Thesis Format
Integrated Article
Degree
Doctor of Philosophy
Program
Chemical and Biochemical Engineering
Supervisor
Ray, Madhumita B.
2nd Supervisor
Prakash, A.
Joint Supervisor
3rd Supervisor
Chunbao Charles Xu
Affiliation
City University of Hong Kong
Co-Supervisor
Abstract
Phenol formaldehyde (PF) foams have been widely utilized in various applications, including floral foam blocks, which have supported flower arrangements since the 1950s. However, the environmental impact of petroleum-based production, coupled with the depletion of non-renewable resources and fluctuating oil prices, has driven increasing interest in renewable alternatives for phenolic resin production.
This study focuses on developing foamable biobased phenol formaldehyde (BPF) resins by substituting phenol with lignin derived from forestry residues at substitution levels of 30 wt% or higher. The resulting resins are used to produce hydrophilic phenolic foams with open-cell morphology, superior wetting properties, and acceptable mechanical characteristics, suitable for applications in floristry, hydroponics, and environmental remediation.
Kraft lignin-substituted foams demonstrated remarkable hydrophilic properties, including near-complete open-cell porosity (~100%), a water absorption capacity of 2100%, and a water uptake rate of 0.9 cm³/s. These foams also exhibited biodegradability of approximately 68% within 15 days. Depolymerized Kraft lignin-substituted foams showed even greater water absorption capacities (up to 2557%), low densities (~62 kg/m³), near-complete open-cell content (~100%), and biodegradability of ~39% after 15 days when exposed to Bacillus sp.. Similarly, lignosulfonate-based foams achieved high water absorption capacities (2409%), rapid water uptake rates (1.53 cm³/s), near-complete open-cell content (~100%), and biodegradability of ~65% over 15 days under similar conditions.
The synthesized foams were found to be comparable to commercially available petroleum-based floral and hydroponic foams in terms of hydrophilic properties and germination performance. Additionally, the research explores the application of these foams for environmental remediation, including adsorptive dye removal and phosphorus recovery, further enhancing their potential as sustainable, multifunctional materials.
Summary for Lay Audience
Floral foam blocks, commonly used to support flower arrangements, have been around since the 1950s. However, these foams are made from petroleum-based materials that harm the environment and rely on limited natural resources. This research explores an eco-friendlier solution by creating foams from renewable forestry waste, specifically lignin, a natural material found in wood. By replacing a portion of the petroleum-based ingredients with lignin, the study developed foams that work just as well as traditional ones while being biodegradable and environmentally sustainable. The newly developed foams absorb water exceptionally well, hold it for extended periods, and support plant growth, making them ideal for use in floristry and hydroponics, such as growing plants in water without soil. These foams also break down naturally in the environment, helping to reduce pollution. Additionally, the study found that these eco-friendly foams can be used for cleaning up environmental contaminants, like removing dyes from water or recovering valuable nutrients like phosphorus. This innovative approach offers a greener alternative to traditional foams, reduces reliance on fossil fuels, and contributes to a more sustainable future across multiple industries.
Recommended Citation
DSouza, Glen Cletus, "Development of biobased phenolic foams for floral, hydroponic and environmental remediation applications" (2025). Electronic Thesis and Dissertation Repository. 10681.
https://ir.lib.uwo.ca/etd/10681
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Included in
Biochemical and Biomolecular Engineering Commons, Bioresource and Agricultural Engineering Commons, Polymer and Organic Materials Commons, Polymer Chemistry Commons, Polymer Science Commons
