Morphology and Properties of Poly(propylene)/Ethylene‐Octene Copolymer Blends Containing Nanosilica

The effect of nanosilica addition on the morphology and mechanical properties of blends of isotactic PP and an ethylene/octene copolymer (EOC) is studied. TEM reveals that the well‐dispersed nanoparticles are localized exclusively in the PP phase. In the presence of a maleated PP compatibilizer addition of nanosilica leads to more finely dispersed EOC domains and a finer co‐continuous morphology. The nanoparticles reduce the rate of coalescence of the dispersed phase domains. The mechanical properties depend on the EOC and PP‐g‐MA content. Tensile and flexural properties are significantly enhanced in the presence of the silica nanoparticles, whereas impact properties are not affected. These enhancements are attributed to the favorable microstructure of the blends.

     

Compatibilization of Poly(propylene)/Polyamide 6 Blends with Functionalized Poly(propylene)s Prepared with Metallocene Catalyst

Summary: Propylene was copolymerized with 10‐undecen‐1‐ol using dimethylsilanylbis(2‐methyl‐4‐phenyl‐1‐indenyl)zirconium dichloride as catalyst and MAO and TIBA as cocatalysts. Comonomer incorporations from 0.1 to 0.9 mol‐% (0.5 to 3.6 wt.‐%) were obtained. These hydroxyl functionalized copolymers were applied as compatibilizers to PP/PA6 blend with a composition of 70/30. For comparison, hydroxyl functionalized polyethylene prepared with metallocene catalyst and commercial MAH grafted ethylene butyl acrylate (E/BA/MAH) and poly(propylene) (PP‐g‐MAH) were also used as compatibilizers. Effects of the compatibilizers on morphology and mechanical and thermal properties of the blends were studied. Enhanced adhesion between the blend components was observed in morphology and dynamic mechanical studies. Although improvement in toughness was not as pronounced as expected, there were indications that the hydroxyl functionalized propylene copolymers prepared with metallocene catalysts could serve as a new type of compatibilizer in polymer blends.

SEM micrograph (5 000×) of an PP/PA6/PP‐co‐OH4 blend.     

Effect of Boehmite Alumina Nanofiller Incorporation on the Morphology and Thermal Properties of Functionalized Poly(propylene)/Polyamide 12 Blends

A composite of boehmite alumina nanoparticles and a PP/PA12 blend is prepared. WAXD and SEM suggest that a low filler loading enhances the coalescence of PA12, whereas a higher loading reverses the situation. DSC, DMA and TGA reveal that the final properties of the blend composites such as crystallization temperatures, flexural storage moduli, or thermal degradation temperatures improve with increasing nanoparticle loading. The data are compared with the neat polymers and the compatibilized blend, and the results show that the compatibility increases only at high nanoparticle loading, and most of the thermal properties improve with increasing nanoparticle content in the blends. The presence of interfacial interactions between the polymer matrices and the filler was confirmed via FTIR.

     

Compatibilization of Polyamide‐6/Polyarylate Blends by Means of an Ionomer

Summary: Polyamide‐6 (PA6)/polyarylate of bisphenol A (PAr) blends rich in PA6 and modified with an additional 15% poly[ethylene‐co‐(methacrylic acid)] partially neutralized with zinc (PEMA‐Zn) as a compatibilizer were obtained by melt mixing. Their phase structure, morphology, and mechanical performance were compared with those of the corresponding binary blends. The ternary blends were composed of a PA6 amorphous matrix and a dispersed PAr‐rich phase in which reacted PA6 and PEMA‐Zn were present. Additionally, minor amounts of a crystalline PA6 phase, and a PEMA‐Zn phase were also present. The chemical reactions observed led to a clear decrease in the dispersed particle size when PEMA‐Zn was added, indicating compatibilization. Consequently, the mechanical behavior of the blends with PEMA‐Zn improved, leading, mainly in the case of the blend with 10% PAr, to significant increases in both ductility and impact strength with respect to those of the binary blends. These increases were more remarkable than the slight decrease in stiffness as a consequence of the rubbery nature of the compatibilizer.

Cryogenically fractured surface of the PA6/PAr‐PEMA‐Zn 70/30‐15 ternary blend.     

