Wright, Harry (2020) Optimisation of a flexible polyurethane foam formulation for use as soilless growing media. PhD thesis, University of Sheffield.
Abstract
Increasing pressure for controlled environmental agriculture (CEA) using hydroponic techniques to reduce their environmental impact as well as the rapid growth of this sector has led to research into more environmentally friendly growing media. Flexible polyurethane foams (fPUF) are a possible alternative to current growing media, however there is little literature reporting the development and optimisation of fPUF for horticultural applications. The aim of this thesis is to use design of experiment (DoE) techniques to understand the influence of the fPUF formulation on select physical and chemical foam properties and optimise these properties for plant growth using hydroponic techniques. Fast, easy to measure techniques were developed or adapted from literature for screening select foam physical properties (density, cell size, water holding capacity, water drop penetration and airflow) and chemical properties (cation exchange capacity) to allow for rapid formulation development. Complete conversion of isocyanate was ensured by using adiabatic temperature rise techniques during the foam reaction. A combination of polyols with a high ethylene oxide polyol composition (58.2 %) composed of a 75:25 ratio of Voranol 1447: Voranol 3322 was selected to make hydrophilic foams. 30 part per hundred polyol (PPHP) of sodium bentonite was used to increase the water holding capacity of the foam. Carefully selected reactive catalysts, dimethylethanolamine (DMEA) and Specflex Activ 2306, a catalytically active polyol reduced the likelihood of reagents leaching out of the foam. Models for fPUF physical properties and reaction responses were developed and verified using DoE techniques. These models used the catalyst and surfactant loadings as factors influencing the responses. Spring onions (Allium cepa) were grown in a set of foams with varying physical properties and growth and nutrition responses were modelled. Cell size and water holding capacity were the most important factors in predicting plant growth and nutrient uptake, with a small cell size and high water holding capacity preferred. An optimised set of physical properties was predicted using these modelsii and an optimum foam formulation was selected. This foam was made its physical properties matched the predicted optimum properties.
Metadata
Supervisors: | Ryan, Anthony and Cameron, Duncan |
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Related URLs: | |
Awarding institution: | University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Chemistry (Sheffield) |
Identification Number/EthosID: | uk.bl.ethos.826822 |
Depositing User: | Mr Harry Wright |
Date Deposited: | 06 Apr 2021 15:23 |
Last Modified: | 01 Jun 2022 09:53 |
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