Compatibilization of polypropylene/poly (ethylene oxide) blends and crystallization behavior of the blends

The compatibilization of incompatible polypropylene (PP)/poly(ethylene oxide) (PEO) blends was studied. The experimental results showed that the graft copolymer [(PP-MA)-g-PEO] of maleated PP(PP-MA) and mono-hydroxyl PEO (PEO-OH) was a good compatibilizer for the PP/PEO blends in which PP-MA also had some compatibilization. The crystallization of the blends was affected by the compatibility between PP and PEO. The interfacial behavior of the compatibilizers had an important effect on crystallization behavior of the PP/PEO blends. PEO showed fractionated crystallization in the PP/PEO blends. This behavior was studied from the view point of the theory of fractionated crystallization. © 1994 John Wiley & Sons, Inc.     

Silicone-based polymer blends: Enhancing properties through compatibilization

Polymer blending is a cost-effective way to control the properties of soft materials, but the propensity for blends to macrophase separate motivates the development of efficient compatibilization strategies. Across this broad area, compatibilization is particularly important for polysiloxanes, which exhibit strong repulsive interactions with most organic polymers. This review analyzes state-of-the-art polysiloxane compatibilization strategies for silicone–organic polymer blends. Emphasis is placed on chemical innovation in the design of compatibilization agents that may expedite the commercialization of new silicone–organic materials. We anticipate that hybrid silicone blends will continue to play an important role in fundamental and applied materials science across industry and academia.     

Biodegradable blends obtained via reactive blending of polylactide and polyamide-6

Blends of polyamide-6 and polylactide are prepared via reactive compatibilization. Their phase morphologies and compositions are characterized by the methods of IR spectroscopy, optical and scanning electron microscopy, NMR, dynamic mechanical analysis, and continuous extraction in a boiling solvent. It is shown that the formation of hydrogen bonds between polylactide and polyamide-6 substantially improves the compatibility of components. A large proportion of a copolymer is formed as a result of interchain exchange between polyamide-6 and polylactide molecules. The results open new possibilities to produce commercially attractive biodegradable materials with high mechanical and thermophysical characteristics.     

EAA增容LLDPE/PEO共混物及其增容机理

以乙烯-丙烯酸共聚物(EAA)为增容剂, 研究了它在线性低密度聚乙烯(LLDPE)/聚环氧乙烷(PEO)共混物中的增容作用及其增容机理。采用电子显微镜(SEM)、动态力学分析(DMA)、DSC和红外光谱(IR)对共混物形态及其微观结构进行了表征。结果表明, EAA对LLDPE/PEO共混物有一定的增容作用; 其增容机理为: EAA和LLDPE两者的非晶区部分相容, 而EAA分子中的羧基与PEO分子中的醚氧基相互作用形成了分子间氢键。     

Fourier-transform infrared studies of polymer blends. III. Poly(β-propiolactone)-poly(vinyl chloride) system

Fourier-transform infrared (FTIR) studies of the poly(β-propiolactone) (PPL)-poly(vinyl chloride) (PVC) blend system are presented. PPL-PVC blends are observed to be incompatible in the molten (80°C) and solid (25°C) states, over the entire range of compositions. This is in marked contrast to our previous results of the poly(?-caprolactone)-PVC blend system which was shown to be compatible in the amorphous state. The results of both studies are compared and discussed with particular reference to the detection of intermolecular interactions by FTIR and correlation with compatibility in polyester-PVC blends. The role of the chemical interactions in the compatibilization of polymer blends is discussed in terms of thermodynamic considerations. Finally, it is well known that changes in refractive index of polymer blend compositions can cause frequency shifts of infrared bands, which are particularly relevant to the interpretation of residual peaks obtained by difference spectroscopy. The FTIR results of the PPL-PVC blends are germane to this subject and are discussed.     

Thermogravimetric analysis and differential scanning calorimetric studies on nanoclay-filled TPU/PP blends

Thermal stability of ester-thermoplastic polyurethane (TPU)/polypropylene (PP) and ether-TPU/PP blends was evaluated by thermogravimetric studies. Thermal studies were made as a function of blend ratio. Effects of compatibilization using MA-g-PP and nanoclay addition on thermal stability were evaluated. Mass loss at 400 °C was found to decrease with increasing PP content were determined. Finally the compatibility and crystallization behavior of the blends were studied by differential scanning calorimetry. Compared to the ether-TPU blend nanocomposites, the ester-TPU blends showed better compatibility and thermal stability.     