聚苯醚与尼龙6共混物的增容改性

以PPE／PA6共混物为基体,进行性能与结构的表征,对比了不同PPE／PA6比例的共混物性能以及添加增容改性树脂、增韧剂的使用效果。结果表明,增容改性树脂可使得PPE树脂粒子变得均匀,在提高共混材料的韧性的同时,改善了材料的拉伸性能;而弹性体虽可以提高PPE与PA6的共混物的冲击性能,但拉伸性能下降;添加5％增容改性树脂有助于改善玻纤增强PPE／PA6材料的力学性能。     

Effect of Organoclay on the Morphology and Properties of Poly(propylene)/Poly[(butylene succinate)‐co‐adipate] Blends

The effect of organically modified clay on the morphology and properties of poly(propylene) (PP) and poly[(butylene succinate)‐co‐adipate] (PBSA) blends is studied. Virgin and organoclay modified blends were prepared by melt‐mixing of PP, PBSA and organoclay in a batch‐mixer at 190 °C. Scanning electron microscopy studies revealed a significant change in morphology of PP/PBSA blend in the presence of organoclay. The state of dispersion of silicate layers in the blend matrix was characterized by X‐ray diffraction and transmission electron microscopic observations. Dynamic mechanical analysis showed substantial improvement in flexural storage modulus of organoclay‐modified blends with respect to the neat polymer matrices or unmodified blends. Tensile properties of virgin blends also improved in the presence of organoclay. Thermal stability of virgin blends in air atmosphere dramatically improved after modification with organoclay. The effect of organoclay on the melt‐state liner viscoelastic properties of virgin blends was also studied. The non‐isothermal crystallization behavior of homopolymers, virgin, and organoclay‐modified blends were studied by differential scanning calorimeter. The effect of incorporation of organoclay on the cold crystallization behavior of PP/PBSA blends is also reported.

     

PP-g-(MAH/VAc)接枝物对PP/PA6体系的增容作用

通过扫描电镜、差示扫描量热仪和力学性能测试等方法研究了聚丙烯接枝马来酸配和酷酸乙烯酷(PP-g-MAH/VAc)对聚丙烯康酸胺6(80/20}共混体系的增容效果。结果表明,PP-g-(MAH/DAc)用于PP/PA6共混体系,分散相PA6的微区尺寸可以减小到5μm以下,相应地提高了共混物的断裂伸长率、拉伸强度和冲击强度。使用接枝率为5.3%的PP-g-(MAH/VAc)作为相容剂,当用量为8%时,体系的拉伸强度为60.88MPa,断裂伸长率为558%,冲击强度为5.28KJ/㎡.DSC分析表明,PP/PA6共混体系各组分相互促进成核,结晶度降低。FTIR结果表明,PP-g-(MAH/VAc)中的MAH上的酸配基团与PA6中的酸胺键发生了化学反应从而改善了体系的相容性。     

Use of Monomethyl Itaconate Grafted Poly(propylene) (PP) and Ethylene Propylene Rubber (EPR) as Compatibilizers for PP/EPR Blends

The use of grafted poly(propylene) (PP) and a random copolymer of ethylene and propylene (EPR) with an itaconic acid derivative, monomethyl itaconate (MMI), as compatibilizer for PP/EPR blends was analyzed. The grafting reaction was performed at 190 °C in a Brabender Plasticorder. 2,5‐Dimethyl‐2,5‐bis(tert‐butylperoxy) hexane was the radical initiator for the functionalization of PP; dicumyl peroxide was used as the radical initiator for the modification of EPR. The obtained degree of grafting was 1.5% by weight for PP and 1.2% by weight for EPR. The compatibilizing effect of modified polymers on the processability, morphology, and mechanical and thermal properties of the blends was of interest. Compatibilization substantially improved the toughness and deformation with little effect on the tensile modulus and strength. Moreover, this effect was particularly evident when both polymeric phases were grafted. Regarding compatibilization, the viscosity of the blends increased due to the high interfacial adhesion. Morphological studies showed that the particle size of the rubbery phase was reduced and the dispersion in the matrix improved by compatibilization. The grafted polymers behaved as nucleating agents, accelerating the PP crystallization.

Change in complex viscosity with angular frequency at 180 °C for unmodified and MMI‐functionalized PP/EPR (70/30) blends.     

Morphology and properties of nylon 6 and high density polyethylene blends in presence of nanoclay and PE‐g‐MA

In this study, we report the synergistic effect of nanoclay and maleic anhydride grafted polyethylene (PE‐g‐MA) on the morphology and properties of (80/20 w/w) nylon 6/high density polyethylene (HDPE) blend. Polymer blend nanocomposites containing nanoclay with and without compatibilizer (PE‐g‐MA) were prepared by melt mixing, and their morphologies and structures were examined with scanning electron microscopy (SEM) and wide angle X‐ray diffractometer (WAXD) study. The size of phase‐separated domains decreased considerably with increasing content of nanoclay and PE‐g‐MA. WAXD study and transmission electron microscopy (TEM) revealed the presence of exfoliated clay platelets in nylon 6 matrix, as well as, at the interface of the (80/20 w/w) nylon 6/HDPE blend–clay nanocomposites. Addition of PE‐g‐MA in the blend–clay nanocomposites enhanced the exfoliation of clays in nylon 6 matrix and especially at the interface. Thus, exfoliated clay platelets in nylon 6 matrix effectively restricted the coalescence of dispersed HDPE domains while PE‐g‐MA improved the adhesion between the phases at the interface. The use of compatibilizer and nanoclay in polymer blends may lead to a high performance material which combines the advantages of compatibilized polymer blends and the merits of polymer nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Morphological and Rheological Properties of Polyamide 6/Poly(propylene)/Organoclay Nanocomposites

