The Mechanical Properties And Polymeric Structure Of Phbv/Hbps Blends

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) is a kind of ideal environment friendly and biomedical material. It has great potential advantages such as resources renewable, biodegradable property, biological compatibility, piezoelectricity, anticoagulation hemorrhagic and so on. However, narrow processing temperature caused by the poor thermal stability and especially brittleness caused by big and perfect spherulites of PHBV have severely restricted its application. Furthermore, secondary crystallization appears in PHBV at room temperature, which also exacerbates its brittleness. In this paper, a biodegradable hyperbranched poly (ester amide)(HBPs) was added into PHBV in order to overcome its brittleness. The main results were as followed:PHBV/HBPs blends were prepared by solution coating and melting blending. The relationship between structure and properties have been studied. The links between aggregation structure, interfacial adhesion and mechanical properties evolution of PHBV/HBPs have been established. Its thermal degradation and mechanical properties of PHBV/HBPs blending films were studied by TGA, DMA and Tensile test respectively. Meanwhile, its thermal melt properties and crystallization properties were studied by DSC, POM and WXRD. The influence of HBPs on the PHBV phase morphology was evaluated using SEM. Reasonable interfacial adhesion, likely H-bond interaction, was evaluated by FTIR.PHBV/HBPs blends were prepared by solution coating. The relationship between the structure and properties have been established. The relationships between aggregation structure, interfacial adhesion and mechanical properties of PHBV/HBPs have been established. Firstly, from aggregation structure, the introduction of HBPs didn’t change the crystal structure of PHBV. Since HBPs is amorphous, it diluted the nuclei of PHBV, causing larger spherulite size. However, the integrity of spherulite decreased. Furthermore, the growth rate of spherulite and crystallinity of PHBV/HBPs decreased. To some extent. HBPs inhibited the crystallization of PHBV. thus had positive influence on improving mechanical properties of PHBV. SEM images showed that when HBPs can have better dispersion in PHBV matrix and smaller size. PHBV/HBPs system had better mechanical properties. Secondly, taking intermolecular forces into consideration, due to HBPs containing a lot of-OH groups, which could combine with-C=O of PHBV. hydrogen bonding interaction of PHBV/HBPs system was formed. Therefore, mechanical properties of PHBV were improved. Mechanical testing showed HBPs strengthened and toughened the system, which depended on deduction of crystallinity. dispersion of between HBPs and PHBV and intermolecular forces of between HBPs and PHBV.PHBV/HBPs blends were prepared by melt blending. Under no solvent and the high-temperature processing condition, the introduction of HBPs had influence on the structure and properties of PHBV. The introduction of HBPs made PHBV crystallization at higher temperature and didn’t change the crystal structure of PHBV. HBPs didn’t dilute the nuclei of PHBV, likely because under high-temperature and strong shear, some small molecular were formed due to molecular chain fracture of PHBV. which acted as the nuclei of PHBV. The ring structure of spherulite gradually disappeared and he integrity of spherulite and crystallinity of PHBV/HBPs decreased. And therefore, HBPs, to some extent, improved brittleness of PHBV. When content of HBPs was few (<10wt%). HBPs can evenly dispersed in the PHBV. The system showed good mechanical properties. Mechanical testing showed HBPs strengthened and toughened PHBV. Elongation of PHBV/5wt%HBPs reached3.15%. increased by about100%than that of PHBV.