Biodegradable soy protein–polyester blends by reactive extrusion process

Blends of soy protein concentrate and biodegradable polyester (Eastar Bio Copolyester, EPE) were prepared by using glycerol as a compatibilizing agent. Good miscibility was obtained only when the soy protein was initially combined with glycerol under high shear and at elevated temperatures in an extruder. Under these conditions, partial denaturing of the soy protein led to specific interactions between functional groups of the protein with the glycerol. The extrusion conditions and appropriate screw configuration were the critical factors affecting the reactivity of the protein and hence, the properties of the blends. Screws with large kneading blocks that produced high shear mixing were preferred and led to thermoplastic blends characterized by high elongation and high tensile strength. The morphology of these soy protein/polyester blends was studied by using environmental scanning electron microscopy (ESEM) and indicated good wetting of the soy protein particles within the polyester matrix. The thermal properties were studied by differential scanning calorimetry (DSC) and showed a lower degree of crystallinity and a continuous depression of the melting point of the polyester as the concentration of protein was increased. The possibility of using soy protein concentrate instead of the more expensive (higher purity) soy protein isolate in the preparation of biodegradable resins should lead to new commercial opportunities based on renewable, agricultural byproducts. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3231–3239, 2004     

Rheology and morphology of polyester/thermoplastic flour blends

Two maize flours (standard and waxy grades) were plasticized in an internal mixer with a constant amount of water and two glycerol contents. The resulting thermoplastic flours (TPFs) were characterized in dynamic oscillatory shear and creep/recovery rheometry. They displayed two different behaviors: the viscoelastic behavior of a high‐molecular‐weight polymer for the first one and a gel‐like behavior for the second one. The TPFs were then mixed with a copolyester [poly(butylene adipate–terephtalate)]. All of the blends contained the same volume fractions and were prepared with the same mixing conditions. The morphology and rheological behavior of each blend were characterized. Different morphologies, ranging from cocontinuous to nodular, were observed. In fixed mixing conditions, the blend morphology was shown to be governed by the rheological behavior of the starchy phase and the plasticizer content. The gel‐like behavior of the second TPF seemed to prevent droplet coalescence; this led to a very fine dispersion. The rheological behavior of each blend appeared to be linked to both the morphology and the rheological behavior of the two phases. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40222.     

Rheology and sheet extrusion of Novatein thermoplastic protein/polybutylene adipate-co-terephthalate blends

Novatein is a thermoplastic polymer made from blood meal proteins, but it has rheological properties very different from commodity thermoplastics. Capillary rheometry revealed an apparent time dependent shear viscosity for Novatein, evident from a decreasing pressure drop over time, measured at constant shear rate. However, blending with polybutylene adipate-co-terephthalate (PBAT) reduced the time dependence for uncompatibilized blends and virtually eliminated time dependence for compatibilized blends containing 30 wt % PBAT. Novatein's extensional viscosity is three orders of magnitude more than its shear viscosity and explained the difficulty in sheet extrusion. In contrast, 30% compatibilized blends had an extensional viscosity similar to neat PBAT and was also the only blend that could be successfully sheet extruded. Although uncompatibilized blends at the same or lower PBAT content also had a lower extensional viscosity, they could not be sheet extruded and the difference was the 30% compatibilized blends had a fine PBAT phase structure (co-continuous in this case), which was sufficiently adhered to the Novatein phase. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47977.     

Optimizing mechanical and morphological properties of biodegradable thermoplastic elastomer based on epoxidized natural rubber and poly(butylene succinate) blends

Biodegradable thermoplastic elastomer (BTPE) blends of epoxidized natural rubber (ENR) and poly(butylene succinate) (PBS) were prepared by the melt mixing process. Influences of the processing parameters mixing temperature, rotor speed, and mixing time on mechanical and morphological properties of BTPE were investigated. Taguchi method was applied to improve the mechanical and morphological properties by optimizing the processing parameters. That is, the experimental design adopted the L9 Taguchi orthogonal array with three manipulated factors (i.e., mixing temperature, rotor speed, and mixing time). Analysis of mean and analysis of variance were also exploited and the mixing temperature was found to be the most significant processing parameter regarding mechanical properties. The mixing temperature showed large contributions to Young's modulus, 100% modulus, tensile strength, and elongation at break, namely 45.33, 40.38, 49.31, and 36.04%, respectively. Furthermore, the optimum conditions found for mixing temperature, rotor speed, and mixing time were 140 °C, 100 rpm and 10 min, respectively. The result was confirmed by atomic force microscopy and scanning electron microscopy micrographs showing fine‐grained co‐continuous phase morphology of the ENR/PBS blends. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46541.     

