A problem-based learning (PBL) methodology was implemented to a project, whose main objectives were to discuss and apply the Twelve Principles of Green Chemistry to the study of poly(vinyl alcohol)'s cross-linking reaction with dicarboxylic acids. The five participating students were oriented to be responsible for their own learning and the professor participated as an advisor. The problem was proposed and students planned all their activities to accomplish the objectives and goals, reviewed recent information in scientific literature and summarized it, made experimental work, prepared written reports, and were evaluated in seminars. The results obtained by the students were assessed through the generation of a final report and also with a final oral presentation in front of faculty members. The experience lived by the collaborative workgroup during the development and execution of the project, is described. This research is an example of how the PBL methodology can motivate the active participation of students when solving problems. The next step is to introduce this tool to teachers and students of other undergraduate courses or laboratories, since it causes a difference in the way education is being perceived in our university, because it emphasizes the application and understanding of concepts over simple memorization.