Abstract
Spanning cultures and continents, reckless plastic production and disposal methods have become defining issues for humanity in recent decades. Scientific research provides alternative polymer chemistries in response to the environmental impacts of plastic pollution and petroleum feedstocks, but none of these replacement materials have been adopted to an extent that disrupts the production of conventional plastics. Chemical engineers are uniquely qualified to bring the relevant discoveries into commodity-scale production. To this end, my technical project built on research into biomass-derived plastics, and designed a feasible production facility for poly(dihydroferulic acid), a biodegradable and potentially renewably-sourced mimic of poly(ethylene terephthalate), that would be competitive in the plastic industry. In parallel, my STS research demonstrated how technical problem solving should implement earnest non-technical research and analysis, specifically in the context of unsustainable plastic use, such that those responsible for technological development – including researchers, regulators, and engineers – are capable of filling essential roles of problem definition and sociotechnical mediation.
My STS analysis of trends in plastic production and utilization formed an interconnected narrative of incremental progress amid deliberate muddying of social discussions about plastic. The application of actor-network theory highlighted disconnects in the stakeholder network, in which the abilities of industry stakeholders, governing organizations, environmental activists, journalists, consumers, and researchers have been confined by limited understandings of plastic pollution. To accelerate cooperative efforts for reducing the environmental impact of plastic, my research identified non-technical practices that would support individual moral growth and humble observation of controversial topics, semi-objective description of sociotechnical landscapes, and also ongoing problem definition and mediation of technical solutions across stakeholder groups. The conclusions of my STS research directly reflected the personal discoveries that arose during the process of applying STS methodologies to a variety of source materials relevant to my technical topic.
My technical design team and I characterized the physical and economic viability of poly(dihydroferulic acid) bioplastic production by performing scale-up calculations. Using the same scale as existing poly(ethylene terephthalate) plants, accounting for 1% of global production of the polymer type, or 330,000 metric tons per year, the resulting facility design represents a significant step in the adoption of more sustainable plastics. Each step of the synthesis process was developed as an industrially feasible operation using published laboratory-scale data. The main feedstock for the bioplastic is vanillin, which constitutes the flavor of vanilla beans, may be abundantly available as a byproduct of paper-pulping waste. Since our estimations of capital and operating expenses suggest that the biopolymer would be directly price-competitive with commodity plastics at $3/kg, but only if petroleum-derived vanillin prices are used, the facility is proposed as part of a broader industrial transition. While the feedstock market for renewably-sourced vanillin grows, poly(dihydroferulic acid) would compete as a biodegradable alternative to conventional petroleum-derived plastics, and the facility would adopt renewable vanillin when economically feasible.
Engaging in a rigorous process of problem definition for STS research helped me frame the proposed biopolymer facility as a component of a comprehensive revision of plastic use. The economic incentives for initially using petroleum-based raw materials indicated that societal innovation would be needed before adopting sustainably-sourced vanillin, and my STS analysis supported this hypothesis, concluding that technical stakeholders will have to develop new problem definition skills in order to approach plastic sustainability effectively. My technical design work also informed the collection of literature for sociotechnical analysis, because a wide range of academic research was explored and referenced in the decision-making process. Both my technical and non-technical findings represent elements of a global transition towards sustainability, insofar as individual mindsets and methods may advance new sociotechnical systems, such as introducing problem definition to engineering education, overcoming narrow and slow-moving discourse by building relationships between stakeholders, or seeking out and applying scientific discoveries that could revolutionize industries.