Compatibilization effects of styrenic/rubber block copolymers in polypropylene/polystyrene blends

Compatibilizing effects of styrene/rubber block copolymers poly(styrene‐b‐butadiene‐b‐styrene) (SBS), poly(styrene‐b‐ethylene‐co‐propylene) (SEP), and two types of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS), which differ in their molecular weights on morphology and selected mechanical properties of immiscible polypropylene/polystyrene (PP/PS) 70/30 blend were investigated. Three different concentrations of styrene/rubber block copolymers were used (2.5, 5, and 10 wt %). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the phase morphology of blends. The SEM analysis revealed that the size of the dispersed particles decreases as the content of the compatibilizer increases. Reduction of the dispersed particles sizes of blends compatibilized with SEP, SBS, and low‐molecular weight SEBS agrees well with the theoretical predictions based on interaction energy densities determined by the binary interaction model of Paul and Barlow. The SEM analysis confirmed improved interfacial adhesion between matrix and dispersed phase. The TEM micrographs showed that SBS, SEP, and low‐molecular weight SEBS enveloped and joined pure PS particles into complex dispersed aggregates. Bimodal particle size distribution was observed in the case of SEP and low‐molecular weight SEBS addition. Notched impact strength (a_k), elongation at yield (ε_y), and Young's modulus (E) were measured as a function of weight percent of different types of styrene/rubber block copolymers. The a_k and ε_y were improved whereas E gradually decreased with increasing amount of the compatibilizer. The a_k was improved significantly by the addition of SEP. It was found that the compatibilizing efficiency of block copolymer used is strongly dependent on the chemical structure of rubber block, molecular weight of block copolymer molecule, and its concentration. The SEP diblock copolymer proved to be a superior compatibilizer over SBS and SEBS triblock copolymers. Low‐molecular weight SEBS appeared to be a more efficient compatibilizer in PP/PS blend than high‐molecular weight SEBS. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 291–307, 1999     

Compatibilization of PP/SEBS-MAH blends by grafting Glycidyl Methacrylate onto Polypropylene

Summary In this paper, the glycidyl methacrylate(GMA) was grafted to Polypropylene(PP) macromolecular backbone by melt radical grafting. The grafted PP-g-GMA was used to compatibilize PP/SEBS-g-MAH blend in a Haake apparatus. The result of Fourier Transform Infrared(FTIR) spectrum showed that the GMA had been grafted to PP. And the reaction between epoxy groups in the GMA and MAH groups in SEBS-g-MAH had taken place. The result of torque test showed that the torque values of the compatibilized blends were higher than that of the uncompatibilized blends. The observation of Scanning Electron Microscopy (SEM) showed that the dispersed phase domain size of compatibilized blends decreased evidently than uncompatibilized blends. When the content of SEBS-g-MAH was 16 wt % and the PP-g-GMA was 2 wt % in the blend, the rubber particle size had a minimum value. Those indicated that the PP-g-GMA could compatibilize PP/ SEBS-g-MAH blends effectively. Notched Izod impact tests showed the addition of PP-g-GMA in the PP/SEBS-g-MAH blends induced a remarkable improvement of toughness and yielded a tougher PP blends.     

Waste ground rubber tire powder/thermoplastic vulcanizate blends: Preparation,characterization, and compatibility

In this article, waste ground rubber tire (WGRT) powder was introduced into thermoplastic vulcanizate (TPV) to prepare the blends of WGRT powder/TPV. The mechanical, rheological, thermal aging, and dynamic properties of the blends were investigated with respect to the particle size and dosage of WGRT powder. The results showed that tensile strength, tear strength, elongation at break, and tensile permanent deformation of the blends increased with the decrease in WGRT particle size and decreased with the dosage of WGRT. The effects of different types and dosages of compatibilizers on mechanical and rheological properties of the blends were studied. The results showed that the compatibilizer PP‐g‐MAH could effectively improve the interfacial compatibility between WGRT and the TPV matrix to enhance the comprehensive properties of blends. The TPV/WGRT/PP‐g‐MAH blends obtained the best overall properties when prepared at the weight ratio 100/30/5. Rheological studies demonstrated that the WGRT/TPV blends represented lower apparent viscosity after PP‐g‐MAH were added, which means that processing performance of the blends was improved by PP‐g‐MAH. Scanning electron microscopy was used to study the morphologies of the blends. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39868.     

