-butyrolactone and γ-butyrolactone using yttrium amine bis(phenolate) catalysts

The synthesis of poly(3-hydroxbutyrate-co-4-hydroxybutyrate) is reported with a family of yttrium amine bis(phenolate) catalysts via ring-opening polymerisation of β-butyrolactone and γ-butyrolactone. Poly(3-hydroxybutyrate), poly(4-hydroxybutyrate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) have been prepared at -40 °C with a 10 M monomer concentration using a range of amine bis(phenolate) catalysts. It is found poly(3-hydroxybutyrate) synthesis is inferior under these conditions to that attainable at room temperature. In contrast, poly(4-hydroxybutyrate) synthesis achieved up to 33% conversion under these conditions. Poly(3-hydroxybutyrate) polymers containing up to 63% 4-hydroxybutyrate inclusion were obtained when β-butyrolactone and γ-butyrolactone are copolymerised, with γ-butyrolactone in excess in the monomer feed. The carbonyl resonances between 169-174 ppm in the 13C NMR spectra of this copolymer are assigned. Gel permeation chromatography on copolymers showed number average molecular weights are consistently greater than the calculated values, and the dispersities are generally greater than 1.4, demonstrating limited control by the catalysts. Despite this restricted control, these catalysts were able to convert appreciable amounts of monomers into polymers either individually or within a copolymerisation

Di‐Iron(II) [2+2] Helicates of Bis‐(Dipyrazolylpyridine) Ligands:The Influence of the Ligand Linker Group on Spin State Properties

Four bis[2‐{pyrazol‐1‐yl}‐6‐{pyrazol‐3‐yl}pyridine] ligands have been synthesized, with butane‐1,4‐diyl (L1), pyrid‐2,6‐diyl (L2), benzene‐1,2‐dimethylenyl (L3) and propane‐1,3‐diyl (L4) linkers between the tridentate metal‐binding domains. L1 and L2 form [Fe2(μ−L)2]X4 (X−=BF4− or ClO4−) helicate complexes when treated with the appropriate iron(II) precursor. Solvate crystals of [Fe2(μ−L1)2][BF4]4 exhibit three different helicate conformations, which differ in the torsions of their butanediyl linker groups. The solvates exhibit gradual thermal spin‐crossover, with examples of stepwise switching and partial spin‐crossover to a low‐temperature mixed‐spin form. Salts of [Fe2(μ−L2)2]4+ are high‐spin, which reflects their highly twisted iron coordination geometry. The composition and dynamics of assembly structures formed by iron(II) with L1−L3 vary with the ligand linker group, by mass spectrometry and 1H NMR spectroscopy. Gas‐phase DFT calculations imply the butanediyl linker conformation in [Fe2(μ−L1)2]4+ influences its spin state properties, but show anomalies attributed to intramolecular electrostatic repulsion between the iron atoms