Suwanprateeb Jintamai, Thammarakcharoen Faungchat, Hobang Nattapat
National Metal and Materials Technology Center (MTEC), 114 Paholyothin Road, Klong 1, Klongluang, Pathumthani, 12120, Thailand.
J Mater Sci Mater Med. 2016 Nov;27(11):171. doi: 10.1007/s10856-016-5784-4. Epub 2016 Oct 4.
A new infiltration technique using a combination of low and high molecular weight polycaprolactone (PCL) in sequence was developed as a mean to improve the mechanical properties of three dimensional printed hydroxyapatite (HA). It was observed that using either high (M ~80,000) or low (M ~10,000) molecular weight infiltration could only increase the flexural modulus compared to non-infiltrated HA, but did not affect strength, strain at break and energy at break. In contrast, a combination of low and high molecular infiltration in sequence increased the flexural modulus, strength and energy at break compared to those of non-infiltrated HA or infiltrated by high or low molecular weight PCL alone. This overall enhancement was found to be attributed to the densification of low molecular weight PCL and the reinforcement of high molecular PCL concurrently. The combined low and high molecular weight infiltration in sequence also maintained high osteoblast proliferation and differentiation of the composites at the similar level of the HA. Densification was a dominant mechanism for the change in modulus with porosity and density of the infiltrated HA/PCL composites. However, both densification and the reinforcing performance of the infiltration phase were crucial for strength and toughening enhancement of the composites possibly by the defect healing and stress shielding mechanisms. The sequence of using low molecular weight infiltration and followed by high molecular infiltration was seen to provide the greatest flexural properties and highest cells proliferation and differentiation capabilities.
开发了一种新的渗透技术，依次使用低分子量和高分子量聚己内酯（PCL）的组合，作为改善三维打印羟基磷灰石（HA）机械性能的一种手段。据观察，与未渗透的HA相比，单独使用高（M80,000）或低（M10,000）分子量渗透只能增加弯曲模量，但不影响强度、断裂应变和断裂能量。相比之下，与未渗透的HA或单独用高或低分子量PCL渗透的HA相比，依次进行低分子量和高分子量渗透的组合增加了弯曲模量、强度和断裂能量。发现这种整体增强归因于低分子量PCL的致密化和高分子量PCL的增强作用同时发生。依次进行低分子量和高分子量渗透的组合还使复合材料的成骨细胞增殖和分化维持在与HA相似的高水平。致密化是渗透的HA/PCL复合材料模量随孔隙率和密度变化的主要机制。然而，致密化和渗透相的增强性能对于复合材料强度和增韧的提高可能通过缺陷愈合和应力屏蔽机制都是至关重要的。先进行低分子量渗透然后进行高分子量渗透的顺序被认为能提供最大的弯曲性能以及最高的细胞增殖和分化能力。
