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91.
Rheological, morphological and thermo-mechanical responses of poly(lactic acid) (PLA)/ethylene-co-vinyl-acetate copolymer (EVA) blends at EVA volume fractions varying in the range of 0–0.35 were evaluated. The micro-structural analysis demonstrated dispersive mixing at low content and co-continuous morphology at 30 wt % of EVA in PLA. Dynamic rheology demonstrated enhanced storage modulus and complex viscosity (η*) with increase in frequency of the blends indicated strong phase interaction. Cole-Cole and Han plots indicated partial miscibility and incompatibility between the polymer matrix and the dispersed phase. Dynamic mechanical analysis (DMA) revealed slight increase in damping parameters which indicated interaction or reinforcement in the blends. Additionally, the thermogravimetric analysis (TGA) of the blends showed two step degradation and enhanced thermal stability. 相似文献
92.
93.
The compatibility between isotactic polypropylene(i PP) and ethylene-propylene-diene terpolymer(EPDM) in the blends was studied. SAXS analysis indicates that i PP and EPDM phases in the binary blend are incompatible. Isothermal crystallization behaviors of i PP in phase-separated i PP/EPDM were studied by in situ POM equipped with a Linkam shear hot stage. It was found that typical spherulites of i PP were formed both in neat i PP and in i PP/EPDM blends. The radial growth rate(d R/dt) of spherulites of i PP in the blend was not influenced by EPDM phases. Further investigations on isothermal crystallization of i PP in i PP/EPDM after shear with a fixed shear time showed that the crystallization rate of i PP in the blends increased with increasing shear rates, whereas, the crystallization rate was much lower than that of neat i PP. WAXD results showed that ?-crystal i PP was formed in neat i PP as well as in i PP/EPDM blends after shearing and the percentage of ?-crystal bore a relationship to the applied shear rate. The presence of EPDM resulted in lower percentage of ?-crystal in the blends than that in neat i PP under the same constant shear conditions. SAXS experiments revealed that shear flow could induce formation of oriented lamellae in i PP and i PP in the blends, and the presence of EPDM led to a reduced fraction of oriented lamellae. 相似文献
94.
Crystallization kinetics and morphology of poly(vinylidene fluoride)/poly(ethylene adipate) blends 总被引:1,自引:0,他引:1
The miscibility, isothermal crystallization kinetics and morphology of the poly(vinylidene fluoride)(PVDF)/poly(ethylene adipate)(PEA) blends have been studied by differential scanning calorimetry(DSC), optical microscopy(OM) and scanning electron microscopy(SEM). A depression of the equilibrium melting point of PVDF was observed. From the melting point data of PVDF, a negative but quite small value of the interaction parameter ?PVDF-PEA is derived using the Flory-Huggins equation, implying that PVDF shows miscibility with PEA to some extent. Nonisothermal and isothermal crystallization kinetics suggest that the crystallization rate of PVDF decreases with increasing the amount of PEA, and a contrary trend was found when PEA crystallizes with the increase of the amount of PVDF. It was further disclosed that the blend ratio and crystallization temperature affect the texture of PVDF spherulites greatly, which determines the subsequent crystallization of PEA. At high temperatures, e.g. 150 ℃, the band spacing of PVDF spherulites increases with the addition of PEA content and the spherulitic structure becomes more open. In this case, spherulitic crystallization of PEA is not observed for all blend compositions. At low temperatures, e.g. 130 ℃, for the PEA-rich blends, the interpenetrated structures are eventually formed by the penetration of the spherulites of PEA growing within the pre-existing PVDF spherulites. 相似文献
95.
96.
97.
Electrorheological properties and creep-recovery behavior of polythiophene/polyoxymethylene-blend having PT(50%)/POM(50%) composition were investigated.Particle size,conductivity and dielectric values were measured to be 24.77μm,3.85×10-5 S·m-1 and 26.75,respectively.Sedimentation ratio was measured to be 64%at the end of 16 days.The effects of dispersed particle volume fraction,external electric field strength,shear rate,frequency and temperature on ER properties and storage modulus of PT/POM-blend/silicone oil(SO) suspensions were examined.Enhancement were observed in the electric field viscosities of the suspensions and thus they were classified as a smart material.Shear thinning non-Newtonian viscoelastic behavior was determined for PT/POM-blend/SO system.Further,time-dependent deformation was examined by creep-recovery tests and recoverable viscoelastic deformation established. 相似文献
98.
Polyethylene blends were studied by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Binary blends of commercial linear polyethylene (LPE) with two low-density polyethylenes (LDPEs) of melt indexes, about 20 and about 0.27 g/10 minutes, were investigated. The blends, with 10% and 50% LPE contents, and the pure LPE were isothermally crystallized at 124°C for up to 48 h under solid-liquid phase segregation conditions. Double melting endotherms were obtained for the blends. Results show that, despite differences in crystallization kinetics between both types of blends, the same depression in the LPE melting temperature and approximately the same LPE crystal thicknesses were found for the blend compositions. In addition, the extent of occurrence of lamellar thickening in LPE during crystallization is a function of its content in the blend. 相似文献
99.
To enhance the impact strength of polyamide 6,hydrolytic polymerization modification by the polyaminoamide-gpoly (ethylene glycol)(PAAEG)derivatives with poly(ethylene glycol)(PEG)molecular weight of 400-10000 was studied. Amide groups of polyaminoamide segments were postulated to form hydrogen bonding with polyamide 6,and hydroxy groups of PAAEG units were expected to react with carboxylic acid groups of polyamide 6 forming copolymers during the polymerization.The improved compatibility in amorphous reg... 相似文献
100.
聚L-乳酸/聚(天冬氨酸-co-乳酸)共混物的制备及其相容性研究 总被引:1,自引:0,他引:1
采用氯仿/乙醇共沸溶液浇铸法制备了混合均匀的聚L-乳酸/聚(天冬氨酸-co-乳酸)共混物(PLLA/PAL)体系.研究了PLLA/PAL共混体系的热性能、结晶行为、形态结构和力学性能,评价了PLLA和PAL之间的相容性.结果表明,PAL对PLLA的结晶行为和热性能产生了较大的影响,共混物的结晶度较低,共混体系中部分PAL会进入PLLA球晶的片晶而导致PLLA球晶结构不完善,熔点降低.PAL的含量小于20%的PLLA/PAL共混物的拉伸强度和断裂延伸率均高于纯PLLA.PLLA和PAL分子链相互缠结,产生的氢键使分子链间存在较强的相互作用,具有较好的相容性. 相似文献