Influence of the morphology and viscoelasticity on the thermomechanical properties of poly(lactic acid)/thermoplastic polyurethane blends compatibilized with ethylene-ester copolymer

Viscoelastic, interfacial properties, and morphological data were employed to predict the thermal and mechanical properties of compatibilized poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends. The combination of interfacial thickness measured by contact angle and entanglement density determined by dynamical mechanical analysis analyze data was employed to evaluate the mechanical behavior of PLA/TPU blends with and without ethylene-butyl acrylate-glycidyl methacrylate (EBG) compatibilization agent. The PLA/TPU blend (70/30 wt %) was prepared in a Haake internal mixer at 190 °C and compatibilized with different contents of EBG. The evaluation of the interfacial properties revealed an increase in the interfacial layer thickness of the PLA/TPU blend with EBG. The scanning electronic microscopy images showed a drastic reduction in the size of the dispersed phase by increasing the compatibilizer agent EBG content in the blend. The compatibilization of the PLA/TPU blends improved both the Izod impact strength and yield stress by 38 and 33%, respectively, in comparison with neat PLA/TPU blend. The addition of EBG into PLA/TPU blends significantly increased the entanglement density and the PLA toughening but resulted in a decrease of PLA deformation at break. The PLA and TPU glass transitions were affected by the EBG, suggesting that the PLA and TPU domains were partially miscible. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48926.     

Effect of Compatibilizer Concentration on Rheological Behavior,Morphologies, and Mechanical Properties of PVDF/TPU Blends

The rheological behavior, morphologies, and tensile properties of reactively compatibilized PVDF/TPU blends are reported. Using PVDF‐g‐AAc as the compatibilizer, PVDF/TPU 90/10 and 10/90 blends are prepared. The carboxylic acid groups of PVDF‐g‐AAc react with the urethane linkages of TPU during melt blending to generate in situ PVDF‐g‐AAc‐g‐TPU which leads to compatibilization of PVDF/TPU blends. The introduction of PVDF‐g‐AAc into the PVDF/TPU blends causes an increase in viscosity. The rheological behavior of the compatibilized PVDF/TPU 90/10 and 10/90 blends are well described by the generalized Zener model. The addition of the compatibilizer PVDF‐g‐AAc reduces the dispersed‐phase domain size and narrows the size distribution. ?Author: The summary has been shortened to comply with the maximum of 700 characters. Pls check/confirm changes!?

     

Dynamic rheological and morphological study of the compatibility of thermoplastic polyurethane/ethylene–octene copolymer blends

Two grafted ethylene–octene copolymers [POEs; i.e., POE‐g‐maleic anhydried (MAH) and aminated POE (denoted by POE‐g‐NH₂) were used as compatibilizers in immiscible blends of thermoplastic polyurethane (TPU) and POE. The effects of the compatibilizers on the dynamic rheological properties and morphologies of the TPU/POE blends were investigated. The characteristic rheological behaviors of the blends indicated that the strong interactions between the two phases were due to the compatibilization. Microstructural observation confirmed that the compatibilizers were located at the interface in the blends and formed a stable interfacial layer and smaller dispersed phase particle size. Compared with POE‐g‐MAH, POE‐g‐NH₂ exhibited a better compatibilization effect in the TPU/POE blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Rheological behavior and morphological and interfacial properties of PLA/TPE blends

Rheological and interfacial tension data were employed to predict the morphology and thermal and mechanical properties of noncompatibilized and compatibilized poly(lactic acid) (PLA)/thermoplastic elastomer (TPE) blends. PLA was melt blended with thermoplastic polyurethane (TPU) and ethylene elastomer (EE) and compatibilized by ethylene–butyl acrylate–glycidyl methacrylate (EBG) in an internal mixer chamber. Both TPU and EE TPEs have higher viscosities than PLA, and the interfacial properties evaluated have revealed better adhesion between domains of PLA–TPU. The efficiency of the compatibilizer agent EBG depended on the TPE type inferred by modifications in the scanning electron microscopy images of PLA/TPE blends and by the Izod impact strength (improved by 23%). The EBG was more effective in the PLA/TPU blend. The TPEs and EBG did not affect the PLA thermal stability, and no thermal event was observed in the usual PLA extrusion and injection temperature range. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47962.     

