Plastic: Reputable Publications
A quick search in my university's library for Life cycle polymer brings me two reputable looking books:


Green composites: Polymer composites and the environment 
Fundamentals of Materials for Energy and Environmental Sustainability


A Google Scholar search for life cycle analysis of plastic yields several good looking hits. A similar result for life cycle analysis of polymers.

This kind of information is out there, and there is a lot of it. My examples hopefully will inspire you to spend the effort (and it's not that much effort) to look for it.