Summary: Polyamide 6 (PA6)/Poly(propylene) (PP)/organoclay (octadecylamine intercalated montmorillonite) systems with and without compatibilizer (maleated poly(propylene) and ethylene/propylene‐based rubber (PPgMA and EPRgMA, respectively)) were produced by extrusion melt blending and the clay dispersion was characterized by transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The rheological behaviour of the nanocomposites was determined by various methods, viz melt flow index (MFI), capillary and plate/plate rheological measurements. Attempts were made to trace the rheological parameters that reliably reflect the observed changes in the clay dispersion. It was found that some parameters in the viscoelastic range derived from frequency sweep measurements using a plate/plate rheometer are a suitable indicator for changes in the clay dispersion. High initial viscosity with a strong reduction as a function of frequency was attributed to improved clay exfoliation. The latter was also reflected by a high initial shear storage modulus (G′) along with its small change with the frequency.

Variation of the storage modulus (G′) as a function of frequency for the PA6/PP nanocomposites. Note: this figure also indicates how the slopes at low and high shear rates were determined.     

Miscibility and Crystallization Behaviors of Polyamide 6/Polytetrafluoroethylene Blends

Summary: The miscibility and crystallization behaviors of polyamide 6 (PA 6)/polytetrafluoroethylene (PTFE) blends, prepared via reactive extrusion, are systematically investigated by means of wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). WAXD measurements show that no co‐crystallization occurred between two components, while DSC and DMTA measurements suggest that a certain degree of miscibility between them might exist due to the formation of some copolymers during the reactive extrusion.

DMTA curves for the pure PA 6 sample and PA 6/PTFE blends with various compositions.     

聚酰胺类热塑性弹性体含量对PLLA/三元聚酰胺共混物形态和性能的影响

以聚酰胺类热塑性弹性体（TPAE）为增容剂增容左旋聚乳酸（PLLA）与三元聚酰胺共混物,采用扫描电子显微镜（SEM）、差热扫描量热仪（DSC）、X射线衍射仪（XRD）等研究了TPAE含量对PLLA/三元聚酰胺（70/30,质量比,下同）共混物的形态、力学性能和热性能的影响。力学性能研究结果表明,添加TPAE后,PLLA/三元聚酰胺共混物的拉伸强度、断裂伸长率、缺口冲击强度显著提高,TPAE含量为5份时,共混物的断裂伸长率为370 %,缺口冲击强度为90 J/m,拉伸强度为39 MPa;SEM分析表明,添加TPAE后,共混物中三元聚酰胺相的粒径显著变小;DSC与XRD分析结果表明,TPAE含量对PLLA/三元聚酰胺共混物的熔融行为和结晶行为无明显影响,而共混物拉伸后,其结晶度显著提高。     

Specific interactions in 4‐hydroxybenzoic acid/poly(2‐vinylpyridine)/poly(N‐vinyl‐2‐pyrrolidone) blends

The specific interactions in ternary 4‐hydroxybenzoic acid (HBA)/poly(2‐vinylpyridine) (P2VPy)/poly(N‐vinyl‐2‐pyrrolidone) (PVP) blends were studied by differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, and electron microscopy. FTIR study shows the existence of hydrogen‐bonding interactions between HBA and P2VPy as well as PVP. The addition of a sufficiently large amount of HBA produces a blend showing one glass‐transition temperature (T_g). Microscopic study shows a drastic reduction in domain size in single‐T_g blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 901–907, 2001     

Solid‐State Structure and Mechanical Properties of Blends of an Amorphous Polyamide and a Poly(amino‐ether) Resin

Summary: Finely dispersed blends of an amorphous polyamide (AP) and a poly(amino‐ether) (PAE) resin were obtained by direct injection moulding. The blend components reacted slightly, mainly in PAE‐rich compositions, as seen by torque increases and FT‐IR. Both negative volumes of mixing and preferential orientation were observed in blends with very high AP contents, leading to synergisms in both the modulus of elasticity and the yield stress. In PAE‐rich blends, the effects of these two structural characteristics were negative, but the higher presence of reacted products also led to an overall synergistic modulus of elasticity. With the exception of blends very rich in PAE, in which the more extensive reactions led to brittle materials, the reactions compatibilized the blends due to the presence of small amounts of reacted copolymers, probably at the interface.