Effects of a diisocyanate compatibilizer on the properties of citric acid modified thermoplastic starch/poly(lactic acid) blends

In this article, for the first time in the literature effects of phenylene diisocyanate (PDI)‐based compatibilizer on the physical and chemical properties of citric acid (CA) modified thermoplastic starch (TPS)/poly(lactic acid) (PLA) blends were investigated with respect to PDI and CA content and blend composition. The blends were prepared by melt compounding in a laboratory microcompounder. Fourier transformation infrared spectroscopy results showed that CA interacted with starch and PDI interacted by both starch and PLA through the hydroxyl groups. It was revealed from SEM micrographs that combinatorial usage of CA and PDI resulted in an improved, finer distribution of TPS in PLA matrix. This improvement affected the mechanical properties of blend, especially the toughness related properties such as impact strength and elongation at break. The thermal properties such as T_g and T_m revealed from differential scanning calorimeter analysis were in line with the morphological structure of the blends by suggesting the compatibilization phenomena in the presence of PDI and CA together. Thermogravimetric analysis showed that compatibilization of two phases improved the thermal stability of the blends. As a general conclusion, the combinatorial usage of PDI and CA can be utilized to obtain tougher PLA/TPS blends‐based materials to overcome the brittleness problem. POLYM. ENG. SCI., 53:2183–2193, 2013. © 2013 Society of Plastics Engineers     

Effects of halloysite nanotubes on the performance of plasticized poly(lactic acid)‐based composites

The objective of this study is processing and characterization of Halloysite nanotube (HNT)/poly(lactic acid) (PLA) nanocomposites. As HNT filler, a domestic source was used (ESAN HNT). The results obtained from this HNT were compared with a well‐known reference HNT (Nanoclay HNT). To achieve the desired physical properties and clay dispersion, composites were compounded via direct melt mixing in a laboratory twin‐screw compounder. However, the constituents were observed to be incompatible without a compatibilizer. To improve the flexibility of nanocomposites and provide compatibilization between PLA and HNT, two types of blends were prepared: PLA plasticized with poly(ethylene glycol) (PEG) denoted as P‐PLA and PLA toughened with a thermoplastic polyurethane (TPU) denoted as T‐PLA. Despite the limited improvement in the P‐PLA blends, TPU addition improved the flexibility of PLA/HNT without deteriorating the tensile strength in a great manner. This was attributed to the relatively better compatibilization effect of TPU and the role of nanotubes acting as bridges between the TPU and PLA phases. POLYM. COMPOS., 37:3134–3148, 2016. © 2015 Society of Plastics Engineers     

The Potential Use of Epoxy-POSS as a Reactive Hybrid Compatibilizers for PLA/PBAT Blends: “Effect of PBAT Molecular Weight and POSS Type”

This article focuses on the effect of molecular weight of poly(butylene adipate-co-terephthalate) (PBAT) on the immiscible poly(lactic acid) (PLA)/PBAT blends compatibilized with epoxidized polyhedral oligomeric silsesquioxanes (Epoxy-POSSs) having different numbers of epoxy groups per molecule. Mechanical, thermomechanical, thermal, rheological, and morphological properties of the blends were investigated as a function of PBAT molecular weight and epoxy-POSS type. Mechanical tests revealed that all epoxy-POSS types significantly improved the performance of the blends containing low-molecular-weight PBAT. On the other hand, epoxy-POSS with three epoxy functional groups (TriEpPOSS) and Epoxy-POSS with multiple-epoxy functional groups (MuEpPOSS) only slightly improved the performance of blends with high-molecular-weight PBAT. Thermomechanical and thermal test results supported that the compatibilization effects of the epoxy-POSSs were more prominent in the PLA/PBAT blends with low-molecular-weight PBAT due to the observation of the shifts in the glass transition temperatures of the PLA phase. According to the rheological results, the addition of epoxy-POSSs increased the interactions between the PLA and PBAT phases much more effectively in the PLA/PBAT with low-molecular-weight PBAT. The dispersed phase size of the PBAT further decreased in the low-molecular-weight PLA/PBAT blend system due to the enhanced compatibility much better. POLYM. ENG. SCI., 60: 398–413, 2019. © 2019 Society of Plastics Engineers     

Tailoring the morphology and properties of poly(lactic acid)/poly(ethylene)‐co‐(vinyl acetate)/starch blends via reactive compatibilization

