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A series of flexible polyurethane slabstock foam samples were prepared with varying surfactant concentration. Several samples were also prepared by quenching small pieces into liquid nitrogen during the foaming process. The morphology of these materials was characterized at many length scales via scanning electron microscopy (SEM), transmission electron microscopy (TEM), wide-angle and small-angle...
Melting peaks and resulted crystal forms in syndiotactic polystyrene (s-PS) subjected to various thermal treatments were thoroughly investigated using DSC and X-ray diffraction. This study concluded that the four major crystal forms were individually generated and no transformation occurred between α', α'', β' and β'' forms during thermal treatments. Thickening of these crystals, however, was likely...
To improve the toughness of silicone-modified epoxy resin, aramid-silicone block copolymer was used as a compatibilizer. Fine silicone phases could be uniformly and stably dispersed in epoxy matrix by the addition of the block copolymer grafted with epoxy oligomers. The architecture of the block copolymer, such as the silicone content of the block copolymer and the molecular weight of epoxy and silicone...
Two types of conventional rubber modifiers and a series of hollow plastic micro-spheres were employed as toughening agents in a diglycidyl ether of bisphenol A (DGEBA) epoxy in Part I (Bagheri R, Pearson RA. Polymer 1996;37:4529) of this study. It was found that the rubber modifiers with different cavitation resistance and hollow plastic micro-spheres which act as pre-existing microvoids toughen epoxies...
Poly(N-methyl-4-piperidyl methacrylate) (PMPMA) was blended with the lithium or zinc salt of poly(styrenesulfonate) (PSSLi and PSSZn, respectively). PMPMA formed complexes with PSSZn but not with PSSLi in water/ethanol (2:1) solutions, indicating the presence of a strong interaction between PSSZn and PMPMA. PMPMA is immiscible with PSSLi as shown by the appearence of two glass transitions in each...
For the first time, nanostructures of polystyrene (PS) were obtained by chemically synthesising PS within the pores of microporous and nanoporous particle track-etched membranes (PTMs). The emulsion polymerisation of styrene into nanopores with diameters ranging from 50nm to 2μm is investigated. The pore size and the polymerisation time have a significant effect on the molecular weights and on the...
The use of butyllithium and butylmagnesium in the polymerization of racemic lactide leads to the formation of polylactide with a partially disyndiotactic structure. A coefficient of stereoselectivity p 2 which describes the content of disyndiotactic structures appears to be higher for the lithium initiator; however an increase in the concentration of this initiator tends to enhance an intermolecular...
Grazing-incidence X-ray diffraction is used to analyze the variation in structural features-such as crystalline index and crystallite size-perfection (CI and CSP)-with depth in several commercially relevant mono- and multi-layer polymer films. The CI and CSP at the casting-roll surface of a melt-cast and biaxially oriented nylon 6 (N6) film is the same as in the bulk, but the air-exposed surface has...
The objective of this article is to investigate the permeation characteristics of several polydispersed macromolecules through the asymmetric and the particulate poly (ethylene-co-vinyl alcohol) (EVAL) membranes. The solutes in examination include two nonionic solutes, dextran and polyethylene glycol (PEG), and one anionic solute, sodium polyacrylate (SPA). The ultrafiltration results indicate that...
Blends of nylon 6 with four acrylonitrile-butadiene-styrene (ABS) materials were investigated over a range of compositions using an imidized acrylic (IA) polymer as the compatibilizing agent. The IA material is miscible with the SAN matrix and is able to react with the amine end groups of nylon 6 during melt processing. The effects of ABS type and blend composition on the morphological, rheological...
Magnetic orientation of a low molecular weight isotactic polypropylene (iPP) is reported. Unlike other crystalline polymers for which the magnetic orientation has already been reported by our group, iPP was less expected to undergo the magnetic orientation because its repeating unit does not contain aromatic rings which are the main source of the diamagnetic anisotropy. The magnetic orientation was...
Solid state NMR studies revealed the hydrogen bonding network characteristics and the substantial changes of molecular motion in phenolic/PEO blend. The PEO crystallinity was reduced owing to the formation of strong hydrogen bonding between PEO and phenolic, as revealed by 13 C chemical shift and DSC. Both T 1ρH relaxation behavior at high field and T 1H ...
In the synthesis of polyaniline-nylon 6 composite films wherein the polymerization was carried out by the immersion of aniline-containing nylon 6 films in an acid solution which has an oxidant ((NH 4 ) 2 S 2 O 8 ), the polymerization time has to be carefully monitored to prevent over-oxidation of the polyaniline. This method is likely to yield polyaniline in the protonated...
Poly(amic acid) (PAA) and poly(amic diethyl ester) (PAE) precursors of poly(p-phenylene biphenyltetracarboximide) (BPDA-PDA), which is a representative polyimide (PI) being used widely in the microelectronic industry as an interdielectric material, were synthesized. The miscibility behavior of these precursors with poly(arylene ether benzimidazole) (PAEBI), which is known to exhibit strong cohesive...
Three maleic anhydride-grafted-polypropylene (PP) derivatives [N, N-dihydroxyethyl monomaleic amide (C-2A), octodecyl monomaleate (C-3), and 2-(N, N-dihydroxyethylamino)ethyl monomaleate (C-4)] were prepared by melt grafting and utilized to compatibilize polypropylene/poly(ethylene terephthalate) (PP/PET) blends. The resulting blends were characterized by means of scanning electron microscopy, thermal...
Methyl methacrylate grafted natural rubber (NR) prepared by free radical polymerisation of methyl methacrylate in NR latex was irradiated to high energy radiation. Their structure and molecular dynamic changes during exposure to high energy radiation were investigated by dynamic mechanical analysis and solid state nuclear magnetic resonance spectroscopy (NMR). The changes of glass transition temperature...
The values of crack growth rate for styrene-butadiene copolymer (SBR) and acrylonitrile-butadiene copolymer (NBR) under dynamic tearing condition were measured in both dry and swollen conditions. For swollen samples, tearing energy was adjusted by a simple geometrical factor λ s2 (where λ s is the linear swelling ratio), in order to take into account the reduction in number of...
Alkoxysilane functionalized isocyanurates were prepared from hexamethylene diisocyanate (HDI) isocyanurate and 3-aminopropyltriethoxysilane. The reactants and functionalized isocyanurate were characterized by 1 H, 13 C and 29 Si NMR, IR and electrospray ionization-mass spectrometry. Two-dimensional NMR was necessary to accurately assign the proton and carbon spectra...
The change in thermal properties induced by irradiation of 10MeV H + , 20MeV He 2+ and 2MeV electron were studied for non-crystalline and crystalline poly(ether-ether-ketone) (PEEK), PEEK-a and PEEK-c, by differential scanning calorimetry (DSC). It was revealed from the analysis of thermal parameter changes that crosslinking proceeds by irradiation in all cases studied. The comparison...
Vapor-liquid-equilibrium (VLE) data are reported for binary mixtures of arborescent polystyrene or linear polystyrene dissolved in chloroform, toluene, or cyclohexane in the range 50-70 o C. Using a classic gravimetric-sorption method, the amount of solvent absorbed by the polymer was measured as a function of solvent vapor pressure. VLE data are compared to osmotic second-virial-coefficient...
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