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breaking frontiers for the utilisation of ROBust BIopolymer NanocompoSite materials through flow-induced and nanofiller-assisted tailoring of biomimetic structure and morphology

Periodic Reporting for period 1 - ROBBINS (breaking frontiers for the utilisation of ROBust BIopolymer NanocompoSite materials through flow-induced and nanofiller-assisted tailoring of biomimetic structure and morphology)

Reporting period: 2019-01-01 to 2020-12-31

This MSCA Individual Fellowship aims to unlock the potential of natural biopolymers such as chitosan, cellulose, and alginate, which have been increasingly appreciated for not only their renewability (in contrast to petroleum-derived polymers), but also their chemical versatility and unique properties (e.g. biodegradability, antimicrobial activity, and biocompatibility), which are advantageous for certain applications (e.g. biomedical, environmental, and agricultural). However, these biomass resources have long been underutilised because of the key challenges associated with processing and overall material performance. Typically, it is extremely challenging to manufacture high-performance biopolymer materials cost-effectively.
The wide adoption of biopolymers as renewable resources could largely benefit the society by contributing to sustainability and bioeconomy. The research into biopolymers can deliver solutions to transform the plastic industry for a circular economy, reducing environmental pollution caused by traditional, petroleum-based synthetic polymers, and delivering new, functional materials for improving people’s health and life.
This fellowship specifically focused on creating high-performance biopolymer composites via novel, cost-effective engineering processes, paving the way for their wide applications. The overall objectives were to 1) understand the physicochemical interactions between biopolymers, nanofillers and plasticisers under “melt” processing conditions and the impact of these interactions on material structures and properties, and 2) establish a cost-effective “melt” processing technology for constructing biopolymer-based materials with tailored properties and enhanced functionality.
A parallel goal of this fellowship is to enable substantial transfer of knowledge and skills between the Fellow (Dr D F Xie) and the host (University of Warwick) and provide the Fellow with widened competencies for research independence and maturity.
This fellowship has not only led to new and important knowledge in (bio)polymer science and engineering, but also allowed the Fellow to achieve broadened expertise, develop new collaborative links, and acquire various transferable skills, which are beneficial for his future career.
On conclusion of this MSCA Individual Fellowship, Dr D F Xie secured a highly prestigious ESPRC Fellowship, which will allow him to establish his own research group and further his career at the University of Warwick.
Research has been conducted for biopolymer material design, biopolymer processing, and the tailoring of biopolymer nanocomposite structure and properties. Specifically, the effects of a wide range of factors related to material formulation and engineering process on material structure and properties have been investigated. For material formulation design, different biopolymers, used alone or in combination, were tested, including chitosan, silk protein, silk peptide, carboxymethyl cellulose, and alginate. Also, the effects of solvents and plasticisers were studied. Moreover, nanoadditives especially graphenic materials were included in the material design. Regarding engineering process, both solution casting (with large amounts of solvents) and “melt” processing (at high biopolymer concentration) were experimented. Detailed processing conditions were considered such as biopolymer concentration, temperature, shearing, pressure, and duration. The materials prepared were characterised by a wide range of techniques including some new ones to the Fellow.
Main results generated include: 1) A new cost-effective method to construct biopolymer composites with tailored properties; 2) Identification of most important factors for nanofiller dispersion in biopolymer matrices; 3) Mechanisms regarding the reinforcement effect of nanofillers on biopolymers (how nanofillers affect material structure and properties); 4) Elaboration of competing interactions between biopolymer, nanofiller and plasticiser; 5) Revelation of unexpected structures and properties of biopolymer composites (e.g. hydrolytic stability and high relative permittivity). Results dissemination have been achieved via night journal publications, three international conferences (for one as an invited speaker), an online workshop (as an invited speaker), and an invited academic seminar.
The Fellow participated in public engagement (e.g. Pint of Science Festival and WMG Family Day) and pitch events to industry, policymakers and the public (e.g. Falling Walls Lab), published two non-scientific online publications and video, provided comments on COVID-19 related plastic issues for TV programs and news articles. He supervised a visiting scholar. He undertook extensive training in technical and transferrable skills (e.g. on public speaking by Debatrix). He was appointed as an Editorial Board Member of two journals (Carbohydrate Polymers, and Coatings), earned a teaching qualification AFHEA, and became a professional member of IOM3 (MIMMM).
While biopolymer processing reported in the literature were predominantly prepared via solution chemistry, which has disadvantages such as low efficiency, difficulty in scaling-up, and the use of large amounts of environmentally contentious solvents. In contrast, this fellowship demonstrates that the feasibility of using industrial relevant techniques to cost-effectively produce biopolymer materials and composites. Based on the new preparation method, how material structure and properties and nanofiller dispersion of nanofillers are affected by material formulation and engineering process is elaborated. Unconventional routes of how nanofillers influence biopolymer structures and properties are revealed, while previous studies of polymer nanocomposites only focused on polymer-nanofiller interfacial interactions and the degree of dispersion of nanofillers. This could allow for more precise control of material structure and properties. Moreover, interesting structures and properties (e.g. unexpected hydrophilic stability) of the biopolymer composites developed are shown. The results generated from this fellowship could enrich the knowledge base in polymer science and engineering and be instrumental to the industrial engineering and wide application of biopolymers.
The growing concerns over resource deficiency and environmental pollution have stimulated the development of new materials renewable and environmentally friendly. For greater resource efficiency, reduced plastic pollution, and finding new materials for demanding applications (e.g. healthcare and environmental), biomass resource has been considered as a strong candidate for a circular economy. Thus, the research findings from this fellowship is anticipated to attract wide interest from the research community for further developing various high-performance biopolymer materials for diverse applications. In the long term, the research outcomes are expected to lead to new supply chains for plastic materials, added value to biomass resources, reduced pollution, and better health. They could also provide basis for policy changes.
Moreover, the communication, dissemination and public engagement activities in this fellowship could lead to enhanced public perception of sustainability, people’s behaviour change and wider involvement towards a circular economy.
Dr David F. Xie (the Fellow) talking in the Falling Walls Lab MSCA 2019 competition in Brussels
Dr David F. Xie (the Fellow) with his supervisor Prof. Tony McNally and visiting scholar Dr Pei Chen