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Segmental and normal mode dynamics in polyhedral oligomeric silsesquioxane (POSS)/poly(propylene oxide) (PPO) non-reactive and reactive nanocomposites were investigated using a broadband dielectric relaxation spectroscopy (DRS) over wide ranges of frequency and temperature. Three POSS reagents with varying side chain architecture were selected for the study: OctaGlycidyldimethylsilyl (OG), TrisGlycidylEthyl...
Two contrasting approaches have been adopted in the current study to obtain environmental benign and superior flame retardant polymer nanocomposites. In the first approach, polyhedral oligomeric silsesquioxane (POSS) is incorporated as an additional filler in polyamide 6/clay nanocomposite to improve the homogeneity of the ‘physical’ barrier, since POSS transforms to a glassy material upon fire and...
In this work thermoassociative gel formation of a new family of aqueous temperature-responsive copolymer solutions has been investigated. This was achieved using a cationic poly(N-isopropyl acrylamide) (PNIPAm) graft copolymer recently prepared [Liu R, De Leonardis P, Cellesi F, Tirelli N, Saunders BR. Langmuir 2008;24:7099]. The PDMA +x -g-(PNIPAm n ) y copolymers have...
Polypropylene (PP)/layered double hydroxide (LDH) nanocomposites were prepared via melt intercalation using dodecyl sulfate anion modified LDH and maleated PP as compatibilizing agent. Evidently the interlayer anions in LDH galleries react with maleic anhydride groups of PP-g-MA and lead to a finer dispersion of individual LDH layers in the PP matrix. The nanostructure was characterized by XRD and...
Ultra small-angle X-ray scattering (USAXS) experiments were conducted in order to examine structural changes in micrometers upon uniaxial stretching of elastomeric segmented polyurethaneureas at room temperature. It was possible to stretch the sample film up to α=7.5 without break, where α designates the stretching ratio. Around α=6.5 the sample became turbid, while it recovered transparency when...
Smectic poly(triethylene glycol p,p′-bibenzoate) (PTEB)/clay hybrids were prepared by a solution blending method. Unmodified (cloisite ® Na) and two organically modified (cloisite ® 10A and cloisite ® 15A) montmorillonites were used. The morphology of the hybrids was characterized by TEM and X-ray diffraction. It has been found that a conventional microcomposite is obtained...
A time-resolved Fourier Transform Infrared-Attenuated Total Reflectance Spectroscopy (FTIR-ATR) technique was set up and used to study the diffusion of eugenol through Linear Low Density Polyethylene (LLDPE) at 16, 23 and 40°C. The 1514cm −1 peak for eugenol (aromatic –CC– stretching) was monitored over time and used to determine the diffusion coefficient (D). The Fickian model was found to...
The mechanism of photodegradation of poly(neopentyl isophthalate), an aromatic polyester as model for industrial polyester coatings, was studied on the molecular level. Changes in the chemical structure of molecules caused by UV irradiation (mercury lamp) were investigated using several analytical techniques. Photodegradation leads both to chain scission and to crosslinking, taking place simultaneously...
We have synthesized poly(octamethylene terephthalate) (POT), poly(octamethylene 2,6-naphthalate) (PON), and poly(octamethylene terephthalate-co-octamethylene 2,6-naphthalate)s [P(OT-co-ON)s] with various comonomer composition by melt-polycondensation reaction and investigated their chain structures, crystalline structures, melting and cocrystallization behavior by using 1 H NMR spectroscopy,...
The thin films of a symmetric crystalline-coil diblock copolymer of poly(l-lactic acid) and polystyrene (PLLA-b-PS) formed lamellae parallel to the substrate surface in melt. When annealed at temperatures well above the glass transition temperature of PLLA block (T gPLLA ), the PLLA chains started to crystallize, leading to reorientation of lamellae. Such reorientation behavior exhibited...
A series of dendronized diblock copolymers having rigid backbone and reactive surface were synthesized by ring-opening metathesis polymerization (ROMP) from dendronized norbornene derivatives using the second generation Grubb's catalyst. The bromine-terminated block of those rigid nanostructures has been converted to more reactive azide groups in one straightforward step. The resulting polymers were...
Water diffusion process in biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx, HHx=12mol%) was investigated by generalized 2D correlation time-resolved ATR–FTIR spectroscopy based on the analysis of v(OH) stretching and δ(OH) bending bands of water as well as v(CO) and v(C–O–C) stretching bands of PHBHHx. Three states of water were figured out during water diffusion process. They...
The present review aims at summarizing the current knowledge on how solid nanoparticles organize in polymer blends. First, the behavior of low viscosity fluid emulsions containing solid colloidal particles is briefly presented. By contrast with polymer blends, they have been the subject of intensive studies for a long time, with both applicative and comprehensive objectives. High viscosity fluid emulsions...
Three novel allyl–maleimide monomers (i.e., A 2 B, AB and AB 2 ) were designed, synthesized and thermally cured to yield a series of high-performance allyl–maleimide resins. All the monomers obtained are readily soluble in common organic solvents enabling an easy solution processing. The thermal properties of the three monomers were studied by the differential scanning calorimetry...
To understand the principle of designing efficient adsorbents toward specific peptides, adsorption mechanism between oligopeptide VVRGCTWW (VW-8) and alkylamine modified polyacrylamide adsorbents was studied in this article. Linear models of the adsorbents were used to facilitate various measurements except for adsorption experiment. 2D 1 H NMR experiments reveal the main binding site of VW-8...
Small amount of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide as a β-form nucleating agent is dissolved beyond 280°C in a molten isotactic polypropylene (iPP) and appears as needle crystals around at 240°C during cooling procedure. Further, iPP molecules crystallize on the surface of the needle crystals, in which c-axis of the β-form iPP crystals grows perpendicular to the long axis of the needle...
Macroporous epoxy monolith was prepared via chemically induced phase separation using diglycidyl ether of bisphenol A (DGEBA) as a monomer, 4,4′-diaminodiphenylmethane (DDM) as a curing agent, and epoxy soybean oil (ESO) as a solvent. The morphology of the cured systems after removal of ESO was examined using scanning electron microscopy, and the composition of epoxy precursors/solvent for phase inversion...
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...
In situ MIR and UV–visible spectroscopies have been combined in a set-up that has been used to monitor anionic (co)polymerizations of styrene and isoprene. This experimental set-up gives access to the simultaneous and real time concentrations of monomers and actives species during the polymerization, through optical fibers probes immersed in the reaction medium. This method allows fast, accurate and...
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