Morphology and Thermal Properties of Compatibilized PA12/PP Blends with Boehmite Alumina Nanofiller Inclusions

Boehmite alumina nanoparticles are added to PP‐g‐MAH‐compatibilized blends of PA 12 and PP to study the effects of nanoparticle loading in the resulting composites. WAXD and SEM data suggest that the nanoparticles enhanced the coalescence of PP. DSC, DMA, and TGA reveal that the final properties such as crystallization temperature, flexural storage modulus, thermal degradation temperature, etc., improve with increasing nanoparticle loading for blend/based composites. FTIR results show that the nanoparticles interfere with the interfacial activity at 5 wt% nanoparticle loading. All results are compared between the neat polymers and the compatibilized blend and show that despite a slight increase in dispersed‐phase domain size, all other properties improve with the addition of AlO(OH).

     

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 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.

     

Thermal Behavior of Isotactic Poly(propylene)/Maleated Poly(propylene) Blends

This paper analyzes the thermal and thermo‐oxidative degradation behavior, phase separation, melting, and crystallization of blends consisting of isotactic poly(propylene) (IPP) and poly(propylene) grafted with maleic anhydride (PP‐g‐MA). It has been established that, depending on the blend composition and crystallization/preparation procedure, the blends of IPP and PP‐g‐MA can either co‐crystallize or evidence phase separation. This conclusion has been attained by comparing the DSC results of crystallization under dynamic and isothermal conditions with X‐ray diffraction results. On the basis of the obtained results, the optimum mixing ratios have been established as 95–85 wt.‐% IPP/5–15 wt.‐% PP‐g‐MA. Thermo‐oxidative behavior has been studied by thermogravimetry and differential thermal analysis.

     

Using Nanosilica to Fine‐Tune Morphology and Properties of Polyamide 6/Poly(propylene) Blends

The effect of hydrophilic and hydrophobic nanosilica on the morphological, mechanical and thermal properties of polyamide 6 (PA) and poly(propylene) (PP) blends is investigated by extrusion compounding. Depending on the difference between the polymer/nanoparticle interfacial tensions, different morphologies are obtained as highlighted by TEM and SEM. Hydrophobic nanosilica migrates mainly at the PA/PP interface, which leads to a clear refinement of PP droplet size. The macroscopic properties of the hybrid blends are discussed and interpreted in relation with the blend morphology and melt‐mixing procedure. The control over coalescence allows a morphology refinement of the blends and improves mechanical properties.

     

Isotactic Poly(propylene) Nanocomposites Based upon Boehmite Nanofillers

The influence of boehmite crystallite sizes, varied between 10 and 60 nm, was studied with respect to the morphology development, crystallization behavior and mechanical properties of the boehmite‐based iPP nanocomposites. The nanometer‐scaled boehmites were formed during twin‐screw melt extrusion of iPP at 200 °C. Even in the absence of polymer compatibilizers, the boehmites, obtained from Sasol's process, enabled very effective deagglomeration and in‐situ dispersion of nanoboehmites. With increase in boehmite crystallite size it was possible to improve simultaneously stiffness and impact strength of iPP. As evidenced by means of DSC, POM and WAXS measurements, the deagglomerated nanoboehmites nucleated crystallization of poly(propylene)'s α‐modification.

     

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。     

Characterization and Properties of Reactive Poly(lactic acid)/Polyamide 610 Biomass Blends

A low molecular weight bisphenol‐A type epoxy resin was used as a reactive compatibilizer for poly(lactic acid) (PLA)/polyamide 610 (PA 610) biomass blends. To the best of our knowledge, this blend is the first biomass PA 610 blend in the literature. The epoxy functional groups could react with the terminal groups of both PLA and PA 610. An ester–amide interchange reaction led to a polyester–polyamide copolymer formation, and improved the compatibility of PLA and PA 610. The blends with epoxy resin showed an enhancement in the phase dispersion and interfacial adhesion compared with the blend without epoxy resin. The differential scanning calorimetry (DSC) analysis showed that the crystallization peak temperatures decreased with increasing epoxy content. The melting temperature of PA 610 decreased with the addition of PLA, but remained unchanged with increased compatibilizer dosages. The dynamic mechanical analysis (DMA) showed that the glass transition temperature (T_g) of the blend, with the addition of 0.5 phr epoxy resin, slightly increased compared with that of neat PLA. However, the T_g of the blends remained unchanged with increasing epoxy resin content, and the higher content of epoxy resin in the blends resulted in improved mechanical properties and higher melt viscosity. The unnotched impact test showed that PA 610 could toughen PLA with the addition of epoxy resin. Moreover, the no‐break unnotched impact behavior was observed with the medium content of the compatibilizer, improving the notch sensitivity of PLA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2563–2571, 2013     