In situ compatibilization of polylactide/thermoplastic polyester elastomer blends using a multifunctional epoxide compound as a processing agent

In situ compatibilized poly(lactic acid)/thermoplastic polyester elastomer (PLA/TPEE) (80/20) blends are prepared by using multifunctional epoxide oligomer (coded as ADR) as a reactive modifier. Experiments such as torque, melt mass flow rate (MFR), SEM, DSC and tensile test were conducted to characterize properties of the PLA/TPEE/ADR blends. In situ reactions between PLA, TPEE and ADR were researched using a lab torque rheometer. It was proposed that ADR may initiate a variety of chain extension/branching reactions between PLA and TPEE under mixing process. In particular, the formed copolymer PLA‐ADR‐TPEE could be viewed as an in situ compatibilizer to improve the compatibility of PLA and TPEE. As expected, the value of MFR decreased greatly with increasing the ADR addition. The morphology reveals that interface adhesion of PLA/TPEE blend was enhanced with the incorporation of ADR, which led to a reduction in TPEE domain size. Moreover, tensile ductility of PLA/TPEE (80/20) blend was improved greatly by addition of the reactive modifier, e.g. the elongation at break was increased from 53% to the maximum value of 213% with addition of 1.2 phr ADR. The toughening effect can be explained by crazing with shear yielding mechanism. Attempts were made to produce ductile films from these PLA/TPEE/ADR blends by using extrusion blowing method. Effect of ADR on blowing stability and tensile property of these blends was investigated. Improvement on blowing stability and tensile ductility of PLA/TPEE/ADR films also shows that ADR is an efficiently reactive compatibilizer, as well as a viscosity enhancer for PLA/TPEE blends. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43424.     

Morphology and properties of poly(ethylene terephthalate) and thermoplastic polyester elastomer blends modified in the melt by a diisocyanate chain extender and filled with a short glass fiber

The structural features and rheological, mechanical, and relaxation properties of poly(ethylene terephthalate) (PET) blends with 7–50 wt % polyester thermoplastic polyester elastomer (TPEE), a block copolymer of poly(butylene terephthalate) and poly(tetramethylene oxide), chemically modified by a diisocyanate chain extender (CE) and reinforced with 30% glass fibers (GF) were studied. The composites were obtained by reactive extrusion with a twin‐screw reactor–mixer with a unidirectional rotation of screws. The molecular–structural changes in the materials were judged against data provided by differential scanning calorimetry, scanning electron microscopy, relaxation spectrometry, and rheological analysis of the melts. Regardless of the TPEE concentration in the blends with GF‐reinforced PET, the addition of CE resulted in the growth of the indices of the mechanical properties at straining, bending, and impact loading and an increase in the melt viscosity. In addition, an increase in the average length of short GFs in the composites and an intensification of interphase adhesion in the polyester binder–GF surface system were observed. The introduction of CE promoted a slowdown in PET crystallization in the composites and intensified the interphase adhesion in the binder–GF system at temperatures higher and lower than the PET glass‐transition temperature. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45711.     

Compatibilization of PLA/PBAT blends by using Epoxy-POSS

Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends were compatibilized using epoxidized polyhedral oligomeric silsesquioxanes (Epoxy-POSS). Three different Epoxy-POSS types were utilized having mono-, tri-, and multi-epoxides per POSS cage. In order to understand the localization of Epoxy-POSS types, wetting coefficients were calculated from surface energy measurements. According to scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was observed that Epoxy-POSS types mostly located at the interface of PLA/PBAT phases. The compatibilization of PLA and PBAT was shown through the decrease in dispersed particles size and the shifts in glass transition temperatures of phases. Mechanical properties of PLA/PBAT improved in the presence of Epoxy-POSS types. The Izod impact strength and elongation in tensile test values were maximized when 0.5% monoepoxy-POSS was used as compatibilizer. The reactions between Epoxy-POSS and polymers were monitored by Fourier transform infrared (FTIR) analysis and rheology. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47217.     

