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1.
The relationships among glass transition, crystallization, melting, and crystal morphology of poly(aryl ether ketone) (PAEK)/poly(other imide) (PEI) blends was studied by thermal, optical and small-angle x-ray scattering (SAXS) methods. Two types of PAEK were chosen for this work: poly(aryl ether ether ketone), PEEK, and poly(aryl ether ketone ketone), PEKK, which have distinctly different crystallization rates. Both PAEKs show complete miscibility with PEI in the amorphous phase. As PAEK crystallizes, the noncrystallizable PEI component is rejected from the crystalline region, resulting in a broad amorphous population, which was indicated by the broadening and the increase of Tg over that of the purely amorphous mixture. The presence of the PEI component significantly decreases the bulk crystallization and crystal growth rate of PAEK, but the equilibrium melting temperature and crystal surface free energies are not affected. The morphology of the PEI segregation was investigated by SAXS measurements. The results indicated that the inter(lamellar-bundle) PEI trapping morphology was dominant in the PEEK/PEI blends under rapid crystallization conditions, whereas the interspherulitic morphology was dominant in the slow crystallizing PEKK/PEI blends. These morphologies were qualitatively explained by the expression δ=D/G, where G was the crystal growth rate and D was the mutual diffusion coefficient. © 1993 John Wiley & Sons, Inc. 相似文献
2.
Polymer miscibility was found for a blend system comprising of a new poly(aryl ether ketone) and a poly(ether imide). Phase homogeneity was preliminarily confirmed using optical and scanning electron microscopy, indicating that the scales of phase homogeneity in the blends were beyond the resolution limits of either microscopy. A composition-dependent, single glass transition temperature (Tg) in the PAEK/PEI blends within the full range of composition was observed using differential scanning calorimetry (DSC). The thermal transition breadth also suggests that the scales of mixing are fine and uniform. 相似文献
3.
A ternary miscible blend system comprising only crystallizable aryl polyesters [poly(ethylene terephthalate), poly(trimethylene terephthalate), and poly(butylene terephthalate)] was characterized with the criteria of thermal analyses, microscopy, and X‐ray characterizations. The reported ternary miscibility (in the quenched amorphous state of blends of the three aryl polyesters) was truly physical and under the condition of no chemical transesterifications; this justified that transesterification was not a necessary condition for miscibility in polyester blends in this case. This study further proposed and tested a novel concept of a new criterion for miscibility characterization for polymer blends of only crystallizable polymers. A single composition‐dependent cold‐crystallization‐temperature (Tcc) peak in blends of only semicrystalline polymers was taken as an indication of an intimate mixing state of miscibility. The theoretical background for establishing the single composition‐dependent Tcc peak as a valid miscibility criterion for crystallizable polymer blends was examined. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2394–2404, 2003 相似文献
4.
Miscibility and morphology of poly(ethylene 2,6-naphthalate)/poly(trimethylene terephthalate)/poly(ether imide) (PEN/PTT/PEI)
blends were investigated by using a differential scanning calorimeter (DSC), optical microscopy (OM), wide-angle X-ray diffraction
(WAXD), and proton nuclear magnetic resonance (1H-NMR). In the ternary blends, OM and DSC results indicated immiscible properties for polyester-rich compositions of PEN/PTT/PEI
blends, but all compositions of the ternary blends were phase homogeneous after heat treatment at 300 °C for more than 30 min.
An amorphous blend with a single T
g was obtained in the final state, when samples were annealed at 300 °C. Experimental results from 1H-NMR identified the production of PEN/PTT copolymers by so-called “transesterification”. The influence of transesterification
on the behaviors of glass transition and crystallization was discussed in detail. Study results identified that a random copolymer
promoted the miscibility of the ternary blends. The critical block lengths for both PEN and PTT hindered the formation of
crystals in the ternary blends. Finally, the transesterification product of PEN/PTT blends, ENTT, was blended with PEI. The
results for DSC and OM demonstrated the miscibility of the ENTT/PEI blends. 相似文献
5.
6.
