Enhancing Properties of Polylactides

EPA Grant Number: R831530
Title: Enhancing Properties of Polylactides
Investigators: Knauss, Daniel M. , Dorgan, John R.
Institution: Colorado School of Mines
EPA Project Officer: Richards, April
Project Period: February 1, 2004 through January 31, 2007 (Extended to January 31, 2008)
Project Amount: $335,000
RFA: Technology for a Sustainable Environment (2003) RFA Text |  Recipients Lists
Research Category: Nanotechnology , Sustainability , Pollution Prevention/Sustainable Development


Polylactides (PLA) are a family of environmentally benign plastics based on a monomer produced by the fermentation of corn. The environmental advantages of these polyesters are numerous and include: 1) production of the monomer from a renewable resource (biomass); 2) sequestration of vast quantities of the greenhouse gas carbon dioxide; 3) energy savings and accompanying pollution prevention; and 4) reduction of municipal landfill volumes. PLA polymers have a unique combination of economic, energy, and environmental benefits. Based on a comprehensive "cradle-to-grave" Life Cycle Inventory (LCI) for PLA using methodology enabling "apples-to-apples" comparisons with petrochemical-based thermoplastics, the most notable benefits of PLA are reductions in both fossil fuel use and global warming potential. For example, compared to PET and Nylon, PLA uses 30-50% less fossil resources that results in 50-70% less CO2 emissions.

The overall objective of the proposed effort is to improve the properties of PLA so that these environmentally benign polymers may be used in the place of more deleterious plastics. Important technical obstacles are hindering the acceptance of polylactides for use in some applications. For example, the heat distortion temperature of PLA is too low and PLA is too brittle for some applications. Also, the rheological (flow) properties of the material are not suited for important applications like paper coating. The permeation properties of PLA are also too high for certain packaging applications. These are surmountable technical challenges because nanocomposites are known to increase the heat stability and decrease the permeability of plastic materials. These nanocomposites consist of nanometer sized (a billionth of a meter) particles dispersed throughout a plastic matrix. Rheological properties can be improved by modifying the molecular architecture of the base polymer to impart specific responses.


One aspect of the project leverages the recent discovery at CSM of a revolutionary new method of preparing bulk quantities of hollow carbon nanospheres. Blends of PLA with these nanospheres will be investigated to produce unique nanocomposites with the nanometer sized particles dispersed throughout the PLA matrix. The nanocomposite work is of particular significance because it represents, for the first time ever, the formation of polymeric nanocomposites from 100% renewable resources and as such is on the vanguard of technological sustainability. In addition, the chemistry and rheology of molecularly branched PLAs will be investigated in order to develop formulations suitable for paper coating and other environmentally important applications. New branching polymerizations will be investigated to modify the architecture of PLA and the new material properties resulting from the architectural change will be investigated.

Expected Results:

The expected outcome of the project is a series of environmentally beneficial plastics with significantly improved physical properties that will be capable of replacing more environmentally deleterious materials. Significant long-term energy savings and resource conservation are expected as a result of the work. Solid waste disposal will be minimized and economic opportunities will be created while minimizing the harmful effects of industrialization on the biosphere. In addition, the training of graduate students will assist in maintaining and developing our technologically based society. Accordingly, the activities will help develop the human resource potential of the Nation.

Publications and Presentations:

Publications have been submitted on this project: View all 27 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 9 journal articles for this project

Supplemental Keywords:

composite, renewable, bio-based materials, natural fibers, bio-polymer, chemical synthesis, scientific discipline, sustainable industry/business, chemistry, chemistry and materials science, engineering, new/innovative technologies, sustainable environment, technology for sustainable environment, cleaner production/pollution prevention, environmental sustainability, environmentally applicable nanoparticles, branched, hyperbranched, dendritic, topology, molecular architecture, adhesives, alternative materials, carbon dioxide, renewable resource, resins, polymer design, polymerization chemistry,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Sustainable Industry/Business, POLLUTION PREVENTION, Sustainable Environment, Energy, waste reduction, Environmental Chemistry, cleaner production/pollution prevention, Technology for Sustainable Environment, Chemicals Management, Environmental Engineering, life cycle analysis, environmentally conscious manufacturing, waste minimization, polylactides, biomass, energy efficiency, environmentally friendly green products, life cycle assessment

Relevant Websites:


Progress and Final Reports:

  • 2004 Progress Report
  • 2005 Progress Report
  • 2006
  • Final Report