Effect of Nanoclay Incorporation on the Thermal Properties of Poly(ethylene terephthalate)/Liquid Crystal Polymer Blends

The effect of OMLS incorporation on the thermal properties of PET/LCP blends is studied. Pure and OMLS‐modified PET/LCP blends were prepared by melt‐extrusion using twin‐screw extruder. The morphological analyses of PET/LCP blends show that OMLS addition enhances the phase‐separated structure of the pure blend. A detailed study on the thermal properties of the pure and OMLS‐modified PET/LCP blends were carried out by means of DSC in both conventional and modulation modes. Results show a complex melting behaviour comprises of successive melting and re‐crystallisation. Finally, non‐isothermal crystal‐growth kinetics of pure and OMLS‐modified blends were investigated.

     

Morphology,Thermal and Mechanical Properties of Poly(propylene) Fibre‐Matrix Composites

Preparation and properties of poly(propylene)‐poly(propylene) composites have been investigated. Poly(propylene) fibres of varying diameter have been incorporated in a random ethylene co‐poly(propylene). The composites prepared from the same semi‐crystalline polymer in the matrix and reinforcement have lead to inherently strong interfacial bonding between the two phases of the same polymer. The composites demonstrated enhanced stiffness, which increased with fibre diameter. The structure, thermal, static and mechanical properties of poly(propylene) long fibre reinforced random co‐poly(propylene) composites have been studied with reference to the fibre diameter. The matrix and fibre components retained their separate melting temperatures. After melting, the two phases remained separate and showed their individual crystallization temperatures on cooling, and melting temperatures on a second heating. The melting temperature of the poly(propylene) fibres increased after formation of the composites. The compression molding of the composites at a temperature below the melting temperature of the fibres caused annealing of the fibre crystals. By incorporation of long poly(propylene) fibre into random co‐poly(propylene), the glass transition, storage and static modulus have been found to be increasing and composite with the largest fibre diameter shows better properties. Transcrystallization of the matrix poly(propylene) was observed.

Optical microscopy of composites with fibre diameter 68 μm.     

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.

     

Effect of Reprocessing Cycles on the Morphology and Properties of Poly(propylene)/Wood Flour Composites Compatibilized with EBAGMA Terpolymer

The present study is aimed to investigate the effect of multiple extrusions of iPP/WF composites with and without EBAGMA used as compatibilizer. The degradation induced by the recycling processes was evaluated through changes in molecular structure, morphology, rheology, thermal and mechanical properties. The results showed that after six cycles, the presence of WF imparts stability to the composite materials. This effect was enhanced for the compatibilized samples. Further, SEM revealed better dispersion of the WF in the matrix. In contrast, it was confirmed that after the first recycling, both the molecular weight and the properties of PP drastically decreased due to chain scission resulting from degradation.

     

Mechanical and Thermal Properties of Flexible Poly(propylene) Composites

Summary: The melting temperature difference between poly(propylene) (PP) fibre and random poly(propylene‐co‐ethylene) (PPE) was exploited to establish processing conditions for all‐PP composite. Under these conditions, the matrix must be liquid to ensure good wetting and impregnation of fibres, though temperatures must be low enough to avoid melting of fibres. The high chemical compatibility of the two components allowed creation of strong physico‐chemical interactions, favouring strong interfacial adhesion. Static and dynamic mechanical properties and morphology of all‐PP composites were investigated according to method of preparation and compared with the behaviour of hot compacted composites, prepared under different moulding conditions. The composites were compacted with varying pressure and time, and mechanical and thermal properties of the resulting sheets were measured. With increased moulding time, more fibres melted or their original properties deteriorated. Fast cooling or quenching caused imperfect morphology. Moulding pressure played an important role. Morphology of the optimum hot compacted composite was investigated using scanning electron microscopy before and after tensile testing. Tensile fracture surfaces showed a melted phase epitaxially crystallised onto the remaining orientated phase. Compacted composites showed fibre shapes under a thin layer of PPE with all of the gaps between fibres filled by melted PPE matrix.

