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A new solid-state NMR experimental equipment was developed to monitor the structural change of polymer and protein fibers under active uniaxial deformation. The equipment was applied to monitoring change in the structure of a biodegradable aliphatic polyester fiber, poly(tetramethylene succinate) (PTMS; [–O(CH2)4OCO–(CH2)2CO–]n), as a function of tensile stress. The crystal transition from α to β...
In this study, we established a correlation between cavitations volume and the brittle–ductile transition (BDT) for particle toughened thermoplastics. The brittle–ductile transition temperature (TBD) was calculated as a function of T∗ and interparticle distance (ID), respectively, where T∗ was a parameter related to the volume of cavitations. The results showed that the smaller the cavitations volume,...
Ternary blends of polypropylene (PP), nylon 6 (N6) and polypropylene grafted with maleic anhydride (PP/N6/PP-g-MAH) as compatibilizer with up to 50wt% of N6 were investigated. PP-g-MAH content was varied from 2.5 to 10%. Blends of the two polymers PP/N6 (80/20) without the compatibilizer were also prepared using an internal batch mixer and studied. The ternary blends showed different rheological properties...
The homopolymer, poly(CzMA), with controlled molecular weight (MW) and narrow molecular weight distributions (MWD) was successfully synthesized by using (1,1,4,4-tetraphenylbutanediyl)dipotassium and diethylzinc (Et2Zn) in THF at various temperatures, 25, −45, and −78°C, under high vacuum conditions. The Et2Zn acted both as a protective group through the formation of coordination with ester enolate...
X-ray diffraction with the assumption of uniform stress has been used for determining the crystal modulus of polymers. Values of the modulus of silk obtained previously using such an approach were found to be an order of magnitude lower than, those obtained by computational modeling. The differences are outside the limits of experimental and computational errors. This study re-examined the values...
Novel (meth)acrylate tetrapolymers based on 2-hydroxyethyl methacrylate (HEMA) were synthesized via free-radical polymerization in refluxing xylene under monomer-starved conditions for use in negative photoresist formulations. 2,2′-Azobis(2-methylbutyronitrile) was used as initiator and 2-mercaptoethanol as chain transfer agent. Optimized resist formulations were obtained with a relatively narrow...
The complexation of copper ions by chitosan and its oligomers is investigated using potentiometric and spectrophotometric methods to study the nature of the complexes involved and the role of the degree of polymerisation. Two complexes are demonstrated. Their structure is proposed, the pH range in which they are respectively stable is determined and their stability constants calculated. Finally a...
The temperature dependence of linear crystal growth rate (G) for various polymers shows a bell shape with the maximum growth rate (Gmax). The Gmax shows remarkable molecular weight dependence. The Gmax was formulated on the basis of a crystallization theory, both for Arrhenius and WLF expressions in the molecular transport term. The plots of the reduced growth rate (G/Gmax) against the reduced temperature...
Amorphous poly(ethylene naphthalate) (PEN) oligomer has been crystallized at room temperature by treating in liquids having solubility parameter, δ, in the range of 15–29(Jcm−3)1/2. It has been observed that the liquids having δ in the range of 18.5–25 are able to crystallize PEN oligomer efficiently. A direct correlation has been observed between δ and crystallite size calculated from WAXS technique.
A method for measuring residual and applied stresses in particulate polymer systems, which utilizes the piezo-spectroscopic effect of the optical fluorescence of filled particles, is presented. Fluorescence piezo-spectroscopy (PS) is non-destructive and provides microscopic lateral resolution upon using an optical microprobe system. Epoxy resin filled with α-alumina particles is used in this study...
This paper examines the application of the statistical mechanics to the analysis of various physical properties of the elastomeric networks. The equilibrium properties of rubber-like networks are discussed, and also some dynamic properties, such as the relaxation spectrum of Gaussian networks. The paper covers a large spectrum of properties of polymer networks such as: fluctuations and chain dimensions...
We report the dielectric relaxation in a ternary system in which a trace amount of poly(n-hexyl isocyanate) (PHIC) is dissolved in concentrated toluene solutions of polybutadiene (PB). The dielectric response is due to the rod-like PHIC molecules having high dipole moment along its chain contour. Solutions of PB form entanglement networks which retard the reorientation of the PHIC molecules. With...
A second-order phase transition of α2 form isotactic polypropylene (iPP) is found at high annealing temperature (Ta=159.3°C) by means of X-ray diffraction method. Although the lattice shape and the space group keep the same as those of the α2 form, i.e. monoclinic and P21/c, with increase of Ta, it has been revealed that there are discontinuous increases in the slopes of the lattice constants a and...
Curing kinetics of a vinylester–urethane hybrid (VEUH) resin consisting of vinylester resin (VE) diluted in styrene and novolac type polyisocyanate (NPI) have been studied by differential scanning calorimetry (DSC). As VEUH is crosslinked via free radical polymerisation between the vinyl functions of styrene and VE, and polyaddition reaction between the secondary –OH groups of VE and –NCO of NPI,...
The miscibility and morphology of poly(caprolactone) (PCL) and poly (4-vinylphenol) (PVPh) blends were investigated by using differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and 13C solid state nuclear magnetic resonance (NMR) spectroscopy. The DSC results indicate that PCL is miscible with PVPh. FTIR studies reveal that hydrogen bonding exists between the hydroxyl...
Thermoplastic epoxy blends are successfully used commercially. The thermoplastic may serve as a toughening agent although other properties may also be improved. In the present study, microscopy and mechanical testing techniques were used to study morphology and ultimate properties of ternary epoxy/Poly(methyl methacrylate) (PMMA)–Poly(ethylene oxide) (PEO) blends. PEO is functioning like a compatibilizer...
The amine salt, N,N-diallyl-N-carboethoxymethylammonium chloride was copolymerized in dimethyl sulfoxide using ammonium persulfate or azo-bis-isobutyronitrile (AIBN) to afford the cationic polyelectrolyte (CPE) having five-membered cyclic structure on the polymeric backbone. The CPE on acidic (HCl) hydrolysis of the pendent ester groups gave the corresponding cationic acid salt (CAS) having the equivalent...
Polycondensation by Stille coupling of 2-decyl-4,7-dibromobenzimidazoles and N-methyl-2-decyl-4,7-dibromobenzimidazole with 2,5-bis(trimethylstannyl)thiophene and 5,5′-bis(trimethylstannyl)-2,2′-bithiophene gave the corresponding π-conjugated polymers, poly(2-decylbenzimidazole-4,7-diyl-thiophene-2,5-diyl) 1b, poly(2-decylbenzimidazole-4,7-diyl-bithiophene-2,5-diyl) 1c and poly(N-methyl-2-decylbenzimidazole-4,7-diyl-thiophene-2,5-diyl)...
Two types of O-carboxymethylated chitosan (O-CMCh)/cellulose polyblends were prepared by mixing cellulose LiCl/N,N-dimethylacetamide (DMAc) solution with O-CMCh aqueous solution (I) or DMAc emulsion (II) and their corresponding films (I and II) were regenerated in water. The (O-CMCh)/cellulose films obtained were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy...
Films of a binary polymer blend comprising of hydrophobic poly(vinylidene fluoride) (PVDF) and hydrophilic poly(vinylpyrrolidone) (PVP) have been prepared by solution-casting. The dependence of surface structure and composition of the films on the PVP content in the blend was investigated by using atomic force microscope (AFM), XRD, XPS, SEM and differential scanning calorimeter (DSC). It has been...
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