The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Time-resolved synchrotron small angle X-ray scattering (SAXS) was used to investigate the early stages of crystallization in melt crystallized polyethylene. Classic Gibbs nucleation or density fluctuation theory can be used to describe the primary nucleation mechanism. At 110 °C, no signal of crystallization can be detected by SAXS for 30 min. When it is lower than 110 °C, the low q scattering intensity...
In this work, we investigated the effects of liquid–liquid phase separation (LLPS) on the crystallization kinetics and morphology of isotactic polypropylene/poly (ethylene-co-octene) (iPP/PEOc) in-reactor alloy with polarized optical microscopy (POM), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS)...
The cyclization mechanism of polyacrylonitrile (PAN) in PAN/functionalized carbon nanotube (CNT) composites was examined. The surface functionalization of CNTs was carried out by using diazonium reagents with 4-substituted aniline. The results strongly suggest that the type of functional groups on the CNTs strongly influences the cyclization mechanism of PAN during the stabilization process. The nitrile...
Using two spirocyclic core building units, microporous polymeric spheres SPOP-5 and SPOP-6 have been successfully prepared through a surfactant-free Suzuki coupling polymerization in a single-phase, which is different from the commonly employed heterogeneous polymerization technique. Especially, for SPOP-6, the SEM image shows that the polymer consists of relatively uniform monodisperse solid microspheres...
A series of isotactic polypropylene/poly(propylene-1-octene) (iPP/PPOc) in-reactor alloys were synthesized by a one-step polymerization process, using Metallocene/Ziegler–Natta hybrid catalyst. The alloys were characterized by FT-IR, DSC, optical microscopy and SEM. The results suggested that the spherical morphology was maintained during one-step polymerization process, which provided a potential...
The deformation, breakup and morphology relaxation of a commercially important polycarbonate (PC)/poly(styrene-co-acrylonitrile) (SAN) blend under and after steady shear flow have been studied in situ by combined phase contrast optical microscopy (PCOM), small angle light scattering (SALS) and rheometry. Under steady shear flow, the morphology of PC/SAN blends evolves via repeated deformation, breakup...
A series of ferroelectric poly(vinylidene fluoride-co-chlorotrifluoroethylene) films with different crystallite sizes have been obtained by varying the film processing conditions. The impact of the crystallite size on the dipole switching and the electric energy density has been systematically studied by the electric displacement–electric field hysteresis loop measurements. The films with smaller...
Several poly(pyridinium salt)s containing various aromatic diamine moieties and tosylate counterions were prepared by the ring-transmutation polymerization reaction of bis(pyrylium tosylate) with aromatic diamines in dimethyl sulfoxide at 130−135 °C for 48 h and their tosylate counterions were exchanged to triflimide polymers by a metatheses reaction in an organic solvent. Their chemical structures...
In this research, poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles less than 100 nm were synthesized first and applied as the solid stabilizer for producing PEDOT-polystyrene (PEDOT-PSt) composite latex by Pickering emulsion polymerization. The results showed that most PEDOT nanoparticles adhered to the PSt core particles having the size from 100 to 250 nm. By casting the latex, the obtained...
The microstructure development of 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BDO) based thermoplastic polyurethane (TPU) under compression was investigated. Influential factors on the permanent compression deformation were discussed in detail. Two types of samples with the same chemical compositions while different aggregation structures were prepared by altering the stirring speed...
Isotactic polypropylene (iPP)/organo-montmorillonite (OMMT) nanocomposite was modified by poly(ethylene-co-octene) (PEOc). PEOc-rich domains were well dispersed in the iPP matrix, with narrowly distributed size. OMMT layers were well dispersed, mainly intercalated and partially exfoliated. Compared with the case in the binary composites, many OMMT layers were preferential distributed inside and around...
Volumetric and thermal properties of cross-linked epoxy systems consisting of diglycidyl ether of bisphenol A (DGEBA) and poly(oxypropylene) (POP) diamines of four different lengths ranging from 3 to 68 units were investigated by molecular dynamics (MD) simulations. The cross-linked structures were built by using the simulated annealing polymerization approach. The density, coefficients of volume...
A well-dispersed multiwall carbon nanotube (MWCNT)/syndiotactic polystyrene (sPS) composite was prepared by simple in-situ polymerization of styrene using pentamethylcyclopentadienyltitanium(IV) trimethoxide (Cp*Ti(OMe) 3 ) attached to the shortened and functionalized MWCNT (f-MWCNT). The attachment of Cp*Ti(OMe) 3 to the f-MWCNT was confirmed by thermogravimetric analysis, X-ray photoelectron...
The reaction induced phase separation behavior was investigated in various epoxy/thermoplastic (TP) blends. Several morphological structures, including the sea-island, dual morphological (epoxy-rich particles may disperse in the TP-rich domains, while TP-rich particles can also have some dispersions in the epoxy-rich phase) or three-layered (TP-rich continuous domains mainly located in the middle...
We report the preparation of thermoresponsive graphene nanosheets functionalized by the polymer brushes. This approach involves the direct growth of thermoresponsive polymer brushes from functional graphene sheets (FGSs) by chemical modification with initiators followed by extension with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) through surface-initiated atom transfer radical polymerization...
We developed an efficient and extensible multiscale analysis to consider the carbon nanotube (CNT) size effect and weakened bonding effect at the interface on the effective elastic stiffness of CNT/polymer nanocomposites using molecular dynamics (MD) simulations and continuum micromechanics. Under the assumption that the CNT molecular structure is an equivalent solid cylinder, molecular mechanics...
To expand the application of electrospun fibers or electrosprayed beads, micro-nano hierarchical structures of polystyrene (PS) have been constructed through the adjustment of solvent, polymer concentration, environment humidity, electrospinning temperature, etc. Primary structures, such as fibers, beads and bead-on-string structure, as well as secondary structures, such as nanopores, nanopapilla...
Ordered dichloro-biphenylene-bridged silsesquioxanes are fabricated by interfacial polymerization at the aqueous/organic phase interface, which involves hydrogen bonding and aromatic π–π stacking interaction, which are responsible for the preferential orientation of the organic bridged units. The high-resolution transmission electronic microscopy images and wide angle X-ray powder diffraction patterns...
Isotactic rich polystyrene was synthesized at 30 °C by the t-BuLi initiated polymerization in the presence of sodium dodecylbenzenesulfonate (SDBS) in hexane or cyclohexane. The polymerization rates at 30 °C were very fast and typically gave quantitative conversions. At SDBS/t-BuLi molar ratios between 0.5 and 1.0, the unfractionated polystyrene had almost the same stereoregularity, with triad and...
This work mainly focused on the nucleation behavior in iPP/OBC (isotactic polypropylene/polyolefin block copolymers) blends with two distinct OBCs. The influence of composition and molecular structure of the OBC component on the crystallization kinetics of the blends was investigated systematically with the aim to better understand the interplay between the two coupled phase transitions in the blends:...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.