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Properties of Polystyrene Microspheres Polystyrene microspheres are in their most pure form, with no surface functionalization, coatings or colorants added. Crosslinked polystyrene is inert,... [more info...]

Bright field polystyrene beads (large diameter: 15µm) in a Trypan blue solution at a concentration of 1 x 10^6 beads/mL.* 4 x 1mL vials good for approximately 200 counts. (* Approximate bead concentration. Refer to COA of lot # for expected concentration.) Total Concentration on CoA. Can be used on all Cellometer instruments. Warranty is valid until the expiration date stated on the product label. If no expiration is listed, the warranty is valid for 12 months from the date of product receipt.

Detergent removal from lipid-protein-detergent micellar solutions is the most successful strategy for reconstitution of integral membrane proteins into proteoliposomes or into two-dimensional crystals. This review establishes the potential of polystyrene beads as a simple alternative to other conventional detergent removing strategies such as dialysis, gel chromatography and dilution. Kinetics and equilibrium aspects of removal of different detergents by hydrophobic adsorption onto polystyrene beads have been systematically investigated. A mechanism of adsorption onto polystyrene beads is proposed and provide useful information about the use of these beads in reconstitution experiments. The usefulness of this detergent removal strategy to produce quasi-ideal proteoliposomes is evaluated by considering the morphology and the size of the reconstituted vesicles, the homogeneity in size and protein distribution, the final protein orientation and the permeability of resulting proteoliposomes. Finally, the advantages of detergent removal by polystyrene beads as an alternative to conventional dialysis in two-dimensional crystallization trials are evaluated through review of recent structural reconstitution studies.

Our carboxylate-modified polystyrene latex microspheres are suitable for the covalent immobilization of proteins, peptides, and nucleic acids. They are synthesized via emulsion polymerization, and are available in diameters up to 20µm, with typical size CVs of 10%. Products are supplied as 10% solids suspension (w/w) in de-ionized water with surfactant and sodium azide.

EDAC-mediated coupling is often used for the covalent immobilization of amine-terminated proteins, DNA, or other molecules on carboxyl-functionalized PS and P(S/DVB) microspheres. Carboxyl polymer microspheres are available as 10% solids (w/w) aqueous suspensions in these standard amounts: 0.5g, 1.0g, 1.5g, and 5.0g. New to beads See our PolyLink Protein Coupling Kit .TechNote 205, Covalent CouplingPDS 732, Polystyrene Microspheres

Polystyrene (PS) /ˌpɒliˈstaɪriːn/ is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene.[5] Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to oxygen and water vapour and has a relatively low melting point.[6] Polystyrene is one of the most widely used plastics, the scale of its production being several million tonnes per year.[7] Polystyrene can be naturally transparent, but can be colored with colorants. Uses include protective packaging (such as packing peanuts and in the jewel cases used for storage of optical discs such as CDs and occasionally DVDs), containers, lids, bottles, trays, tumblers, disposable cutlery,[6] in the making of models, and as an alternative material for phonograph records.[8]

As a thermoplastic polymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 C, its glass transition temperature. It becomes rigid again when cooled. This temperature behaviour is exploited for extrusion (as in Styrofoam) and also for molding and vacuum forming, since it can be cast into molds with fine detail.

Under ASTM standards, polystyrene is regarded as not biodegradable. It is accumulating as a form of litter in the outside environment, particularly along shores and waterways, especially in its foam form, and in the Pacific Ocean.[9]

The company I. G. Farben began manufacturing polystyrene in Ludwigshafen, about 1931, hoping it would be a suitable replacement for die-cast zinc in many applications. Success was achieved when they developed a reactor vessel that extruded polystyrene through a heated tube and cutter, producing polystyrene in pellet form.[14]

In 1954, the Koppers Company in Pittsburgh, Pennsylvania, developed expanded polystyrene (EPS) foam under the trade name Dylite.[20] In 1960, Dart Container, the largest manufacturer of foam cups, shipped their first order.[21]

In chemical terms, polystyrene is a long chain hydrocarbon wherein alternating carbon centers are attached to phenyl groups (a derivative of benzene). Polystyrene's chemical formula is (C8H8)n; it contains the chemical elements carbon and hydrogen.[22]

