scholarly journals Transparent PC/PMMA Blends with Enhanced Mechanical Properties via Reactive Compounding of Functionalized Polymers

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 73
Author(s):  
Tobias Bubmann ◽  
Andreas Seidel ◽  
Holger Ruckdäschel ◽  
Volker Altstädt

Reactive compounding of terminally phenolic OH-functionalized polycarbonate (PC) with epoxy-functionalized polymethylmethacrylate (PMMA) prepared by copolymerization with glycidyl methacrylate was investigated. It was spectroscopically demonstrated that a PC/PMMA copolymer was formed during the melt reaction of the functional groups. Zirconium acetylacetonate could catalytically accelerate this reaction. Correlations of the phenomenological (optical and mechanical) properties with the molecular level and mesoscopic (morphological) structure were discussed. By the investigated reactive compounding process, transparent PC/PMMA blends with two-phase morphologies were obtained in a continuous twin-screw extruder, which, for the first time, combined the high transmission of visible light with excellent mechanical performance (e.g., synergistically improved tensile and flexural strength and high scratch resistance). The transparency strongly depended on (a) the degree of functionalization in both PC and PMMA, (b) the presence of the catalyst, and (c) the residence time of the compounding process. The in-situ-formed PC/PMMA copolymer influenced the observed macroscopic properties by (a) a decrease in the interphase tension, leading to improved and stabilized phase dispersion, (b) the formation of a continuous gradient of the polymer composition and thus of the optical refractive indices in a diffuse mesoscopic interphase layer separating the PC and PMMA phases, and (c) an increase in the phase adhesion between PC and PMMA due to mechanical polymer chain entanglement in this interphase.

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1058
Author(s):  
Hikaru Okubo ◽  
Haruka Kaneyasu ◽  
Tetsuya Kimura ◽  
Patchiya Phanthong ◽  
Shigeru Yao

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.


2013 ◽  
Vol 804 ◽  
pp. 102-105
Author(s):  
Tao Yin ◽  
Yu Qi Gu ◽  
Chun Yu Yu ◽  
Zi Xin Li

Poly (phenylene sulfide) (PPS) was blended with polyamide 66 (PA66) in a wide range of compositions by using a co-rotating twin-screw extruder. Dynamic mechanical analysis was used in determination of the co-continuous phase. The results allowed to precisely detecting the range of co-continuity. In addition, the mechanical properties of PPS/PA66 composites can also be used to identify the dispersed/matrix phase or co-continuous phase structure.


2014 ◽  
Vol 496-500 ◽  
pp. 327-330
Author(s):  
Shou Hai Wang ◽  
Jun Gao ◽  
Shu Xia Lin ◽  
Ping Zhang ◽  
Jun Huang ◽  
...  

Ethylene methacrylate (EMA) copolymer toughened acrylonitrile-butadiene-styrene (ABS)/polymethyl methacrylate (PMMA) were prepared in a co-rotating twin-screw extruder. The effect of EMA on mechanical properties and surface gloss of ABS/PMMA blends was investigated. Experiment results show that the toughness of ABS/PMMA is improved effectively with the incorporation of EMA, while the tensile strength and glossiness decrease slightly. ABS/PMMA/EMA blends present optimum mechanical and luster properties when the content of EMA is 6wt%.


2011 ◽  
Vol 12 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Yusof Yusliza ◽  
Ahmad Zuraida

ABSTRACT : The effect of fiber content on mechanical properties and thermal stability of the cotton/albumen composites (CAC) were investigated and presented in this paper. The composites having 0%, 3%, 6%, 10%, 13 %, and 16% w/w of cotton fiber were considered.  Hands lay-up technique was used to prepare the CAC specimens and dried for 24 hours before characterised and evaluated for their mechanical performance. The structure and thermal stability of the composites were characterized by using x-ray and thermogravimetry analysis, respectively. The tensile strength and impact resistance of CAC are found maximum with the value of 8.7 MPa and 19.0 kJ/m2, respectively. Analysis on the morphological structure by SEM revealed that the mechanical properties of the composites depend on good wettability and adhesion between fiber/matrix.


2005 ◽  
Vol 881 ◽  
Author(s):  
B. Krevet ◽  
M. Kohl

AbstractIn this work, we present simulations of the thermo-magneto-mechanical performance of a ferromagnetic SMA microactuator in the inhomogeneous field of a CoSm permanent magnet and compare it with experimental results. For the simulations, a combination of different finite element (FEM) programs is used allowing the coupling of electrical, thermal, magnetic and mechanical properties. The field of a permanent magnet is calculated along the trajectory of the microactuator, from which the magnetic forces Fmag and their gradients are derived. Shape memory forces FSME are calculated based on a two-phase macromodel. Both forces, Fmag and FSME, determine the quasi-static behavior of a NiMnGa microscanner, which has been proposed recently.


Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 633
Author(s):  
Vasile Tiron ◽  
Ioana-Laura Velicu ◽  
Teodora Matei ◽  
Daniel Cristea ◽  
Luis Cunha ◽  
...  

