Bioplastics are emerging as most promising materials to replace oil based thermoplastics particularly in packaging. Bioplastics can mitigate and address concerns about the negative role of plastics in the environment creating pollution and depleting resources hence bioplastics can enable an innovative approach toward addressing these issues. However, manufacturing of bioplastic is still costly and their mechanical and thermal properties require extensive development. Therefore there has been substantial interest to improve processing and properties of bioplastics to diminish the environmental impacts caused by continuous use of synthetic polymers of petroleum origin. In this research, Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV and Polybutylene succinate (PBS) composites and blends were developed to improve the properties of PHBV as the matrix polymer and hence produce a novel formulation for product development. Three approaches were studied in this work:  The effect of talcum powder as a nucleating agent and reinforcing filler.  The effect of oligomer chain extenders on miscibility, crystallinity, thermal and thermomechanical, mechanical and morphological properties of PHBV/PBS blends.  The effect of acrylic core-shell impact modifier on crystallinity, thermal and thermomechanical, mechanical and morphological properties of PHBV were also evaluated. All the above scientific approaches have been studied. It was noticed that talc can change the sluggish crystallinity of PHBV. Talc enhances nucleation of PHBV in the composites which leads to a faster crystallization rate. The heat distortion temperature, crystallinity and the modulus of PHBV/talc composite were also increased. In the presence of the chain extender (CE) the miscibility conditions of PHBV/PBS blends were changed. The results were supported by calculation of the activation energies. The elongation at break and tensile strength of PHBV/PBS/Chain extender blends increased indicating miscibility change. The possible reaction mechanism between PHBV, PBS and CE are proposed and the results supported by using FTIR. Immiscibility results of the PHBV/PBS blends are supported by SEM images. Addition of the impact modifier to PHBV reduced the crystallization rate and prolonged crystallization time. It has been found that the shell of impact modifier (PMMA) is partially miscible with PHBV. The absorbed impact energy is improved by the impact modifier but the improvement was not as satisfactory as results noted for PLA. The SEM images showed the average fine dispersion of different sized particles inside the matrix.

Yes / Thermal degradation of polyamide 6 (PA6)/organoclay nanocomposites is a serious impediment to wider applications of these nanocomposites. In this study, a solution is proposed based on the well‐established use of chain extenders. As in PA6, thermal degradation, in the absence of moisture, produces broken polymer chains with amide end groups, a chain extender with anhydride functionalities, known to be strongly reactive with amide groups, was used to reconnect the chains. Experiments conducted using a laboratory twin‐screw extruder were first checked, through transmission electron microscopy observations, to have produced good organoclay intercalation and exfoliation into PA6. Following from this, samples with the chain extender added were produced and characterized. The data obtained were conclusive in the effectiveness of the chain extender: for the chain extended nanocomposites, there is an enhancement in the value of the complex viscosity by 7 times and in the storage modulus by 88 times, while the tensile modulus increased by 57% compared with the neat PA6. The nonchain extended nanocomposite achieved in comparison an enhancement of 2 times the value of the complex viscosity and 19 times the storage modulus while the tensile modulus increased by 53% compared to the neat PA6. These data provide conclusive proof on the rationale that anhydride functionalities should be sought when developing chain extenders for PA6 nanocomposites. / Government of Turkey

This master thesis deals with the direct synthesis of polymers from lactic acid. The theoretical part focuses on both natural and synthetic ways of production the lactic acid monomer, their advantages and properties. Furthermore, the theoretical part focuses on the synthesis of poly(lactic acid) (PLA) from lactide, and direct polycondensation from lactic acid discussing about influences of catalysts, co-catalysts as well as chain extenders. The experimental part focuses on the synthesis of PLA polymers and co-polymers wherein investigates suitable catalysts, reaction medium for azeotropic dehydration and co-catalyst influence on products. Thermal and analytical analysis of PLA polymers are mentioned at the end of the experimental part.