Category

Polymer research

(Natural) polymersApplicationCharacterizationCustomer publicationsFibersMaterialOrientation analysisPolymer researchTechniqueWAXS

Thermally Conductive and Electrically Insulating PVP/Boron Nitride Composite Films for Heat Spreader

Liu, Y.; Wang, N.; Ye, L.; Zehri, A.; Nylander, A.; Nkansah, A.; Lu, H.; Liu, J.

Thermally conductive materials with electrically insulating properties have been extensively investigated for thermal management of electronic devices. The combined properties of high thermal conductivity, structural stability, corrosion resistance and electric resistivity make hexagonal boron nitride (h-BN) a promising candidate for this purpose. Theoretical studies have revealed that h-BN has a…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacterizationCustomer publicationsMaterialPhase analysisPolymer researchSAXSTechnique

Unraveling the high strain-rate dynamic stiffening in select model polyurethanes – the role of intermolecular hydrogen bonding

Wu, You-Chi Mason; Hu, Weiguo; Sun, Yuchen; Veysset, David; Kooi, Steven E.; Nelson, Keith A.; Swager, Timothy M.; Hsieh, Alex J.

This study elucidates the influence of molecular attributes on the observed dynamic stiffening in select two-component polyurethanes upon high strain-rate impact. Unlike typical segmented elastomers, polyurethanes consisting of poly(tetramethylene oxide), PTMO, and a diisocyanate, but without a chain extender, are investigated. The hexamethylenediisocyanate (HDI)-based polyurethane, HDI?PU,…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacterizationCustomer publicationsFractal dimensionMaterialPolymer researchSAXSSizeTechnique

Reinforcement of polychloroprene by grafted silica nanoparticles

Abbas, Zaid M.; Tawfilas, Massimo; Khani, Mohammed M.; Golian, Karl; Marsh, Zachary M.; Jhalaria, Mayank; Simonutti, Roberto; Stefik, Morgan; Kumar, Sanat K.; Benicewicz, Brian C.

Reversible addition-fragmentation chain transfer polymerization of chloroprene on the surface of silica nanoparticles was performed to obtain polychloroprene-grafted-silica nanoparticles (PCP-g-SiO2 NPs). These particles were dispersed in a commercial polychloroprene matrix to obtain PCP nanocomposites with different silica core loadings (1, 5, 10, and 25?wt%). Two different chain graft densities…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacteristic dimensionCharacterizationCustomer publicationsMaterialPolymer researchSAXSTechniqueWAXS

Gas separation properties of polybenzimidazole/thermally-rearranged polymer blends

Moon, Joshua D.; Bridge, Alexander T.; D’Ambra, Colton; Freeman, Benny D.; Paul, Donald R.

Polybenzimidazole (PBI) is highly selective for H2 removal from mixtures with CO2, but it exhibits low gas permeabilities. Celazole® PBI was blended with more permeable HAB-6FDA-CI, an ortho-functional thermally rearrangeable polyimide, to improve its gas permeabilities while attempting to maintain high selectivity. A compatibilizer, 1-methylimidazole, enhanced phase dispersion when added…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacteristic dimensionCharacterizationCustomer publicationsMaterialPhase analysisPolymer researchSAXSTechnique

Gradient supramolecular interactions and tunable mechanics in polychaete jaw inspired semi-interpenetrating networks

Thompson, Chase B.; Chatterjee, Sourav; Korley, LaShanda T. J.

Polychaete worms display a remarkable jaw structure, where a gradient in metal-ligand coordination down the length of the jaw results in a shift from hard to soft mechanics. To mimic these gradient structures, a Zn-coordinated supramolecular polymer is crosslinked into a covalent matrix to afford supramolecular semi-interpenetrating networks (SIPNs). These…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacteristic dimensionCharacterizationCustomer publicationsMaterialOrientation analysisPolymer researchSAXSTechnique

Mechanism of stress induced crystallization of polyethylene

Yakovlev, Sergey; Fiscus, David; Brant, Pat; Butler, Jeff; Bucknall, David G.; Downing, Kenneth H.