Compatibilization of PP/PE blends and scraps with Royalene: Mechanical properties,SAXS, and WAXS

PP/PE 93/7 model virgin blends and recycled scraps were compatibilized with Royalene (EPDM/PE 65/35 blend) and mechanically tested. No differences in impact and tensile properties between them were found. However, the tensile-impact strength increased almost twice with 10%-compatibilized sample in comparison with uncompatibilized ones. The yield stress of blends containing 10% Royalene decreased to 75–80% of the original value. This effect is in agreement with microhardness measurements; the increase in the compatibilizer content causes softening of the blend. The elongation at break and elongation at yield do not depend on the compatibilizer concentration. The compatibilizer does not influence the degree of crystallinity (WAXS data) of the blends either. Vickers microhardness is in good agreement with Tabor's relationship. The differences between long periods of HDPE in Royalene and LDPE in PP/PE blends (SAXS) proved PE/EPDM interaction. The interaction plays a key role in the toughening of PP/PE blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Compatibilization of styrene–butadiene–styrene block copolymer in polypropylene/polystyrene blends by analysis of phase morphology

Effect of compatibilization of styrene–butadiene–styrene (SBS) block copolymer in polypropylene/polystyrene (PP/PS) blends was studied by means of small angle X‐ray scattering (SAXS) and scanning electron microscope (SEM). According to SAXS, a certain amount of SBS was located at the interface in all the analyzed samples, forming the relatively thicker interface layer penetrating into homopolymers, and the thickness of the interface layer was quantified in terms of Porod light scattering theory. The incorporation of SBS into PP/PS blends resulted in a decrease in domain size following an emulsification curve as well as an uniform size distribution, and consequently, a fine dispersion of PP domains in the PS matrix. This effect was more pronounced when the concentration of SBS was higher. A critical concentration of SBS of 15% above which the interface layer approaches to saturation and domain size attains a steady‐state was observed. Further, the morphology fluctuation of unetched fracture surface of umcompatibilized and compatibilized blends was analyzed using an integral constant Q based on Debye‐Bueche light scattering theories. Variation of Q as a function of the concentration of SBS showed that, due to the penetrating interface layer, adhesion between phases was improved, making it possible for applied stress to transfer between phases and leading to more uniform stress distribution when blends were broken; accordingly, a more complicated morphology fluctuation of fracture surface appeared. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:365–370, 2007     

Improving the toughening in poly(lactic acid)‐thermoplastic cassava starch reactive blends

Poly(lactic acid) (PLA), a physical blend of PLA and thermoplastic cassava starch (TPCS) (PLA‐TPCS), and reactive blends of PLA with TPCS using maleic anhydride as compatibilizer with two different peroxide initiators [i.e., 2,5‐bis(tert‐butylperoxy)‐2,5‐dimethylhexane (L101) and dicumyl peroxide (DCP)] PLA‐g‐TPCS‐L101 and PLA‐g‐TPCS‐DCP were produced and characterized. Blends were produced using either a mixer unit or twin‐screw extruder. Films for testing were produced by compression molding and cast film extrusion. Morphological, mechanical, thermomechanical, thermal, and optical properties of the samples were assessed. Blends produced with the twin‐screw extruder resulted in a better grade of mixing than blends produced with the mixer. Reactive compatibilization improved the interfacial adhesion of PLA and TPCS. Scanning electron microscopy images of the physical blend showed larger TPCS domains in the PLA matrix due to poor compatibilization. However, reactive blends revealed smaller TPCS domains and better interfacial adhesion of TPCS to the PLA matrix when DCP was used as initiator. Reactive blends exhibited high values for elongation at break without an improvement in tensile strength. PLA‐g‐TPCS‐DCP provides promising properties as a tougher biodegradable film. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46140.     

