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Novel, facile, and stable mediating agent (dithiobenzoic copper(II)) combining atom transfer radical polymerization (ATRP) and reversible addition fragmentation transfer (RAFT) characteristics was firstly designed by replacing the halogen of ATRP metal catalyst with thiocarbonyl carboxylic group of RAFT agent. As two kinds of mediating agents (ATRP activator and RAFT agent) may be formed in situ during...
Ring-banded spherulites have never been formed directly from the glassy state of poly(l-lactide) (PLLA), particularly in case of its copolymers containing some stereodefective D-lactic units, which kinetically hinder the crystallization. By utilizing compressed CO2, banded spherulites have been directly obtained by treating the glassy PLLA containing 4–6% d-isomer. Specifically, ring-banded spherulites...
Donor–acceptor (D–A) copolymers P1–P4 containing 1,6-naphthodipyrrolidone as acceptor unit are synthesized and characterized. Copolymers P1 and P2 are prepared upon Suzuki coupling of 3,8-di(4-bromophenyl)-1.6-bis(dodecyl)-2,7-dioxo-1,2,6,7-tetrahydronaphtho[1,2-b:5,6-b′]dipyrrole (M1) or 3,8-di-(4-bromophenyl)-1.6-bis(2-octyldodecyl)-2,7-dioxo-1,2,6,7-tetrahydronaphtho[1,2-b:5,6-b′]dipyrrole (M2)...
The conditioning history of amorphous syndiotactic polystyrene (sPS) in mild supercritical CO2 (scCO2) changes significantly the thermal behavior and crystal phase transformation of sPS in further thermal treatment by inducing the formation of helical segments. The results of differential scanning calorimetry and temperature-dependent Fourier transform infrared spectroscopy show that polymer chains...
A universal nitrogen based ligand, tris[2-(dimethylamino) ethyl] amine (Me 6 TREN), was firstly employed as both reducing agent and ligand for atom transfer radical polymerization with activators regenerated by electron transfer (ARGET ATRP) of methyl methacrylate (MMA) in bulk and solution, using CuBr 2 as the catalyst and 2-bromoisobutyrate as the initiator. Remarkably high activity...
Multi-walled carbon nanotubes (MWCNTs) filled poly(l-lactic acid) (PLLA) and PLLA/poly(d-lactic acid) (PDLA) composites were prepared through a directly melt mixing process. A special crystalline structure of stereocomplex was formed by PLLA and PDLA, which was easily found when mixing two polymers with identical chemical composition but different steric structures. The electrical conductivities were...
Rheological properties of cellulose dissolved in two ionic liquids (ILs), 1-allyl-3-methylimidazolium chloride (AmimCl) and 1-butyl-3-methylimidazolium chloride (BmimCl), with co-solvent dimethylsulfoxide (DMSO), are studied in the concentration range of cellulose from 0.070 to 6.0 wt%. The viscosities of ILs are exponentially decreased by adding DMSO in the concentration range of 0–100 wt%. The co-solvent...
A cellulose-based macro-initiator, cellulose 2-bromoisobutyrylate, for atom transfer radical polymerization (ATRP) was successfully synthesized by direct homogeneous acylation of cellulose in a room temperature ionic liquid, 1-allyl-3-methylimidazolium chloride, without using any catalysts and protecting group chemistry. ATRP of methyl methacrylate and styrene from the macro-initiator was then carried...
Improving and understanding the electrospinnability of native cellulose in room temperature ionic liquids (RTIL) have been a hot issue in recent years. In this study, the electrospinning of cellulose in a highly efficient RTIL of 1-allyl-3-methylimidazolium chloride (AMIMCl) was investigated. The introduction of co-solvent dimethyl sulfoxide (DMSO), which significantly decreased the surface tension,...
Ternary blends composed of a liquid crystalline polymer (LCP), nano-SiO 2 and polysulfone (PSF) were prepared by melt blending. Very long and perfectly oriented LCP fibrils were in situ formed in capillary flows by adding 5vol% of nano-SiO 2 to binary PSF/LCP blend. Dynamic rheology analysis indicated that the sharp increase of elasticity was caused by higher content of nano-SiO ...
Induced by different fillers, various hydrodynamic effects enhance the fibrillation of liquid crystalline polymer (LCP) in in situ hybrid composites. Through choosing CaCO 3 whisker as the filler and polysulfone (PSF) as the matrix, the effect of the filler size and the affinity between components on the morphological evolution of LCP droplets has been investigated. In contrast to the spherical...
Hybrid composites composed of a thermotropic liquid crystalline polymer (TLCP), nano-SiO 2 and polycarbonate (PC) were prepared by melt blending in a twin-screw extruder. Infrared spectroscopy analysis indicated that the transesterification between PC and TLCP molecules during melt blending was significantly reduced in TLCP/PC blends filled with nano-SiO 2 , compared to the unfilled...
Very long and perfectly oriented fibrils of a liquid crystalline polymer (LCP) were in situ formed in capillary flows by adding large amounts of glass beads (GB) to a polycarbonate (PC)/LCP blend. Thermodynamically the different interfacial tensions between the components made GB migrate to the LCP phase. Then the high content of GB spheres produced a confined condition, so that the LCP droplets passed...
The influence of well-dispersed nano-clay filler on the morphology of thermotropic liquid crystalline polymer (TLCP) in nylon-6 matrix was investigated by melt extrusion process. The good dispersion of clay in the hybrid blends was confirmed by X-ray diffraction, transmission electron microscopy and rheological measurement. Morphological observation showed that the clay platelets had dramatic influences...
The hierarchical structure of thermotropic liquid crystalline polymer (TLCP), especially microfibrils with an average diameter of 30nm has been obtained in polyamide 6 (PA6)/TLCP/glass bead (GB) ternary blends by capillary flows. Thermodynamically the different interfacial tensions between PA6 and GB, and between TLCP and GB, make the glass beads migrate to the vicinity of the TLCP melt droplets....
The physical gelation in carbon nanotubes (CNTs)/polycarbonate composites was revealed by rheological analysis (Winter–Chambon method), based on the data reported by Paul [Polymer 43 (2002) 3247]. The gelation concentration c g , the relaxation exponent n and the gel strength S g characterizing the critical gel point for the composites are 1.6wt%, 0.75 and 770Pasn, respectively, which...
Maleic anhydride-grafted polysulfone (PSF-g-MAH) was prepared by copolymerization in a solution. Compared to polysulfone, the surface tension and its polar fraction of PSF-g-MAH were increased by modification. The PSF-g-MAH was used to compatibilize polysulfone (PSF)/thermotropic liquid crystalline polymer (TLCP) (Vectra B950) blends. DRS–FTIR investigations showed that the special interaction between...
The conformation of atactic poly(methyl methacrylate) (a-PMMA) freeze-extracted from solvents of various molecular size was investigated by IR and Raman spectroscopy. IR studies showed that self-aggregates and partial helix conformation of polymer chain existed in the annealed a-PMMA sample freeze-extracted from a-PMMA/poly(ethylene glycol) (PEG) solution. Temperature dependence of IR I1240cm ...
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