Thesis

Synthesis and characterisation of crosslinked polymer resins derived from epoxidised natural rubber latex

Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2024
Thesis identifier
  • T16930
Person Identifier (Local)
  • 201790447
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Epoxidised natural rubber (ENR) latex is a renewable material and very attractive as a novel feedstock for the production of crosslinked polymer resins. ENR latex is chemically complex. Therefore, its surrogates, poly(divinylbenzene-co-glycidyl methacrylate) (poly(DVB-co-GMA)) microspheres were synthesised by precipitation polymerisation. Poly(DVB-co-GMA) microspheres (2 - 5 μm in diameter) were self-assembled using an inverse-suspension evaporation technique (solids contents 15 -28% w/w, relative to water) into closest packing particles with irregular superstructures (diameters ranging from 20 – 200 μm). These non-porous superstructures were stable in both polar and non-polar solvents. The self-assembly methodology was subsequently applied to ENR latex at a range of dry rubber contents (DRCs). All formulations yielded brown gels, which formed hard coagulum upon drying. Attempts to stabilise the ENR latex by installing ethylenediamine-based crosslinks between ENR latex chains prior to self-assembly failed to deliver useful products. Crosslinking of ENR latex using maleic anhydride (MA) was far more successful. Through the epoxide ring-opening chemistry, the epoxide groups were ring-opened forming ester crosslinks within the main chains. The anhydride-crosslinked ENR latex particles produced were approximately 50x larger than the ENR latex particles from which they were derived. The reactions could be accelerated by the inclusion of 1- Methylimidazole (1-MI) in the formulations. Increases in the glass transition temperatures (Tg) of the products relative to the ENR latex starting material were consistent with crosslinking. However, the products were non-porous in the dry state. Free radical copolymerisation of unaccelerated and 1-MI accelerated anhydridecrosslinked ENR latex particles with 3-(Trimethoxysily)propyl methacrylate (TMSPMA) produced white, free-flowing powders with an average particle sizes in the range of 45 - 78 μm. The powder microspheres consist of densely packed particles and were porous in the dry state. Silica networks that encapsulated the powder microspheres allowed them to remain stable in polar protic, polar aprotic, and nonpolar solvents. These novel materials have significant potential for exploitation as renewable polymer resins.
Advisor / supervisor
  • Cormack, Peter A. G.
Resource Type
Note
  • This thesis was previously held under moratorium from 17th May 2024 until 17th May 2026.
DOI
Funder
Embargo Note
  • The digital copy of this thesis is restricted to Strathclyde users only until 17th May 2029.

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