Foaming process can be monitored under batch or continuous flows conditions. In the batch process, foaming is time-dependent and the foaming efficiency is controlled by the operator. On the other hand, in the continuous process, the foaming efficiency is only monitored by gas and liquid flow rates. The aim of this work is to compare the two technologies to perform porous scaffold biomaterial based on chitosan (a biocompatible polysaccharide) as well as calcium (Ca²⁺) and silica (SiO₂) (two osteogenesis compounds). Diverse recipes using chitosan (CS) solution (2% ()) in acetic acid (1% ( in distilled water)) mixed with whey protein isolate (WPI) (2% ()) as natural surfactant were studied. They were supplemented or not by hydroxyapatite powder (HAp) and tetraethyl orthosilicate (TEOS). A jacketed narrow annular gap unit (NAGU) was used to perform the continuous foaming process. For all experimentations, the mixture flow rate was maintained at 30 mL min^-1. The influence of operating conditions such as gas and liquid flow rates was studied to obtain foams and final scaffold material with different densities and porosities. Some other recipes followed foaming under batch conditions. Generally, the recipes were placed in a vessel under mixing allowing the gas phase to come from the roof of the vessel. In this case, it becomes very difficult to control the density and the size distribution of bubbles in the final product. In both cases, liquid foams were analysed (density, bubble size distribution) and then freeze-dried for mechanical and porosity investigations using the dynamic mechanical analysis (DMA) system and scanning electron microscopy (SEM). It has been shown that the controlled injected gas affected the continuous phase, resulting in a lighter and higher porous structure, a more homogeneous appearance, and a more uniform distribution of osteogenesis components compared to one obtained using batch operation. The obtained porous materials exhibited good properties (porosity, interconnectivity, and good HAp and silica distribution) and potential for future bone regeneration applications.

中文翻译：

---

分批和连续过程获得壳聚糖基高多孔生物材料的比较研究

可以在间歇或连续流动条件下监控发泡过程。在间歇过程中，发泡是时间依赖性的，发泡效率由操作员控制。另一方面，在连续过程中，起泡效率仅通过气体和液体的流速来监控。这项工作的目的是比较两种基于壳聚糖（一种生物相容性多糖）以及钙（Ca ²⁺）和二氧化硅（SiO ₂）（两种成骨化合物）的多孔支架生物材料的技术。使用壳聚糖（CS）溶液的各种配方（2％（）在乙酸中（1％（ 在蒸馏水中））与乳清蛋白分离物（WPI）混合（2％（））作为天然表面活性剂进行了研究。是否添加羟基磷灰石粉（HAp）和原硅酸四乙酯（TEOS）。使用带夹套的窄环形间隙单元（NAGU）进行连续发泡过程。对于所有实验，混合物流速均保持在30 mL min ^-1。研究了诸如气体和液体流速之类的操作条件的影响，以获得具有不同密度和孔隙率的泡沫和最终支架材料。在间歇条件下起泡之后，还有一些其他配方。通常，将食谱在混合下放置在容器中，以使气相来自容器的顶部。在这种情况下，很难控制最终产品中气泡的密度和尺寸分布。在这两种情况下，都分析了液体泡沫（密度，气泡大小分布），然后使用动态力学分析（DMA）系统和扫描电子显微镜（SEM）将其冷冻干燥，以进行机械和孔隙率研究。已经表明，受控的注入气体会影响连续相，从而导致更轻和更高的多孔结构，与使用分批操作获得的外观相比，其外观更加均匀，并且成骨成分的分布更加均匀。所获得的多孔材料表现出良好的性能（孔隙度，互连性以及良好的HAp和二氧化硅分布），并具有未来骨再生应用的潜力。