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1.
合成了端异氰酸酯/环氧丙烯酸树脂互穿网络聚合物,在环氧树脂交联网络中引入柔性链段,达到增韧的目的。通过改变端异氰酸酯和环氧丙烯酸树脂的组分比,合成不同组成的互穿网络聚合物(IPNs)。借助红外光谱和扫描电镜等分析方法,研究了IPNs的分子混合形态结构。同时采用差热分析法(DSC)测试了聚合物的玻璃化转变温度,结果表明:端异氰酸酯预聚体含量越高,聚合物的玻璃化转变温度越低。对成膜物的力学性能研究表明,INPs的拉伸强度在端异氰酸酯/环氧丙烯酸树脂比例为30:70时,拉伸强度为55.24 MPa,是纯环氧树脂的2.5倍。 相似文献
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Marco Sangermano William Carbonaro Roberta Bongiovanni Richard R. Thomas Charles M. Kausch 《大分子材料与工程》2010,295(5):469-475
A fluorinated acrylic resin was synthesized for use as a co‐monomer with a commercially available epoxy resin for UV‐cured interpenetrating polymer network preparation. Hybrid IPN networks were achieved with morphology ranging from a co‐continuous IPN to complete phase separation simply by changing monomer ratios. Highly hydrophobic coatings with good adhesion properties on glass substrates were obtained.
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Various numbers of diphenyl-siloxane groups were incorporated in α,ω-bis(aminopropyl)polydimethylsiloxane (APPS) to prepare
α,ω-bis(aminopropyl)-polydimethyldiphenylsiloxane (APPPS) oligomers of three different number-average molecular weights(Mn
= 547,772,1210 g mol−1).These APPPS oligomers were than used, together with 3,3′,4,4′-bezonphenone tetracarboxylic dianhydride (BTDA) and 2-2′-bis[4-(3-aminophenoxy)phenyl]
sulfone (m-BAPS), to synthesize a series of APPPS containing poly(imide siloxane) (PIS) copolymers. Microstructural studies
showed that at certain APPPS content, a critical microphase separation point existed, beyond which, microphase separation
began to develop. This critical point of microphase separation was found to be affected by the Mn of the APPPS oligomers (8.0,
4.3 and 2.1 mol% for Mn of 547, 772 and 1,210 g mol−1, respectively). Diphenyl-siloxane significantly improved compatibility between polyimide and polysiloxane segments. Physical
studies showed that the introduction of diphenyl siloxane changed the thermal stabilities and mechanical properties of the
PIS copolymers. These findings have potential applications for design purposes in engineering polymers. 相似文献
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Epoxy anhydride networks were modified with Siloxane/PMMA hybrid materials, obtained from sol/gel method. The effects of thermal annealing of the Siloxane/PMMA hybrids and of the hybrid composition on the nanostructure of the epoxy network were investigated by means of SAXS. The composites containing Siloxane/PMMA materials with low amount of MMA present a hierarchical nanostructure whose first level is made of siloxane nanoparticles spatially correlated in the matrix forming larger secondary hybrid aggregates. Small amounts of hybrid material decrease the glass temperature of the composite, but increase the storage modulus, indicating its nanoreinforcing action.
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《国际聚合物材料杂志》2012,61(9):681-702
Poly(ether ether ketone) (PEEKDT), hydroxyl terminated poly(ether ether ketone) (PEEKDTOH) and fluorine terminated poly (ether ether ketone) (PEEKDTF) with pendent ditert-butyl groups were synthesized by the nucleophilic substitution reaction of 4,4′-difluorobenzophenone with 2,5-ditert-butylhydroquinone in N-methyl-2-pyrrolidone medium using anhydrous potassium carbonate as catalyst. Diglycidyl ether of bisphenol-A epoxy resin was blended with PEEKDT, PEEKDTOH, and PEEKDTF, and cured with 4,4′-diaminodiphenylsulfone (DDS). The polymers formed heterogeneous blends before curing, and upon curing the polymers got dispersed in the epoxy matrix. The mechanical properties of the cured blends were slightly lower than that of the unmodified resin. The fracture toughness increased with the addition of ditert-butyl PEEK into epoxy resin and the extent of improvement was dependent on the type of modifier used. Hydroxyl terminated polymers gave up to 40% increase in fracture toughness. The dynamic mechanical spectrum of the blends showed only a single Tg due to the proximity of the glass transition temperature of modified PEEK and DDS cured epoxy resin. 相似文献
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Hyperbranched poly(trimellitic anhydride ethylene glycol) epoxy (HTME) not only has relatively low viscosity and high molecular weight but also is a functional additive of enhancement and toughness and is used in the thermosetting resin field widely. The curing kinetics and thermal degradation kinetics of HTME/diglycidyl ether of bisphenol-A epoxy hybrid resin were studied in detail using differential scanning calorimetry and thermogravimetric analysis technique, respectively, by the Coats-Redfern model. The effect of molecular weight or generation and content of HTME on activation energy, reaction order, curing time, and curing reaction were discussed and analyzed, and the results indicated that HTME could accelerate curing reaction and reduce activation energy and reaction order of the curing reaction. 相似文献