SEM of compacted all‐PP composite without quenching.     

Dynamic Mechanical and Thermal Properties of Modified Poly(propylene) Wood Fiber Composites

Dynamic mechanical and thermal properties of poly(propylene) (PP)/wood fiber composites have been studied using Dynamic Mechanical Analysis (DMA). In order to modify the PP matrix maleated poly(propylene) (PPMA) and poly(butadiene‐styrene) rubber were used as compatibilizer and impact modifier, respectively. tan δ peak temperature of the compatibilized systems was found to increase in comparison to that of composites without coupling agent, indicating improved adhesion and interaction between PP matrix and wood fibers. The storage modulus (E′)‐temperature (T) relationship of all composites is characterized by two transition points. The E′ of compatibilized composites exhibits higher values than those of the uncompatibilized ones at low temperatures (up to the β‐relaxation). In the temperature interval from β‐transition to 60 °C, the composites containing PPMA have lower modulus, and above 60 °C the E′‐T curves tend to converge. DSC indicates that the wood fibers act as nucleating agent for PP. Maleated poly(propylene) slightly retards the crystallization rate, resulting in a composite structure, composed mainly of large spherulites, with a higher crystallinity index. Fourier Transform Infrared (FT‐IR) microscopy was also applied to explore the interface between wood fibers and PP matrix. The strong absorption band at 1 738 cm^?1 in the IR spectrum scanned at the interfacial region between the fiber and matrix indicated that PPMA had probably reacted either by formation of ester bonds or hydrogen bonding with hydroxyl groups from cellulose.

Optical micrograph of PPWF composite in polarized light.     

Mechanical and Rheological Properties of Poly(ethylene terephthalate)/ Polypropylene Blends

Poly(ethylene terephthalate) and polypropylene (PET/PP) were compounded and pelletized with a single-screw extruder. Standard ASTM tensile test specimens were made by injection moulding. The blends are stronger and stiffer than the plain PP specimens. The addition of a compatibilizer, EPOLENE E-43, is found to improve the strength and stiffness of the blends at loadings of 50% and 70% PET. At 10% PET loading, E-43 has the opposite effect of slightly reducing the tensile properties. All the blends are more brittle relative to either plain PET or PP. The addition of E-43 results in negligible improvement in the elongation at break. E-43 is also found to be an effective lubricant in improving the processability of the blends. The blends with E-43 added have lower viscosities and less shear-thinning characteristics than those without E-43. © 1997 SCI.     

Thermal,Mechanical and Rheological Properties of Polypropylene/Poly(ethylene-co-methyl acrylate) Blends

Isotactic polypropylene (PP) has been blended with poly(ethylene-co-methyl acrylate) (EMA) (75/25 wt/wt%) in a single-screw extruder. The compatibilizing effect of polypropylene grafted with maleic anhydride (PP-g-MAH) has been examined. The nonisothermal crystallization of the developed blends has been investigated using differential scanning calorimetry (DSC) and analyzed using Avrami, Tobin and Liu models. The thermal stability of the blends was assessed through thermogravimetric analysis (TGA). The tensile and impact properties, as well as the melt viscosity, have also been determined. The presence of rubber accelerates the crystallization of PP. The thermal stabilities of the blends are intermediate between those of their constituents. Tensile strength and modulus are reduced upon incorporation of EMA into PP, but ultimate elongation and impact strength are improved. The melt viscosity variation with shear rate for all the systems was typical of shear-thinning behavior. The compatibilizing agent has a pronounced effect on enhancing the thermal and mechanical properties of the blend.     

Morphological Features of Poly (3-Hydroxybutyrate)/Low Density Polyethylene Blends

Abstract

In an effort to investigate the morphology of biodegradable films, the combination of DSC, SEM and FTIR polarization spectroscopy methods are used. The methods enable us to examine the structural and morphological peculiarities of extruded blend compositions on the base of PELD and poly(3-hydroxybutyrate) (PHB) at concentration of the latter ranges from 0 to 32 wt%. The blend components are thermodynamically incompatible and form morphological elements with good visible interfaces between disperse phase (PHB) and continuous matrix (LDPE). For film extrusion, blend components affect each other that is seen as the crystallinity drop for both PHB and LDPE. The dichroism measurements show that the axes of LDPE and PHB molecules are presumably located at right angle, therewith, the biggest axes of the PHB crysrlallites are oriented along the extrusion direction. The matrices at all blend ratios, besides 32wt% composition, are reinforced by alternative band and cylinder-like fibriles of PHB. The architecture of such morphological elements is carefully studied by SEM method.     

