Polyolefins form one of the most important classes of polymeric materials.  Polyethlyene (PE), Polypropylene (PP), and Ethylene-Propylene copolymers (EP Rubber) account for almost 60% of the total polymer production in the United States.  Taken for granted by most people, polyolefins have a profound impact on our daily lives - from bags and bottles to hoses and tires.  Despite the advantages of polyolefins (ease of processability, price, mechanical/chemical properties, light weight, etc.) problems still exist.  The chemical inertness of these polymers translates into poor interaction with other materials such as glass, metal, and most polymers.  This lack of compatibility has rendered the majority of polyolefins useless for applications that demand adhesion, compatibility, wettability, and printability.
    In order to overcome this lack of interaction, functionalities must be introduced to these materials.  Functionality promotes the ability to form covalent bonds.  Polyolefins possessing this property would therefore be able to interact with other materials, greatly expanding the potential uses of these polymers.  Chemically modifying polyolefins to impart functionality is one of the primary research interests in this lab.
    The approach to overcoming this problem has involved using boron containing monomers and transition metal catalysts.  These borane monomers as they are called (boron alkyls) possess chemistry that is similar to their plain alkane counterparts, therefore not significantly altering the properties of the material.  The most desirable reason, however, for using borane monomers is that once polymerized, they can easily be converted into a plethora of functionalities in a wide range of geometries.
This is shown in the figure to the right.  Borane monomers also possess an added advantage in that they can be polymerized using a Ziegler-Natta route without the problems of catalyst poisoning that were encountered in polymerizing "pre-functionalized" monomers.
    Preparing polymer using borane monomers is relatively straightforward.  A borane monomer such as 5-hexenyl-9-BBN (where 9-BBN is 9-borabicyclo [3,3,1]-nonane) is copolymerized with any alpha-olefin in a commercial Zielger-Natta catalyst.  The reaction is usually done at room temperature and high molecular weight polymer is achieved at relatively short reaction times.  Once polymerized, the borane containing polymer can be functionalized using NaOH for example.  For a more thorough treatment, refer to the "Publications" section.
    Developing functionalized polyolefins has consequently led to a variety of new and exciting materials.  These include PP coatings, hydrophilic PP membranes, graft polymers, and commodity blends among others.

PP Coatings
   Polypropylene is sought after because of its unique physical properties.  Among these are its mechanical properties, chemical stability, and moisture impermeability.  Being able to coat a material such as glass or metal with polypropylene could substantially augment the properties already possessed by the substrate material.  Due to the lack of functionality in PP, the benefits of these coatings could not be fully realized.  Previous methods of substrate coating resulted in relatively poor adhesion between coating and substrate.
    Imparting functionality in polypropylene has overcome this problem.  PP with hydroxyl (-OH) groups on the chain exhibits a 7 to 10 fold increase in peel strength.

Hydrophilic PP Membranes
    Another exciting application of functional PP is in membrane preparation.  Functional PP can be used to convert hydrophobic membrane surfaces to hydrophilic surfaces.  This new generation of membrane finds extensive use in areas such as dialysis and filtration.  In addition to this, these membranes are far more durable than their previous counterparts.  The microstructure of one such membrane is shown below.