Poly(lactic acid)/poly(ethylene‐co‐vinyl acetate)/starch (PLA/EVA/starch) ternary blends were prepared by multi‐step melt processing (reactive extrusion) in the presence of maleic anhydride (MA), benzoyl peroxide and glycerol. The effects of MA and glycerol concentration on the morphology and properties of the PLA/EVA/starch blends were studied using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, the Molau experiment, dynamic mechanical thermal analysis and differential scanning calorimetry etc. The plasticization and compatibilization provided a synergistic effect to these blends accompanied by a significant reduction in starch particle size and an increase in interfacial adhesion. Starch was finely dispersed in the ternary blends with a dimension of 0.5 ? 2 µm. Furthermore, EVA‐coated starch or a starch‐in‐EVA type of morphology was observed for the reactively compatibilized PLA/EVA/starch blends. The EVA with starch gradually changed into a co‐continuous phase with increasing MA concentration. Consequently, the toughness of the blends was improved. Since property stability of starch is an issue, the tensile properties of these blends were measured after different storage times and the blends showed good property stability. Copyright © 2012 Society of Chemical Industry     

Study of morphology influence on rheological properties of compatibilized TPU/SAN blends

The compatibilizing efficiency of three different compatibilizers on the thermoplastic polyurethane/styrene‐co‐acrylonitrile (TPU/SAN) blends properties was investigated after compatibilizer's incorporation via melt‐mixing. The compatibilizers studied were as follows: poly‐ε‐caprolactone (PCL) of different molecular weight (M_w), a mixture of polystyrene‐block‐polycaprolactone (PS‐b‐PCL) and polystyrene‐block‐poly (methyl methacrylate) (PS‐b‐PMMA), and a mixture of polyisoprene‐block‐polycaprolactone (PI‐b‐PCL) and polybutadiene‐block‐poly (methyl methacrylate) (PB‐b‐PMMA). In our study, the effect of 5 wt % added compatibilizers on TPU/SAN blends morphology was examined. The transmission electron microscopy (TEM) was used to study the morphology at different length scales and to determine the compatibilizer's location. Investigations showed the different improvement of properties, because of the different incorporation of compatibilizers in the polymer blend. The morphology influence on the rheological behavior of compatibilized blends was investigated with a stress‐controlled rheometer (Rheometric Dynamic Stress Rheometer, SR‐500). Different compatibilization activity was found for different system. It was also found that compatibilization activity of added compatibilizer strongly depends on the comaptibilizer's M_w. Blends compatibilized with PCL showed superior properties as compared with the other examined blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2303–2316, 2006     

Phase structure and viscoelastic properties of compatibilized blends of PET and HDPE recyclates

Immiscible blends of recycled poly(ethylene terephthalate) (R‐PET), containing some amount of polymeric impurities, and high‐density polyethylene (R‐PE), containing admixture of other polyolefins, in weight compositions of 75 : 25 and 25 : 75 were compatibilized with selected compatibilizers: maleated styrene–ethylene/butylene–styrene block copolymer (SEBS‐g‐MA) and ethylene–glycidyl methacrylate copolymer (EGMA). The efficiency of compatibilization was investigated as a function of the compatibilizer content. The rheological properties, phase structure, thermal, and viscoelastic behavior for compatibilized and binary blends were studied. The results are discussed in terms of phase morphology and interfacial adhesion among components. It was shown that the addition of the compatibilizer to R‐PET‐rich blends and R‐PE‐rich blends increases the melt viscosity of these systems above the level characteristic for the respective binary blends. The dispersion of the minor phase improved with increasing compatibilizer content, and the largest effects were observed for blends compatibilized with EGMA. Calorimetric studies indicated that the presence of a compatibilizer had a slight affect on the crystallization behavior of the blends. The dynamic mechanical analysis provided evidence that the occurrence of interactions of the compatibilizer with blend components occurs through temperature shift and intensity change of a β‐relaxation process of the PET component. An analysis of the loss spectra behavior suggests that the optimal concentration of the compatibilizers in the considered blends is close to 5 wt %. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1423–1436, 2001     

Effect of TPU hard segment content on the rheological and mechanical properties of PLA/TPU blends

Blends of an amorphous polylactide (PLA) with three different thermoplastic polyurethane (TPU) grades having various hard segment (HS) contents are prepared at the blending ratio of 85/15 wt% through a twin-screw extruder (TSE) at processing temperatures of 150 and 190°C. Blends of a semicrystalline PLA with 15 wt% of the noted TPU grades are also processed in the TSE at 190°C to investigate the matrix crystallization effect on the morphology and property enhancements. The rheological experiments reveal that the increase in TPU HS content significantly increases the phase compatibility between PLA and TPU as also suggested by the finer morphology of the TPU phase, although the use of lower HS TPUs is more favorable to enhance the ductility and impact properties of the blends.     

