Materials and sample preparation

As indicated in Fig. 23.1, a sample consists of a rigid glass indenter and an elastomer substrate of crosslinked poly(dimethyl siloxane) (PDMS), which are both coated with the polymer layers of interest. These layers include a semicrystalline layer of poly(ethylene oxide) (PEO) sandwiched between glassy polymer layers of poly(tetramethyl bisphenol A polycarbonate) (TMPC). These polymers will be described in more detail within this section along with the steps that were taken to select these polymers for the study of a glassy/semicrystalline interface. 

23 Contact Mechanics and Inteifacial Fatigue Studies Between Semicrystaiiine and Poiymer Fiims 

To make samples for the adhesion experiments, a crosslinked PDMS elastomer substrate was oxidized by a 30 min exposure to UV/ozone [21-24], using a Jelight Company Model 42 UVO-Cleaner. A thin layer of polystyrene (M = 38000 g mol ) with a trimethoxysilyl end group was spin-cast onto this oxidized elastomer from a solution in toluene. These functionalized chains were grafted onto the oxidized PDMS surface by annealing for 1.5 h at 125 °C, and the excess polystyrene chains were removed by rinsing the sample in toluene 

In order to perform the adhesion tests, the prepared samples were mounted in position in the heating chamber as shown in Fig. 23.3. The elastomer side of the sample was previously attached to a glass slide using a silicone glue and the slide was fastened into place on the sample holder, which was then coimected 

Tests were also performed with a pre-annealing step before the sample and indenter were brought into contact. The sample and indenter were held out of contact at 80 °C for a specified period of time and then brought into contact to 

For the preparation of filler reinforced elastomer composites, most frequently commercial rubber grades with variable microstructure and broad molar mass distribution are applied. The typical rubber grades, considered in the present review, are as follows  

Ethylene-propylene-diene rubber EPDM (Keltan 512 55 vol.% ethylene) 

Nitrile-butadiene rubber NBR (Perbunan 3307 33 vol.% acryl-nitrile) 

In addition to the commercial rubber grades, model polymers with variable molar mass and narrow molecular weight distribution are often used for studying reinforcement mechanisms. (In Sect. 4.3 we consider a special S-SBR type with 29 vol.% vinyl and 25 vol.% styrene units Mw/Mn=l.l). 

As polymeric model fillers with specific surface groups and narrow size distribution, different microgel types, e.g., poly(styrene)-microgel, PS(m), and poly(methoxy-styrene)-microgel, PMS(m), are applied. They can be prepared by emulsion polymerization techniques as described, e.g., in [48]. 

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Materials and Sample Preparation. The starting materials are commercial Union Carbide zeolites NaX and NaY, in powder form. The chemical compositions are Na86(AlO2)86(SiO2)i06 H2O and Nase-(A102)56(Si02)i36 H2O, respectively. 

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