In order to impart utility to polymeric materials particularly in high performance applications, polymers are oftentimes compounded with particles that reinforce and improve properties. These particles include fibers, metal oxides, and engineered nanoparticles to name a few. Arguably the most important thermal property of a polymer is the glass transition temperature, which can be tailored through the incorporation of nanofillers that reinforce polymer chains at the molecular scale. Here we present two methods to enhance thermal properties of two different types of nanocomposites. In the first system, we use boron cage compounds to tailor rheology, thermal properties, and the dielectric spectrum of segmented polybutadiene/polyurethane-based multi-block copolymers. Upon incorporation of n-hexylcarborane, we observe plasticization of PU hard segments and reinforcement of PBD soft segments. Broadband dielectric spectroscopy reveals multiple relaxations consistent with glass transition measurements made via DSC and DMA. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/241nm/uploads/74542_reaction_of_rearrangement_and_reduction.jpg' alt='' /> In the second system, we evaluate the influence of small molecule nanofillers on thermal properties of an epoxy matrix. Here we observe that chemical modification of the epoxy matrix with an anthracene moiety combined with the inclusion of anthracene as nanofiller results in a substantial enhancement of thermal properties. The combination of matrix modification and nanofiller synergistically imparts increased degradation and glass transition temperatures, and interesting thermomechanical response. This cooperative effect manifests itself in distinct irreversible contraction upon thermal cycling even though the system is fully cured.

Effects of nanofillers on polyurethane-polybutadiene multiblock copolymers and epoxy resins: Thermal, mechanical, and dielectric properties

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.