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Simultaneous electrospinning of two polymer solutions in a side-by-side fashion is conducted for two bicomponent polymer systems—poly (vinyl chloride)/segmented polyurethane (PVC/Estane ® ) and poly(vinyl chloride)/poly(vinylidiene fluoride) (PVC/PVDF). The new experimental device is described and suitable process conditions to electrospin bicomponent fibers are described. Field emission scanning...
The crystallization from the melt of the trans-planar mesomorphic form of syndiotactic polypropylene is investigated at different quenching temperatures. The formation of the trans-planar mesomorphic form at −5, 0 and 6 °C is followed as a function of the residence time at these temperatures by X-ray diffraction and FTIR spectroscopy. The quenching temperature influences the rate of formation of the...
The N-oxide group of the cellulose solvent N-methylmorpholine-N-oxide showed a strong preference for the axial position compared with N-methyl as determined by NMR experiments and computational studies. In solvents with negligible solvent–solute interaction, about 95% of the NMMO molecules obtained a typical chair conformation with an axial N–O (1) while 5% had an equatorial N–O (2) at room temperature...
The molecular mechanics (MM) method with COMPASS force field was used to study the H-bonds in the polyether based polyurethane model molecules. Availability of the calculation was firstly verified in comparison of some H-bonded model molecules, which were studied by using ab initio calculation, and those calculated by MM. Based on a urethane model molecule 1,3-dimethylcarbamate, which can be donor...
The mechanical behaviour of a styrene-butadiene rubber, containing 23.5% styrene and filled with up to 55% by weight with silica nanoparticles, has been examined. The tanδ spectra of these composites show a second relaxation of relatively low intensity located about 40 °C above the main α relaxation, the glass transition T g , which occurs at −34.5 °C in the unfilled polymer. This is attributed...
Hydrogels for biomedical purposes, made from synthetic polymers as starting materials and free of co-adjuvant molecules, have been produced almost exclusively by high-energy radiative processes. On the other hand, UV photocrosslinking of such materials has been used in conjunction of monomers and/or photoinitiators. This work was addressed to the analysis of poly(N-vinyl-2-pyrrolidone) (PVP) submitted...
The propagation reaction in the anionic polymerization of styrene with lithium as counter ion in cyclohexane has been investigated for six different concentrations of 1,2,4,5-tetramethylbenzene (durene) in the range of living ends concentration between 10 −5 and 10 −3 M at 20 °C. The values of the apparent dissociation constant of PStLi dimer and the weighted rate constants of all...
BAK poly(ester amide)s differing in the amide/ester ratio have been synthesized and characterized, considering spectroscopic data and both thermal and mechanical properties. Degradability under different media (water at 70 °C, acid or enzymatic catalysis at 37 °C) has also been studied by evaluating the changes in intrinsic viscosity, in the NMR spectra and in the surface texture of samples. The use...
The microbeam small- and wide-angle X-ray scattering (SAXS/WAXS) technique gives the novel information about micron-scale structural inhomogeneity of polymer crystal. By using this technique, we have studied structural inhomogeneity of lamella within the band spherulite of miscible polymer blend poly(ε caprolactone) (PCL)/poly(vinyl butyral) (PVB) and the structure development of lamella during crystallization...
An equation using the critical volume fraction and segment number of polymer was proposed for the partial molar entropy change of a polymer for mixing in dilute solution. The partial molar enthalpy change of polymer for mixing was determined from the thermodynamic equilibrium property of two polymer phases at the critical temperature. The solubility or cohesion parameter of a polymer fraction at the...
Acrylamide hydrogels were synthesized in a series of hydro-organic solvents to examine how solvent affects the network structure by influencing properties of the first formed polymer in the reaction mixture. The looser and more heterogeneous network structure of gels formed in aqueous solutions of ethylene glycol or propylene glycol was found to be largely due to the reduced chain lengths of the primary...
A colorless fluorinated diamine, 3′-trifluoromethyl-3,4′-oxydianiline (3′-CF 3 -3,4′-ODA) (II) was prepared through the nucleophilic substitution reaction of 3-nitrophenol and 2-chloro-5-nitrobenzotrifluoride by catalytic reduction with hydrazine and Pd/C. A series of Polyimides V were synthesized from the diamine II with various aromatic dianhydrides III a–f via thermal and chemical...
This work deals with the synthesis of a gradient structure material from a homogeneous system of monomers. This new synthesis involved hydroxyethylmethacrylate, a hydroxytelechelic polybutadiene, and 4,4′-methylene-bis(cyclohexylisocyanate). These materials were made in two steps. The first one consisted in creating a photopolymerization gradient in methacrylic double bonds under UV exposure thanks...
The structural changes in the Brill transition of aliphatic Nylons m/n have been investigated by carrying out the temperature-dependent infrared spectral measurement for Nylon 6/10 –[–NH–(CH 2 ) 6 –NHCO–(CH 2 ) 8 –CO–] n –, Nylon 6/12 –[–NH–(CH 2 ) 6 –NHCO–(CH 2 ) 10 –CO–] n – and Nylon 10/10 –[–NH–(CH 2 ) ...
High-throughput development of catalysts, initiators, and polymeric materials combines automated parallel catalyst synthesis and automated polymerization reactors. The reactors can be additionally equipped with on-line monitoring (ReactIR from Mettler) based on ATR-FT-IR technique. This powerful tool has proven to be a very valuable probe for high-throughput experiments. During copolymerizations of...
Inclusion of a polymer cushion between a lipid bilayer membrane and solid surface has been suggested as a means to provide a soft, deformable layer that will allow for transmembrane protein insertion and mobility. In this study, we evaluate the properties of a disulfide- and lipid-modified polyacrylamide polymer cushion. High molecular weight random copolymers with various degrees of disulfide and...
Side-chain polyesters and polyester hydrochlorides were synthesized from α-(bis(2-hydroxyethyl)amino)-ω-(4′-methoxy biphenyl-4-oxy) alkanes with different spacer lengths (Cn-diol, n=6, 8, 10) and terephthaloyl chloride. Since N-substituted diethanolamine acts as a stronger acid acceptor than triethylamine or pyridine, polyester hydrochlorides are formed during polyesterification instead of polyesters...
A new positive-working photosensitive polyimide (PSPI) has been developed, which is based on polyimide bearing sulfo groups (PIS) and 1-{1,1-bis[4-(2-diazo-1-(2H)naphthalenone-5-sulfonyloxy)phenyl]ethyl}-4-{1-[4-(2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl]methylethyl}benzene (S-DNQ) as a photosensitive compound. PIS was prepared by ring-opening polyaddition of 1,3-phenylenediamine-4-sulfonicacid...
A method was described for synthesis of exfoliated poly(styrene-co-methyl methacrylate)/clay nanocomposites through an emulsion polymerization with reactive surfactant, 2-acrylamido-2-methyl-1-propane sulfonic (AMPS) which made the polymer end-tethered on pristine Na-MMT. AMPS widened the gap between clay layers and facilitates comonomers penetrate into clay. Silicate layers affect the composition...
Photopolymerizations were carried out using monofunctional monomers methyl or ethyl-(α-hydroxymethyl)acrylate (MHMA and EHMA, respectively) with multifunctional crosslinkers. The effect of crosslinker type (acrylate versus methacrylate) and functionality (di-, tri-, tetra- and penta/hexaacrylates) on polymerization rates and conversions were investigated. RHMA systems (monomer plus crosslinker) reached...
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