Foamed polystyrene

Why is commercial polystyrene an amorphous polymer Why is it sometimes referred to as crystal polystyrene  

Why is it possible to manufecture polystyrene by radical) anionic cationic and coordination polymerization methods  

What is it about the monomer that promotes a syndiotactic arrangement of the pendant styrene group Why is the polymer still considered atactic if the syndiotactic addition is more energetically favorable  

Describe the bulk polymerization process for the manufacture of polystyrene. What limitations exist with this method  

in the production of styrene co-acrylonitrOe, do we introduce a 62 38 ratio of -styrene to acrylonitrile in the reaction vessel  

IW m BASF KuammoH wd ab STYtOFOR B ndtnd. STYROPOR Mmf ad SIYROPOR ti Peidorw a dm H—dd 

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The penetration of visible light through foamed polystyrene has been shown to foUow approximately the Beer-Lambert law of light absorption (22). This behavior presumably is characteristic of other ceUular polymers as weU. 

Eresh fmit and vegetable packaging is often in bulk in a variety of traditional wooden boxes and crates, and cormgated fiberboard cases. At or near the retail level, bulk produce may be repackaged in oxygen-permeable flexible materials such as PVC, with or without a tray of foamed polystyrene. 

Foaming polystyrene resin prepared by blending with gas deHvers an opaque, low density sheet useful for beverage-bottle and plastic can labels as a water-resistant paper substitute (see Styrene polymers). 

Foamed plastics (qv) were developed in Europe and the United States in the mid-to-late 1930s. In the mid-1940s, extmded foamed polystyrene (XEPS) was produced commercially, foUowed by polyurethanes and expanded (molded) polystyrene (EPS) which were manufactured from beads (1,2). In response to the requirement for more fire-resistant ceUular plastics, polyisocyanurate foams and modified urethanes containing additives were developed in the late 1960s urea—formaldehyde, phenoHc, and other foams were also used in Europe at this time. 

Plastics. Citric acid and bicarbonate are used as an effervescent blowing agent to foam polystyrene for insulated food and beverage containers replacing blowing agents such as chlorinated fluorocarbons (194—206). 

Property ASTM Test Phenolics Foamedin Syntactic Place Castable Polyvinyl Chloride Rigid Closed Cell Phenylene Oxide Foamable Resin Polycarbonate Polystyrene Medium-Density Foam Polystyrene Molded Extruded Polyurethane Rigid Closed Cell... 

By depositing low concns of PETN on foamed polystyrene, Archibald (Ref 47A) obtained very low density expl systems. At an apparent PETN density of 0.09g/cc he found D = 2.05 mm/p sec. D could be varied by changing the PETN concn... 

About half of the styrene produced is polymerized to polystyrene, an easily molded, low-cost thermoplastic that is somewhat brittle. Foamed polystyrene can be made by polymerizing it in the presence of low-boiling hydrocarbons, which cause bubbles of gas in the solid polymer after which it migrates out and evaporates. Modification and property enhancement of polystyrene-based plastics can be readily accomplished by copolymerization with other substituted ethylenes (vinyl monomers) for example, copolymerization with butadiene produces a widely used synthetic rubber. 

Foamed polystyrene sheet is thermoformed into single use plates, insulated cups, fast food clam shell packages, and take home containers. 

Foamed polystyrene - which is also known as expanded polystyrene - is used extensively in a variety of applications, ranging from packaging peanuts to insulation board and single-use cups and plates. We produce it by two processes foam extrusion and bead expansion. Both types of expanded polystyrene consist of closed cells, i.e., bubbles with continuous walls. We can visually distinguish the two types of foam by the fact that products made by the expanded bead process consist of discrete beads that are welded together... 

Compare and contrast the bead expansion and foam extrusion methods of creating foamed polystyrene. 

What properties of foamed polystyrene make it amenable for the manufacture of packing peanuts ... 

Experiments pertaining to a new system for the application of bromine to flame retardant polypropylene and foamed polystyrene are described. The FR compound, ammonium bromide, is formed in the amorphous regions of the polymer phase by the interaction of bromine sorbed on the polymer and ammonia, sorbed subsequently. Gaseous nitrogen which is also produced, expands and brings about the rearrangement of the chains to produce a porous structure. The ammonium bromide produced is finely divided and imparts FR properties to the polymer. 

Foamed boards, 23 403—404 Foamed polystyrene, 23 403 Foamed sheet polystyrene, 23 408 Foamex, commercial defoamer, 3 24 It Foam extrusion, 19 549 Foam-forming materials, injection of, 12 22-23... 

Foamed polystyrene, too, dates from the thirties. The method of adding blowing agents to polystyrene in an extruder so that the extrudate expands was developed by Dow (L5). It is still used today on a large scale. 

Packaging applications are the most extensive. Meat, poultry, and egg containers arc thermoformed from extruded foamed polystyrene sheet. The fast-food market also accounts for a substantial amount of polystyrene for takeout containers where the insulation value of a foamed container is an advantage. Containers, tubs, and trays formed from extruded impact polystyrene sheets are used for packaging a large variety of food. Biaxially oriented polystyrene film is thermoformed into blister packs, meat trays, container lids, and cookie, candy, pastiy, and other food packages where clarity is required. 

As of 1992, the first specialty platable plastic, acrylonitrile—butadiene—styrene (ABS) terpolymer (see Acrylonitrile polymers, abs resins), is used in over 90% of POP applications. Other platable plastics include poly(phenylene ether) (see Polyethers), nylon (see Polyamides), polysulfone (see Polymers containing sulfur), polypropylene, polycarbonate, phenolics (see Pphenolic resins), polycarbonate—ABS alloys, polyesters (qv), foamed polystyrene (see Styrene plastics), and other foamed plastics (qv). 

Gendron R, Champagne MF, Delaviz Y, Polasky ME (2006) Foaming polystyrene with a mixture of C02 and ethanol. J Cell Plast 42 127-138... 

Other Isobutane-Based Chemicals. Isobutane can be directly dehydrogenated to isobutylene by a modification of the Houdry process. This can then be converted to MTBE. The estimated use is over 1 billion lb of isobutane. Because of their inertness and higher vapor pressures, high-purity propane and butanes have become the important substitutes for fluorocarbons as aerosol propellants. Isobutane can also be used as a solvent in polymer processing, and as a blowing agent for foamed polystyrene. 

The measurements can be carried out in natural waters. A basin, made of steel concrete and bulkhead steel, has a buffering floor made of to foamed polystyrene. Air is blown in along the bulkhead walls for damping purposes, so that an air curtain is formed. 

Properly ASTM Test Phenolic Chi onile Rigid Closed Cell Plienylcne Oxide Foam able Resin Polyethylene Medium- Polycarbonate Density Foam Polystyrene Polyurethane Rigid Closed Cell... 

This work was motivated by the need to quantify the pentane vapor diffusion through closed-cell polystyrene foam (Salejova et al., 2005). Once the polystyrene foam is formed, the pentane as the blowing agent has to diffuse out from the cellular microstructure and is replaced by air. Freshly foamed polystyrene is not dimensionally stable and it shrinks as it relaxes on the timescale of days to weeks. Environmental concerns call for the reduced consumption of pentane as the blowing agent. 

In 2005, Japanese company Kaneka developed the first beads-process, foamed resin moulded product, which is based on polylactic acid. The new KanePearl product has the strength and shock-absorbing properties of existing beads-process, foamed polystyrene products. 

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