Correlation of miscibility and mechanical properties of polypropylene/olefin block copolymers: Effect of chain composition

Liu, Guoming; Zhang, Xiuqin; Li, Xiuhong; Chen, Hongyu; Walton, Kim; Wang, Dujin

doi:10.1002/app.36244

Cited by 40 publications

(26 citation statements)

References 47 publications

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“…Obviously, the chemical composition and CCDs vary in the two OBCs, and PBE-2 contains harder-softer segment alternating molecular chains. From the impact test results, we can reasonably infer that the hard-soft segment alternating molecular chains could possess as excellent a toughening effect as the ethylene/1octene random molecular chain [34]. The third type of PBE is a propylene-based propylene/ethylene copolymer, and most propylene/ethylene (P/E) copolymer chains are soluble, which indicates that the PBE-4 consists basically of the E/P random copolymer.…”

Section: Tref Analysismentioning

confidence: 85%

Toughened High-Flow Polypropylene with Polyolefin-Based Elastomers

Wang

Guo

et al. 2019

Polymers

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Polyolefin is the most widely used and versatile commodity polymer. In this work, three types of polyolefin-based elastomers (PBEs) were adopted to toughen a high-flow polypropylene to improve its overall performance. The chain microstructures of these PBEs, including ethylene/1-octene (E/O) random copolymer from Dow Chemical s polyolefin elastomer (POE), olefin block copolymers (OBCs) of E/O from Dow, and ethylene/propylene random copolymer from ExxonMobil's propylene-based elastomer, were elucidated by GPC, 13 C NMR, TREF, and DSC techniques. The mechanical, thermal and optical properties, and morphology analysis of the PP/PBE blends were also studied to investigate the toughening mechanism of these PBEs. The results showed that all three types of PBEs can effectively improve the Izod impact strength of the PP/PBE blends by the addition of the rubber compositions, at the cost of the stiffness. PBE-1 and PBE-2 were found to have a great stiffness-toughness balance with about 1700 MPa of flexural modulus, about 110 • C of HDT and 3.6 kJ/m 2 of impact strength on the prepared PP/PBE blends by forming separated rubber phase and refined spherulite crystals. As a result, the OBC with alternating hard and soft segments could achieve a similar toughening effect as the E/P random copolymer. Surprisingly, no obvious rubber phase separation was observed in the PP/PBE-4 blend, which might be due to the good compatibility of the E/P random chains with the isotactic PP; therefore, the PP/PBE blend obtains great toughness performance and optical transparency with the highest Izod impact strength of 4.2 kJ/m 2 and excellent transparency. 22 million tons. Due to rapid market expansion of takeout for dining box and automobile industries in China, the high-flow homo polypropylene market has also witnessed a dramatic increase to about above 600 kilotons annually in the recent few years.Although the high-flow homo polypropylene with high melting index (typically above 50 g/10 min) and good processability possesses high flexural modulus, the impact strength is relatively low compared to the ethylene/propylene copolymer and easily suffers from brittle fracture [22]. In order to solve this problem, two approaches are typically adopted to improve the overall performance of the polymer. One alternative is to introduce an extra operation line for the incorporation of a small amount of ethylene into the isotactic chain in the PP production facility, and the other method is to make post-modifications of the high-flow polypropylene by blending elastomer with PP, and glass fibers for automobiles [23][24][25].The Polyolefin-based elastomers (PBEs) have received considerable attention because of their low density, recycling potential, better chemical resistance, processing advantages, and good resilience without permanent deformation. Unlike rubber, they do not require vulcanization. In addition, the low cost together with the wide availability of ethylene, propylene and α-olefin monomers makes the polyolefin-based elastomers more desirable. T...

