"We will present successes and challenges in the interdisciplinary PLAST project (2016–2021), where environmental scientists, communication researchers and psychologists research risks and social responses associated with plastic in the environment. We aim to discuss 1) that although we successfully developed an interdisciplinary theoretical model, we struggle in integrating results and 2) why we still consider our joint research to be very successful. 1) We integrated three disciplinary perspectives to understand (a) the current environmental scientific evidence on plastic risks, (b) how these are publicly communicated and (c) what psychological factors are crucial for sustainable transformation. This holistic approach helped tremendously in better understanding the complexity of plastic problems. However, our disciplinary empirical findings tend to be too specific to be generalized under our joint model. 2) Despite this challenge, the cooperation under the joint model has improved our interdisciplinary competencies and output in research and teaching: We have found ways to deal with significant differences in disciplinary definitions, understanding of (un)certain scientific evidence, time tables and budgets. Furthermore, our theoretical considerations were integrated into disciplinary study programs. Finally, this project has been a basis for further largescale interdisciplinary project applications, collaborations and an interdisciplinary master program at our university. "