Complex ORAL health products (CORAL): Characterisation, modelling and manufacturing challenges

牙膏-尤其是主要凝胶成分不是水基的专业药物牙膏-有着令人惊讶的复杂和令人费解的制造过程。有一种背景流体，它已经是粘性液体和聚合物的混合物；然后加入固体颗粒。它们是研磨性的，可以进行大部分牙齿清洁；但它们在加工过程中也会膨胀，当添加它们时，系统会变得更厚。最后，加入表面活性剂以帮助牙膏在口腔中产生泡沫；更复杂的是，在加工过程中，气泡也会悄悄进入。在这个项目中，我们将系统地解决牙膏加工的所有阶段。我们将进行精确的小规模流变学测量，以发现颗粒如何膨胀以及膨胀后它们如何相互作用：例如，它们是吸收部分长聚合物分子以形成网络，还是部分吸附的聚合物起到推动膨胀颗粒分离的“刷子”的作用？我们还将测量系统每个阶段的整体行为(背景流体本身、颗粒或气泡)，并根据其组成创建系统行为的相图。我们将使用先进的数学建模技术来推导新的方程，这些方程可以描述混合物的行为--例如，背景流体和膨胀的颗粒--就像它是单一材料一样。最后，我们将在计算机模拟中使用我们的新本构方程来预测糊料在真实加工环境中的行为，解决这些新配方带来的制造挑战，并提出克服这些挑战的新策略。这项研究需要一个拥有多种不同专业能力的团队，涵盖实验、建模和模拟，还需要与行业密切联系，以确保我们提出正确的问题。葛兰素史克是该项目的主要合作者。该项目还得到了喷墨打印技术领先者Xaar的支持。有了我们的理解，他们希望使他们的制造过程更高效、更可靠，并开发新的配方来满足未来客户的需求。

Toothpastes - and especially specialised pharmaceutical toothpastes, whose major gel component is not water-based - have a surprisingly complex and ill-understood manufacturing process. There is the background fluid, which is already a mixture of a viscous liquid and a polymer; then solid particles are added. These are abrasive and do much of the tooth cleaning; but they also swell during processing, and the system becomes much thicker when they are added. Finally surfactant is added to help the toothpaste to foam in the mouth; and just to complicate matters further, air bubbles also creep in during processing. In this project, we will systematically address all the stages of toothpaste processing. We will carry out precise small-scale rheological measurements to discover how the particles swell and how they interact once they have swollen: for example, do they absorb parts of the long polymer molecules to form a network, or do partly-absorbed polymers act as "brushes" to push swollen particles apart? We will also measure the overall behaviour of each stage of the system (the background fluid on its own, or with particles, or with bubbles) and create a phase map of system behaviour in terms of its composition. We will use advanced mathematical modelling techniques to derive new equations that can describe the behaviour of a mixture - for example, background fluid and swollen particles - as if it were a single material. Finally, we will use our new constitutive equations in computer simulations to predict the behaviour of the paste in a real processing environment, address the manufacturing challenges such novel formulations entail and propose new strategies to overcome these.The research needs a team with many different specialist abilities, across experimentation, modelling and simulation, and also needs close ties with industry to ensure we are asking the right questions. GSK is a major collaborator on this project. The project is also supported by Xaar the leader in inkjet printing technology. With the understanding we generate, they hope to make their manufacturing processes both more efficient and more reliable and also develop new formulations to address future customer needs.