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Section: Tref Analysismentioning

confidence: 85%

Toughened High-Flow Polypropylene with Polyolefin-Based Elastomers

Wang

Guo

et al. 2019

Polymers

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“…The random copolymerization of propylene with other α‐olefins has been proven to be an effective method for broadening the application of isotactic polypropylene (iPP). For instance, iPP has relatively poor impact resistance, and its toughening modification has received scientific and industrial attention for decades . When copolymerizing with a certain amount of ethylene units, propylene–ethylene random copolymers (PPR) were found to be more ductile and tougher than iPP .…”

Section: Introductionmentioning

confidence: 99%

Correlation between the fracture toughness and β‐crystal fraction in a β‐nucleated propylene‐based propylene–ethylene random copolymer

Zhang

Liu

Jiang

et al. 2015

J of Applied Polymer Sci

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Propylene‐based propylene–ethylene random copolymer (PPR) has been widely used in the production of hot‐water pipes. To further improve its toughness and thermal resistance, β‐nucleating agents (β‐NAs) are frequently incorporated. In this study, PPR containing 5.6 mol % ethylene units was modified by two kinds of β‐NAs, that is, calcium pimelate and N,N′‐dicyclohexylterephthalamide. The notched Izod impact strength of PPR increased with the addition of the β‐NAs. Drastically different toughening effects were found between the two β‐NAs. The structure of PPR with and without a β‐NA was investigated by calorimetry, X‐ray diffraction, and thermomechanical analysis. The results indicated that the relative fraction of β crystals (kβ) in the injection‐molded specimens was determined by the type and content of β‐NA. The relationship between kβ and the impact toughness was summarized. A critical value for kβ (0.68) was identified for the brittle–ductile transition of PPR. PPR with β‐NA having a kβ greater than 0.68 displayed a higher impact strength than the other mixtures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42930.

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“…This phenomenon can be attributed to the mismatch in thermal expansion coefficients between the PP and the dispersed elastomer (EOC), which is reported by other researchers . The slight reduction of T g of PP in PP/EOC blend represents the partial miscibility of EOC block copolymer with PP …”

Section: Resultsmentioning

confidence: 73%

Morphology and properties of polypropylene/ethylene-octene copolymer/clay nanocomposites with double compatibilizers

Bagheri-Kazemabad

Fox

Chen

et al. 2014

Polym. Adv. Technol.

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The influence of nanoclay on the morphology and properties of the polypropylene (PP)/ethylene–octene block copolymer (EOC) blend with double compatibilizers of maleated PP (PP‐g‐MA) and maleated EOC (EOC‐g‐MA) was investigated and compared with the nanocomposites containing either PP‐g‐MA or EOC‐g‐MA as a compatibilizer. X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy were utilized for morphological characterization in conjunction with dynamic mechanical thermal analysis, mechanical testing, and rheological evaluation of these nanocomposites. The results suggested that in the nanocomposite including both compatibilizers of PP‐g‐MA and EOC‐g‐MA, clay was dispersed as a mixed structure of intercalation and exfoliation in both phases of the polymer blend. Comparing the mechanical properties of the studied nanocomposite with nanocomposites of PP/EOC/PP‐g‐MA/clay and PP/EOC/EOC‐g‐MA/clay also indicated that the nanocomposite containing mixed compatibilizers displayed higher tensile modulus, tensile strength, and complex viscosity because of the better dispersion of clay in both phases. The results also confirmed the increased structural stability and reduced dispersed phase size of PP/EOC/PP‐g‐MA/EOC‐g‐MA blend in the presence of clay that proposed the compatibilization role of clay in this nanocomposite. Copyright © 2014 John Wiley & Sons, Ltd.

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Correlation of miscibility and mechanical properties of polypropylene/olefin block copolymers: Effect of chain composition

Cited by 40 publications

References 47 publications

Toughened High-Flow Polypropylene with Polyolefin-Based Elastomers

Toughened High-Flow Polypropylene with Polyolefin-Based Elastomers

Correlation between the fracture toughness and β‐crystal fraction in a β‐nucleated propylene‐based propylene–ethylene random copolymer

Morphology and properties of polypropylene/ethylene-octene copolymer/clay nanocomposites with double compatibilizers

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