Synthesis, Characterization, And Biocompatibility Of Novel Block Compolymer Based On Polyhydroxyalkanoate

Polyhydroxyalkanoates (PHAs) are a group of biodegradable polyesters accumulated by many bacteria under unbalanced growth conditions. For their biodegradability and biocompatibility, PHAs have received much attention as an eco-friendly material recently. Using 1,6-hexamethylene diisocyanate (HDI) as a coupling agent, two series (PU3/4HB and PHA-b-PPG) of poly(ester urethane)s (PUs) based on microbial polyesters poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-4- hydroxybutyrate) were synthesized successfully.The chemical structure, molecular weight and distribution of PU3/4HB were systematically characterized by ~1H nuclear magnetic resonance spectrum (NMR), Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). DSC curves revealed that the PU3/4HB polyurethanes have their T_g from -25.6°C to -4.3°C, crystallinity from 2.5% to 25.3%, being almost amorphous to semi-crystalline. TGA study showed that the PU3/4HB keep the good thermal stability. The obtained PU3/4HBs are hydrophobic (water contact angle 77.4o to 95.9o), and their surface free energy (SFE) were studied. The morphology of L929 and CCK-8 assay showed that the PU3/4HB is non-toxic and well for cell growth and proliferation. The morphology of platelets adhered on the polyurethane film observed by SEM showed that platelets were activated on the PU3/4HB films which would lead to blood coagulation. The lactate dehydrogenase (LDH) assay revealed that the PU3/4HBs displayed higher platelet adhesion property than raw materials and biodegradable polymer polylactic acid (PLA) and would be potential hemostatic materials.The chemical structure, molecular weight and distribution of PHA-b-PPG weresystematically characterized by 1H NMR, FTIR and GPC. DSC curves showed that the polyurethane have their T_g from -59.5°C to -5.2°C and X_c% from 0 to 28.3%, depending on the PHA-diol and the 3HB content. TGA curves displayed two steps thermal degradation and maintained the good thermal stability. CCK-8 assay revealed that PHA-b-PPG polyurethane can prevent L929 adhered on them, but not limited its cell growth. PHA-b-PPG polyurethane maybe the anti-adhere materials.