Reactive compatibilization of nylon copolymer/EPDM blends: experimental aspects and their comparison with theory

In situ reactive compatibilization was first time applied to a low melting nylon (nylon 6 and 66 copolymer) and EPDM blend system. The effects of in situ compatibilization and concentration of compatibilizer on the morphology and mechanical properties of nylon/EPDM blends have been investigated. The influence of EPM‐g‐MA on the phase morphology was examined by the scanning electron microscopy (SEM) after preferential extraction of the minor phase. The SEM micrographs were quantitatively analyzed for domain size measurements. The compatibilizer concentrations used were 0, 1, 2.5, 5, and 10 wt%. The graft copolymer (nylon‐g‐EPM) formed at the interface showed relatively high emulsifying activity. A maximum phase size reduction was observed when 2.5 wt% of compatibilizer was added to the blend system. This was followed by a leveling‐off at higher loadings indicating interfacial saturation. The conformation of the compatibilizer at the interface was deduced based on the area occupied by the compatibilizer at the blend interface. The experimental compatibilization results were compared with theoretical predictions of Noolandi and Hong. It was concluded that the molecular state of compatibilizer at interface changes with concentration. The in situ compatibilized blends showed considerable improvement in mechanical properties. Measurement of tensile properties shows increased elongation as well as enhanced modulus and strength up on compatibilization. At higher concentrations of compatibilizer, a leveling‐off of the tensile properties was observed. A good correlation has been observed between the mechanical properties and morphological parameters. Copyright © 2007 John Wiley & Sons, Ltd.     

Linear viscoelastic properties of high‐density polyethylene/polyamide‐6 blends extruded in the presence of ultrasonic oscillations

Blends of high‐density polyethylene (HDPE) and polyamide‐6 (PA6) were produced by ultrasonic extrusion. Ultrasonic irradiation leads to degradation of polymers and in situ compatibilization of blends as confirmed by variations in linear viscoelastic properties. The results showed that the effect of ultrasonic irradiation on dynamic rheological properties depends on the composition and experimental temperature. At the same time, the relationship between storage modulus and loss modulus indicated the effect of ultrasonic irradiation on compatibility of HDPE/PA6 blends. Based on an emulsion model, the interfacial tension between the matrix and the dispersed phase was predicted. The data obtained showed that ultrasonic irradiation can decrease the interfacial tension and then enhance the compatibility of HDPE/PA6 blends. This finding was consistent with our previous work. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1260–1269, 2005     

Compatibilization of blends of incompatible polymers via filling

The features of compatibilization of incompatible polymer blends via their filling with solid powders are studied, and possible mechanisms of the process are analyzed. It is shown that compatibilization is associated with the adsorption binding of dissimilar macromolecules by filler particles. This situation is possible if particles are localized between polymer components.     

PAmXD,6/PP-g-MA blends. I. Compatibilization

This work deals with the study of PAmXD,6/PP-g-MA blends [poly(meta-xylylene adipamide)] and (maleic-anhydride-functionalized-polypropylene) blends. Compatibilization occurs during the blending of the components in a Brabender plastograph at 265 ± 5°C and at a mixing rate of 45 rpm. Kinetic data from the literature indicate that the rate of amine/anhydride reaction is much faster than the rate of amide/anhydride reaction. This interpretation is confirmed by the use of model systems constituted of PAmXD,6 and pyromellitic dianhydride or of PP-g-MA and meta-xylylene diamine. Infrared analyzes of extracted nodules of PAmXD,6/PP-g-MA blends also confirm the extent of the imidization and show that the length of the PAmXD,6 blocks is lower than the free PAmXD,6 one. Segregation mechanisms during the compatibilization are discussed to explain this observation. The structure of the copolymers was deduced from those results and from the previous characterizations of PP-g-MA and PAmXD,6. It consists in a block of PP linked with some blocks of PAmXD,6. The average number of PAmXD,6 blocks depends on the average length of the poly(maleic anhydride) functionality carried on by PP-g-MA. © l997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 901–915, 1997     

Oxazoline functionalization of polyethylenes and their blends with polyamides and polyesters

The compatibilization of blends of polyamide‐6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two‐steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy and scanning electron microscopy (SEM). The rheological and mechanical properties of the blends were also investigated. The results show that functionalization of the polyethylenes can be achieved by melt blending with ricinoloxazoline maleinate even in the absence of free radical initiators. The compatibilization of the blends enhances the dispersion of the minor phase significantly, increases the melt viscosity, and improves the mechanical properties. The one‐step preparation of the compatibilized blends was also found to be effective, and is thought to be even more promising in view of commercial application.     

