Modern products often consist of several materials, with each material conferring desirable properties to the end product. This ensures strong and light weight products with advanced properties and reduces the consumption of raw materials. A key challenge in hybrid products is the formation of strong joints, and commercial adhesion systems often consist of polymeric solutions applied in thick layers, which often do not meet the required mechanical durability and strength. Recently, a new adhesion technology that uses nanometer-thin polymer brush films to compatibilize dissimilar materials has emerged. Polymer brushes can interpenetrate a bulk polymer, if the enthalpy of mixing is zero or negtive, and form a nano-scale mechanical interlocking. This creates an unique type of bond that facilitates bonding between metals and plastics. With this thesis, the author intends to extend the scope of applications for polymer brush adhesion technology by investigating and developing a new polymer brush systems to compatibilize metal and rubber compounds.

The experimental work includes a thorough description and characterization of different polymer brushes grafted from stainless steel. Initially, the thermal stability of polymer brushes is investigated using infrared reflection absorption spectroscopy. Next, different strategies are used to cross-link polymer brushes and introduce reactive functional groups compatible with rubber. The brush modified steel is then overmolded with rubber and subsequently the fracture toughness is evaluated by peel experiments. Polymer brushes reinforced by intermolecular covalent cross-links prove to bond strongly with ethylene-propylene-diene M-class (EPDM) rubber and obtain maximum fracture toughness similar to a micro-meter thick commercial bonding agent. Last-ly, an emerging click reaction called sulfur fluoride exchange (SuFEx), is investigated as a potentially fast and reliable surface reaction.

Essentially, the work demonstrates an easy synthesis route for cross-linked polymer brushes that bond strongly to EPDM rubber. Together, the results are highly promising for future industrial applications and stresses that brush-modified materials are at the frontier of adhesion technology.