Miscibility, biodegradability and rheological properties of Poly(butylene succinate)/Poly(butylene terephthalate) blends

Abstract

The disposal of nondegradable synthetic polymers has become a worldwide environmental issue. Therefore, it is necessary to develop biodegradable polymers. Aliphatic polyester, poly(butylene succinate) and aromatic polyester, poly(butylene terephthalate) were blended or reacted to develop a new biodegradable polymer blends. Poly(butylene succinate) is a crystalline polymer which has the biodegradability. It has poor thermal stability and is expensive to use commercially. Hence, an aromatic polyester, poly(butylene terephthalate) was chosen to make a new polymer blends. Poly(butylene terephthalate) is also a crystalline polymer which can crystallize fast. It has good mechanical properties and moldability. We tried to investigate the miscibility of PBS/PBT blends by various methods, differential scanning calorimeter (DSC), dielectric analyzer (DEA), dynamic mechanical thermal analyzer (DMTA), and rotational rheometer. The most commonly used method for establishing miscibility in polymer-polymer blends or partial phase mixing in such blends is through determination of the glass transition in the blend versus those of the unblended constituents. Blends of crystalline polymers are more complex due to the potential crystallization of one or both components. Transitional behavior in such mixtures is generally very difficult to assess by traditional DSC due to the breadth and relatively low intensity of the glass transitions. In this study, we cannot get the glass transitions of the samples by DSC due to the poor sensitivity. DEA and DMTA were used to obtain the glass transitions of the samples because they are more sensitive than the traditional DSC. But we cannot get the transitions of PBT phase of the PBS rich blends by DEA because of the rapid rise caused by the increasing ionic conductivity. The ionic conductivity increased significantly due to premelting of the PBS phase. DMTA shows two distinct glass transitions and no significant changes of glass transitions of ...