Compatibilization of polypropylene/polystyrene blends with poly(styrene-b-butadiene-b-styrene) block copolymer

The compatibilizing effect of the triblock copolymer poly(styrene-b-butadiene-b-styrene) (SBS) on the morphology and mechanical properties of immiscible polypropylene/polystyrene (PP/PS) blends were studied. Blends with three different weight ratios of PP and PS were prepared and three different concentrations of SBS were used for investigations of its compatibilizing effects. Scanning electron microscopy (SEM) showed that SBS reduced the diameter of the PS-dispersed particles as well as improved the adhesion between the matrix and the dispersed phase. Transmission electron microscopy (TEM) revealed that in the PP matrix dispersed particles were complex “honeycomblike” aggregates of PS particles enveloped and joined together with the SBS compatibilizer. Wide-angle X-ray diffraction (WAXD) analysis showed that the degree of crystallinity of PP/PS/SBS slightly exceeded the values given by the addition rule. At the same time, addition of SBS to pure PP and to PP/PS blends changed the orientation parameters A₁₁₀ and C significantly, indicating an obvious SBS influence on the crystallization process in the PP matrix. SBS interactions with PP and PS influenced the mechanical properties of the compatibilized PP/PS/SBS blends. Addition of SBS decreased the yield stress and the Young's modulus and improved the elongation at yield as well as the notched impact strength in comparison to the binary PP/PS blends. Some theoretical models for the determination of the Young's modulus of binary PP/PS blends were used for comparison with the experimental results. The experimental line was closest to the series model line. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 69: 2625–2639, 1998     

Localized compatibilization in immiscible blends of thermoplastic polyurethane and ethylene‐octylene copolymer

To prepare thermoplastic polyurethane (TPU)/ethylene‐octylene copolymer (POE) blends, which are thermodynamically immiscible, maleated POE and aminated POE were incorporated as compatibilizers. Effect of addition of the compatibilizers and their contents on morphology, coalescence, and mechanical properties of TPU/POE blends were investigated. The microstructural observation revealed that the compatibilizers are located at the interface in the blends, forming a stable interfacial layer. As a result, the dispersed phase particle size was greatly reduced and tensile properties of the blends were significantly improved. POE‐NH₂ provides the blends with higher compatibility than POE‐MA. The interfacial interaction offered by the compatibilizers was found to be a function of the amount of the reactive groups grafted onto POE. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Improvement of polyamide/thermoplastic polyurethane blends with polyamide 6-polyurethane copolymer prepared via suspension polymerization as compatibilizer

The polyamide 6-polyurethane copolymer (PA6-b-PU-b-PA6) was synthesized through anionic suspension polymerization and then mixed with polyamide 6/thermoplastic polyurethane (PA6/TPU) and polyamide 6, 6/thermoplastic polyurethane (PA66/TPU) blends using as the compatibilizer. The results show that the PA6-b-PU-b-PA6 copolymers powders several can be obtained through suspension polymerization using dimethicone as disperse medium. The average diameter of PA6-b-PU-b-PA6 copolymer powders decreased with the increasing of PU content. With the addition of PA6-b-PU-b-PA6, the TPU phase dispersed more uniformly in PA6 or PA66 matrix, and the size of TPU dispersed phase decreased obviously. The PA6-b-PU-b-PA6 copolymer with higher PU content shows better compatibilizing effect. Addition of PA6-b-PU-b-PA6 can improve both strength and toughness of the PA/TPU blends. When the amount of PA6-PU25% copolymer was 5 phr, the tensile strength and notched impact strength of PA6/TPU/PA6-PU25% blends increased 29 and 159.4%, respectively, compared to the PA6/TPU blend without compatibilizer.     

Compatibilization of polypropylene/Poly(acrylonitrile‐butadiene‐styrene) blends by polypropylene‐graft‐cardanol

