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.
The conformational conversion between an extended and a helical conformation of PTT chains during uniaxially cold drawing with different draw rates at temperatures below and above glass transition temperature (Tg) was investigated by time-resolved polarized IR analysis. When the draw rate (γ˙) is faster than the retraction rate (1/τb) of chain segments, the drawing-induced extended conformation can...
During the cold crystallization of poly(trimethylene terephthalate), PTT, multistage preordering activities associated with hierarchically structural evolution and origin of mesomorphic domains were investigated with time-resolved Fourier transform infrared (FTIR), photoluminescence (PL) and dielectric spectra (DS), and simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS). The observed...
Translocation of polymer chains under the application of an external force has been studied through coarse-grained Monte Carlo simulations. The chains are pulled through a nanotube of finite length and diameter and their translocation times measured. The average translocation time, τ follows a scaling relation involving the chain length, N and applied force, F as, τ∼N ν′ F −μ , where...
The structure–property relationships of poly(trimethylene 2,6-naphthalate)/layered clay nanocomposites are being investigated under uniaxial drawing by using synchrotron wide angle X-ray diffraction, small angle X-ray scattering, transmission electron microscope and dynamic mechanical analyzer. The cold crystallization at 110°C of PTN and nanocomposites samples under drawing induced the α-crystal...
We have investigated the crystallization effect on the phase separation of a poly(ɛ-caprolactone) and poly(ethylene glycol) oligomer (PCL/PEGo) blending system using simultaneous small-angle light scattering and differential scanning calorimetry (SALS/DSC) as well as simultaneous small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and DSC (SAXS/WAXS/DSC). When the PCL/PEGo system,...
Experimentally observed a +-type H v and a circular-type V v scattering patterns from small-angle light scattering (SALS) measurement indicated a random assembly of sheaf-like or rod-like superstructure for poly(trimethylene terephthalate) (PTT) under cold-crystallization. The long period and crystallite thickness of cold-crystallized PTT have been determined by small-angle X-ray scattering...
In poly(trimethylene terephthalate) (PTT) spherulites during isothermal crystallization, the morphological changed from an axialite/or elliptical banded spherulite to banded spherulite and then non-banded spherulite with temperature decreasing were studied by following the lamellar growth behaviors. We report lamellar growth mechanism on varied crystallization temperature, which explicitly probes...
In this work, the isothermal crystallization kinetics of polytrimethylene terephthalate (PTT) was first investigated from two temperature limits of melt and glass states. For the isothermal melt crystallization, the values of Avrami exponent varied between 2 and 3 with changing crystallization temperature, indicating the mixed growth and nucleation mechanisms. Meanwhile, the cold crystallization with...
In this work, a three-phase model consisting of crystalline, mobile amorphous and rigid amorphous phases (RAP) was used to describe the structural formation of poly(trimethylene terephthalate) (PTT) at various crystallization conditions. The variation in thickness and fraction of each phase was studied on both crystallization temperature T c and crystallization time t c effects from...
The present study elucidates the effects of solvent quality and polymer concentration on the aggregation behavior of polyvinyl alcohol (PVA) solutions from the dilute solution to semi-dilute solution regions. Combination of the results in static and dynamic light scattering indicates that in dilute solution the thermodynamic driving forces primarily dominate the dynamic behavior of PVA/N-methylpyrrolidone...
In this work, the phase separation and gelation behaviors in poly(vinylidene fluoride)/tetra(ethylene glycol) dimethyl ether (PVDF/TG) solutions were studied through the time-resolved light scattering and the gelation kinetic analyses. Combination of the phase diagram and the results of gelation kinetics shows that the gelation behaviors in PVDF/TG solutions could be separated into three diverse regions...
In this work, the aggregation behavior of polyvinyl chloride/dioxane (PVC/DOA) solution was discussed through light scattering and viscometric measurements. From the static light scattering results, PVC/DOA solution has a negative value of the second virial coefficient, A 2 value (ca. -3.65x10 -4 cm 3 molg -2 ) at 30 o C, implying that a repulsive...
In this work, the effect of co-solvent complex on preferential adsorption phenomenon in polyvinyl alcohol (PVA)/N-methyl-2-pyrrolidone (NMP)/water ternary solutions was studied. It should be noticed that in this system one NMP molecule could bind with two water molecules to form NMP(water)2 ter-solvency complex. The formation of the NMP(water)2 complex is found to significantly affect the preferential...
In this work, the network structure and chain mobility of dried polyvinyl chloride/dioxane (PVC/DOA) gels prepared by the freeze-drying method are studied by SEM, FTi.r., WAXD, EDTA and pulsed NMR analyses. The results of FTi.r. and WAXD show no remarkable change in the crystallinity of either dried or wet PVC gels; however, the elasticity of wet gels and the gelation time of semi-dilute solutions...
In this work, the structure and physical properties of polyvinyl chloride (PVC) gels prepared from the solutions of bromobenzene (BrBz) and dioxane (DOA) under different gelation conditions are studied. The average size of the junction point for PVC gels in the initial gelation state are the combination of ca. two to three chains in width and ca. six to eight syndiotactic sequences in length to form...
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.