Linear and branched butyl rubber ionomers and thermoplastic elastomers from "click" chemistry

丁基橡胶（异丁烯-异戊二烯橡胶，IIR）是一种具有特殊物理性能的材料，可用于不同领域，包括汽车，建筑和生物医学应用。良好的弹性（变形后的形状恢复）对于所有这些应用都是必要的。这对于IIR来说是可能的，因为聚合物链含有低浓度（约100%）。1%）的异戊二烯（不饱和）单元，允许链共价（永久）交联成三维网络结构。共价键合方法虽然提供了良好的尺寸稳定性，但仅允许对材料的机械性能进行有限的控制。另一方面，众所周知，离子相互作用对于改变橡胶和塑料的机械性能（例如刚度、软化温度、抗撕裂性）非常有用，并且已在Surlyn®树脂等商业产品中得到应用，用作泡罩包装的高抗撕裂材料。含有低浓度的聚合物结合的离子基团（离聚物）的聚合物的改进的性能归因于离子部分的聚集，在低温至中等温度下充当多价物理交联。应用离聚物概念来改善丁基橡胶的机械性能受到的关注很少，主要是由于离聚物的含量非常低（约100%）。1%）的异戊二烯含量。朗盛公司最近开发的新工艺。允许合成含有高达5%异戊二烯单元的丁基橡胶。这将允许合成具有更高离子部分含量的离聚物，并且相应地具有比传统IIR宽得多的机械性能范围。在拟议的项目中，将为1）通过“点击”化学技术衍生化高异戊二烯含量线性IIR，2）合成支化IIR大分子及其衍生为离聚物，和3）合成衍生自丁基橡胶的支化热塑性弹性体建立反应条件。将研究所有这些聚合物的机械性能，以将其特征（结构，组成）与观察到的性能相关联。

Butyl rubber (isobutylene-isoprene rubber, IIR) is a material with unusual physical properties, useful in different areas including automotive, architectural, and biomedical applications. A good resilience (shape recovery upon deformation) is necessary for all these applications. This is possible for IIR because the polymer chains contain a low concentration (ca. 1%) of isoprene (unsaturated) units in addition to isobutylene, allowing covalent (permanent) cross-linking of the chains into a 3-dimensional network structure. The covalent bonding approach, while providing good dimensional stability, allows only limited control over the mechanical properties of the material. Ionic interactions, on the other hand, are known to be very useful to modify the mechanical properties (e.g. rigidity, softening temperature, tear resistance) of rubbers and plastics, and have found applications in commercial products such as the Surlyn® resins, used as highly tear-resistant materials for blister packaging. The improved properties of polymers containing a low concentration of polymer-bound ionic groups (ionomers) are attributed to the aggregation of the ionic moieties, acting as multivalent physical cross-links at low to moderate temperatures. The application of the ionomer concept to improve the mechanical properties of butyl rubber has received very little attention, mainly due to the very low (ca. 1%) isoprene content achieved in the traditional butyl rubber synthesis. New processes developed very recently at LANXESS Inc. allow the synthesis of butyl rubber containing up to 5% of isoprene units. This would allow the synthesis of ionomers with higher ionic moieties contents, and correspondingly a much wider range of mechanical properties than for traditional IIR. In the proposed project, reaction conditions will be established for 1) the derivatization of high isoprene content linear IIR by "click" chemistry techniques, 2) the synthesis of branched IIR macromolecules and their derivatization to ionomers, and 3) the synthesis of branched thermoplastic elastomers derived from butyl rubber. The mechanical properties of all these polymers will be investigated to correlate their characteristics (structure, composition) with the observed properties.