Structure-property relationships and development of new molecules and polymeric materials for nonlinear optics

1992 ◽  
Author(s):  
Bruce A. Reinhardt
Author(s):  
L. C. Sawyer

Structure-property relationships are important in the process optimization and fundamental understanding of many polymeric materials, including membranes. Polymer membranes are currently being used for separation, concentration or purification in a wide range of industrial process applications. The process used to manufacture the membrane, and the polymer type, determines the morphology, which influences the membrane transport properties and potential applications. The morphology includes: pore size, shape, distribution and their overall three dimensional arrangement. Microscopical methods are needed to image the structures formed by the various processes, in order to systematically study changes in variables for specific applications.


2002 ◽  
Vol 740 ◽  
Author(s):  
Li-Piin Sung ◽  
Stephanie Scierka ◽  
Mana Baghai-Anaraki ◽  
Derek L. Ho

ABSTRACTMetal-oxide nanoparticles can be used to optimize UV absorption and to enhance the stiffness, toughness, and probably the service life of polymeric materials. Characterization of the nano- and microstructure dispersion of particles is necessary to optimize the structure-property relationships. Characterizations of both TiO2 particles dispersed in an acrylic-urethane matrix and TiO2 nanostructured films obtained through sol-gel synthesis are discussed. Experimental methods include microscopy (confocal, AFM) and small angle neutron scattering (SANS). Results from SANS experiments, which yield information about the cluster size of the nano-TiO2 particles and the spatial dispersion in various nanoparticle/polymer samples are presented and compared to the results of microscopy studies.


1991 ◽  
Author(s):  
Seth R. Marder ◽  
Lap-Tak A. Cheng ◽  
Bruce G. Tiemann ◽  
David N. Beratan

2021 ◽  
Author(s):  
Hatice Kaplan Can ◽  
Serap Kavlak ◽  
Fatma Gurbuz ◽  
Mehmet Odabaşı

Abstract Extracellular polymeric substances (EPSs) can be defined as renewable, high molecular weight polymeric materials produced by bacteria and microorganisms. EPSs are composed of primarily polysaccharides and proteins, with minor amounts of nucleic acids, lipids, and humic substances. Cyanobacterial extracellular polymeric subtances have a significant physiological effect on bloom formation and stress tolerance in adverse conditions. Therefore, cyanobacterial EPS has an important factor for aquatic life, environment and human life. For these reasons, determining the structure and structure-property relationships of cyanobacterial EPS is important for understanding its behavior and performance. In this study, the identification of the structure-property relationships, thermal and viscoelastic properties of cyanobacterial extracellular polymeric substance, X-ray diffraction (XRD) analysis, differential thermal analysis (DTA) and dynamic mechanical analysis (DMA) have been performed. Viscoelastic properties of the polymeric materias have been interpreted by certain DMA parameters at a fixed frequency depending on the temperature to understand the performance of cyanobacterial EPS.


2019 ◽  
Vol 6 (3) ◽  
pp. 69 ◽  
Author(s):  
Aaron C. Wilson ◽  
Shih-Feng Chou ◽  
Roberto Lozano ◽  
Jonathan Y. Chen ◽  
Pierre F. Neuenschwander

Hemocompatibility remains a challenge for injectable and/or implantable medical devices, and thromboresistant coatings appear to be one of the most attractive methods to down-regulate the unwanted enzymatic reactions that promote the formation of blood clots. Among all polymeric materials, polyurethanes (PUs) are a class of biomaterials with excellent biocompatibility and bioinertness that are suitable for the use of thromboresistant coatings. In this work, we investigated the thermal and physico-mechanical behaviors of ester-based and ether-based PU films for potential uses in thromboresistant coatings. Our results show that poly(ester urethane) and poly(ether urethane) films exhibited characteristic peaks corresponding to their molecular configurations. Thermal characterizations suggest a two-step decomposition process for the poly(ether urethane) films. Physico-mechanical characterizations show that the surfaces of the PU films were hydrophobic with minimal weight changes in physiological conditions over 14 days. All PU films exhibited high tensile strength and large elongation to failure, attributed to their semi-crystalline structure. Finally, the in vitro clotting assays confirmed their thromboresistance with approximately 1000-fold increase in contact time with human blood plasma as compared to the glass control. Our work correlates the structure-property relationships of PU films with their excellent thromboresistant ability.


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