Functionalization of polycaprolactone

The oil reserves depletion and the growing concerns about plastic waste accumulation in the environment has let to the investigation of substitutes for plastic material. Polycaprolactone (PCL) and starch can be used in the blend as such a substitute. Phase separation occurs when these two polymers are mixed, so a compatibilizer must be added. In this research this compatibilizer is made by functionalization of high molecular weight polycaprolactone in supercritical carbon dioxide. The goal of this research is to develop compatibilizer precursors using high molecular weight PCL and supercritical carbon dioxide. The functionalization degree of the compatibilizer precursors as function of the monomer and initiator intake is investigated and used in developing a mathematical model. The R2-value of our model is 0,967; this implies that the model has a good fit with the experimental data. GPC analysis showed that no degradation/cross linking occurred during the reactions due to the use of supercritical carbon dioxide as the solvent in the reaction. The advantage of using supercritical carbon dioxide as an environmental benign solvent is that milder reaction conditions can be used. The compatibilizer precursors are tested for their performance in starch-PCL blends. These blends are made in the melt using a brabender. Different compatibilizers are used in different amounts to investigate changes in mechanical properties of the blends. In addition, the ratio of PCL and starch is changed. From the results can be concluded that the compatibilizer improves the mechanical properties. The amount and functionalization degree of the compatibilizer precursor have no influence on the mechanical properties. In addition, a compatibilizer made with normal melt processing is used in the blends to look to the difference with the compatibilizers made in supercritical carbon dioxide. The results show that the blends with a compatibilizer precursor made in supercritical carbon dioxide have better mechanical properties.