Various phase behavior of blends of poly(vinyl ether)s with polyesters of two types (highly crystalline and less crystalline with different main‐chains) were examined using differential scanning calorimetry (DSC) and optical microscopy (OM). Effects of varying the main‐chain polarity of the constituent polyesters on the phase behavior of the blends were analyzed. Miscibility in PVME/polyester blends was found only in polyesters with backbone CH2/CO ratio = 3.5 to 7.0). Tg‐composition relationships for blends of PVME with highly crystalline polyesters (PBA, PHS) were found to differ significantly from those for PVME blends with less‐crystalline polyesters (PTA, PEAz). Crystallinity of highly crystalline polyester constituents in blends caused significant asymmetry in the Tg‐composition relationships, and induced positive deviation of blends' Tg above linearity; on the other hand, blends of PVME with less crystalline polyesters exhibit typical Fox or Gordon‐Taylor types of relationships. The χ parameters for the miscible blends were found to range from ?0.17 to ?0.33, reflecting generally weak interactions. Phase behavior was analyzed and compared among blends of PVME with rapidly crystallizing vs. less‐crystallizing polyesters, respectively. Effects of polyesters' crystallinity and structures on phase behavior of PVME/polyester blends are discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2899–2911, 2007 相似文献
7.
Li-Ting Lee Eamor M. Woo Wei-Ting Chen Ling Chang Kai-Cheng Yen 《Colloid and polymer science》2010,288(4):439-448
Miscibility with a linear T
g–composition relationship was proven for blend of poly(butylene adipate-co-butylene terephthalate) [P(BA-co-BT)] with poly(4-vinyl
phenol) (PVPh). In comparison to the blends of PBA/PVPh and poly(butylene terephthalate) (PBT)/PVPh, the Kwei’s T
g model fitting on data for the P(BA-co-BT)/PVPh blend yields a q value between those for the PBA/PVPh and PBT/PVPh blends. The q values suggest that the interaction strength in the P(BA-co-BT)/PVPh blend is not as strong as that in the PBT/PVPh blend.
Upon mixing the PVPh into the immiscible blend of PBA and PBT, the ternary PBA/PBT/PVPh blends only exhibits partial miscibility.
Full-scale ternary miscibility in whole compositions is not possible owing to the significant ∆χ effect (χ
ij
– χ
ik
). The wavenumber shifts of the hydroxyl IR absorbance band indicates that the H-bonding strength is in decreasing order—PBT/PVPh
> P(BA-co-BT)/PVPh > PBA/PVPh—and shows that the BA segment in the copolymer tends to defray interactions between P(BA-co-BT)
and PVPh in blends. 相似文献
8.
L. Vincent S. N. Connolly F. Dolan P. H. Willcocks S. A. A. Jayaweera 《Journal of Thermal Analysis and Calorimetry》2006,86(1):155-164
The fracture toughness of blends
of polypropylene terephthalate (PPT) with polyethylene terephthalate (PET)
and polybutylene terephthalate (PBT) were investigated. Binary blends were
prepared comprising 10:90, 30:70, 50:50, 70:30 and 90:10 mass/mass%. The fracture
toughness was determined for each blend using the essential work of fracture
(EWF) method and thin film double edge notched tension (DENT) specimens. The
specific essential work of fracture, w
e,
values obtained for blends of PET/PPT ranged from 27.33 to 37.38 kJ m–2
whilst PBT/PPT blends yielded values ranging from 41.78 to 64.23 kJ m–2.
Differential scanning calorimetry (DSC) was employed to assess whether or
not crystallinity levels influence the mechanical properties evaluated. The
fracture toughness of PPT deteriorated with PET incorporation. However, high
we values exceeding that of pure PPT were obtained for PBT/PPT blends across
the composition range studied. 相似文献
9.
A. Zabaleta 《European Polymer Journal》2009,45(2):466-473
Rubber toughening of poly(ether imide) (PEI) has been elusive up to now due to the high processing temperature of PEI, which leads to degradation of the rubber. In this study, by profiting from the miscibility between PEI and poly(butylene terephthalate) (PBT), and the low Tg of PBT, we prepared a blend by melt extrusion with 20 wt% PBT in an attempt to render it toughenable by decreasing its Tg and processing temperature. The PEI-rich blend was subsequently mixed with maleic anhydride (0.9 wt%) grafted poly(ethylene-octene) copolymer (mPEO) up to 30 wt%. The decrease in Tg and processing temperature resulted in no observable degradation of the mPEO, and to the formation of a homogeneous morphology of rubber particles with a fine particle size, indicating that compatibilization was achieved. Upon rubber addition, stiffness decreased, while a very large toughness increase occurred with only 15% mPEO (impact strength more than 10-fold that of the PEI-PBT matrix). Upon observation of the fracture surface, the increase in impact strength was attributed partially to the cavitation and debonding of the rubber particles, and mostly to the deformation and yielding of the PEI-PBT matrix. 相似文献
10.
