Foam extrusion of modified bioplastic on basis of polylactide (PLA)

泡沫塑料的特点是密度非常低，导热系数非常低，吸声能力强，加工成本低。大多数泡沫塑料用于寿命相对较短的运输包装，例如电子设备和绝缘应用。聚乳酸(PLA)是一种可生物降解的生物基塑料，其生产过程中含有大量具有商业价值的高性价比乳酸。为了在保质期后和/或稀缺的化石资源中为泡沫塑料包装提供额外的处置选择，需要在聚乳酸的基础上建立挤出泡沫塑料。由于其较低的熔体强度，这目前是不可能的。尽管有几种通过长链支化来增加熔体强度的方法，但对于长链支化的构象仍有几个开放的问题。计划研究项目的目的是澄清关于线性聚乳酸和改性聚乳酸共混物的各种零粘度、不同数量的官能团、不同的改性反应机理和相互作用等悬而未决的问题，以增加其熔体硬度，从而实现挤出发泡。

Foams are characterized by very low density, very low thermal conductivity, high sound absorption and low tooling costs. Most foamed moldings are used in relatively short-living transport packaging, e.g. electronic devices and in insulation applications. Polylactide (PLA) is a biodegradable and biobased plastic, which is produced in commercially significant amount of cost-effective lactic acid. In order to provide additional disposal option for foamed packaging after the lifetime and/or to scarce fossil resources, it is desirable to establish extrusion foams on the basis of PLA. Due to its low melt strength, this is not currently possible. Despite several approaches to increase the melt strength through long chain branching there are several open questions to the conformation of long chain braching. The aim of the projected research project here is to clarify open questions regarding various zero viscosities, different numbers of functional groups, different reaction mechanisms of modification and interactions in blends of linear and modified PLA to increase its melt stiffness and thus to enable the extrusion foaming.