The material's properties are determined by short-range van der Waals attractions between polymers chains. Since the molecules consist of thousands of atoms, the cumulative attractive force between the molecules is large. When heated (or deformed at a rapid rate, due to a combination of viscoelastic and thermal insulation properties), the chains can take on a higher degree of confirmation and slide past each other. This intermolecular weakness (versus the high intramolecular strength due to the hydrocarbon backbone) confers flexibility and elasticity. The ability of the system to be readily deformed above its glass transition temperature allows polystyrene (and thermoplastic polymers in general) to be readily softened and molded upon heating. Extruded polystyrene is about as strong as an unalloyed aluminium but much more flexible and much less dense (1.05 g/cm3 for polystyrene vs. 2.70 g/cm3 for aluminium).[23]

In polystyrene, tacticity describes the extent to which the phenyl group is uniformly aligned (arranged at one side) in the polymer chain. Tacticity has a strong effect on the properties of the plastic. Standard polystyrene is atactic. The diastereomer where all of the phenyl groups are on the same side is called isotactic polystyrene, which is not produced commercially.[citation needed]

The only commercially important form of polystyrene is atactic, in which the phenyl groups are randomly distributed on both sides of the polymer chain. This random positioning prevents the chains from aligning with sufficient regularity to achieve any crystallinity. The plastic has a glass transition temperature Tg of 90 C. Polymerization is initiated with free radicals.[7]

Polystyrene is relatively chemically inert. While it is waterproof and resistant to breakdown by many acids and bases, it is easily attacked by many organic solvents (e.g. it dissolves quickly when exposed to acetone), chlorinated solvents, and aromatic hydrocarbon solvents. Because of its resilience and inertness, it is used for fabricating many objects of commerce. Like other organic compounds, polystyrene burns to give carbon dioxide and water vapor, in addition to other thermal degradation by-products. Polystyrene, being an aromatic hydrocarbon, typically combusts incompletely as indicated by the sooty flame.[citation needed]

The process of depolymerizing polystyrene into its monomer, styrene, is called pyrolysis. This involves using high heat and pressure to break down the chemical bonds between each styrene compound. Pyrolysis usually goes up to 430 C.[26] The high energy cost of doing this has made commercial recycling of polystyrene back into styrene monomer difficult.[citation needed]

In 2016, it was also reported that superworms (Zophobas morio) may eat expanded polystyrene (EPS).[30] A group of high school students in Ateneo de Manila University found that compared to Tenebrio molitor larvae, Zophobas morio larvae may consume greater amounts of EPS over longer periods of time.[31]

In 2022 scientists identified several bacterial genera, including Pseudomonas, Rhodococcus and Corynebacterium, in the gut of superworms that contain encoded enzymes associated with the degradation of polystyrene and the breakdown product styrene.[32]

The bacterium Pseudomonas putida is capable of converting styrene oil into the biodegradable plastic PHA.[33][34][35] This may someday be of use in the effective disposing of polystyrene foam. It is worthy to note the polystyrene must undergo pyrolysis to turn into styrene oil.[citation needed]

Polystyrene is commonly injection molded, vacuum formed, or extruded, while expanded polystyrene is either extruded or molded in a special process.Polystyrene copolymers are also produced; these contain one or more other monomers in addition to styrene. In recent years the expanded polystyrene composites with cellulose[39][40] and starch[41] have also been produced. Polystyrene is used in some polymer-bonded explosives (PBX).[citation needed]

PS foams also exhibit good damping properties, therefore it is used widely in packaging. The trademark Styrofoam by Dow Chemical Company is informally used (mainly US & Canada) for all foamed polystyrene products, although strictly it should only be used for "extruded closed-cell" polystyrene foams made by Dow Chemicals.

Expanded polystyrene (EPS) is a rigid and tough, closed-cell foam with a normal density range of 11 to 32 kg/m3.[47] It is usually white and made of pre-expanded polystyrene beads. The manufacturing process for EPS conventionally begins with the creation of small polystyrene beads. Styrene monomers (and potentially other additives) are suspended in water, where they undergo free-radical addition polymerization. The polystyrene beads formed by this mechanism may have an average diameter of around 200 μm. The beads are then permeated with a "blowing agent", a material that enables the beads to be expanded. Pentane is commonly used as the blowing agent. The beads are added to a continuously agitated reactor with the blowing agent, among other additives, and the blowing agent seeps into pores within each bead. The beads are then expanded using steam.[48] 59ce067264


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