Anisotropic Wetting Behavior on Injection Molded Polypropylene Parts Inspired by Surface Structure of Moss

During the last years the carmakers interest is focused on polymer manufacturers to develop breakthrough solutions addressing the key drivers of reducing weight and cost. The use of polypropylene (PP) and other thermoplastic olefins is growing because of their low cost and good properties. Unfortunately, some of the same properties that make these plastics attractive to designers, also make them difficult to bond with adhesives or varnish. Non-polar character of PP results in poor surface properties and low wettability. Several methods of surface pretreatments have been used to improve its wettability, but all involves cost extending additional processing. Based on lessons from nature, one of the ways how to increase wettability is surface structuring. Injection mold insert designing and manufacturing process inspired by hydrophilic structure of the moss is presented. Due to cost reducing demands were used conventional processing methods.

Interfacial Characterization of Multiple Layer Coatings on Thermoplastic Olefins (TPO)

Thermoplastic olefins (TPO) have made significant inroads as polymeric materials for interior and exterior automotive parts. Spray applied chlorinated polyolefins (CPO) are often used to improve paint adhesion to the low surface energy TPO substrates. The penetration of the CPO into the substrate is difficult to quantify, but is critical to achieving a good paint/TPO bond. The interphase between each layer in a coated TPO coupon was investigated using a combination of instrumented indentation and confocal Raman microscopy. The degree of CPO interpenetration was Thermoplastic olefins (TPO) have made significant inroads as polymeric materials for interior and exterior automotive parts. Spray applied chlorinated polyolefins (CPO) are often used to improve paint adhesion to the low surface energy TPO substrates. The penetration of the CPO into the substrate is difficult to quantify, but is critical to achieving a good paint/TPO bond. The interphase between each layer in a coated TPO coupon was investigated using a combination of instrumented indentation and confocal Raman microscopy. The degree of CPO interpenetration was altered by using three different CPOs exposed to two different manufacturing methods for the same TPO and base/clear coat system. It was found that the interfaces, CPO/base coat or CPO/TPO, were chemically and mechanically sharp at the 1 μm lateral resolution of both techniques. A gradient in the modulus through the thickness of the clear coat was observed using instrumented indentation.