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1.
Poly(trimethylene 2,6-naphthalate) (PTN)/poly(ethylene glycol) (PEG) copolymers were synthesized by the two-step melt copolymerization
process of dimethyl-2,6-naphthalenedicarboxylate (2,6-NDC) with 1,3-propanediol (PD) and PEG. The copolymers produced had
different PEG molecular weights and contents. The structure, thermal property, and hydrophilicity of these copolymers were
studied by proton nuclear magnetic resonance (1H-NMR) analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and by contact angle, moisture
content, and instantaneous elastic recovery measurements. The intrinsic viscosity and the instantaneous elastic recovery of
the PTN/PEG copolymers increased with increasing PEG molecular weight and content, whereas the glass transition, melting,
and cold crystallization temperatures, and the heat of fusion of the PTN/PEG copolymers all decreased with increasing PEG
molecular weight or content. The thermal stability of the copolymers was not affected by PEG molecular weight or content.
The hydrophilicity, as determined by contact angle and moisture content measurements of the copolymer films, was significantly
improved with increasing PEG molecular weight and content. 相似文献
2.
Poly(trimethylene terephthalate) (PTT)/poly(ethylene naphthalate) (PEN) blends of various compositions were prepared by the
solution-blending and melt-blending methods. The changes in miscibility and crystallization behaviors of the blends upon thermal
treatment above the melting temperature of the blends at 280°C were investigated by using DSC, DMA,1H NMR, and SAXS analyses. Without any thermal treatment, the blend systems were not miscible, and the thermal transitions,
such as glass transition, cold crystallization, and crystal melting of the individual components were observed in the DSC
and DMA analyses. With thermal treatment, though, they became miscible as the thermal transitions of each component disappeared
and single glass transition peaks were observed in the thermal analysis. The chain randomness determined using1H NMR spectroscopy revealed that thermal treatment at 280°C for more than 30 min brought about transesterification reactions
between the PTT and PEN segments resulting in an increase in their miscibility. These results were confirmed by the small
angle X-ray analysis conducted to determine the long period (L), the thickness of the crystalline lamella stack (l
c
), and the thickness of the amorphous region (l
a
). After short thermal treatment, the melt-blended sample followed the values for the individual components. However, with
extended thermal treatment, the blend became homogeneous, possessing different crystalline morphologies which resulted in
different values ofL, l
c
, andl
a
. 相似文献
3.
Ionic conductivity and mechanical properties of a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresin
type M (CRM) with various lithium salts and plasticizer were examined. The CRM used was a copolymer of cyanoethyl pullulan
and cyanoethyl poly(vinyl alcohol) with a molar ratio of 1:1, mixed plasticizer was ethylene carbonate (EC) and propylene
carbonate (PC) at a volume ratio of 1:1. The conductive behavior of polymer electrolytes in the temperature range of 298∼338
K was investigated. The PEG/LiClO4 complexes exhibited the highest ionic conductivity of ∼10−5 S/cm at 25°C with the salt concentration of 1.5 M. In addition, the plasticized PEG/LiClO4 complexes exhibited improvement of ionic conductivity. However, their complexes showed decreased mechanical properties. The
improvement of ionic conductivity and mechanical properties could be obtained from the polymer electrolytes by using CRM.
The highest ionic conductivity of PEG/CRM/LiClO4/(EC-PC) was 5.33×10−4 S/cm at 25°C. 相似文献
4.
Poly(trimethylene terephthalate-co-trimethylene 2,6-naphthalate)s (P(TT-co-TN)s) with various copolymer composition were synthesized,
and their chain structure, thermal property and crystalline structure were investigated by using1H-NMR spectroscopy, differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), respectively. It was
found from sequence analysis that all the P(TT-co-TN) copolymers synthesized have a statistical random distribution of TT
and TN units. It was also observed from DSC thermograms that the glass transition temperature increases linearly with increasing
the TN comonomer content, whereas the melting temperature of copolymer decreases with increasing the corresponding comonomer
content in respective PTT- and PTN-based copolymer, showing pseudo-eutectic melting behavior. All the samples melt-crystallized
isothermally except for P(TT-co-66 mol % TN) exhibit multiple melting endotherms and clear X-ray diffraction patterns. The
multiple melting behavior originates from the dual lamellar population and/or the melting-recrystallization-remelting. The
X-ray diffraction patterns are largely divided into two classes depending on the copolymer composition, i.e., PTT and PTNβ-form diffraction patterns, without exhibiting cocrystallization. 相似文献
5.
Min Ho Jee Jin Soo Lee Ju Yong Lee Young Gyu Jeong Doo Hyun Baik 《Fibers and Polymers》2010,11(1):1-7
Poly(ethylene 2,6-naphthalate)/multi-walled carbon nanotube (PEN/MWNT) nanocomposites are prepared by in situ condensation polymerization in the presence of various acid-treated MWNT (a-MWNT) contents and their morphology, rheological
and mechanical properties are investigated as a function of the a-MWNT content. SEM image of a plasma-etched nanocomposite
exhibits that a-MWNTs are dispersed well in the PEN matrix by forming an interconnected network structure. Accordingly, rheological
properties such as complex viscosities and shear moduli of PEN/a-MWNT nanocomposites at the terminal region of low frequency
are much higher than those of pure PEN. Glass transition temperatures of nanocomposites also increase with the increment of
the a-MWNT content, which stems from the reduced chain mobility due to the specific interaction between a-MWNTs and PEN matrix.
Dynamic and tensile mechanical properties of nanocomposites are also higher than those of pure PEN and they increase with
the increment of the a-MWNT content. The highly improved mechanical properties of PEN/a-MWNT nanocomposites are explained
to originate from the interconnected network structure of a-MWNTs in PEN matrix as well as the strong interfacial adhesion
between a-MWNTs and PEN matrix. 相似文献
6.
Poly(ethylene terephthalate) fabrics were metallized through electroless plating of copper. The copper plating was performed
on palladium-decorated polyaniline surfaces, and polyaniline was present as an intermediate layer on fabrics to facilitate
palladium formation. Different oxidation states of polyaniline were tested in their efficacy in Pd (II) reduction and subsequent
Cu plating. X-ray photoelectron spectroscopy was used to monitor the surface changes along the metallization procedure, and
surface resistance was measure to probe the electrical properties of the metallized fabrics. 相似文献
7.
Conductive polyaniline (PAn)/poly(ethylene terephthalate) (PET) composite fibers were prepared by chemical polymerization
of aniline in the presence of PET fibers using benzoyl peroxide (Bz2O2) in organic solvent/aqueous hydrochloric acid mixtures. The effects of polymerization conditions such as organic solvent/water
ratio, oxidant, aniline and hydrochloric acid concentrations and temperature were investigated on the amount of PAn deposited
on PET fiber and the electrical surface resistance of composite fibers. The maximum PAn content and the lowest electrical
surface resistance of composite fibers were observed at HCl concentrations of 0.5 mol L−1. The properties of PAn/PET composite fibers such as density, diameter, tensile strength and breaking elongation were also
investigated in comparison with those of pure PET. Characterization of conductive composite fibers was carried out by FTIR,
TGA, SEM techniques, surface resistance measurements, and cross section images taken by optical microscope. 相似文献
8.
The thermal degradation of poly(ethylene terephthalate-co-isophthalate)s (PETIs) is investigated by using isothermal thermogravimetric analysis at the temperature range of 280–310°C.
The degradation rate of PETIs is increased as the mole ratio of ethylene isophthaloyl (EI) units in PETIs increases. The activation
energies for the thermal degradation of poly(ethylene terephthalate), PETI(5/5), and poly(ethylene isophthalate) are 33.4,
16.6, and 8.9 kcal/mole, respectively. The degradation rate of PETIs is influenced by their volatile cyclic oligomer components
formed during the polymerization and the thermal degradation. It is simulated by the rotational isomeric state model that
the content of cyclic dimer in PETIs, which is the most volatile cyclic oligomer component, increases with the EI units in
PETIs. 相似文献
9.
In this study, we evaluated the effect of the molecular weight of the polymer on electrospun poly(ethylene terephthalate)
(PET) nonwovens, and their mechanical properties as a function of the linear velocity of drum surface. Polymer solutions and
electrospun PET nonwovens were characterized by means of viscometer, tensiometer, scanning electron microscope (SEM), wide
angle X-ray diffraction measurement (WAXD) and universal testing machine (UTM). By keeping the uniform solution viscosity,
regardless of molecular weight differences, electrospun PET nonwovens with similar average diameter could be obtained. In
addition, the mechanical properties of the electrospun PET nonwovens were strongly dependent on the linear velocity of drum
surface. From the results of the WAXD scan, it was found that the polymer took on a particular molecular orientation when
the linear velocity of drum surface was increased. The peaks became more definite and apparent, evolving from an amorphous
pattern at 0 m/min to peaks and signifying the presence of crystallinity at 45 m/min. 相似文献
10.
The kinetic parameters, including the activation energyE, the reaction ordern, and the pre-exponential factorZ, of the degradation of the copolymers based on the poly(L-lactide) (PLLA) or poly(p-dioxanone-co-L-lactide) (PDO/PLLA) and diol-terminated poly(ethylene glycol) (PEG) segments have been evaluated by the single
heating methods of Friedman and Freeman-Carroll. The experimental results showed that copolymers exhibited two degradation
steps under nitrogen that can be ascribed to PLLA or PDO/PLLA and PEG segments, respectively. However, copolymers exhibited
almost single degradation step in air. Although the values of initial decomposition temperature were scattered, copolymers
showed the lower maximum weight loss rate and degradation-activation energy in air than in nitrogen whereas the higher value
of temperature at the maximum rate of weight loss was observed in air. 相似文献
11.
The thermal behavior, morphology, ester-interchange reaction of Poly(trimethylene terephthalate) (PTT)/Poly(ethylene terephthalate)
(PET) melt blends were investigated over the whole composition range(xPTT/(1-x)PET) using a twinscrew Brabender. The melt
blends were analyzed by differential scanning calorimetry (DSC), nuclear magnetic resonance spectroscopy (13C-NMR), and scanning electron microscopy (SEM). Single glass transition temperature (T
g
) and cold crystallization temperature (T
cc
) were observed in all melt blends. Melt blends were found to be due to the ester-interchange reaction in PTT/PET blend. Also
the randomness of copolymer increases because transesterification between PTT and PET increases with increasing blending time.
This reaction increases homogeneity of the blends and decreases the degree of crystallinity of the melt blends. In PTT-rich
blends, mechanical properties decrease with increase of PET content compared with that of pure PTT. And, in PET-rich blends,
tensile modulus decreases with increase of PTT content, but tensile strength and elongation is similar to that of pure PET. 相似文献
12.
Guoquan Zhu 《Fibers and Polymers》2008,9(2):107-112
Poly(n-butyl methacrylate)/poly(methyl methacrylate) polymer networks were synthesized by two-step emulsion polymerization with
sodium dodecylsulfonate and polyoxyethylene nonylphenolether as the emulsifier, distilled water as the continuous medium,
and potassium persulfate as the initiator. The kinetics of two-step emulsion polymerization was studied. Effects of emulsifier
concentration, initiator concentration, and polymerization temperature on monomer conversion and polymerization rate were
investigated in detail. Experimental data indicate that both the steady state polymerization rate and monomer conversion increase
with the augment of emulsifier concentration, initiator concentration, or reaction temperature. 相似文献
13.
In this work, the method, in principle of the box complex algorithm was adopted to obtain stress-induced crystallization coefficient
C and the strain-optical coefficientA
op
with the value of 295 and 1.5×10−9, respectively, and some parametersA
1=0.27,A
2=5.06,a=3.5,b=1.8 relative to the elongational viscosity of poly(trimethylene terephthalate)(PTT) fiber. The vitrification distance as
a function of the take-up velocity and mass throughput was also gotten. The effects of spinning conditions on filament temperature,
velocity gradient, spinning tension, birefringence and crystallinity, and effect of viscoelasticity on take-up velocity had
been discussed. 相似文献
14.
Luciane CalabriaNathália Vieceli Otávio BianchiRicardo Vinicius Boff de Oliveira Iraja do Nascimento FilhoVanessa Schmidt 《Industrial Crops and Products》2012,36(1):41-46
A slow release fertilizer system consisting of materials derived exclusively from biomass, and suitable for i) production of injection-molded parts such as containers for growing plants, and ii) use as granules, is reported. Soy (Glycine max L. Merr.) protein isolate/poly(lactic acid) blends plasticized with triacetin (SPI/PLA-TA) were used as matrix for NPK fertilizer incorporation. Upon melt processing, this composite material formed a highly ordered porous matrix of SPI in which PLA domains are homogeneously dispersed with NPK salts. Dynamic conductivity measurements indicated good release properties as the cumulative amount increased much slower with time as compared to pure NPK sample. Biodegradation was accessed by examining weight loss and surface morphology as a function of incubation time in soil. 相似文献
15.
Ismail Karacan 《Fibers and Polymers》2005,6(3):206-218
A selection of commercially available poly(ethylene terephthalate) fibers with different degrees of molecular alignment and
crystallinity have been investigated utilizing a wide range of techniques including optical microscopy, infrared spectroscopy
together with thermal and wide-angle X-ray diffraction techniques. Annealing experiments showed increased molecular alignment
and crystallinity as shown by the increased values of birefringence and melting enthalpies. Crystallinity values determined
from thermal analysis, density, unpolarized infrared spectroscopy and X-ray diffraction are compared and discussed in terms
of the inherent capabilities and limitations of each measurement technique. The birefringence and refractive index values
obtained from optical microscopy are found to decrease with increasing wavelength of light used in the experiments. The wide-angle
X-ray diffraction analysis shows that the samples with relatively low orientation possess oriented non-crystalline array of
chains whereas those with high molecular orientation possess well defined and oriented crystalline array of chains along the
fiber axis direction. X-ray analysis showed increasing crystallite size trend with increasing molecular orientation. SEM images
showed micro-cracks on low oriented fiber surfaces becoming smooth on highly oriented fiber surfaces. Excellent bending characteristics
were observed with knotted fibers implying relatively easy fabric formation. 相似文献
16.
New film forming aromatic poly(amide-imide)s containing isoindoloquinazolinedione (IQ) unit in the backbone chain (polymerXIV) have been successfully synthesized by preparing prepolymers of poly(amic acid-carbonamide), followed by subsequent thermal
cyclization of the prepolymers. 4,4′-Diamino-3′-carbamoylbenzanilide (DACB)V has been synthesized by reduction of 3′-carbamoyl-4′-amino-4-nitrobenzanilideIV. The prepolymers of poly(amic-acid-carbonamide) (polymersVII andVIII) which exhibit viscosities ranging from 1.4 to 1.7 dl/g have been prepared by a condensation polymerization of monomers such as BPDA, ODA, and DACB. PolymerXIV has been obtained by thermal cyclization of the polymersVII andVIII. During the thermal cyclization reaction, imide ring structure was first introduced and then transformed to the structure
of IQ unit. The thermal degradation rate of the resultant polymers were influenced by the cleavage of amide bond but the final
char yield was comparable to that of poly(BPDA-ODA). 相似文献
17.
The effect of casting solvent on the structural characteristics and miscibility of regenerated silk fibroin/Poly(vinyl alcohol) blends 总被引:1,自引:0,他引:1
Regenerated silk fibroin(SF)/Poly(vinyl alcohol)[PVA] blend films were prepared using different casting solvents, water and
formic acid, to elucidate the effect of casting solvent on the structure and miscibility of SF/PVA blends. FTIR and XRD measurement
suggested thatβ-sheet conformation of SF was not changed by addition of PVA in case of formic acid casting and the casting solvent determined
the crystallized component of SF/PVA, leading to a different trend in the overall crystallinity between the two blends. The
casting solvent had a dominant role in deciding phase behavior and molecular miscibility of blend films. SEM observation and
DMTA measurement elucidated that water solvent produced phase-separated blend films while formic acid yielded one phase blend
films with partial miscibility in molecular level indicating that the miscibility of SF blend can be improved by choosing
a proper co-solvent. 相似文献
18.
Emad A. Jaffar Al-Mulla Adeel H. SuhailSaadon Abdulla Aowda 《Industrial Crops and Products》2011,33(1):23-29
Biodegradable polymers, such as poly(lactic acid) (PLA) have attracted a lot of attention in the scientific community recently due to a rapid growth of intensive interest in the global environment for alternatives to petroleum-based polymeric materials. Fatty nitrogen compounds (FNCs), fatty amides (FA), fatty hydroxamic acids (FHA), and carbonyl difatty amides (CDFA), which were synthesized from vegetable oils, were used as one of organic compounds to modify natural clay (sodium montmorillonite). The clay modification was carried out by stirring the clay particles in an aqueous solution of FA, FHA, and CDFA, by which the clay layer thickness increased from 1.23 to 2.61, 2.84 and 3.19 nm, respectively. The modified clay was then used in the preparation of the PLA/epoxidized soybean oil (ESO) blend nanocomposites. They were prepared by incorporating 2% of CDFA-MMT and 3% of both FA-MMT and FHA-MMT. The interaction of the modifier in the clay layer was characterized by X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Elemental analysis was used to estimate the presence of FNCs in the clay. The nanocomposites were synthesized by solution casting of the modified clay and a PLA/ESO blend at the weight ratio of 80/20, which has the highest elongation at break. The XRD and transmission electron microscopy (TEM) results confirmed the production of nanocomposites. PLA/ESO modified clay nanocomposites show higher thermal stability and significant improvement of mechanical properties in comparison with those of the PLA/ESO blend. The novelty of this study is use of FNCs which reduces the dependence on petroleum-based surfactants. 相似文献
19.
Phase behavior and spinodal phase separation kinetics in binary blends of a random copolymer of vinylidene fluoride and trifluoroethylene
(75/25) [P(VDF/TrFE)] and poly(1,4-butylene adipate) (PBA) have been investigated by means of optical microscopic observation
and time-resolved light scattering. The blends exhibited a typical lower critical solution temperature (LCST)∼34 °C above
the melting temperature of the P(VDF/TrFE) crystals over the entire blend composition range. P(VDF/TrFE) and PBA were totally
miscible in the temperature gap between the melting point of P(VDF/TrFE) and the LCST. Temperature jump experiments of the
3/7 P(VDF/TrFE)/PBA blend were carried out on a light-scattering apparatus from a single-phase melt state (180 °C) to a two-phase
region (205∼215 °C). Since the late stage of spinodal decomposition (SD) is prevalent in the 3/7 blend, SD was analyzed using
a power law scheme. Self-similarity was preserved well in the late stage of SD in the 3/7 blend. 相似文献
20.
Xian Zhang Xingyou Tian Xiayin Yao Jin Zheng Wentao Liu Yong Li Ping Cui 《Fibers and Polymers》2008,9(3):360-364
The isothermal and non-isothermal shrinkage behaviors of highly oriented Poly(ethylene terephthalate) yarns were investigated.
In isothermal measurements, shrinkage and shrinkage stress firstly monotonously increased due to more and more activated frozen
molecular segments with increasing time and temperature, and then relaxed at high temperature resulting from intermolecular
slipping of micro-fibrils. According to the different contributions of amorphous and crystalline regions to shrinkage behavior,
non-isothermal shrinkage and shrinkage stress curves were fitted by Gauss curves and the entire shrinkage process was divided
into three stages: contraction of micro-fibrils, contraction of extended interfibrillar tie molecules and relative displacement
of micro-fibrils. 相似文献