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The presented contribution deals with the material properties of chainextended polylactide. In the course of this study, two different functional additives were used, namely an epoxidized and a maleated styrene-acrylic copolymer. Both additives were compounded together with polylactide using a conventional twinscrew extruder, and were then injection moulded to standardized testing specimens. The main focus of the investigation is on structural changes as well as the mechanical performance, e.g. crack propagation and arresting mechanisms that are affected by reactive chain extension. The first section of the experimental part consists of results regarding modifications achieved on the macromolecular level. Based on size exclusion chromatography and DSC-OIT experiments, different structural changes and their influence on the material behaviour are presented. Subsequently, a comprehensive analysis of the quasi-static tests and the impact strength of notched and unnotched specimens was performed, and correlated with the following fatigue experiments. A discussion concerning morphological aspects and finally a correlation to the fracture surface topography after fatigue test completes the experimental part.

The presented research study deals with the processability of two different polylactides (PLAs). The main focus is on the melt behavior during compounding on a twin‐screw extruder and laboratory kneader, and the resulting change in the polymeric structure. In addition, a comparative analysis of the thermal stability further contributes to the frame of the investigation. Finally, the processability of reactive extended PLA will be discussed. This new approach focuses on understanding the molecular architecture of the biopolymer, and, furthermore, customizing the innovative modification of the structure using multifunctional additives. The basic principle is hereby the utilization of reactive processing via specific chain extenders, which allows defined formations on the molecular level. As a result, a significant improvement of the polymer melt behavior – specifically the melt flow and thermo‐mechanical stability – can be achieved.

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In this article, the effect of the addition of halloysite nanotube (HNT) on the mechanical and thermal stability of polypropylene (PP) and PP/kenaf fiber biocomposites has been investigated. Different volume contents of HNTs ranging from 1 to 10 vol.% were melt mixed with PP and PP/kenaf fibers. The volume content of kenaf fibers was kept constant at 30%. The morphology of HNTs within the PP matrix has been studied via scanning electron microscopy (SEM). The morphological results revealed that HNT was uniformly dispersed in the PP matrix already at a low concentration of 1 and 2 vol.%. The mechanical properties of the manufactured nanocomposites and hybrid biocomposites such as Young’s modulus, tensile strength, elongation at break, flexural modulus, flexural strength, and notched Izod strength have been measured. The results show that Young’s modulus and strengths have been improved along with the addition of low content of HNTs. Moreover, the gain of notched Izod impact strength obtained by the addition of short kenaf fibers was maintained in hybrids with low concentrations of HNTs. Finally, the thermogravimetric analysis shows that at 10% and 50% weight loss, the thermal degradation rate of the PP and PP/kenaf biocomposites decreased by the addition of HNTs.

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