Flory-huggins interaction parameters of LCP/thermoplastic blends measured by DSC analysis 总被引:4,自引:0,他引:4
Xie X. L. Li R. K. Y. Tjong S. C. Tang C. Y. 《Journal of Thermal Analysis and Calorimetry》2002,70(2):541-548
Liquid crystalline polymer/polyamide 66 (LCP/PA66) and LCP/poly(butyl terephthalate) (LCP/PBT) blends were compounded using
a Brabender Plasticorder equipped with a mixing chamber. The LCP employed was a semi-flexible liquid crystalline copolyesteramide
based on 30 mol% of p-amino benzoic acid (ABA) and 70 mol% of poly(ethylene terephthalate) (PET). The Flory-Huggins interaction parameters (χ12)
of the LCP/ PA66 and LCP/PBT blends are estimated by melting point depression from DSC measurement. The results indicate that
c12 values all are negative for LCP/PA66 and LCP/PBT blends, and when the LCP content in these blends is more than 10 mass%,
the absolute value of χ12 decreases. Thereby, we can conclude that LCP/PA66 and LCP/PBT blends are fully miscible in the molten state, the molecular
interaction between the LCP and PA66 is stronger than that between LCP and PBT. As the LCP content in LCP/PA66 and LCP/PBT
blends is more than 10 mass%, the molecular interaction between LCP and matrix polymer decreases.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
Fully miscible poly(ether imide) (PEI)/poly(trimethylene terephthalate) (PTT) blends were obtained by melt mixing in an extruder followed by injection moulding. The viscosity of PEI, represented by the pressure at the extruder output, almost halved upon the addition of only 10% PTT, allowing the use of PEI in applications where either complex parts or thin sections must be moulded. The modulus of elasticity showed a synergistic behaviour which was absolute (modulus higher than that of any of the two components) in the blend with 10% PTT. This was attributed mainly to the decrease in specific volume upon blending. The additional absolute synergism in the yield stress of PEI‐rich blends and their ductile nature depict a set of properties that make these new materials attractive in a number of new applications. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
12.
By using wide-angle X-ray diffraction (WAXD), thermal analysis, scanning and optical microscopy, and nuclear magnetic resonance (NMR) analyses, this study has demonstrated that blends of two semicrystalline polyesters, poly(trimethylene terephthalate) and poly(ethylene naphthalate) (PTT/PEN), were initially immiscible in as-blended state. The process of blend phase/morphology changes upon extended heating/annealing at elevated temperatures was monitored and probed. With reactions induced at heating/annealing at high temperatures (300°C) for long enough times, the original two phases quickly merged into a single phase. NMR analyses have shown that the products of the transreactions are identified as the random copolyesters (termed as EN-TT). From the NMR results, statistical analyses revealed that the average sequence lengths decreased upon heating, and the degree of chain randomness increased with time of heating at the fixed temperature. Upon extended heating, all PTT and PEN chains could be fully transformed into random copolymers of higher randomness with only a single but amorphous phase. Results are compared to another blend system comprised of PEN and a homologous polyester, PPT, of different structure. Influence of polyester structure on transreactions and phase homogenization process is analyzed. 相似文献
13.
Zeynep Mutlu Mayank Jain Sung Ho Yook Mukerrem Cakmak 《Journal of polymer science. Part A, Polymer chemistry》2021,59(18):2045-2056
Mechano-optical behavior and related structural evolution during uniaxial stretching of melt miscible poly (ethylene terephthalate) (PET)/poly (ether imide) (PEI) blends were studied near their glass transition temperature using an instrumented machine that measures true stress, true strain and spectral birefringence simultaneously. Stretching from amorphous state, two distinct stress-optical regimes were observed at temperatures between Tg and Tcc (cold crystallization). Near Tg, a typical photoelastic behavior persists until a critical temperature above which temperature independent initial stress optical behavior is observed. At those temperatures above Tg, where glassy behavior is observed, decreasing stretching rate was also found to eliminate this glassy photo elastic regime leading to the observation of a linear initial stress optical behavior that becomes temperature independent as expected from linear stress optical rule. Increasing PEI concentration in the blends suppresses crystallizability and increases temperature at which initial elastic region disappears giving way to pure liquid behavior where linear stress optical behavior is observed. This is attributed to the increase and broadening of the glass transition temperature with the addition of noncrystallizable PEI. In PET/PEI blends, the stress-optical coefficient (SOC), determined in a linear stress optical regime, was found to increase linearly with the increase in PEI concentration. 相似文献
14.