Rheology and morphology of polytrimethylene terephthalate/ethylene propylene diene monomer blends in the presence and absence of a reactive compatibilizer

The dynamic rheological behavior and phase morphology of Polytrimethylene terephthalate (PTT) and ethylene propylene diene monomer (EPDM) uncompatibilized blends and those compatibilized with maleic anhydride grafted EPM (EPM‐g‐MA) were investigated. Effects of blend ratio and reactive compatibilization on the morphology and rheological properties of compatibilized and uncompatibilized blends have been analyzed. The viscosity ratio between the polymers was found to be sensitive to frequency which gave an indirect idea about the unstable morphology. The complex viscosity and dynamic modulus increased with increase in compatibilizer addition up to critical micelle concentration. Palierne and Choi‐Schowalter models were used to calculate the interfacial tension between the polymers. The interfacial tension decreased with the addition of compatibilizer up to CMC. It was also found that the minimum value of interfacial tension was found at CMC beyond that a levelling off is observed. The rheological properties of both compatibilized and uncompatibilized blends are found to be closely related to their phase morphology. POLYM. ENG. SCI., 50:1945–1955, 2010. © 2010 Society of Plastics Engineers     

Compatible blends of polypropylene with an amorphous polyamide

Compatible polymer blends of polypropylene (PP) with an amorphous polyamide (aPA) were obtained through reactive compatibilization by adding 20% maleic anhydride‐modified copolymer (PP‐g‐MA) to the blends. The blends were made up of a pure PP phase and an aPA‐rich phase where very small amounts of PP were detected. The dispersed phase particle size decreased considerably indicating that compatibilization occurred. Young's modulus of the compatibilized blends increased with respect to that of the uncompatibilized ones. The compatibilized blends were highly ductile, and the impact strength also improved, proving that compatibilization occurred under a broad range of experimental conditions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013     

Compatibilization method applied to the chitosan‐acid poly(L‐lactide) solution

We are testing the compatibilization of the chitosan/PLA blends by addition of diisocyanate and at studying the effect of several MDI concentrations (0.5 and 2.5% of the global blend mass, w/w). To evaluate the MDI efficiency as a compatibilizer of chitosan/PLA blends, we worked with the following methods: IRTF spectra with higher peak at 1558 cm⁻¹ is due to the  NH bonds that exist in urea and urethane, thermal properties shows that the temperature of the endothermic peaks of the chitosan/PLA blends with MDI is very close to the temperature of pure chitosane and SEM micrography shows that MDI addition decreases the PLA particles size in the chitosan mixture; they also comply with the compatibilization theory. After that the mechanical properties have been characterized: we can notice that the MDI compatibilized chitosan/PLA blends have a higher Young's modulus than the noncompatibilized blends. we are showed that the use of 0.5% MDI is not enough sufficient to obtain a compatibilization, because a part of the MDI can be consumed by water. The addition of MDI increases the performance of the mechanical properties of the blends. Therefore, with this compatibilization, we could obtain some chitosan/PLA blends that would be water‐resistant and that would also keep their mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polyoxymethylene/thermoplastic polyurethane blends compatibilized with multifunctional chain extender

Novel compatibilized polyoxymethylene/thermoplastic polyurethane (POM/TPU) blends are successfully developed using multifunctional chain extender, Joncryl ADR‐4368, as the compatibilizer. The outstanding compatibilization efficiency of Joncryl on POM/TPU blend was demonstrated by its even higher mechanical properties with only 0.5 wt % of Joncryl than those with 5 wt % of three commonly used compatibilizers. Addition of only 0.5 wt % Joncryl can double the impact strength and significantly improve its tensile strength and flexural strength for POM/TPU (75/25) blend. SEM images show that Joncryl can reduce TPU particle size and enhance the interfacial interactions between POM and TPU. The interparticle distance of TPU in POM/TPU/Joncryl blends was calculated as 0.2 μm, quite close to the critical matrix ligament thickness of POM/TPU blends (0.18 μm). The impact force profile vividly shows that the addition of Joncyl in POM/TPU blends can dramatically increase the total impact energy absorbed by this blend system and enhance the interfacial interactions between POM and TPU. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Morphology monitoring of PE/PBT blends by reactive processing

