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Polymers crystallized at high temperatures, such as poly(aryl ether ether ketone) (PEEK), poly(ethylene terephthalate) and a thermoplastic polyimide, exhibit well developed lamellar stacks. We have obtained small angle X-ray scattering (SAXS) and wide angle X-ray diffraction data at 290°C and 25°C for PEEK and have also utilized literature SAXS data taken at 25°C for the other materials. To model...
Poly(ethylene terephthalate) copolymers were prepared by melt polycondensation of dimethyl terephthalate and excess amount of ethylene glycol with 2-20 mol% of poly(ethylene glycol) (E) or poly(butylene glycol) (B), where the molecular weights (MW) of E and B are 200-7500 and 1000-3000, respectively. Reduced specific viscosity of copolymer increased with increasing MW and the content of polyglycol...
3,3-Bis[4-(4-aminophenoxy)phenyl]phthalimidine (2) was used as the monomer with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to synthesize polyamides and polyimides, respectively. The diamine 2 was derived by a nucleophilic substitution of 3,3-bis(4-hydroxyphenyl)ptthalimidine withp -chloronitrobenzene in the presence of K 2 CO 3 and then reduced by hydrazine...
Polymerization of monomer-containing single-phase Winsor-IV microemulsions was studied and the morphology of the polymer obtained was found to be related to the structure of the microemulsion. The hydrophobic component of the microemulsions was formed with methyl methacrylate together with ethylene glycol dimethacrylate. Methacrylic acid was found to be effective as a polymerizable cosurfactant...
The segmental dynamics of the p-phenylenediamine rings of poly(p-phenyleneterephthalamide) (PPTA) have been examined via two-dimensional exchange solid state 2 H n.m.r. spectroscopy. Fully and partially relaxed experiments were performed over the temperature range -119°C to 75°C. Two populations of phenylene rings can be differentiated by their spin-lattice relaxation times and are associated...
Biosynthesized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) copolymers with 3HV mole fraction of 36 and 61% were fractionated by fractional precipitation methods using a solution of acetone--water. Both samples were mixtures of random copolymers having a wide variety of 3HV composition. The melting points of the fractionated samples showed pseudoeutectic changes with minimum breaking...
Kink bands with a thickness ranging from 45 nm to 1.8 μm were observed in polybenzobisoxazole (PBO) fibres examined in the transmission electron microscope. These bands are localized, and oriented at 69° ± 3° with respect to the fibre axial direction. The average shear strain is about 0.7 along the band. Bands of intermediate thicknesses (e.g. 0.1-0.3 μm) are wavy and relatively less uniform than...
A hydrogel was prepared by mixing poly(allylbiguanido-co-allylamine) hydrochloride (PAB) with poly(vinyl alcohol) (PVA) and by repeatedly freezing and thawing the blend. The swelling behaviour of the gel was studied as a function of the pH and ionic strength of the medium. The performance of the gel was compared to that of a blend hydrogel made from poly(allylamine) hydrochloride (PAA) and PVA....
Two t-butyloxycarbonyl (t-BOC) protected maleimide monomers, N-(t-butyloxycarbonyloxy)maleimide (t-BOCOMI) and N-[p-(t-butyloxycarbonyloxy)phenyl]maleimide (t-BOCOPMI), have been synthesized and polymerized. The t-BOC group was used to protect the hydroxy groups of the starting N-substituted maleimides, N-hydroxymaleimide (HOMI) and N-(p-hydroxyphenyl)maleimide (HOPMI). t-BOCOMI and t-BOCOPMI were...
The Monte Carlo sampling technique, in which polymers are sampled randomly from an infinite number of polymer molecules in the reaction system, is used to make computer simulations for the molecular-weight distribution (MWD) change during crosslinking and degradation processes. In this method, since one can investigate each polymer molecule directly, very detailed structural information can be easily...
The interdiffusion of n-alkane molecules in the crystal state is investigated in the binary system of C 21 H 44 and C 23 H 48 . A mechanical junction between a single crystal of C 23 and polycrystalline C 21 is held at a temperature just above the transition to the rotator phase in C 21 , and optical changes...
The possibility of porosity control in nylon-6 membranes was investigated. By adding water onto the surface of a concentrated nylon-6 solution in calcium chloride-methanol mixture in a cylindrical glass bottle, a three-phase structure of solid, gel and solution (in order from the top) appeared. The thickness of the gel phase was 2.5-4 mm and became larger as the time elapsed after adding water. ...
The effects of polymer associations on miscibility are investigated for polymer blend solutions of one-end-aminated polystyrene (APS) and one-end-carboxylated poly(ethylene glycol) (CPEG), which are able to associate with each other by means of the functional groups at the end of the respective polymer chains. Cloud points are measured for their toluene solutions, where the strength of association...
A range of polyethylenes has been studied by X-ray diffraction during deformation. Changes in the crystalline orientation have been related to the load-extension curve. This was altered by changing the molecular weight, concentration of branches and strain rate. Crystalline orientation was first observed just after the maximum load, before any visible signs of yield. At about the same point, the...
Poly(vinyl alcohol) (PVA) hydrogels were prepared by quenching solutions containing PVA polymer in pure water or an aqueous solution of dimethylsulfoxide (DMSO). Remarkably different PVA hydrogels were obtained by varying processing parameters, i.e. DMSO concentration, initial PVA concentration and quench temperature. The bulk structure of PVA hydrogels was investigated by scanning electron microscopy...
We describe the preparation and characterization of a solvatochromic dye-doped polymer for the detection of polar additives in hydrocarbon blends. This polymer is prepared by inclusion of the strongly solvatochromic Reichardt's dye (RD) into poly(methyl methacrylate) (PMMA). The influence of various parameters on the detection of methanol, tert-butyl alcohol (TBA) and tert-butyl methylether (TBME)...
Polypropylene (PP) films with a high content of β crystal were prepared at crystallization temperatures (T cr ) of 20 and 110°C and then uniaxially drawn at different temperatures (T dr ). The drawn film prepared atT cr = 20°C had smaller pore volume and average pore radius than the one prepared at T cr = 110°C under similar drawing conditions (T...
A previously developed non-conventional J integral based on hysteresis energy and the ASTM E813 methods have been employed to test the fracture toughness of a polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) blend. A systematic study of the effect of the specimen thickness (from B=4 to 15 mm) and the presence of a V-shaped side groove on the resultant J 1c has been carried out...
Novel regular network aliphatic-aromatic and aromatic polyimide films were prepared from mellitic acid (Y H ) and aliphatic and aromatic diamines or diisocyanates. Prepolymers prepared by solution polycondensation were cast and successively post-polymerized to form a network. The resultant films were insoluble in any organic solvents. The heat distortion temperature (T h ) and density...
A series of polybutadiene/polystyrene (PB/PS) network composites in the form of latexes were prepared via the concentrated emulsion polymerization method. The polymerization rate and the relative content of the crosslinked species were determined and compared at various polymerization temperatures, concentrations of initiator, and with vinyl-terminated PBs of different molecular weights. The mechanical...
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