Morphology control of sulfonated poly(ether ketone ketone) poly(ether imide) blends and their use in proton-exchange membranes 总被引:1,自引:0,他引:1
Polymer blends based on sulfonated poly(ether ketone ketone) (SPEKK) as the proton-conducting component and poly(ether imide) (PEI) as the second component were considered for proton-exchange membranes (PEMs). The PEI was added to improve the mechanical stability and lower the water swelling in the fuel cell environment. Membranes were cast from solution using N-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc). The ternary, polymer/polymer/solvent, phase diagram was determined to provide guidance on how to control the morphology during solvent casting of blend membranes.
For blends of SPEKK (ion-exchange capacity = 2 mequiv/g) with PEI as the minority component, the morphology consisted of dispersed particles of 0.5–6 μm. Larger particles were achieved by increasing the PEI content and/or lowering the casting temperature. High-temperature annealing after solution casting did not affect the morphology of blend membranes, due to the low mobility and compatibility of the two polymers.
The possible use of SPEKK/PEI blends in PEMs is discussed in terms of existing theories of ion transport in polymers. 相似文献
15.
The melting, crystallization, and self-packed ring patterns in the spherulites of miscible blends comprising poly(trimethylene
terephthalate) (PTT) and poly(ether imide) (PEI) were revealed by optical, scanning electron microscopies (PLM and SEM) and
differential scanning calorimetry (DSC). Morphology and melting behavior of the miscible PTT/PEI blends were compared with
the neat PTT. Ringed spherulites appeared in the miscible PTT/PEI blends at all crystallization temperatures up to 220 °C,
whereas at this high temperature no rings were seen in the neat PTT. A postulation was proposed, and interrelations between
rings in spherulites and the multiple lamellae distributions were investigated. The specific interactions and the segregation
of amorphous PEI were discussed for interpreting the morphological changes of 220 °C-melt-crystallized PTT/PEI samples. Interlamellar
segregation of PEI might be associated with multiple lamellae in the spherulites of PTT/PEI blends; therefore, rings were
more easily formed in the PTT/PEI blends at all crystallization temperatures. A postulated model of uneven lamellar growth,
coupled with periodical spiraling, more properly describes the possible origin of ring bands from combined effects of both
interactions and segregation between the amorphous PEI and PTT in blends. 相似文献
16.
Ya-Ting Hsieh Nai-Tzu Kuo Eamor M. Woo 《Journal of Thermal Analysis and Calorimetry》2012,107(2):745-756
Abstract
Thermal behavior, miscibility, and crystalline morphology in blends of low-molecular-weight poly(l-lactic acid) (LMw-PLLA) or high-molecular-weight PLLA (HMw-PLLA) with various polyesters such as poly(butylene adipate) (PBA), poly(ethylene adipate) (PEA), poly(trimethylene adipate) (PTA), or poly(ethylene succinate) (PESu), respectively, were explored using differential scanning calorimeter (DSC), and polarized-light optical microscopy (POM). Phase behavior in blends of PLLA with other polyesters has been intriguing and not straight forward. Using a low- and high molecular weight PLLA, this study aimed at mainly using thermal analyses for probing the phase behavior, phase diagrams, and temperature dependence of blends systems composed of PLLA of two different molecular weights (low and high) with a series of aliphatic polyesters of different structures varying in the (CH2/CO) ratio in main chains. The blends of LMw-PLLA/PEA and LMw-PLLA/PTA show miscibility in melt and amorphous glassy states. Meanwhile, the LMw-PLLA/PESu blend is immiscible with an asymmetry-shaped upper critical solution temperature (UCST) at 220–240 °C depending on the blend composition. In contrast to miscibility in LMw-PLLA/PTA and LMw-PLLA/PEA blends, HMw-PLLA with polyesters are mostly immiscible; and HMw-PLLA/PTA blend is the only one showing an asymmetry-shaped UCST phase diagram with clarity points at 195–235 °C (depending on composition). Reversibility of UCST behavior, with no chemical transreactions, in these blends was proven by solvent recasting, gel permeation chromatography, and Fourier transform infrared spectroscopy (FT-IR). Crystalline morphology behavior of the LMw-PLLA/PEA and LMw-PLLA/PTA blends furnishes addition evidence for miscibility in the amorphous phase between LMw-PLLA and PTA or PEA. 相似文献17.