The polypropylene‐graft‐cardanol (PP‐g‐cardanol) was prepared by reactive extrusion with polypropylene (PP) and natural renewable cardanol which could increase the interfacial energy of PP and inhibit the degradation of PP during the process of reactive extrusion and usage. In this article, PP‐g‐cardanol and polypropylene‐graft‐maleic anhydride (PP‐g‐MAH) were used as compatibilizers of the polypropylene (PP)/poly(acrylonitrile‐butadiene‐styrene) (ABS) blends. PP/ABS (70/30, wt %) blends with PP‐g‐cardanol and PP‐g‐MAH were prepared by a corotating twin‐screw extruder. From the results of morphological studies, the droplet size of ABS was minimized to 1.93 and 2.01 μm when the content of PP‐g‐cardanol and PP‐g‐MAH up to 5 and 7 phr, respectively. The results of mechanical testing showed that the tensile strength, impact strength and flexural strength of PP/ABS (70/30) blends increase with the increasing of PP‐g‐cardanol content up to 5 phr. The complex viscosity of PP/ABS (70/30) blends with 5 phr PP‐g‐cardanol showed the highest value. Moreover, the change of impact strength and tensile strength of PP/ABS (70/30) blends were investigated by accelerated degradation testing. After 4 accelerated degradation cycles, the impact strength of the PP/ABS (70/30) blends with 5 phr PP‐g‐cardanol decrease less than 6%, but PP/ABS (70/30) blends with 5 phr PP‐g‐MAH and without compatibilizer decrease as much as 12% and 32%, respectively. The tensile strength of PP/ABS (70/30) blends has a similar tendency to that of impact strength. The above results indicated that PP‐g‐cardanol could be used as an impact modifier and a good compatibilizer, which also exhibited better stability performance during accelerated degradation testing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41315.     

Effective structure regulation of poly(vinylidene fluoride) via soy protein isolate: A morphological study

The microstructures of poly(vinylidene fluoride) (PVDF)/soy protein isolate (SPI) films were successfully modulated via denatured SPIs. While vegetable proteins have been extensively researched as functional biomaterials in fabrication of polymer blends, the diverse polymer‐protein interactions because of complex protein structures have not received sufficient attention. In this study, the PVDF‐SPI interactions were tuned by different denaturation treatments including heat, sonication, and chemical denaturation by 2‐mercaptoethanol and sodium dodecyl sulfate, respectively. Phase morphologies, crystal structures of PVDF, and secondary structures of SPI were analyzed by scanning electron microscope, fluorescence imaging, X‐ray diffraction, and Fourier transformed infrared spectroscopy. While 90 °C denaturation and sodium dodecyl sulfate led to nonporous structures, all other denatured SPIs produced distinctive porous structures. The crystallinity of PVDF was reduced to different degrees, depending on the denaturation of SPI. The distinctive microstructures of PVDF/SPI films indicated the diversity of PVDF‐SPI interactions and its importance in functional polymer/protein blends. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 134, 46706     

弹性体接枝马来酸酐对PP/PA6 的增容作用

以4种弹性体接枝马来酸酐(MAH)共聚物作为聚丙烯/聚酰胺6(PP/PA6)共混体系的增容剂,从界面相互作用、形态结构和力学性能等方面比较了它们的增容作用。乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)和乙丙三元共聚物接枝MAH(EPDM-g-MAH)使PP与PA6两相间的界面相互作用增强,增容效果较好;POE-g-MAH为增容剂时,PA6粒子分布较均匀,粒径约为1μm。POE-g-MAH能明显改善PP/PA6共混体系的韧性和强度,具有良好的增容作用。当w(POE-g-MAH)为10%时,w(PA6)为60%的共混体系拉伸强度最高,达到53.4MPa;适当增加PA6用量,可明显改善共混体系的流动性。     

Properties and preparation of olefin block copolymer/thermoplastic polyurethane blends

The properties of olefin block copolymer (OBC)/thermoplastic polyurethane (TPU) blends with or without maleic anhydride (MA) modification were characterized and compared. Compared with the OBC/TPU blends, OBC‐g‐MA/TPU blends displayed finer morphology and reduced domain size in the dispersed phase. The crystallization temperatures of TPU decreased significantly from 155.9 °C (OBC/TPU) to 117.5 °C (OBC‐g‐MA/TPU) at low TPU composition in the blends, indicating the inhibition of crystallization through the sufficient interaction of modified OBC with TPU composition. The modified systems showed higher thermal stability than the unmodified systems over the investigated temperature range due to the enhanced interaction through inter‐bonding. The highest improvement in tensile strength was more than fivefold for OBC‐g‐MA/TPU (50/50) in comparison with its unmodified blend via the enhanced interfacial interaction between OBC‐g‐MA and TPU. This also led to the highest Young's modulus of 77.8 ± 3.9 MPa, about twofold increase, among the investigated blend systems. A corresponding improvement on the ductility was also observed for modified blends. The modification did not vary the glass transition temperature and crystalline structure much, thus the improvement in the mechanical properties was mainly attributed to the improved compatibility and interaction from the compatibilization effect as well as increased viscosity from the crosslinking effect for modified blends. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43703.