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Polysulphones with cross-linkable pendant vinylbenzyl groups (PSF-VB) were prepared via chloromethylation of commercial polysulphones. The curing reactivity of PSF-VB was investigated by differential scanning calori-metry. Interpenetrating polymer networks (IPNs) were prepared based on bisphenol A diglycidyl ether (DGEBA) and PSF-VB, where DGEBA was cured by 4,4′-diaminodiphenyl sulphone and VB groups of PSF-VB were radically polymerized using dicumyl peroxide (DCP). Polysulphones having pendant benzyl groups (PSF-Bz) were also prepared and used as non-reactive modifiers. The fracture toughness (KIC) for the resulting epoxy/PSF-VB IPN increased by 65% with no loss of mechanical properties on 10wt% addition of PSF-VB (7·9mol% VB unit, MW 74000). Non-reactive PSF-Bz was less effective than PSF-VB. Although the PSF-Bz modified resin had a particulate structure, the morphologies of the PSF-VB/epoxy IPNs were not clear from scanning electron micrographs. Furthermore, the epoxy/PSF-VB IPNs had higher solvent resistance than the epoxy/PSF-Bz blends. Morphological behaviour, modification results and high solvent resistance of the cured epoxy/PSF-VB resins indicate that cross-linked PSF-VB and the epoxy network entangled fully in the presence of DCP. © of SCI. 相似文献
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Hsiu-Jung Chiu 《Journal of Polymer Research》2002,9(3):169-174
Spherulitic morphology and crystallization kinetics of the blends of poly(vinylidene fluoride) (PVDF) and poly(vinyl acetate) (PVAc) prepared by solution casting films have been investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results suggested that PVAc was mainly segregated into the interlamellar and/or interfibrillar regions due to the volume-filling spherulitic morphology observed. As for the results of crystallization kinetics, it was found that both the PVDF spherulitic growth rate (G
PVDF) and the overall crystallization rate constant (k
n
) were depressed with either the addition of PVAc component or the increase of crystallization temperature (T
c). The kinetics retardation was attributed to the decrease in PVDF molecular mobility and dilution of PVDF concentration due to the addition of PVAc, which has a higher glass transition temperature (T
g). 相似文献
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A new kind of binary polymer brushes was synthesized from two immiscible polymers, PMMA and PEG, on GPS‐modified silicon wafers. Surface composition, layer thickness, coverage, chain density, wetting ability, morphology and protein adsorption of the binary brushes were investigated by XPS, ellipsometry, AFM and contact angle measurements. The results show that both PMMA and PEG were successfully grafted onto the surface. The surface coverage and the chain density of PMMA and PEG brushes can be controlled by modulating the reaction temperature and time. This kind of binary polymer brushes exhibits a distinct microphase‐separated structure and excellent protein‐preventing property.
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The lamellar morphology of a melt-miscible blend consisting of two crystalline constituents, poly(3-hydroxybutyrate) (PHB) and poly(ethylene oxide) (PEO) have been investigated by means of small angle X-ray scattering (SAXS). The blend was a crystalline/amorphous system when temperatures lay between the melting point of PEO (ca. T
m
PEO=60C) and that of PHB (ca. T
m
PHB=170C), while it became a crystalline/crystalline system below T
m
PEO. The crystalline microstructures of the blends were induced by two types of crystallization history, i.e. one-step and two-step crystallizations. In the one-step crystallization, the blends were directly quenched from the melt to room temperature to allow simultaneous PHB and PEO crystallization. The two-step crystallization involved first cooling to 70C to allow PHB crystallization for 72 h followed by cooling to room temperature (ca. 19C) to allow PEO crystallization. In the crystalline/crystalline state, two scattering peaks have been observed in the Lorentz-corrected SAXS profiles, irrespective of the crystallization histories, meaning that crystallization created separate PHB and PEO lamellar stack domains. One-step crystallization yielded lamellar stack domains containing almost pure PHB and PEO lamellae. Two-step crystallization generated almost pure PHB lamellar domains and the PEO lamellar domains with inserted PHB lamellae. In the crystalline/amorphous state, the composition dependence of the amorphous layer thickness (l
