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In this article, the crystalline morphology of the cast film was controlled by the nucleating agent self-assembled into supramolecular structures at different temperature fields. Subsequently, the effect of crystalline morphology and orientation on porosity and uniformity of microporous membranes was investigated. The morphology of β nucleating agent (NA) networks changes from needle-like agglomerates...
Novel waterborne fluorinated polyurethane (WFPU) based on hydroxyl-terminated poly(fluoroalkyl methacrylates) (HTPFMA) was prepared successfully. The microstructures and micro-phase separation of WFPU were evaluated through infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic mechanical analysis (DMA), and scanning electron microscope (SEM). FT-IR revealed that the H-bonded carbonyl in...
Two kinds of ethylene-α-octene copolymers (ethylene-α-octene block copolymer, OBC, and ethylene-α-octene random copolymer, ORC) and their composites with MWCNTs were investigated by means of various solid-state NMR techniques. 13C MAS NMR revealed that there were only orthorhombic crystals in OBC composites, which resulted in stronger volume exclusion effect towards MWCNTs than that in ORC composites...
A thermodynamic and kinetic method based on the selective distribution and migration of multi-walled carbon nanotubes (MWCNTs) in polyoxyethylene (PEO)/ethylene-α-octene random copolymer (ORC) composite system was reported to improve the dispersion of MWCNTs in ORC. Scanning electron micrographs and transmission electron micrographs confirmed that MWCNTs could almost completely migrate from the PEO...
Simultaneous improvement of stiffness and toughness of isotactic polypropylene (iPP) has caught tremendous effort for decades and previously we have shown that the modification of iPP with combined nanofillers and β-nucleating agent (β-NA) is an efficacious way to balance its stiffness and toughness. However, simultaneous introduction of reinforcing fillers and β-NA generates nucleation competition...
Polymer grafted nanoparticles with different surface properties have been prepared and widely used in different fields recently. In this study, through the rheological study on the strength of interfacial adhesion relevant to the complex viscoelasticity and relaxation response of the well-defined polymer (polylactide, PLLA) grafted-nanoparticles (silica) mixed with free chains of the same polymer...
A strong shear flow was imposed on the melt of polycarbonate (PC) microfibril reinforced high density Polyethylene (HDPE) during a secondary melt flow process, i.e. gas assisted injection molding (GAIM). Classic shish-kebabs and typical transcrystallinity were simultaneously observed in the entire thickness of the GAIM HDPE/PC microfibril composites, which were closely related to the strong shear...
Surface-initiated ring-opening metathesis polymerization (SI-ROMP) was employed to prepare polymer-grafted graphene oxide (GO). Grubbs catalysts were immobilized onto GO surfaces followed by ROMP of norbornene from these active catalyst sites to result in polynorbornene (PNb)-functionalized GO (GO-PNb), whose structure and morphology were fully characterized by FTIR, Raman, NMR, XRD, TGA and SEM....
The low melt strength greatly limits the application of PLA as biodegradable package materials produced by film blowing method. Modified silica nanoparticles are introduced into PLA matrix to solve this problem in this study. To build Poly (l-lactide) nanocomposites successfully, two kinds of convenient and efficient methods are conducted to synthesize well-defined topological PLLA grafted SiO ...
A series of efficient and spectrally stable blue light-emitting polyfluorene derivatives containing 3,7-dibenzothiophene-S,S-dioxide (SO) unit in main chain and oxadiazole (OXD) moiety in the side chain were synthesized via Suzuki copolymerization. It was realized that the glass transition temperatures of the resulted copolymers PFSO-OXD increased gradually with the content of OXD, while the UV-vis...
β phase isotactic polypropylene (β-iPP) with the β phase lamellae oriented parallel to the melt extrusion direction, was employed to investigate the deformation-induced structure evolution at various temperatures (25, 80, 110, 130 and 140 °C). The orientation change of β phase during deformation greatly influences the β to α phase transformation and its temperature dependence. At temperatures lower...
A low temperature approach to prepare stereocomplex of high-molecular-weight poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) at temperatures much lower than those adopted in conventional melt blending, is presented in this paper. Wide-angle X-ray diffraction and differential scanning calorimetry results verified that complete stereocomplex crystallites without any evidence of the formation of homocrystallites...
Green light-emitting polyfluorenes were synthesized by Suzuki polycondensation via introducing dibenzothiophene-S,S-dioxide-(di-)tri-phenylamine (G 1 and G 2 ) moieties and dibenzothiophene-S,S-dioxide (SO) unit into the polyfluorene backbone, respectively. PF–SO–G copolymers show a high thermal stability and a moderate photoluminescence quantum yield in the range of 20–40%. The lowest...
The crystalline morphologies of high-density polyethylene (HDPE) molded by multi-melt multi-injection molding (MMMIM) and conventional injection molding (CIM) were studied by employing polarizing light microscopy (PLM) and scanning electronic microscopy (SEM). It was found that a special double skin-core structure was formed in MMMIM parts. Namely cylindritic structures appeared in both sub-skin layer...
Diblock and miktoarm star-shaped thermoresponsive copolymers composed of single-stranded DNA (ssDNA) and poly(N-isopropylacrylamide) were successfully synthesized with combination of atom transfer radical polymerization (ATRP) and click chemistry. This approach should be generalizable to other DNA-functionalized copolymers. Such copolymers self-assemble into spherical micelles with ssDNA corona in...
A series of bimodal polyethylenes with different molecular weight distribution characteristics were prepared by melt blending, and the fracture behavior of these bimodal polyethylenes was studied by the method of essential work of fracture. The results show that specific essential work of fracture, w e , increases obviously with the molecular weight distribution characteristic, A L/U ...
A novel conjugated alternating copolymer (PCzDBSe) based on N-9′-heptadecanyl-2,7-carbazole and 5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzoselenadiazole) was synthesized by Suzuki polycondensation. The polymer reveals excellent thermal stabilities with the decomposition temperature (5% weight loss) of 390°C and the glass-transition temperature of 140°C. The absorption peaks of the polymer are located at...
The focus of this study was the effect of spatial confinement on the development of nucleating agent-induced β phase polypropylene (PP) in the dynamically vulcanized thermoplastic elastomers (TPVs) based on dynamically vulcanized PP/ethylene-propylene-diene rubber (EPDM) blend. The melting behaviors, crystalline structures and the morphologies of the blends were studied by differential scanning calorimetry...
The selective distribution of aluminum borate whisker in isotactic polypropylene (iPP)/syndiotactic polypropylene (sPP) blends was studied. For iPP/sPP/whisker composites, whiskers are distributed in iPP phase, which follow the theory of interfacial tension. When Irganox 1010 is introduced into the composites, the distribution of whiskers is changed from iPP phase to sPP phase. The results of contact...
Novel white-emitting polyfluorenes were synthesized by mixing fluorescence and phosphorescence emission. Benzothiadiazole(BT) and iridium(III)bis(2-(1-naphthalene)pyridine-C 2′ ,N)-2,2,6,6-tetramethyl-3,5-heptanedione[(1-npy) 2 Ir(tmd)] units were incorporated into polyfluorene backbone as green and red chromophores by Suzuki polycondensation. The device from PFG03–IrR07 shows a maximum...
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