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Wiegand T.,KRATON Polymers | Hiebner K.,University of Nebraska - Lincoln | Gauza L.,University of Nebraska - Lincoln | Schwartz C.,University of Nebraska at Kearney | And 7 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2014

Biomimetic composites were constructed using anorganic bone to initiate the polymerization of cyclic lactones. The resulting anorganic bone/polylactone composites preserve the inorganic structure and the mechanical properties of the original bone. Thermal conditions used to prepare the anorganic bone were shown to control the surface functionalities, surface area, and crystallinity, all of which influence the rates of subsequent polymerizations. Thermal pretreatment of anorganic bone was examined as a function of time and temperature, ranging from 400°C to 800°C. Polymerization rates of different monomers were also compared. Additionally, in vitro evaluations of anorganic bone/poly-l-lactide and anorganic bone/polyglycolide composites for osteoblast and osteoclast competence suggest that these composites are good candidates for potential in vivo use, since both composites promoted osteoblast differentiation. The anorganic bone/poly-l-lactide composite also promoted osteoclast differentiation. © 2013 Wiley Periodicals, Inc. Source

Mogawer W.,University of Massachusetts Amherst | Austerman A.,University of Massachusetts Amherst | Kluttz R.,KRATON Polymers | Roussel M.,University of Massachusetts Amherst
Transportation Research Record | Year: 2012

A high-performance thin asphalt overlay (HPThinOL) is specified as having a thickness of 1 in. or less and is used in applications requiring high levels of rutting and fatigue resistance. HPThinOLs are used as a pavement preservation strategy and are placed on pavements that have remaining structural capacity that is expected to outlive that strategy. Current specifications for HPThinOLs generally call for a polymer-modified asphalt (PMA). However, PMA binders are more expensive than unmodified asphalt binders. This expense, coupled with the higher binder content requirement generally associated with HPThinOL, could lead to an initial higher cost in relation to other pavement preservation strategies. Although the higher initial cost can be offset by incorporating high amounts of reclaimed asphalt pavement (RAP), the use of high amounts of RAP in PMA mixtures might adversely affect the mixture performance (stiffness, cracking, or workability). Warm-mix asphalt (WMA) technology may improve the workability of HPThinOL that incorporates high RAP content and PMA binders. This study evaluated the effect of PMA binders, high RAP content, and WMA technology on the stiffness, resistance to reflective cracking, moisture susceptibility, and workability of HPThinOL mixtures. PMA binders and high RAP content increased the stiffness of HPThinOL significantly; however, the use of WMA technology lowered mixture stiffness and improved workability. PMA may improve the cracking resistance, moisture susceptibility, and rutting resistance of high-RAP HPThinOL mixtures, depending on whether a WMA technology is used. Source

Wright K.J.,Kraton Polymers U.S. LLC | Ding R.,KRATON Polymers
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2010

Urethane based thermoplastic elastomers (TPU) have an impressive range of performance characteristics such as outstanding scratch/abrasion resistance, excellent oil resistance and high tensile and tear strengths. However, application of TPUs is limited when low hardness (<70 A) is required. Soft TPU materials with low level of hard segment are difficult to process. Commercially, low hardness products are produced by adding phthalate plasticizers, which are not desirable in some applications. The objective of this project is to study TPU hardness modification using styrenic block copolymers to achieve soft TPU alloys without significantly sacrificing other physical properties. Source

Wiegand T.,U.S. LLC | Vervoort F.,Kraton Polymers Research Bv | Kafka C.,KRATON Polymers
Society of Plastics Engineers - 14th-Annual SPE TPO Automotive Engineered Polyolefins Conference | Year: 2012

Kraton Polymers has developed Kraton™ ST 5100, a new proprietary compound to expand the use of TPEs into the slush molding process. Kraton products have been used extensively in automotive interior soft touch over-mold applications for decades. This new and innovative system brings the advantages of Kraton materials to components not previously accessible to TPEs. Kraton's new TPE slush molding compound has significant advantages over current materials such as lower density, improved fogging performance. Kraton™ ST 5100 also has significant benefits above TPO materials currently employed in thermoforming. Traditionally TPO materials have had less than ideal haptics. They are boardy and have a very plastic feel similar to rigid polypropylene. Contemporary TPOs also require a primer coat or flame treatment to be able to have adequate adhesion to the PU foam substructure. This extra process step adds cost to the final construction. Source

Kluttz R.Q.,KRATON Polymers | Jellema E.,KRATON Polymers | Woldekidan M.F.,Technical University of Delft | Huurman M.,BAM Wegen
Airfield and Highway Pavement 2013: Sustainable and Efficient Pavements - Proceedings of the 2013 Airfield and Highway Pavement Conference | Year: 2013

Porous asphalt pavements with a large percentage of air voids such as open graded friction courses (OGFC) have been built across the United States since the 1950s. The OGFCs have several benefits such as a higher degree of friction and permeability providing drainage of rain water from the surface of the pavement. However, only a few cold winter nights can cause years' worth of raveling damage to a road when stresses due to traffic loads and day to night temperature variations reach the binder's breaking point. Delft University of Technology developed a finite element model, the Lifetime Optimization Tool (LOT), to study this phenomenon by predicting asphalt mix response from asphalt mortar properties. Mortars of long-lasting porous asphalt roads were compared with those from early-failure roads. The study concluded that two factors are critical to prevent winter damage: ≤ Limited binder stiffness at low temperature, particularly after aging ≤ Binder stress relaxation at these low temperatures. In a search for improved binder performance, four different highly modified binders were produced by Kraton Polymers Research B.V. Master curves were developed on laboratory-aged binders for viscoelastic properties, and the mortar performance was evaluated at different temperatures and temperature fluctuations using the protocol of the LOT model. The results were compared with literature data of the existing road sections and showed a dramatic improvement in raveling resistance. The SBS polymer-modified binders demonstrated exceptional performance in the winter and at least an equally good performance under summer conditions. © 2013 American Society of Civil Engineers. Source

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