Polymer miscibility has been discovered in a blend system comprising poly(ether imide) (PEI) and a new poly(ether diphenyl
ether ketone) (PEDEK). The miscibility of the PEDEK/PEI polymer system (quenched from the molten state) was investigated in
this study using differential scanning calorimetry and Fourier transform (FT-IR) spectroscopy. A composition-dependent single
glass-transition temperature (T
g) in the PEDEK/PEI blends over a full composition range was observed; the sharp transition width and the T
g–composition relationship both suggest that the scale of mixing is fine and uniform. Evidence based on observation of the
cold-crystallization peak and suppression of the blend crystallinity and melting peak also indicated intimate intermolecular
mixing. The FT-IR result yielded further evidence that the physical interactions leading to miscibility were weak, with no
apparent specific interactions between the constituent polymers. Relationships between structures and interactions responsible
for the miscibility in PEI and several ether-ketone-type polymers are briefly discussed.
Received: 8 July 1999 Accepted in revised form: 21 October 1999 相似文献
18.
M. Soccio N. Lotti L. Finelli M. Gazzano A. Munari 《Journal of Polymer Science.Polymer Physics》2008,46(2):170-181
Poly(propylene/neopenthyl terephthalate) random copolymers (PPT‐PNT) and poly(neopenthyl terephthalate) (PNT) were synthesized and subjected to molecular characterization. Afterwards, the polyesters were examined by TGA, DSC, andX‐ray. The copolymers, which displayed a good thermal stability, at room temperature appeared as semicrystalline materials: the main effect of copolymerization was a lowering in the amount of crystallinity and a decrease of the melting temperature with respect to homopolymer PPT. XRD measurements allowed the identification of the PPT crystalline structure in all cases. Amorphous samples were obtained after melt quenching, with the exception of PPT‐PNT5, and an increment of Tg as the content of NT units is increased was observed due to the effect of the side methylene groups in the polymeric chain. The Wood equation described well Tg‐composition data. Lastly, the presence of a rigid‐amorphous phase was evidenced in the copolymers, whose amount depended on composition and on thermal treatment. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 170–181, 2008 相似文献
19.
L. Vincent S. N. Connolly F. Dolan P. H. Willcocks S. A. A. Jayaweera R. Pendlebury 《Journal of Thermal Analysis and Calorimetry》2006,86(1):147-154
The essential work of fracture
(EWF) method has been used to study the relationship between molecular structure
and thin film fracture toughness for three ductile polyesters at ambient temperature.
The fracture toughness of PPT is of particular interest. Successful fracture
characterisation of thin film polyesters has been achieved by the EWF method
using double edge notched tension (DENT) specimens. The specific essential
work of fracture, w
e,
for polyethylene terephthalate (PET), polypropylene terephthalate (PPT) and
polybutylene terephthalate (PBT) films is found to be 35.54±2.56, 41.03±3.23
and 31.34±8.60 kJ m–2, respectively.
Differential scanning calorimetry (DSC) has been employed to investigate the
crystallinity of the polymers concerned and the effect of this on their EWF
values. 相似文献
20.
Poly(pentamethylene terephthalate) (PPT), a less studied aryl polyester, was synthesized by polycondensation and characterized by 1H NMR and gel permeation chromatography. The crystallization kinetics were investigated by means of differential scanning calorimetry and polarized light microscopy. The average value of the Avrami exponent was calculated to be 2.9, which indicated an athermal nucleation process followed by three‐dimensional crystal growth. The kinetics of spherulitic growth of PPT were analyzed with the Lauritzen–Hoffman (L–H) secondary nucleation theory, and the nucleation constants (Kg) for regimes II and III were thus determined from the slope of the L–H plot with an activation energy (U*) of 3500 cal/mol. The validity of the U* value was examined. Meanwhile, the existence of a transition from regime II to regime III at 95 °C was determined, and the value of Kg(III)/Kg(II) was 2.04. The equilibrium melting temperature of PPT was estimated to be 149.4 °C with the linear Hoffman–Weeks extrapolation method. The lateral surface free energy, fold surface free energy, and work of chain folding were estimated. These thermodynamic properties of PPT were then compared to those of other terephthalic polyesters. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1265–1274, 2004 相似文献