Use of maleic anhydride compatibilization to improve toughness and other properties of polylactide blended with thermoplastic elastomers

Polylactide (PLA) being a very brittle biopolymer could be toughened by blending with thermoplastic elastomers such as thermoplastic polyurethane elastomer (TPU) and thermoplastic polyester elastomer (TPE); unfortunately, these blends are immiscible forming round domains in the PLA matrix. Therefore, the purpose of this study was to investigate the effects of using maleic anhydride (MA) compatibilization on the toughness and other properties of PLA blended with TPU and TPE. MA grafting on the PLA backbone (PLA‐g‐MA) was prepared separately by reactive extrusion and added during melt blending of PLA/thermoplastic elastomers. IR spectroscopy revealed that MA graft might interact with the functional groups present in the hard segments of TPU and TPE domains via primary chemical reactions, so that higher level of compatibilization could be obtained. SEM studies indicated that PLA‐g‐MA compatibilization also decreased the size of elastomeric domains leading to higher level of surface area for more interfacial interactions. Toughness tests revealed that Charpy impact toughness and fracture toughness (K_IC and G_IC) of inherently brittle PLA increased enormously when the blends were compatibilized with PLA‐g‐MA. For instance, G_IC fracture toughness of PLA increased as much as 166%. It was also observed that PLA‐g‐MA compatibilization resulted in no detrimental effects on the other mechanical and thermal properties of PLA blends. Copyright © 2014 John Wiley & Sons, Ltd.     

Compatibilization of blends of polybutadiene and poly(methyl methacrylate) with poly(butadiene-block-methyl methacrylate)

Compatibilization of blends of polybutadiene and poly(methyl methacrylate) with butadiene-methyl methacrylate diblock copolymers has been investigated by transmission electron microscopy. When the diblock copolymers are added to the blends, the size of PB particles decreases and their size distribution gets narrower. In PB/PMMA7.6K blends with P(B-b-MMA)25.2K as a compatibilizer, most of micelles exist in the PMMA phase. However, using P(B-b-MMA)38K as a compatibilizer, the micellar aggregation exists in PB particles besides that existing in the PMMA phase. The core of a micelle in the PMMA phase is about 10 nm. In this article the influences of temperature and homo-PMMA molecular weight on compatibilization were also examined. At a high temperature PB particles in blends tend to agglomerate into bigger particles. When the molecular weight of PMMA is close to that of the corresponding block of the copolymer, the best compatibilization result would be achieved. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 85–93, 1998     

Phase behavior and structure formation in ternary blends: studies on blends of PVDF/PMMA/PVAC

The phase behavior of ternary blends was analyzed on the basis of the lattice approach. Both compatibilization and incompatibilization effects are predicted to occur depending on the relative magnitudes and the sign of the interaction parameters of the binary subsystems. Thermodynamic, structural and kinetic properties were investigated for a ternary model blend composed of poly(vinylidene fluoride), poly(methyl methacrylate) and poly(vinyl acetate). This particular ternary system is characterized by a specific symmertry with respect to the interactions in the binary subsystems. This symmetry affects both thermodynamic and structural properties. The experimentally determined interaction parameters were used to model the phase diagram on the basis of the lattice model: the theoretical phase diagram was found to be close to the experimental one. The crystallization processes were analyzed both for the binary and the ternary systems on the basis of a modified Turnbull–Fisher equation. The conclusions are that the properties of the ternary systems can be understood to a first approximation on the basis of those of the corresponding binary systems and the symmetry of the interactions.     

Enhancing toughness of poly (lactic acid)/Thermoplastic polyurethane blends via increasing interface compatibility by polyurethane elastomer prepolymer and its toughening mechanism

Due to the environmental pollution caused by the petroleum-based polymer, poly (lactic acid) (PLA), a biodegradable and biocompatible polymer that obtained from natural and renewable sources, has attracted widespread attention. However, the brittleness of PLA greatly limits its application. In this study, the super toughened PLA-based blends were obtained by compatibilizing the PLA/thermoplastic polyurethane (TPU) blends with the polyurethane elastomer prepolymer (PUEP) as an active compatibilizer. The mechanical properties, thermal properties and corresponding toughening mechanism of PLA/TPU/PUEP system were studied by tensile test, instrumented impact test, dynamic mechanical analysis (DMA), scanning electronic microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All the results demonstrate that the isocyanate (−NCO) group in PUEP is successfully reacted with the –OH groups at both sides of the PLA and the obtained polyurethane (PU)~PLA copolymer (PU ~ cõ PLA) significantly improves the interfacial compatibility of PLA/TPU blends. The gradually refined dispersed phase size and fuzzy phase interface as displayed in SEM images suggest a good interfacial compatibilization in the PLA/TPU/PUEP blends, probably due to the isocyanate reaction between PLA and PUEP. And the interfacial reaction and compatibilization among the components led to the formation of super toughened PLA/TPU/PUEP blends. And the instrumented impact results indicate that most of the impact toughness is provided by the crack propagation rather than the crack initiation during the entire fracture process.     

