POLY(p-PHENYLENE SULFIDE)—AN OVERVIEW OF AN IMPORTANT ENGINEERING THERMOPLASTIC

Characterization of PPS Piston and Packing Ring Materials for High-Pressure Hydrogen Applications

The widespread adoption of renewable energy hinges on the efficient transportation of hydrogen. Reciprocating piston compressor technology in non-lubricated operation will play a key role, ensuring high flow rates and compression ratios. These systems rely on advanced high-strength sealing solutions for piston and rod packing rings utilizing advanced fiber-reinforced polymers. Polyphenylene sulfide (PPS) polymer matrix composites have seen use in tribological applications and promise high mechanical strength and wear resistance. The presented work describes carbon and glass fiber-reinforced PPS matrix polymers in comparison, which are characterized by complementary methods to investigate their properties and potential for application in reciprocating compressor under non-lubricated operation. Thermo-mechanical and tribological testing was supported by microstructure analysis utilizing advanced X-ray and electron imaging techniques. New insights in micromechanical deformation behavior in regard to fiber materials, interface strength and orientation in fiber-reinforced polymers are given. Conclusions on the suitability of different PPS matrix composites for high-pressure hydrogen compression applications were obtained.

Rapid biodegradation of polyphenylene sulfide plastic beads by Pseudomonas sp

Pseudomonas sp. isolated from soil, are bioremediating microorganisms that are capable of degrading various types of plastics. Polyphenylene sulfide (PPS) has the most excellent structural stability among general plastics and thus is extremely difficult to break down using physical or chemical methods. This study demonstrates the efficient biodegradation of PPS by Pseudomonas sp., which exists in the gut of superworms. Compared with the conventional film-type of plastic, the degradation efficiencies to the bead form of plastic were significantly improved and thus the biodegradation time was dramatically shortened. Therefore, instead of film-type plastics, we used 300 μm diameter plastic beads for the measurement of Pseudomonas sp.-mediated biodegradation of PPS during a 10-day period. This method not only can be used for comparison and verification of the biodegradation efficiency of different types of plastics within a short reaction time of 10 days, but also provides the possibility to develop a new and more efficient screening system to rapidly identify the most efficient species of bacteria for the biodegradation of various types of plastics.

Reversible and Irreversible Color Change during Photo and Thermal Degradation of PolyphenyleneSulfide Composite

The effect of the light spectral composition and temperature on the change of color characteristics and reflection spectra during the irradiation of polyphenylene sulfide reinforced by short glass fibers in the SUNTEST apparatus was analyzed. The scales of reversible color change upon successive exposure to total radiation corresponding to the sunlight spectrum and to visible light wereevaluated and the possible mechanisms for the observed effects are discussed. The features of the color change upon visible light irradiation of previously thermally aged samples wereconsidered. Possible causes for deviation from the Arrhenius law during thermal aging of the composite are discussed. It wasdemonstrated that even with a significant change in color, the physicomechanical and electrotechnical characteristics of the composite only changedslightly or remained virtually at the same high level.

Preparation and mechanical properties of poly(p-phenylene sulfide) nanofiber sheets obtained by CO2 laser supersonic multi-drawing

In this study, poly(p-phenylene sulfide) (PPS) nanofiber sheets were fabricated by winding PPS nanofibers onto a spool. Previously, PPS nanofibers have been prepared by irradiating a PPS fiber with a CO2 laser while drawing it at supersonic speeds by single-fiber injection through an orifice. Here, we incorporated the nanofibers obtained into large nanofiber sheets and determined their mechanical properties. Supersonic air was introduced into a vacuum chamber through eight fiber injection orifices to obtain large PPS nanofiber sheets. The nanofibers were collected for 10 min, producing a rectangle sheet with dimensions of 17 cm×18 cm, a thickness of 70 μm, and an average fiber diameter of 700 nm. The dependence of the sheet’s mechanical properties on winding speed was investigated in the machine direction (MD) and traverse direction (TD) at four winding speeds.

The effect of limited monomer solubility in heterogeneous step-growth polymerization

Limited monomer solubility imposes very intriguing features on poly(p-phenylenebenzobisoxazole) polymerization. Only one type of functional group is detected at oligomer chain ends, and a high-molecular-weight polymer is obtained even when an excess of the monomer with low solubility is used. These remarkable phenomena are interpreted as an unprecedented "spoon-feeding-of-monomer" mechanism. A novel apparatus for staged polymerization is described that was triggered by the uniqueness of the heterogeneous step-growth polymerization. Hyperbranched polyesters and a polyurethane/polyethylene blend, which represent two phases in the polymerization process, are also discussed.