Polyethylene (PE)/poly(butylene terephthalate) (PBT) blends were in situ compatibilized during a processing operation by the addition of a partially hydroxylated ethylene vinyl acetate copolymer (EVAh). This copolymer, obtained from ethylene vinyl acetate (EVA), was as compatible with PE as EVA was before modification. In the presence of EVAh, the dispersion of PBT in the PE matrix was finer, and the interfacial adhesion was improved. These results are relevant for the compatibilization of PE/PBT blends. Moreover, such blends present good toluene barrier properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3568–3577, 2001     

Morphology development of in situ compatibilized semicrystalline polymer blends in a co-rotating twin-screw extruder

This paper concerns the morphology development of in situ compatibilized semicrystalline polymer blends in a co-rotating, intermeshing twin-screw extruder, using polypropylene (PP) and polyamide 6 (PA-6) blends as model systems. The morphology of in situ compatibilized blends develops much faster that of mechanical ones. The size of the dispersed phase (PA-6) undergoes a 10⁴ fold reduction from a few millimeters to sub-micron during its phase transition from solid pellets to a viscoelastic fluid. The final morphology is reached as soon as the phase transition is completed, which usually requires only a small fraction of the screw length in a co-rotating twin screw extruder. Screw profiles and processing conditions (screw speed, throughput and barrel temperature) control the PA-6's melting location and/or rate, but do not have significant impact on the ultimate morphology and mechanical properties of in situ compatibilized blends. The finding that morphology of PP/PA-6 reactive blend develops rapidly makes it possible to produce compatibilized PP/PA-6 blends by the so-called one-step reactive extrusion. It integrates the traditionally separated free radical grafting of maleic anhydride onto PP and the compatibilization of PP/PA-6 into a single extrusion step.     

Compatibilized TPU‐PDMS blends: Pros and cons of melt mixing and solution mixing techniques

The present work describes the influence of processing route on thermomechanical properties of thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) compatibilized blends. In this study, compatibilized blends of TPU and PDMS prepared by melt mixing and solution mixing techniques were compared. Ethylene methyl acrylate at different doses of 1, 2, 3, and 4 phr was used as the compatibilizer in 90:10, 80:20, and 70:30 blend ratios of TPU and PDMS. Optimum percentage of compatibilizer was same in both the methods and which was increased with the percentage of PDMS. As compared to melt mixed blends, solution mixed blends showed improved mechanical properties. From the dynamical mechanical analysis it was observed that the glass transition temperature (T_g) obtained was higher for the solution mixed blends due to the stiffer chains. The enhanced physicomechanical properties of the solution mixed blends were attributed to the improved thermal stability of the blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45164.     

Effect of compatibilizer on the crystallization,rheological, and tensile properties of LDPE/EVOH blends

The effect of the compatibilizer on the crystallization, rheological, and tensile properties of low-density polyethylene (LDPE)/ethylene vinyl alcohol (EVOH) (70/30) blends was investigated. Maleic anhydride-grafted linear low-density polyethylene (LLD-g-MAH) was used as the compatibilizer in various concentrations (from 1 to 12 phr). The interesting effect of compatibilization on the crystallization kinetics of the blends was noted, and the correlation between the morphology and the rheological and tensile properties was also discussed. Morphological analysis showed that the blends exhibited a regular and finer dispersion of the EVOH phase when LLD-g-MAH was added. Nonisothermal crystallization exotherms of the compatibilized LDPE/EVOH blends showed the retarded crystallization of the dispersed EVOH phase, which probably resulted from the constraint effect of the grafted EVOH (EVOH-g-LLD) as well as the size reduction of the EVOH domains. The blends exhibited increased melt viscosity and storage modulus and also enhanced tensile properties with the addition of LLD-g-MAH, which seemed to be attributable to both dispersed particle-size reduction and improved interfacial adhesion. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1245–1256, 1998