Centro de Investigación Científica de Yucatán, A.C., Calle 43 # 130 Col. Chuburná de Hidalgo, Mérida, Yucatán, Mexico.
Acta Biomater. 2010 Jun;6(6):2035-44. doi: 10.1016/j.actbio.2009.12.010. Epub 2009 Dec 22.
Biodegradable segmented polyurethanes (BSPUs) were prepared with poly(caprolactone) as a soft segment, 4,4'-methylene bis (cyclohexyl isocyanate) and either butanediol (BSPU1) or dithioerythritol (BSPU2) as a chain extender. BSPU samples were characterized in terms of their physicochemical properties and their hemocompatibility. Polymers were then degraded in acidic (HCl 2N), alkaline (NaOH 5M) and oxidative (H(2)O(2) 30wt.%) media and characterized by their mass loss, Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Undegraded BSPU1 and BSPU2 exhibited different properties, such as the glass transition temperature T(g) of the soft segment (-25 vs. 4 degrees C), mechanical properties (600% vs. 900% strain to break) and blood coagulating properties (clotting time=11.46 vs. 8.13min). After acidic and alkaline degradation, the disappearance of the 1728cm(-1) band of polycaprolactone (PCL) on both types of BSPU was detected by FTIR. However, the oxidative environment did not affect the soft segment severely as the presence of PCL crystalline domains were observed both by DSC (melting temperature T(m)=52.8 degrees C) and XRD (2theta=21.3 degrees and 23.7 degrees ). By TGA three decomposition temperatures were recorded for both BSPU samples, but the higher decomposition temperature was enhanced after acidic and alkaline degradation. The formation of the porous structure on BSPU1 was observed by SEM, while a granular surface was observed on BSPU2 after alkaline degradation.
可生物降解的嵌段聚氨基甲酸酯（BSPU）是以聚己内酯（PCL）作为软段，4,4'-亚甲基双（环己基异氰酸酯）和丁二醇（BSPU1）或二硫代赤藓糖醇（BSPU2）作为扩链剂合成的。从物理化学性能和血液相容性两方面对 BSPU 样品进行了表征。然后，将聚合物在酸性（HCl 2N）、碱性（NaOH 5M）和氧化（H(2)O(2) 30wt.%）介质中降解，并通过质量损失、傅里叶变换红外光谱（FTIR）、差示扫描量热法（DSC）、热重分析（TGA）、X 射线衍射（XRD）和扫描电子显微镜（SEM）进行了表征。未降解的 BSPU1 和 BSPU2 表现出不同的性能，如软段的玻璃化转变温度 T(g)（-25 对 4 摄氏度）、力学性能（断裂应变 600%对 900%）和血液凝固性能（凝固时间=11.46 对 8.13 分钟）。在酸性和碱性降解后，两种类型的 BSPU 上的聚己内酯（PCL）的 1728cm(-1) 峰均通过 FTIR 消失。然而，氧化环境并没有严重影响软段，因为通过 DSC（熔融温度 T(m)=52.8 摄氏度）和 XRD（2theta=21.3 度和 23.7 度）观察到 PCL 结晶域的存在。通过 TGA 记录了两种 BSPU 样品的三个分解温度，但在酸性和碱性降解后，较高的分解温度得到了提高。通过 SEM 观察到 BSPU1 形成了多孔结构，而在碱性降解后 BSPU2 表面呈现出颗粒状。
