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Poly(ethylene terephthalate)/polycarbonate blends were produced in a twin-screw extruder with and without added transesterification catalyst, lanthanum acetyl acetonate. The miscibility of the blends was studied from their crystallisation behaviour and variation in glass transition temperature with composition using differential scanning calorimetry, scanning electron microscopy and change in mechanical...
The effect of physical aging above T g on ionic aggregation in the zinc salt of sulfonated poly(ethylene-co-propylene-co-ethylidene norbornene) ionomer was investigated by differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and dynamic mechanical thermal analysis (DMTA). The time-dependent development of a high temperature DSC endotherm and a high temperature tanδ...
The silylation reaction of dextran with 1,1,1,3,3,3-hexamethyldisilazane (HMDS) in DMSO was studied as the first step of the synthesis of new amphiphilic polyester-grafted dextrans. According to the experimental conditions, i.e. dextran molar weight, medium temperature and reaction time, HMDS/OH ratio, addition of a catalyst and co-solvent, partially or totally silylated dextrans were recovered. The...
Poly(dl-lactide), i.e., poly(dl-lactic acid) (PDLLA), poly(l-lactide), i.e. poly(l-lactic acid) (PLLA), and poly(d-lactide), i.e., poly(d-lactic acid) (PDLA) were synthesized to have similar molecular weights. The non-blended PDLLA, PLLA, and PDLA films and PLLA/PDLA(1/1) blend film were prepared to be amorphous state, and the effects of l-lactide unit content, tacticity, and enantiomeric polymer...
The equilibrium CO 2 sorption isotherms and isobars for rubbery EVA containing various amounts of vinyl acetate (VA) over a wide pressure range 10-340atm and 25-52 o C were investigated. The normalized CO 2 sorption concentration (in cm 3 (STP) CO 2 /mole VA) isotherms of these polymers as a function of pressure consisted of two distinct regions turning at near...
Morphology in an extruded poly(ethylene terephthalate)/poly(ethylene-2,6-naphthalate) was investigated using time-resolved light scattering, optical microscope and small-angle X-ray scattering. During annealing at 280 o C, the domain structure via spinodal decomposition preceded, the transesterification followed, and then the transesterification between the two polyesters induced the dissolution...
A novel technique based on in situ steady state fluorescence measurements is introduced for studying swelling processes of gels formed by free radical crosslinking copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM) in homopolymer solutions. Gels were prepared at 55+/-2 o C for various EGDM contents. After drying these gels, swelling experiments were performed...
We report diffusion rates and equilibrium concentrations of water in a polyelectrolyte SPEES/PES film using ATR/FTIR spectroscopy. The data for water obtained by fitting spectral intensities to a dual mode diffusion model in the presence of different counter ions (at 0.2moldm -3 ) follow the order Li + >Cs + >Na + >Ca 2+ >K + ....
The γ->α crystalline phase transition in nylon 6/clay nanocomposite prior to melting was investigated by X-ray diffraction. The phase transition in the nanocomposite took place at 160 o C, 40 o C higher than that of nylon 6 at 120 o C. The transition extent in the nanocomposite was lower than that in nylon 6. This could be caused by the strongly confined spaces between layers,...
The process of melting in poly(ethylene oxide) (PEO) is followed in real-time at elevated temperatures by atomic force microscopy (AFM) using a simple hot stage apparatus. AFM imaging of the morphology above the onset of melting revealed the dynamics of a complex melting process. The observed melting behavior of PEO is associated with the existence of separate dominant and subsidiary morphological...
Novel polyaspartimides were successfully synthesized via Michael addition reactions involving phosphorus-containing diamines and bismaleimides as monomers and using p-toluenesulfonic acid and N-N-dimethylacetamide as a catalyst and a solvent, respectively. The yields of the polymerization and the molecular weights and inherent viscosities of the polymers increased with the increasing monomers' concentrations,...
The earliest stage of crystallization during melt spinning was examined for four polymers: HDPE, PVDF, nylon 6 and poly(oxymethylene). The four polymers have very similar melt viscosities. Of particular interest is the dependence of the time for the onset of detectable crystallization on the take-up speed. The results for all four polymers lie on the same onset time versus take-up speed curve, indicating...
The diffusion coefficients (D) of tert-butyloxycarbonyl-l-phenylalanine (Boc-Phe) in Merrifield network polystyrene gels, used as a solid-phase reaction field have been determined as a function of the amino acid concentration over the temperature range from 30 to 50 o C by means of the 1 H pulsed-field-gradient spin-echo NMR method. From these experimental results, it was found that...
The thermal degradation of two commercial poly(ethylene terephthalate) (PET) samples and two laboratory prepared polyesters, poly(ethylene isophthalate) and poly(diethylene glycol terephthalate), was studied using thermogravimetry and thermal analysis-Fourier transform infrared spectroscopy. The commercial PET samples were copolymerised with diethylene glycol and isophthalic acid groups in different...
The present paper describes a novel class of norbornene-based copolymers containing 7,7-dimethyloxepan-2-one acid labile groups. Poly(3-(bicyclo[2.2.1]hept-5-en-2-ylhydroxymethyl)-7,7-dimethyloxepan-2-one- co-5-((2-decahydronaphthyl)oxycarbonyl)-norbornene-co-5-norbornene-2-carboxy lic acid-co-maleic anhydride) was synthesized and evaluated as a potential chemically amplified resist for ArF lithography...
The significance of the Liftshitz/van der Waals, Lewis-acid, and Lewis-base contributors to the total surface energy of an homologous series of poly(di-1H,1H,2H,2H-perfluoroalkylitaconate)s is discussed in terms of the molecular design features and surface organisation phenomena characterising these, comb-like, polymers. Comparison of the characteristics specific to films prepared from this class...
Et 3 GeOMe-initiated polymerizations of ε-caprolactone were studied at six different temperatures, but even at 180 o C the conversion was below 50% after two days. Ge(OEt) 4 proved to be more reactive and a temperature of 120 o C was found to allow for a nearly quantitative conversion after two days. All four ethoxy groups were active in the initiation process, but...
Cyclocopolymerization of 1,6-heptadiyne with dipropargyl ether was carried out under nitrogen atmosphere using KSCN, KBr and KI as initiators in N,N-dimethyl formamide. The course of polymerization was monitored through UV-Vis spectroscopy. The rate of cyclocopolymerization was determined at different polymerization conditions and the relative efficiency of different initiators was evaluated. KSCN...
A copolymer of N-isopropyl acrylamide and acrylic acid was modified in a polymer analogous reaction by an acridizinium chromophore capable of reversible photochemical dimerization. The acridizinium chromophore allows a faster and more complete photocrosslinking and a better photoreversibility as compared to stilbene and stilbazolium chromophores. Due to its hydrophilic nature the chromophore only...
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