Physical Properties of Isotactic Poly(propylene)/Silver Nanocomposites: Dynamic Crystallization Behavior and Resultant Morphology

Summary: The presence of silver nanoparticles (0.01–5 wt.‐%) increased the crystallization temperature of isotactic poly(propylene) (iPP) (e.g., a 5 wt.‐% content increases the temperature by ca. 7 °C) and produced a sharper crystalline peak. It had little effect on the melt rheology of the nanocomposites. The shear‐induced crystallization behavior of iPP was accelerated with increasing Ag content and imposed frequency. In addition, the promoting effect of Ag nanoparticles on the overall crystallization behavior was more notable at 140 °C than at 130 °C. The wide‐angle X‐ray diffraction scans of iPP nanocomposites with 5 wt.‐% Ag crystallized at 130 °C clearly presented another peak at a 2θ value of 15.8°, which corresponded to a β‐form crystal. The nanocomposites with 5 wt.‐% Ag crystallized at 130 °C gave double melting peaks at 154 and 166 °C. On the other hand, the samples crystallized at 140 °C produced two melting peaks at 166 and 172 °C. The introduction of as much as 0.1 wt.‐% of Ag nanoparticles increased both the tensile strength and elongation at break, but subsequent further addition caused a decrease. In addition, iPP nanocomposites with more than 1 wt.‐% Ag exhibited a higher modulus than pure iPP.

Time dependence of G′ of iPP and iPP/Ag nanocomposites at 130 °C at ω = 1 rad · s^?1.     

Blends of poly(propylene) and polyacetal compatibilized by ethylene vinyl alcohol copolymers

Polymer blends of poly(propylene) (PP) and polyacetal (polyoxymethylene, POM) with ethylene vinyl alcohol (EVOH) copolymers were investigated by differential scanning calorimetry (DSC), rheological, tensile, and impact measurements, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The PP–POM–EVOH blends were extruded with a co‐rotating twin‐screw extruder. The ethylene group in the EVOH is partially miscible with PP, whereas the hydroxyl group in the EVOH can form hydrogen bonding with POM. The EVOH tends to reside along the interface, acting as a surfactant to reduce the interfacial tension and to increase the interfacial adhesion between the blends. Results from SEM and mechanical tests indicate that a small quantity of the EVOH copolymer or a smaller vinyl alcohol content in the EVOH copolymer results in a better compatibilized blend in terms of finer phase domains and better mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1471–1477, 2003     

Investigation on the microstructure and the electric property of poly(propylene)/chlorinated poly(propylene)/poly(aniline) composites

The article presents results of studies on composites made from poly(propylene) (PP) modified with poly(aniline) (PANI) doped with dodecylbenzene sulfonic acid (DBSA) and chlorinated poly(propylene) (CPP). The volume resistivity of PP/CPP/PANI composites was detected, and the results show that the volume resistivity decreases with increasing CPP content, and there exists a minimum volume resistivity. Effects of CPP on the microstructure and crystalline structure of the PP/CPP/PANI composites and the relationship between the effects and the electric property were carefully analyzed by scanning electron microscope (SEM) and wide angle X‐ray diffraction (WAXD). The method that the specimens of SEM are polished is appropriate to investigate the morphology of conducting polymer composites. The obtained results illuminate that the area of conducting parts and insulating parts obtained from the digital analysis of the SEM image is obviously influenced by the CPP content, the parameters of the lamellar‐like structure are immediately related to CPP content and denote the dispersion of PANI‐DBSA, and the percent crystallinity and mean crystal size of PP are directly correlated with the CPP content. The increasing area of conducting parts, the increasement of layer distance, the decreasement of size and layer number of the lamellar‐like structure of PANI‐DBSA, and the increasement of the percent crystallinity and mean crystal size of PP are beneficial to the improvement of the conductive property of PP/CPP/PANI composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009