Stability analysis and scattering properties of charged crosslinked blends in solution

The phase behavior and scattering properties of crosslinked charged polymer blends in solution are examined. De Gennes' analogy between the effects of crosslinks in a network and electrostatic charges in a dielectric medium on the scattering properties and the phase behavior of crosslinked polymer blends is used. This analogy is extended to include the effects of screening in order to improve its agreement with the experimental data in the small q range. The excluded volume interactions are explicitely introduced through the blob model. The enhancement of compatibility of the mixture and the increase of its rigidity constant are evaluated in certain cases. The limit of neutral polymers is discussed because it corresponds to the case of charged mixtures in the presence of excess salt. The kinetics of the microphase separation transition is briefly discussed. A dynamical model including the long range hydrodynamic interaction is presented. The relaxation frequency of the stable modes and the growth rate of unstable ones are also considered.     

On the compatibility of low density polyethylene/hydrolyzed collagen blends. II: New compatibilizers

Compatibility/compatibilization of low density polyethylene (LDPE) and hydrolyzed collagen (HC) in the presence of some reactive compatibilizing agents (CA), like acrylic acid functionalized low density polyethylene (LDPE-g-AAc) and bismaleinimide-functionalized low density polyethylene (LDPE-g-BMI) have been discussed. It has been established that, by 20-30 wt% HC incorporation in LDPE matrix, in the presence of LDPE-g-AAc and LDPE-g-BMI compatibilizing agents, materials with good mechanical and surface properties can be obtained. Because of the high reactivity of bismaleinimide, the efficacity of LDPE-g-BMI as a compatibilizing agent is higher than that of LDPE-g-AAc.     

Compatibilized blends of thermoplastic polyurethane (TPU) and polypropylene

Compatibilized blends of thermoplastic polyurethane (TPU) and polypropylene (PP) were developed using amine (primary or secondary) functionalized PP's (PP-g-NH₂ or PP-g-NHR). The strategy of reactive compatibilization is based on fast reactions between amine functional groups and urethane linkages or traces of free isocyanates released by thermal degradation of TPU. Excellent compatibilization between TPU and PP was confirmed by rheological, morphological, and mechanical properties. Much finer domain size, higher interfacial adhesion, and more stable morphologies were clearly observed by scanning electron microscopy. Significant improvements in the overall mechanical properties (tensile, tear, abrasion) imply significantly more reaction between TPU and PP phases in the two TPU/PP blends containing PP-g-NH₂ or PP-g-NHR than a TPU/PP blend using PP-g-MA as a compatibilizing agent.     

The role of lubricants in reactive compatibilization of polyolefin blends

Reactive compatibilization using liquid polybutadienes and dialkyl peroxides was studied in model low‐density polyethylene/polystyrene (4/1) blends and the commingled waste of composition similar to these blends. The influence of three types of lubricants (Ca stearate, stearic acid ‐ Loxiol G20 and paraffin ‐ Loxiol G22) on the structure and toughness of these blends was determined. In spite of the fact that in the waste material, a coarse morphology and poor toughness were found in comparison with the blend of virgin polyolefins, reactive compatibilization has approximately the same effect in both types of the blends as far as the structure parameters and mechanical behaviour are concerned. This effect is enhanced by addition of lubricants, the most efficient being the paraffin in the model blends, probably due to its partial miscibility with LDPE. In the commingled waste, liquid polybutadienes supported on precipitated SiO₂ appear to be quite efficient. No influence of the reactive compatibilization on both the crystal modification and the crystalline content was observed in both types of these blends.     

Fractionated crystallization in blends of functionalized poly(tetrafluoroethylene) and polyamide

Blends of poly(tetrafluoroethylene)/polyamide (PTFE/PA) were prepared to combine the good processing properties of PA with the excellent sliding properties of PTFE. For the compatibilizing of the immiscible components the chemical reaction of functional groups of modified PTFE (micro powder produced by electron irradiation in air) and polar PA during a reactive extrusion process was used. The parameter influencing the efficiency of the in‐situ reaction between both components were varied. The crystallization and melting behaviour of the different blends was investigated by DSC. In dependence on the degree of compatibilization the phenomenon of fractionated crystallization of the dispersed PTFE component was observed. In this way a qualitative characterization of the dispersity of PTFE in dependence on the functionality of the components and the processing conditions is possible, and therefore an estimation of the efficiency of the in‐situ reaction.