From the environmental assessment that we have conducted on the presence of DEHP in wastewater, we have confirmed that the increasing concern with DEHP is not unjustified and that DEHP is contaminating our environment. After this discovery, we resolved to minimize the presence of DEHP by looking for alternatives that could replace it entirely in its main application as a PVC plasticizer, thus reducing entirely its harmful effects on the environment.

Both epoxidized Carthamus tinctorius oil and the copolymers of PLA-MePEG and PCL-MePEG were found to be possible alternatives for DEHP of varying application. In fact, ECTO was of significantly higher plastic performance than DEHP. This novel, water resistant PVC plasticizer was synthesized from Carthamus tinctorius oil via a chemo-enzymatic reaction, and its performance evaluated through various tests.

Thus, ECTO has great potential in replacing DEHP, as it exhibits superior plasticizing effects. Not only can ECTO impart more flexibility to the polymer matrix, but it also has the added advantage of being a heat stabilizer. The use of ECTO not only has the potential to reduce the production of DEHP significantly but can also minimize the manufacture of heat stabilizers, chemicals that are often hazardous to the environment. ECTO is the derivative of a natural vegetable oil and is more environmentally friendly than DEHP and other petroleum-based plasticizers. If it were implemented on a wide scale basis, there would be less DEHP environmental contamination and impact on aquatic organisms and other wildlife.  

One factor we must consider regarding ECTO is its economic viability. Though ECTO is more expensive than is DEHP, it may eventually become an economically viable alternative. The enzyme used to epoxidize the oil is re-usable. Our study also found that a smaller amount of ECTO can be used to achieve the same effect as DEHP. Carthamus tinctorius oil itself, is also relatively cheap and is produced on a global scale. The United States, India, and Ethiopia are three of the greatest producers of this oil. The mass production of ECTO as a PVC plasticizer could boost the North American economy, and could also act as a door opener for less economically developed countries.

FUTURE STUDIES

There are a number of future studies that could be conducted. The leaching rates of the diblock and ECTO plasticizers could be studied. The effect of a greater percentage of epoxidation could also be investigated to determine whether a higher percentage of epoxidation yields a more effective plasticizer. A third future study that we hope to conduct, involves the investigation of creating a biodegradable PVC polymer. In our study, we found biodegradable PVC plasticizers, but hope to eventually create an entirely biodegradable product.

Acknowledgements
We’d like to extend a sincere thank-you to:

Dr. Helen Burt and Mr. John Jackson  for covering the costs of materials, and for allowing us to conduct our experiment in their laboratories.

Dr. Geoffrey Gabbott, our sponsor teacher, for his invaluable support.

Without these people, our project would not have been possible.

References
For references, please click here.