Preparation and Characterization of high‐strength poly(ether ether ketone) films

Li, Wenlei; Wang, Guibin; Jiang, Zhenhua; Liu, Chuan; Huo, Pengfei; Zhang, Shuling

doi:10.1002/app.40172

Cited by 8 publications

(11 citation statements)

References 31 publications

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“…Later, the reduction of crystallinity in these PEEK/PEI blends, which is hindered completely, particularly at high cooling rates [12] when PEI content reaches 50% [5,12,17]. It is worth mentioning here the effect of crystallinity: it is well known that the best mechanical properties, thermal, and/or solvent resistance are not reached unless there is substantial crystallization [18][19][20][21]. Moreover, crystallinity plays an important role in the adhesion and mechanical properties of PEEK composites [22].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of PEEK/PEI Multilayer Composites

et al. 2020

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Polyetheretherketone (PEEK)/polyetherimide (PEI) blends (50/50, v/v) keeping the crystal phase of PEEK have been manufactured by alternate PEEK/PEI layer stacking. This strategy avoided the complete miscibility of both polymers, keeping layers of PEEK and PEI unmixed along the sample thickness, as well as promoting the formation of a smooth interfacial layer where PEEK and PEI were mixed. The properties of this interface after processing at molten state and different times was studied by DSC, DMA, and X-Ray synchrotron. These techniques allowed monitoring the evolution of glass transition, where isolated Tg’s for both pristine polymers were observed even after long processing time. PEEK crystallinity slightly decreased during manufacturing, whereas PEEK crystal parameters did not vary. These observations show that, although the interface—the zone where both polymers are mixed—grew, layers with pristine polymers remained even after prolonged processing time. The preservation of the PEEK crystallinity was also observed in the mechanical properties of the multilayer PEEK/PEI films, which were compared with pristine PEEK and PEI films. Multilayer samples processed for shorter times rendered higher young modulus, tensile strength, and strain at break.

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Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of PEEK/PEI Multilayer Composites

et al. 2020

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“…When subjecting the semi-crystalline PEEK beyond its glass transition temperature, the polymer chains begin to rearrange and hitherto initiate the crystallization process, which has been found to be highly effective at enhancing strength and stiffness. For instance, Li et al [ 15 ] revealed that, after keeping the neat PEEK film at 210 °C for a prolonged period of time, the overall crystallinity reached 29.7%, and the resultant strength reached 140.0 MPa, almost a 25.0% increase from the amorphous PEEK matrix. Crystallization also promotes electrical conductivity through expelling the conductive fillers to the boundaries of crystals, as dictated by the classic volume percolation theory [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Non-Isothermal Crystallization Kinetics of Polyether-Ether-Ketone Nanocomposites and Analysis of the Mechanical and Electrical Conductivity Performance

et al. 2022

Polymers

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High-performance polyether-ether-ketone (PEEK) is highly desirable for a plethora of engineering applications. The incorporation of conductive carbon nanotubes (CNTs) into PEEK can impart electrical conductivity to the otherwise non-conductive matrix, which can further expand the application realm for PEEK composites. However, a number of physical properties, which are central to the functionalities of the composite, are affected by the complex interplay of the crystallinity and presence of the nanofillers, such as CNTs. It is therefore of paramount importance to conduct an in-depth investigation to identify the process that optimizes the mechanical and electrical performance. In this work, PEEK/CNTs composites with different carbon nanotubes (CNTs) content ranging from 0.5 to 10.0 wt% are prepared by a parallel twin-screw extruder. The effects of CNTs content and annealing treatment on the crystallization behavior, mechanical properties and electrical conductivity of the PEEK/CNTs composites are investigated in detail. A non-isothermal crystallization kinetics test reveals a substantial loss in the composites’ crystallinity with the increased CNTs content. On the other hand, mechanical tests show that with 5.0 wt% CNTs content, the tensile strength reaches a maximum at 118.2 MPa, which amounts to a rise of 30.3% compared with the neat PEEK sample after annealing treatment. However, additional annealing treatment decreases the electrical conductivity as well as EMI shielding performance. Such a decrease is mainly attributed to the relatively small crystal size of PEEK, which excludes the conductive fillers to the boundaries and disrupts the otherwise conductive networks.

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“…This implies that after total integration and subsequent cooling, PEI will remain unchanged [ 23 ], but the diffusion and infiltration of PEI chains into PEEK will inhibit the nucleation and growth of crystallites in the latter polymer. Reduced crystallinity has direct consequences on both the mechanical properties of the homogeneous polymer blend [ 24 , 25 ] and its ability to form a good bonding interface in PEEK-reinforced composite materials [ 26 , 27 ]. The multilayer polymer (MLP) stacking technique is an alternative strategy to handle these drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Processing Conditions and Mechanical Properties for PEEK/PEI Multilayered Blends

et al. 2022

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The goal of producing polyetheretherketone/polyetherimide (PEEK/PEI) blends is to combine the outstanding properties that both polymers present separately. Despite being miscible polymers, it is possible to achieve PEEK/PEI multilayered blends in which PEEK crystallinity is not significantly inhibited, as opposed to conventional extruding processes that lead to homogeneous mixtures with total polymer chain interpenetration. This study investigated a 50/50 (volume fraction) PEEK/PEI multilayered polymer blend in which manufacturing parameters were tailored to simultaneously achieve PEEK–PEI adhesion while keeping PEEK crystallinity in order to optimize the mechanical properties of this heterogeneous polymer blend. The interface adhesion was characterized with the use of three-point bending tests, which proved that a processing temperature below the melting point of PEEK produced weak PEEK–PEI interfaces. Results from differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and X-ray diffraction analysis (XRD) showed that under a 350 ∘C consolidation temperature, there is a partial mixing of PEEK and PEI layers in the interface that provides good adhesion. The thickness of the mixed homogeneous region at this temperature exhibits reduced sensitivity to processing time, which ensures that both polymers essentially remain separate phases. This also entails that multilayered blends with good mechanical properties can be reliably produced with short manufacturing cycles. The combination of mechanical performance and potential joining capability supports their use in a wide range of applications in the automotive, marine, and aerospace industries.

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Preparation and Characterization of high‐strength poly(ether ether ketone) films

Cited by 8 publications

References 31 publications

Fabrication and Characterization of PEEK/PEI Multilayer Composites

Fabrication and Characterization of PEEK/PEI Multilayer Composites

Non-Isothermal Crystallization Kinetics of Polyether-Ether-Ketone Nanocomposites and Analysis of the Mechanical and Electrical Conductivity Performance

Optimization of Processing Conditions and Mechanical Properties for PEEK/PEI Multilayered Blends

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