Polystyrene, plastics

A variety of cellular plastics exists for use as thermal iasulation as basic materials and products, or as thermal iasulation systems ia combination with other materials (see Foamed plastics). Polystyrenes, polyisocyanurates (which include polyurethanes), and phenoHcs are most commonly available for general use, however, there is increasing use of other types including polyethylenes, polyimides, melamines, and poly(vinyl chlorides) for specific appHcations. 

Self-Test F.5A The molar mass of styrene, which is used in the manufacture of the plastic polystyrene, is 104 g-mol", and its empirical formula is CH. Deduce its molecular formula. 

ISO 1622-1 1994 Plastics - Polystyrene (PS) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 1622-2 1995 Plastics - Polystyrene (PS) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 2561 1974 Plastics - Determination of residual styrene monomer in polystyrene by gas chromatography... 

Plasticized Polystyrene. Samples of polystyrene containing 0, 5, 10, and 20% plasticizer were provided by the Koppers Co., Inc., Research Department. The plasticizer used was Union Carbides DOP [di-(2-ethylhexyl)phthalate]. All of the samples were derived from the same base lot of polystyrene and were compounded with the plasticizer by means of a small extruder. The samples were provided as small pellets. The number-average molecular weight of the base polystyrene was measured by the Koppers Co. Research Department as 122,000. The weight-average molecular weight by several measurements was reported as approximately 260,000. 

The equilibrium gas concentration, and thus die equilibrium sample deflection of plasticized polystyrene samples, should be inversely proportional to the diffusivity of the gas in a plasticized polymer. The measured diffusivities for hydrogen in unplasticized polystyrene and polystyrene containing 20% plasticizer differ by a factor of about 2 (Figure 16). From the 0 and 20% plasticizer points in Figure 13, curve C, we see that the equilibrium deflections also differ by a factor of about 2 to 3. 

The plasticized polystyrene materials provided by the Koppers Co. Research Department are also appreciated. 

Polymer bonded explosives (PBXs) were developed to reduce the sensitivity of the newly-synthesized explosive crystals by embedding the explosive crystals in a rubber-like polymeric matrix. The first PBX composition was developed at the Los Alamos Scientific Laboratories in USA in 1952. The composition consisted of RDX crystals embedded in plasticized polystyrene. Since 1952, Lawrence Livermore Laboratories, the US Navy and many other organizations have developed a series of PBX formulations, some of which are listed in Table 1.2. 

Figure 1. Glass transition temperature of plasticized polystyrene vs. reciprocal of the number average molecular weight of the mixture (6)...

Figure 9. The Extension Tp — Tq of the Elastic Range of Plasticized Polystyrene...

Figures 1 to 3 also show that the decrease from the rubbery plateau to the rubbery flow is more rapid for plasticized PVC than for the pure polymer. This has been previously observed for polystyrene and plasticized polystyrene (27). Maximum relaxation times have been shown to be shorter for the plasticized sample due to the decrease in T0 as well as to a decrease in apparent average molecular weight (27). A similar interpretation applies in the case of plasticized polyviny. chloride.

The entire procedure is performed in plastic (polystyrene) tubes and carried out at room temperature. Freshly collected venous blood is anticoagulated with hirudin (1 volume + 9 volumes of animal blood) or ACD solution (1 volume + 9 volumes of human blood) and centrifuged at 170 x g for 15 min to obtain platelet-rich plasma (PRP). The PRP-supematant is carefully removed, and the rest is further centrifuged at 1500 x g for 10 min to obtain platelet-poor plasma (PPP). PRP is diluted with PPP to a platelet count of 3 x 108/ml before use in the aggregation assays. To obtain washed platelets (WP), 8.5 volumes of human blood are collected into 1.5 volumes of ACD and centrifuged as for PRP. PRP is acidified to a pH of 6.5... 

The entire procedure is performed in plastic (polystyrene) tubes at room temperature according to Marguerie et al. (1979). 

The entire procedure is performed in plastic (polystyrene) tubes and carried out at room temperature. Blood is drawn from healthy adult volunteers, who had not received medication for the last 2 weeks. 9 ml venous blood are anti-coagulated with 1 ml of sodium citrate and kept in a closed tube at room temperature for 30-60 min until the start of the test. 

Natural polymers include cellulose (the "fibre" in your food) and DNA. Synthetic polymers include plastics, polystyrene (see below), and the material you will produce in this activity. 

Bonding of hydrophobic plastic materials to wood to create new wood-plastic (polystyrene) materials with improved mechanical and physical properties that incorporate the desirable features of each constituent is difficult to achieve. This is due to poor interfacial adhesion between the wood and polystyrene components because of their inherent incompatibility. New, well-defined, tailored cellulose-polystyrene graft copolymers have recently been prepared using anionic polymerization techniques. Preliminary bonding studies showed that these graft copolymers can function effectively as compatibi-lizers or interfacial agents to bond hydrophobic plastic (polystyrene) material to wood, evolving into a new class of composites. 

Figure 2. Continuous three-dimensional network of plastic (polystyrene) linked to wood via a cellulose-polysytrene graft copolymer.

Kambour RP, Gruner CL, Romagosa EE (1973) Solvent crazing of dry polystyrene and dry crazing of plasticized polystyrene. J Polym Sci Polym Phys 11 (10) 1879—1890... 

Polystyrene is an amorphous, white and brittle plastic. Polystyrene has many applications due to its rigidity. Polystyrene is used for making products such as toys, display boxes, packaging material, egg cartons and styrofoam. 

Amorphous materials can be found as hard glassy plastics (polystyrene) or can be soft, flexible and rubbery (polyisoprene). This means that there is a temperature range where an amorphous material is in a glassy state and above which it is rubbery. This temperature is known as the glass-transition temperature Tg. However, a truly amorphous material cannot have a crystalline melting point (Tm). Crystalline materials (usually an amorphous—crystalline mixture) can have a Tg—in the case of polyethylene this is around -85°C. 

Fig. 33. Small-angle X-ray scattering of a single crack in plasticized polystyrene measured at different positions along the crack. A smaller number at the profile designates a position closer to the crack tip [60]...

Capillary Rheometer and an Extruder Are They in Agreement One can ask a reasonable question If rheology data are obtained in a capillary rheometer, are they applicable to an extruder To answer this question, at least for a specific set of conditions, a direct comparison was made [31]. It was found that the capillary rheometer and extruder are in good agreement for neat plastics (polystyrene and polypropylene), but extruder systematically measures lower viscosities in glass-fiber-filled plastics. 

Empee 1%. [Monmouth Plastics] Polystyrene to inj. molded and extrud p. ... 

Styron. [Dow Plastics] Polystyrene general-purpose, impact, and structural foam resins. 

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