To pursue a post-doctoral position in natural fiber-reinforced polymer composites, identify potential research groups, prepare a tailored application including a research proposal, and apply through formal channels or reach out directly to faculty members. Additionally, explore funding opportunities to support your research.
I would suggest searching publications around the topic, and then contacting the group involved in those publications. Normally, sending an email to the group leader or director showing interest is a good first step.
The other option would be to look for the opportunity in different webpages. Regarding this, I recently found a LinkedIn post with different websites you can check: