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1.
Profiles development of the melt spinning process of poly(trimethylene terephthalate) (PTT) was simulated by a numerical method.
The spinning speed of 3 km/min to 5 km/min was analyzed and the characteristic of PTT spinning process was compared with that
of poly(ethylene terephthalate) (PET). Velocity development of PTT was slower than that of PET. Although PTT’s spinning temperature
was lower than PET’s, the PTT solidified slower because of a smaller super-cooling and the large specific heat capacity. The
diameter profile of PTT decreases gradually in comparison with that of PET. PTT’s strain rate has a broader distribution than
PET’s and its maximum ranged from 541 to 570 s−1 for PET and 136 to 149 s−1 for PTT. PTT’s tensile stress was smaller than PET’s. 相似文献
2.
Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) [copoly(ET/CPT)] was prepared using poly(ethylene terephthalate) (PET) as a flexible
spacer, terephthalic acid (TPA), and chlorohydroquinone diacetate (CHQDA). All reactions involved in the copolymerization
were investigated using some model compounds: TPA was used for acidolysis, diphenylethyl terephthalate (DPET) for interchange
reaction between PET chains, and di-o-chlorophenyl terephthalate (DOCT) and di-m-chlorophenyl terephthalate (DMCT) for interchange reaction between PET and rigid rodlike segments. Activation energies obtained
for the acidolysis of PET with TPA and for interchange reaction of PET with DPET, DOCT, and DMCT were 19.8 kcal/mole, 26.5
kcal/mole, 60.2 kcal/mole, and 45.9 kcal/mole, respectively. This result supports that the copolymerization proceeds through
the acidolysis of PET with TPA first and subsequent polycondensation between carboxyl end group and CHQDA or acetyl end group,
which is formed from the reaction of CHQDA and TPA. Also, it was found that ester-interchange reaction can be influenced by
the steric hindrance. Copoly(ET/CPT)s obtained had ethylene acetate end groups formed from acetic acid and hydroxy ethylene
end groups and showed almost the random sequence distribution for all compositions. 相似文献
3.
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
4.
Chang Soo Lee Kwan Han Yoon Jae Cheol Park Hong-Un Kim Young-Bin Park 《Fibers and Polymers》2014,15(7):1493-1499
Poly(ethylene terephthalate) (PET)/CaCO3 and PET/modified-CaCO3 (m-CaCO3) nanocomposites were prepared by melt blending. The morphology indicated that m-CaCO3 produced by reacting sodium oxalate and calcium chloride, was well dispersed in PET matrix and showed good interfacial interaction with PET compared to CaCO3. No significant differences in the thermal properties such as, glass transition, melting and degradation temperatures, of the nanocomposites were observed. The thermal shrinkage of PET at 120 °C was 10.8 %, while those of PET/CaCO3 and PET/m-CaCO3 nanocomposites were 2.9–5.2 % and 1.2–2.8 %, respectively depending on filler content. The tensile strength of PET/CaCO3 nanocomposite decreased with CaCO3 loading, whereas that of PET/m-CaCO3 nanocomposites at 0.5 wt% loading showed a 17 % improvement as compared to neat PET. The storage modulus at 120 °C increased from 1660 MPa for PET to 2350 MPa for PET/CaCO3 nanocomposite at 3 wt% loading, and 3230 MPa for PET/m-CaCO3 nanocomposite at 1 wt% loading. 相似文献
5.
Blends of poly(butylene terephthalate) (PBT)/thermoplastic polyurethane (TPU) were prepared by melt compounding. The miscibility, crystallization behaviors and toughening mechanism of the PBT/TPU blends were studied. Dynamic mechanical analysis results demonstrated that PBT was immiscible with TPU. Differential scanning calorimetry and wide angle X-ray diffraction results showed that the crystallinity of PBT decreased with increasing TPU content. Furthermore, blending with TPU did not modify the crystal structure of PBT. The small angle X-ray scattering results indicated that the crystal layer thickness decreased and the amorphous layer thickness increased with increasing TPU content, indicating that TPU mainly resided in the interlamellar region of PBT spherulites in the blends. An obvious improvement in toughness of PBT was achieved with addition of TPU. Neat PBT had elongation at break and impact strength of about 15 % and 2.9 kJ/m2, respectively. However, the elongation at break and impact strength of the 70/30 PBT/TPU blend reached 410 % and 62.9 kJ/m2, respectively. The morphology of the PBT/TPU blends after tensile and impact tests was investigated, and the corresponding toughening mechanism is discussed. It was found that the PBT showed obvious shear yielding in the blend during the tensile and impact tests, which induced dissipation of energy and, therefore, led to the improvement in toughness of the PBT/TPU blends. 相似文献
6.
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
7.
Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) (50/50, mole/mole) [PECPT] was synthesized and blended with polycarbonate (PC).
LC properties of PECPT and thermal, morphological, and rheological behaviors of the PECPT/PC blend were studied. PECPT showed
the nematic LC phase and much longer relaxation time than poly(ethylene terephthalate) (PET). The apparent melt viscosity
of PECPT was one third of that of PET. An abrupt torque change was observed during the blending process due to the orientation
of LC domains. For the blends containing 10∼30 wt% of PECPT, the complex viscosities were higher than that of PC. As PECPT
content increases above 40 wt%, shear thinning was observed. The lowest complex viscosity was obtained at 40∼50 wt%. Transesterification
of PECPT and PC was confirmed by the selective chemical degradation of carbonate groups in PC. 相似文献
8.
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
9.
The cross-section shape, longitudinal self-crimping configuration of various PTT (Polytrimethylene terephthalate)/PET (Polyethylene terephthalate) filaments were observed and measured via microscope. The crimp parameters of the filaments, including helixes pitch, crimp radius, crimp curvature and regular crimp proportion were calculated, and the relationship between crimp parameters and self-crimping configurations of PTT/PET filament was analyzed. Various shapes of PTT/PET fiber cross-section were detected such as round, peanut, dog bone and pear like shapes. Crimp configurations were found not always regular spatial helix along the longitudinal direction of filament and had significant difference according to the fact whether the filament was undergone textured process. With the length rate of the long axis to the short axis of cross-section increasing, the crimp curvature of filament will also increase. The helix pitch and radius will increase while the crimp curvature will decrease with the increasing linear density for the same cross-section shape of PTT/PET filament. 相似文献
10.
Poly(ethylene terephthalate) was annealed at different temperature and pressure of supercritical carbon dioxide (CO2) using samples quenched from the melt. Crystallization and molecular relaxation behavior due to CO2-annealing of samples were investigated using differential scanning calorimetric and dynamic mechanical measurements. The
glass transition and crystallization temperatures significantly decreased with increasing temperature and pressure of CO2. The dynamic mechanical measurement of samples annealed at 150 °C in supercritical CO2 showed three relaxation peaks, corresponding to existence of different amorphous regimes such as rigid, intermediate, and
mobile domains. As a result, the mobile chains were likely to facilitate crystallization in supercritical state. It also led
to the decreased modulus of CO2-annealed samples with increasing pressure. 相似文献
11.
Ruoming Ye Qiang Wang Xuerong Fan Yuanyuan Yu Jiugang Yuan Ping Wang 《Fibers and Polymers》2013,14(7):1128-1133
This study aimed at comparatively investigating the enzymatic hydrolysis of a new model substrate water-soluble polyester (WSP) and polyethylene terephthalate (PET) with cutinase. The changes of WSP solution properties were investigated by measuring pH value, alkali consumption, and specific viscosity. The results indicated that pH value of enzymatically treated WSP solution was decreased, causing an increase in alkali consumption. The decreases in specific viscosity and the glass transition temperature (T g ) of WSP treated with cutinase indicate the decrease in its molecular weight as demonstrated in gel permeation chromatography analysis (GPC). Cutinase treatment resulted in an improvement of the hydrophilicity of PET fabrics, which was determined by dye uptake and water contact angle. 相似文献
12.
Mazeyar Parvinzadeh Gashti Siamak Moradian Abosaeed Rashidi Mohamad-Esmail Yazdanshenas 《Fibers and Polymers》2013,14(5):743-751
Poly(ethylene terephthalate) [PET] based nanocomposites containing three differently modified silica particles were prepared by melt compounding. The influence of type of nano-silica on dispersibility, thermal and dyeing properties of the resultant nanocomposite was investigated by various analytic techniques, namely, polarized optical microscopy (POM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), reflectance spectroscopy (RS), and light fastness. Optical microscopy images illustrated that nano-silica particles tended to increase the number of spherulites in the PET matrix which were dependent on nano-silica type and content. Thermal studies of the resultant nanocomposites showed a slight decrease in the melting temperature compared to a pristine PET. Silica nanocomposites were finally dyed with a disperse dye and their reflectances were determined by the aid of reflectance spectrophotometer. Such reflectances were converted to the corresponding color coordinate values which are indicative of dyeability of such nanocomposites. 相似文献
13.
The purpose of this paper is to study the biostability of PTT samples as an implantable biomaterial. In this study accelerated
hydrolytic and enzymatic degradation tests were performed on PTT filaments so as to predict the relative rates of in vivo biodegradation. PTT filaments were subjected to a highly alkaline environment (pH 13.5) for periods of up to 10 days, and
to PBS buffer and neutral enzymatic papain solutions for up to 9 weeks. Changes in weight loss, surface appearance, filament
diameter, thermal properties, infra-red spectrum and tensile modulus were monitored over these time periods. PET samples were
also exposed to the same solutions as a comparison to PTT samples. The results show that PTT filaments are more stable in
alkaline solution, but less stable in PBS neutral buffer and enzymatic papain environments compared to PET filaments. The
decrease of tensile moduli of the degraded PTT samples confirms the decrease of crystallinity and conform change of the trimethylene
glycol conformers during the degradation. 相似文献
14.
Jenny Alongi 《Fibers and Polymers》2011,12(2):166-173
Zn phosphinate, organo-modified sepiolite and poly(ethylene terephthalate) (PET) have been melt blended to develop a new flame
retardant system for PET plastics and textiles. The combination of Zn phosphinate and sepiolite have been exploited in order
to enhance the flame retardancy of PET for both plastics and textiles. The thermal stability of PET blends evaluated by thermogravimetric
analysis and differential scanning calorimetry results remarkably affected by the loaded fillers. The combustion tests by
cone calorimetry reveal a relevant decrease of combustion rate and a high increase of fire performance index for both plastics
and textiles due to the presence of this novel flame retardant mixture. Analogously, limiting oxygen index has been found
increased in a remarkable way. 相似文献
15.
Thermotropic liquid crystalline polymer made up of poly(p-hydroxybenzoate) (PHB)-poly(ethylene terephthalate) (PET) 8/2 copolyester, poly(ethylene 2,6-naphthalate) (PEN) and PET were
mechanically blended to pursue the liquid crystalline phase of ternary blends. Complex viscosities of blends decreased with
increasing temperature and PHB content. DSC thermal analysis indicated that glass transition temperature (Tg) and melting temperature (Tm) of blends increased with increasing PHB content. Both tensile strength and initial modulus increased with raising PHB content
and take-up speed of monofilaments. In the WAXS diagram, only PEN crystal reflection at 2Θ=15.5o appeared but PET crystal reflection was not shown in all compositions. The degree of transesterification and randomness of
blends increased with blending time but sequential length of both PEN and PET segment decreased. 相似文献
16.
This research evaluates the miscibility and performance of polypropylene (PP)/polybutylene succinate (PBS) and PP/polylactic acid (PLA) blend and natural-flour-filled, PP/PLA and PP/PBS blend bio-composites. The melting temperature (T m ) and glass transition temperature (T g ) of pure PP, PBS and PLA showed a single peak but differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) presented two peaks for the T m and T g of the PP/PBS and PP/PLA blends. These results indicated that the PP/PBS and PP/PLA blend systems existed as immiscible blends. These results were also confirmed by the scanning electron microscopy (SEM) micrographs of the tensile fracture surface of the PP/PBS and PP/ PLA blends. At a PP/PBS and PP/PLA blend ratio of 70/30, the tensile and flexural strengths of bamboo flour (BF)- and wood flour (WF)-filled, PP/PBS and PP/PLA blend bio-composites were similar to those of BF- and WF-filled, PP and PBS bio-composites. In addition, these strengths of maleic anhydride-grafted PP (MAPP)- and acrylic acid-grafted PP (AAPP)-treated, BF- and WF-filled, PP/PBS and PP/PLA blend bio-composites were higher than those of non-treated bio-composites. 相似文献
17.
Helium-oxygen plasma treatments were conducted to modify poly(trimethylene terephthalate)(PTT) and poly(ethylene terephthalate)
(PET) warp knitted fabrics under atmospheric pressure. Lubricant and contamination removals by plasma etching effect were
examined by weight loss (%) measurements and scanning electron microscopy (SEM) analysis. Surface oxidation by plasma treatments
was revealed by x-ray photoelectron spectroscopy (XPS) analyses, resulting in formation of hydrophilic groups and moisture
regain (%) enhancement. Low-stress mechanical properties (evaluated by Kawabata evaluation system) and bulk properties (air
permeability and bust strength) were enhanced by plasma treatment. Increasing interfiber and interyarn frictions might play
important roles in enhancing surface property changes by plasma etching effect, and then changing low-stress mechanical properties
and bulk properties for both fabrics. 相似文献
18.
We have prepared the blends of poly(pentamethylene 2,6-naphthalate) (PPN) with poly(heptamethylene 2,6-naphthalate) (PHepN)
by solution blending method and investigated their glass transition behaviour, melting behaviour, and tensile properties.
It was observed that the blends of PPN/PHepN(9/1) and PPN/PHepN(1/9) have a single glass transition, reflecting a homogeneous
phase, whereas those of PPN/PHepN(7/3), PPN/PHepN(5/5), and PPN/PHepN(3/7) exhibit double glass transitions, representing
the existence of two phases. The PPN homopolymer annealed below 90 °C shows triple melting peaks (T
m1, T
m2, and T
m3). It was proved that T
m1 is attributed to melting of thin lamellar formed during secondary crystallization process, T
m2 to melting of thick lamellar created during primary crystallization, and T
m3 to melting of crystals recrystallized after melting the primary crystals at T
m2. For the annealed PHepN homopolymer, double melting endotherms (T
m1 and T
m2) were observed, caused by dual lamellar population with different thickness, i.e. T
m1 corresponding to the melting of secondary crystal and T
m2 to primary one. The Hoffman-Weeks plots, applied to the melting of primary crystals (T
m2s), indicate that the equilibrium melting temperatures of PPN homopolymer, PPN/PHepN(9/1), and PPN/PHepN(7/3) blends are same
to be 147 °C, and those of PHepN homopolymer, PPN/PHepN(1/9), and PPN/PHepN(3/7) blends to be 145 °C. Both the glass transition
and melting behaviours demonstrate that the PPN/PHepN blend system is partially miscible. In addition, both the modulus and
strength for the blends almost follow additive rule against blend composition, indicating that the PPN/PHepN blends are mechanically
compatible over all blend compositions. 相似文献
19.
A series of CNTs/SiO2/thiazole dye hybrid materials prepared via the sol-gel process is synthesized from carbon nanotubes (CNTs) and tetraethoxysilane
with heteroaryl 4-phenyl-2-amino-thiazole dyes. Heterocyclic 4-phenyl-2-aminothiazole dyes are processed with the hydrolysis-condensation
reaction at a constant ratio of vinyltriethoxysilane and tetraethoxysilane condensed with modified CNTs in appropriate proportion
under a catalyst. The structures of the CNTs/SiO2/thiazole dye hybrid materials are characterized by Fourier transform infrared spectroscopy (FTIR). Polytrimethylene terephthalate
(PTT) fabrics are used to evaluate the morphology structure by scanning electron microscopy (SEM). SEM images show that a
uniform dyeing on the PTT fabrics to confirm the reaction of hybrid materials with PTT fabrics. The washing fastness, color
evenness, water contact angle, air permeability, electric conductivity, and weatherability of PTT fabrics dyed with CNTs/SiO2/thiazole dye hybrid materials are evaluated, with results indicating improved conductivity and water-repellent. 相似文献
20.
Solid-state polymerization of poly(trimethylene terephthalate)(PTT) was carried out to obtain high molecular weight polymers.
Two kinds of commercial PTT chips were polymerized in the solid state by the heat treatment at 190∼220°C for various times
and they were characterized by end group content, molecular weight, thermal analysis, and X-ray diffraction. In the solid-state
polymerization of PTT, the overall reaction rate was governed by the solid-state polymerization temperature and time, and
pellet size. The content of carboxyl end groups decreased during the solid-state polymerization with increasing solid-state
polymerization temperature and time. The melting temperature and crystallinity of the PTT were higher for the ones treated
at higher temperature and longer time. The activation energy for the solid-state polymerization of PTT was in the range of
24∼25 kcal/mol for both chips. Through the solid-state polymerization of commercial PTT chips, high molecular weight polymers
up to an intrinsic viscosity of 1.63 dl/g was obtained, which corresponded to about a 117,000 weight-average molecular weight. 相似文献