a), the presence of zero-angle scattering, and the volume fraction of the PHB lamellar stack (s) revealed that both one-step and two-step crystallizations, generated the interfibrillar segregation morphology, where the extent of interfibrillar segregation of amorphous PEO increased with increasing PEO content. 相似文献
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用DSC法研究环氧树脂/环氧封端酚酞聚芳醚腈的固化特性 总被引:4,自引:0,他引:4
利用差示扫描量热法研究了AG - 80环氧树脂和环氧封端酚酞聚芳醚腈 (简称E -PCE)共混物中固化剂含量对树脂基体固化反应温度、反应热的影响。此共混环氧树脂基体的最低固化反应温度为1 61 .3℃ ,固化反应表观活化能为 60 .66kJ/mol,固化反应级数为 0 .875。 相似文献
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The lamellar morphology of a melt-miscible blend consisting of random poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(HB-co-HV)) copolymer containing 10 mol% HV units and poly(methyl methacrylate) (PMMA) prepared by solution casting films have been investigated by means of small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and polarized optical microscope (POM). The composition dependence of the amorphous layer thickness (la), and the volume fraction of the P(HB-co-HV) lamellar stack (φs) revealed that the interfibrillar segregation morphology was generated, where the extent of interfibrillar segregation of PMMA increased with increasing PMMA content. The Lorentz-corrected SAXS profiles of the blends crystallized at Tc=40 ○C has observed “zero-angle scattering”, attributed to the electron density contrast between the lamellar stack domains consisting of alternating crystalline/amorphous layers and the PMMA-rich domains located outside the lamellar stack domains. 相似文献
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Toshikazu Kobayashi Barbara A. Wood Gregory S. Blackman Akio Takemura 《应用聚合物科学杂志》2011,120(6):3519-3529
Bio‐based PTT and PTT blends with PEEA of two different ion contents (275 ppm Na and 3515 ppm Na) and PEG 400 bis (2‐ethylhexanoate) were prepared by melt processing. The blends were characterized by differential scanning calorimetry, dynamic mechanical analysis, transmission electron microscopy, and atomic force microscopy. Electro‐static performance was also investigated for those PTT blends since PEEA is known as an ion conductive polymer. Here we confirmed that PEG 400 bis (2‐ethylhexanoate) improves the static decay performance of PTT/PEEA blends. DMA strongly suggests that PEG 400 bis (2‐ethylhexanoate) and PEEA are miscible pairs, and PEG 400 bis (2‐ethylhexanoate) selectively goes into the PEEA phase rather than the PTT phase, which lowers the Tg of PEEA. Besides topographic analysis of morphology and phase separation, tunneling atomic force microscopy was also applied to see if we can observe the surface directly for the static dissipative material. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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The preparation of polyurethane/poly(bismaleimide–urethane bismaleimide) [PU/P(BMI–UBMI)] IPNs were carried out in two steps. The two-network interaction and the morphology of PU/P(BMI–UBMI) IPNs were characterized by FTIR and TEM. The effect of the interpenetration of P(BMI–UBMI) and PU on the hydrogen bonds of N—H and the pyrolysis procedure of PU/P(BMI–UBMI) IPNs were investigated by DSC and TG. The results indicate that the interpenetration of P(BMI–UBMI) and PU reinforces the hydrogen bonding of N—H, and the incorporating of UBMI enhances the compatibility of the two networks, leading to ideal interpenetrating, which weakens the force constant of C—N—C in maleimide rings. The morphology of PU/P(BMI–UBMI) IPNs shows multiphase domains which have an obvious phase interface. The domains are connected to each other and the domain dimensions are far smaller than those of PU. The thermal weight loss shows obvious stages at different pyrolysis periods. The thermal stability of PU/P(BMI–UBMI) IPNs are much better than that of PU given the content and crosslink density of P(BMI–UBMI) in a certain range. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1689–1694, 1998 相似文献
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用等温差示扫描量热法和红外光谱(FT-IR)研究了聚苯醚(PPE)/环氧树脂(EP)体系的固化反应,得出了固化反应程度与反应时间的关系曲线,结果表明在所研究的温度范围内,等温固化温度越高,PPE/EP体系的反应速率越快,最终的反应程度越高.红外的研究结果表明,在180℃固化2 h后,EP不能固化完全,这是由于在固化过程中,伴随着体系的凝胶及EP分子量的逐步增加,引起体系的粘度增大所致.采用扫瞄电子显微镜和综合热分析仪,分别研究了PPE/EP混合物固化材料的形态和耐热性.研究结果表明在PPE/EP体系中加入TAIC(triallylisocyanurate)可有效地提高体系的耐化学药品性,但体系的耐热性也将随着TAIC的加入降低;PPE/EP混合物的耐热性随着PPE含量的增加而提高. 相似文献