In this contribution, based on the detailed understanding of the processes’ characteristics during reactive high-power impulse magnetron sputtering (HiPIMS), we demonstrated the deposition of silicon oxide (SiO2) thin films with improved optical and mechanical performances. A strategy for stabilizing the arc-free HiPIMS of Si target in the presence of oxygen was investigated. Arcing was suppressed by suitable pulse configurations, ensuring good process stability without using any feedback control system. It was found that arcing can be significantly alleviated when ultra-short HiPIMS pulses are applied on the target. The optical and mechanical properties of SiO2 coatings deposited at various pulsing configurations were analyzed. The coatings prepared by ultra-short pulse HiPIMS exhibited better optical and mechanical performance compared to the coatings prepared by long pulse HiPIMS. The optimized SiO2 coatings on quartz substrates exhibited an average transmittance of 98.5% in the 190–1100-nm wavelength range, hardness of 9.27 GPa, hardness/Young’s modulus ratio of 0.138, and critical adhesion load of 14.8 N. The optical and mechanical properties are correlated with the film morphology, which is inherently related to energetic conditions and process stability during film growth.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4358
Author(s):  
Jörg Weise ◽  
Dirk Lehmhus ◽  
Jaqueline Sandfuchs ◽  
Matthias Steinbacher ◽  
Rainer Fechte-Heinen ◽  
...  

Metal foam inserts are known for their high potential for weight and vibration reduction in composite gear wheels. However, most metal foams do not meet the strength requirements mandatory for the transfer of sufficiently high levels of torque by the gears. Syntactic iron and steel foams offer higher strength levels than conventional two-phase metal foams, thus making them optimum candidates for such inserts. The present study investigates to what extent surface hardening treatments commonly applied to gear wheels can improve the mechanical properties of iron-based syntactic foams. Experiments performed thus focus on case hardening treatments based on carburizing and carbonitriding, with subsequent quenching and tempering to achieve surface hardening effects. Production of samples relied on the powder metallurgical metal injection molding (MIM) process. Syntactic iron foams containing 10 wt.% of S60HS hollow glass microspheres were compared to reference materials without such filler. Following heat treatments, the samples’ microstructure was evaluated metallographically; mechanical properties were determined via hardness measurements on reference samples and 4-point bending tests, on both reference and syntactic foam materials. The data obtained show that case hardening can indeed improve the mechanical performance of syntactic iron foams by inducing the formation of a hardened surface layer. Moreover, the investigation indicates that the respective thermo-chemical treatments can be applied to composite gear wheels in exactly the same way as to monolithic ones. In the surface region modified by the treatment, martensitic microstructures were observed, and as consequence, the bending limits of syntactic foam samples were increased by a factor of three.


2013 ◽  
Vol 685 ◽  
pp. 19-23 ◽  
Author(s):  
Ali Sinan Dike ◽  
Harun Mindivan

The present work aims to compare the mechanical properties of Polypropylene (PP) based composites reinforced with B4C. Maleic Anhydride Modified Polypropylene (MAPP) was added to improve the B4C-matrix interphase. Processing has been carried out by twin-screw extrusion and injection molding. By adding the B4C particles to the PP and PP+MAPP matrix, the yield strength, shore D hardness, microhardness and relative scratch resistance increased gradually, but PP+MAPP/B4C composites showed better overall mechanical properties than the PP/B4C composites. However, elongation at break values occurred for all composites dropped with the B4C content, and PP+MAPP/B4C composites exhibited lower elongations at break than PP/B4C composites.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2070 ◽  
Author(s):  
Tobias Bubmann ◽  
Andreas Seidel ◽  
Volker Altstädt

The effect of different catalysts on reactive compatibilization of 50/50 polycarbonate (PC)/polymethylmethacrylate (PMMA) blends achieved via transesterification that occurs during compounding in a twin-screw extruder was investigated on a phenomenological (optical and mechanical properties), mesoscopic (phase morphology), and molecular level (PC-graft(g)-PMMA-copolymer formation and polymer molecular weight degradation). Formation of PC-(g)-PMMA-copolymer by transesterification resulting in transparent mono-phase PC/PMMA blends with obviously improved compatibility of the two polymer constituents requires use of a suitable catalyst. As a side-effect, PC-(g)-PMMA-copolymer formation by transesterification is always accompanied by a significant simultaneous decomposition of the molecular weight (Mw) of the PC. For the first time, a colorless, transparent (mono-phase) PC/PMMA 50/50 blend was achieved by a twin-screw extrusion process that can be easily transferred into industrial scale. To achieve this milestone, 0.05 wt% of a weakly acidic phosphonium salt catalyst had to be applied. As a result of the decrease in Mw of the PC, the mechanical properties (e.g., tensile strain at break and impact strength) of the obtained blends were significantly deteriorated rather than improved as targeted by the polymer compatibilization; therefore, the produced transparent PC/PMMA blends are considered not yet technically suitable for any industrial applications. Different manufacturing process strategies that do not inherently result in PC degradation as a side effect of PC-graft(g)-PMMA-copolymer formation have to be developed to potentially achieve transparent PC/PMMA blends with a useful balance of properties. Based on the experimental observations of this study, a new mechanism of the transesterification reaction occurring during reactive compounding of PC and PMMA in the presence of the effective catalysts is proposed.


2013 ◽  
Vol 320 ◽  
pp. 473-477 ◽  
Author(s):  
Ze Peng Liu ◽  
Yong Yan Cui

Effects of PMMA resin on the mechanical properties and processability of CPVC/PMMA(Chlorinated polyvinyl chloride/polymethyl methacrylate) blends were studied in this paper. The results showed, the impact strength of CPVC/PMMA blends were improved, the heat distortion temperature and tensile strength didn't reduce significantly when the content of PMMA was set to 15 phr, the melt viscosity decreased as the content of PMMA increased in the blends, and the surface gloss were improved. The miscibility of CPVC/PMMA blends in which the content of PMMA was set to 15 phr were studied. The microscopic structure of two-phase was also showed in the SEM micrographs.


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