Cryogenically fractured surface of the skin of the AP/PAE 80/20 w/w blend.     

Non‐Linear Long‐Term Tensile Creep of Poly(propylene)/Cycloolefin Copolymer Blends with Fibrous Structure

The tensile deformation of materials with Poisson's ratio smaller than 0.5 generates an additional free volume, which means that tensile creep under constant stress and temperature is a non‐iso‐free volume process. Fractional free volume rising proportionally to the creep strain accounts for a continuous shortening of retardation times. To account for this effect, “internal” time has been introduced which is related to a hypothetical pseudo iso‐free‐volume state. The shift factor along the time scale in the time‐strain superposition is not constant for an isothermal creep curve, but rises monotonically from point to point with the elapsed creep time. The reconstructed compliance dependencies obtained for various stresses approximately obey the time‐strain superposition thus forming a generalised creep curve. A routinely used empirical equation has been found suitable to describe the effects of time and stress on compliance of parent polymers and their blends. The previously proposed predictive format for the time‐dependent compliance of polymer blends has been found applicable also to poly(propylene) (PP)/cycloolefin copolymer (COC) blends with fibrous morphology. As COC shows a tendency to form fibres in a PP matrix, the mixing rule customarily used for fibre composites has been found more appropriate for injection moulded specimens than the equivalent box model for isotropic blends. The predicted compliance curve for a pseudo iso‐free‐volume state can be transformed into a “real” curve for a selected stress σ (in the interval up to the yield stress).

SEM microphotograph of the fractured surface (perpendicular to the injection direction) of the PP/COC blend 60/40.     

PA6/EPM/EPM-g-MAH共混物结构与性能研究

采用二元乙丙橡胶接枝马来酸酐(EPM-g-MAH)作为二元乙丙橡胶(EPM)增韧聚酰胺6(PA6)的增容剂,研究了PA6/EPM/EPM-g-MAH三元共混物的流变性能、力学性能和微观形态。结果表明,EPM-g-MAH可以与PA6发生增容反应生成接枝共聚物,改善了PA6和EPM的界面相容性。随着EPM-g-MAH含量的增加,共混物中分散相粒径更加细化,共混物的熔融峰温下降,缺口冲击强度显著提高,当EPM/EPM-g-MAH的配比为10/10时,共混物的冲击强度达到最大为47 kJ/m2,比纯PA6提高了8倍。     

On Blends of Polyamide 6 and a Hyperbranched Aramid

The hyperbranched (HB) aromatic polyamide synthesised by direct polycondensation of 5‐(4‐aminobenzoylamino)isophthalic acid (ABZAIA) has been solution‐ and melt‐ blended with polyamide 6 (PA6) incorporating different end groups. The concentration of p(ABZAIA) in PA6 has been varied from 5 to 30 wt.‐% in order to evaluate the influence of hyperbranched polymer content on blend properties. Viscosity and glass transition (T_g) data of the solution blends underlined the full miscibility between the components in the explored composition range. The miscibility was not related to any specific type of PA6 end group, thus suggesting a major role for its amide groups in interacting (presumably via hydrogen bonding) with HB functional end groups. Well‐separated powder particles have been obtained by precipitation from diluted solutions both for the neat polymers and for the blends. Also, in the case of blends prepared by melt mixing T_g linearly increased with the HB polymer content, again confirming full miscibility between the blend components. Blend characterisation, solubility tests and melt rheology supported the idea that p(ABZAIA) forms reactive blends with polyamide 6 by melt mixing. As a consequence of these reactions, the hyperbranched aramid strongly modified the rheological behaviour of PA6.

Formation of well dispersed spherical and homogeneous particles after precipitation of a PA6 dilute solution.     

车用尼龙合金PA6／PP的研制

制备了马来酸酐接枝ＰＰ作为ＰＡ６／ＰＰ合金的相容剂，研究了相容剂对ＰＡ６／ＰＰ合金结构与性能的影响，以及原料和工艺对合金性能的影响。     

Effect of Maleic‐Anhydride Grafting on the Physical and Mechanical Properties of Poly(L‐lactic acid)/Starch Blends

MA is grafted onto both PLLA and starch in an internal mixer in the presence of DCP in a one‐step reactive compatibilization process. The effect of maleation of MA on the physical and mechanical properties and morphology of the blends was assessed. The onset decomposition temperature of the PLLA/starch blends decreased as the starch content increases due to the lower thermal stability of starch and the low effect of the maleation reaction on the thermal stability of the blends. PLLA/starch blends without grafted MA showed higher crystallinity as the starch content increased. Reactive compatibilized blends with less than 20 wt% starch had higher storage modulus, indicating that the compatibility between the two phases was improved.