Segregated poly(arylene sulfide sulfone)/graphene nanoplatelet composites for electromagnetic interference shielding prepared by the partial dissolution method

Segregated conductive polymer composites have been proved to be outstanding electromagnetic interference shielding (EMI) materials at low filler loadings. However, due to the poor interfacial adhesion between the pure conductive filler layers and segregated polymer granules, the mechanical properties of the segregated composites are usually poor, which limit their application. Herein, a simple and effective approach, the partial dissolution method, has been proposed to fabricate segregated poly(arylene sulfide sulfone) (PASS)/graphene nanoplatelet (GNP) composites with superior EMI shielding effectiveness (SE) and high tensile strength. Morphology examinations revealed that the GNPs were restricted in the dissolved outer layer by the undissolved cores, and there was a strong interaction between the PASS/GNP layer and the pure PASS core. The resultant PASS/GNP composites showed excellent electrical conductivity (60.3 S m^-1) and high EMI SE (41 dB) with only 5 wt% GNPs. More notably, the tensile strength of the PASS/GNPs prepared by partial dissolution reached 36.4 MPa, presenting 136% improvement compared to that of the conventional segregated composites prepared by mechanical mixing. The composites also exhibited high resistance to elevated temperatures and chemicals owing to the use of the special engineering polymer PASS as a matrix.

The influence of processing aids on the melt stability and mobility of poly(arylene sulfide sulfone)

The phosphorous antioxidant bis[2,4-bis(1-methyl-1-phenylethyl)phenyl] pentaerythritol diphosphite (s-9228), hindered phenol antioxidant N, N′-hexane-1,6-diylbis-[3,5-di-tert-butyl-4-hydroxyphenylpropionamide] (1098), and zinc acetate (ZnAc) were chosen as processing aids to improve the melt stability and mobility of poly(arylene sulfide sulfone) (PASS). Different contents and components of the processing aids were discussed. The capillary rheometer test demonstrated that 3 wt% ZnAc showed better effect with the change of the shear rates. In contrast, the parallel-plate rheometer test proved that the complex antioxidant, including 0.8 wt% s-9228 and 1.6 wt% 1098, showed better effect with the change of temperature. Both the capillary rheometer and parallel-plate rheometer test showed that the compounding aid consisting of 0.8 wt% s-9228, 1.6 wt% 1098, and 3 wt% ZnAc showed the best effect with the dramatically improved melt stability and mobility. Also, PASS could be processed successfully by extruding and through an injection machine with the help of the compounding aid. Meanwhile, the effects of the applied processing aids on melt complex viscosity and modulus were also discussed.

Effect of air dielectric barrier discharge plasma treatment on the adhesion property of sanded polyphenylene sulfide

Air dielectric barrier discharge (DBD) plasma was employed to treat the sanded polyphenylene sulfide (PPS) surface. The plasma-treated PPS samples were bonded with epoxy adhesive, and the adhesion strength was measured by the single lap-joint specimen test. Scanning electron microscopy (SEM), water contact angle analysis, and X-ray photoelectron spectroscopy (XPS) were applied to investigate the effect of the plasma treatment on the PPS surface property. A slight etching trace was detected after the plasma treatment according to the SEM images. XPS and water contact angle analysis indicated that the plasma treatment introduced sulfide oxides (S=O and O=S=O) onto the PPS surface leading to a higher surface energy. A steady improvement of bonding shear strength was achieved with the increase of plasma treatment time or discharge power density, which was consistent with the failure mode study. According to the above analysis, the air DBD plasma treatment could effectively improve the adhesion property of PPS.