Bianco, Antonino; Burg, Stephanie L.; Parnell, Andrew J.; Fernyhough, Christine M.; Washington, Adam L.; Hill, Christopher J.; Smith, Patrick J.; Whittaker, David M.; Mykhaylyk, Oleksandr O.; Fairclough, J. Patrick A.
Control of the Porous Structure of Polystyrene Particles Obtained by Nonsolvent Induced Phase Separation
Porous polystyrene microspheres were produced by a process of nonsolvent induced phase separation (NIPS) from ternary polymer–solvent–nonsolvent (polystyrene–toluene–ethanol) systems and characterized by scanning electron microscopy (SEM) and small-angle X-ray scattering (SAXS) techniques. This study provides evidence for a link between the structural morphology of the porous polystyrene…
Controlling Crystal Microstructure To Minimize Loss in Polymer Dielectrics
Miranda, Daniel F.; Zhang, Shihai; Runt, James
A model semicrystalline polymer, poly(ethylene naphthalate) (PEN), was used to examine how morphological factors inhibit chain segment relaxations that contribute to dielectric loss. This was achieved by manipulating the extent of crystallization and the crystalline microstructure through a combination of annealing and uniaxial drawing and investigating the effects on dielectric…
Controlling the generation of bilayer and multilayer vesicles in block copolymer/epoxy blends by a slow photopolymerization process
Puig, J.; Ceolín, M.; Williams, R. J. J.; Schroeder, W. F.; Zucchi, I. A.
Vesicles are a highly attractive morphology to achieve in micellar dispersions of block copolymers (BCP) in epoxy thermosets due to the fact that small amounts can affect a large volume fraction of the matrix, a fact that is important for toughening purposes. However, generating vesicles in epoxy matrices requires operating…
Converting Carbohydrates to Carbon-Based Photocatalysts for Environmental Treatment
Hu, Zhuofeng; Shen, Zhurui; Yu, Jimmy C.
Carbohydrates in biomass can be converted to semiconductive hydrothermal carbonation carbon (HTCC), a material that contains plenty of sp2-hybridization structures. Under solar light illumination, HTCC generates photoexcited electrons, holes, and hydroxyl radicals. These species can be used for photocatalytic treatment such as water disinfection and degradation of organic pollutants. The…
Crack growth mechanism of styrene-butadiene rubber filled with silica nanoparticles studied by small angle X-ray scattering
Weng, Gengsheng; Chang, Aijun; Fu, Kun; Kang, Jian; Ding, Yaxuan; Chen, Zhongren
The crack growth mechanism of rubber composites has not been explored clearly. Here, we focus on the microstructure evolution of styrene-butadiene rubber/silica (SBR/silica) composites during crack propagation. Two groups of SBR/silica composites are constructed. The silica nanoparticles used in the two groups have different sizes but the same surface properties.…
Crowding-Controlled Cluster Size in Concentrated Aqueous Protein Solutions: Structure, Self- and Collective Diffusion
Braun, Michal K.; Grimaldo, Marco; Roosen-Runge, Felix; Hoffmann, Ingo; Czakkel, Orsolya; Sztucki, Michael; Zhang, Fajun; Schreiber, Frank; Seydel, Tilo
We investigate the concentration-controlled formation of clusters in β-lactoglobulin (BLG) protein solutions combining structural and dynamical scattering techniques. The static structure factor from small-angle X-ray scattering as well as de-Gennes narrowing in the nanosecond diffusion function D(q) from neutron spin echo spectroscopy support a picture of cluster formation. Using neutron…
Creep-resistant behavior of beta-polypropylene with different crystalline morphologies
Jia, Chenfei; Liao, Xia; Zhu, Jingjun; An, Zhu; Zhang, Qiongwen; Yang, Qi; Li, Guangxian
β-Phase isotactic polypropylene (β-iPP) specimens with different contents of β-phase nucleating agent were employed to investigate the deformation-induced microstructure evolution during creep behavior. Morphological investigations by SEM showed that the crystalline morphologies of β-iPP were controlled by the content of the β-phase nucleating agent, namely, well-developed β-spherulites induced…
Crystallization and melting of isotactic polypropylene crystallized from quiescent melt and stress-induced localized melt
Lu, Ying; Wang, Yaotao; Chen, Ran; Men, Yongfeng
Temperature dependency of crystalline lamellar thickness during crystallization and subsequent melting in isotactic polypropylene crystallized from both quiescent molten state and stress-induced localized melt was investigated using small angle X-ray scattering technique. Both cases yield well-defined crystallization lines where inverse lamellar thickness is linearly dependent on crystallization…
Crystallization of hard segments in MDI/BD-based polyurethanes deformed at elevated temperature and their dependence on the MDI/BD content
Li, Xuke; Lu, Ying; Wang, Hai; Pöselt, Elmar; Eling, Berend; Men, Yongfeng
Morphological variation of thermoplastic polyurethanes (TPUs) with different hard segment contents (HSCs) stretched at 100 °C higher than the Tg of hard domain was monitored by in-situ wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) techniques. WAXS patterns reveal that the crystalline modification of TPUs with high HSCs transforms from…
Crystallization of Polymer Chains Chemically Attached on a Surface: Lamellar Orientation from Flat-on to Edge-on
Chen, Yihuang; Gan, Tiansheng; Ma, Chunfeng; Wang, Linge; Zhang, Guangzhao
Crystallization of polymer chains confined on a surface greatly influences surface properties. We have grafted comb-like copolymer, consisting of poly(2-hydroxyethyl methacrylate) (PHEMA) backbone and semicrystalline poly(ε-caprolactone) (PCL) side chains, on silicon surface and investigated the crystallization of such confined PCL chains upon solvent evaporation by using atomic force microscopy…