When polymer melt is subjected to stress, molecular chains become aligned along the elongation direction. However, when polyethylene film crystallizes under stress, molecular chains frequently align perpendicular to the elongation direction. In this paper we investigate why this happens. Evaluating metallocene LLDPE film we show that under the stress lamellae…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacterizationCompositesCustomer publicationsMaterialParticlesPolymer researchPore size and pore size distributionSAXSShapeTechnique

Understanding the Static Interfacial Polymer Layer by Exploring the Dispersion States of Nanocomposites

Genix, Anne-Caroline; Bocharova, Vera; Carroll, Bobby; Lehmann, Michelle; Saito, Tomonori; Krueger, Susan; He, Lilin; Dieudonné-George, Philippe; Sokolov, Alexei P.; Oberdisse, Julian

The dynamic and static properties of the interfacial region between polymer and nanoparticles have wide-ranging consequences on performances of nanomaterials. The thickness and density of the static layer are particularly difficult to assess experimentally due to superimposing nanoparticle interactions. Here, we tune the dispersion of silica nanoparticles in nanocomposites by…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacterizationCustomer publicationsGISAXSMaterialPhase analysisPolymer researchSAXSShapeSizeSurface structure and patternsTechnique

Adjustable self-assembly in polystyrene-block-poly(4-vinylpyridine) dip-coated thin films

Konefa?, Magdalena; Zhigunov, Alexander; Pavlova, Ewa; ?ernoch, Peter; Pop-Georgievski, Ognen; Špírková, Milena

This work studies the influence of dip-coating parameters on self-assembly in ultra-thin films of asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) copolymers from a 1-chloropentane solution using a combination of several experimental techniques. Small-Angle X-ray Scattering, Atomic Force Microscopy, Grazing Incidence Small Angle X-ray Scattering and Transmission Electron Microscopy…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacterizationCustomer publicationsGIWAXSMaterialPolymer researchSurface structure and patternsTechnique

Addition of Monovalent Silver Cations to CH3NH3PbBr3 Produces Crystallographically Oriented Perovskite Thin Films

Siegler, Timothy D.; Zhang, Yangning; Dolocan, Andrei; Reimnitz, Lauren C.; Torabi, Aida; Abney, Michael K.; Choi, Junho; Cossio, Gabriel; Houck, Daniel W.; Yu, Edward T.; Li, Xiaoqin; Harvey, Taylor B.; Milliron, Delia J.; Korgel, Brian A.

The incorporation of monovalent silver (Ag+) cations into methylammonium lead bromide (CH3NH3PbBr3) perovskite films leads to a strongly preferred (001) crystallographic orientation on a wide variety of substrates, ranging from glass to mesoporous TiO2. CH3NH3PbBr3 films deposited without Ag+ exhibit only a weakly preferred (011) orientation. Compositional maps and depth…
sergio.rodrigues@xenocs.com
27 January 2020
(Natural) polymersApplicationCharacteristic dimensionCharacterizationCustomer publicationsMaterialPolymer researchSAXSSelf-assembled materialTechnique

Self-assembly of oppositely charged polyelectrolyte block copolymers containing short thermoresponsive blocks

Hees, I. A. van; Swinkels, P. J. M.; Fokkink, R. G.; Velders, A. H.; Voets, I. K.; Gucht, J. van der; Kamperman, M.

The assembly of oppositely charged block copolymers, containing small thermoresponsive moieties, was investigated as a function of salt concentration and temperature. Aqueous solutions of poly--b-poly (NIPAM44-b-DMAEMA216) and PNIPAM-b-poly-b-PNIPAM (NIPAM35-b-AA200-b-NIPAM35) were mixed in equal charge stoichiometry, and…
sergio.rodrigues@xenocs.com
27 January 2020