Plasticization, viii

Recyclingplas VIII Plastics Recycling as a Business Opportunity. Conference Proceedings. 

The major substances with production volumes in millions of pounds per year for organics, inorganics, polymers and plastics and primary derivatives of petroleum are noted in Tables VII, VIII, IX and X. 

Table VIII lists some representative T0 values of unplasticized polymers. Very flexible polymers such as polyethylene, polyisoprene, polybutadiene, have low T0 values, whereas polymers with stiff backbone chains and bulky side groups, such as poly(methyl methacrylate) and polystyrene, have a high Tg. Clearly, it is a polymer with a high revalue where plasticization is most needed and where a significant lowering of Tg owing to the plasticizer may be expected.

The electrical properties of such internally plasticized copolymers are quite unusual (6), and as we can see deserve much more thorough study (Table VIII). 

A new ASME code for calculating high pressure vessels (Sect VIII Div. 3) is based on the formulae to determine the internal pressure pcompi-pi for complete plastic yielding through the full wall with some assumptions, e.g. perfectly elastic-plastic material behavior and the GE-hypothesis [2]. 

The pressure vessel design codes and standards include lists of acceptable materials, in accordance with the appropriate material standards. The ASME BPV Code Sec. II Part D gives maximum allowable stresses as a function of temperature and maximum temperatures permitted under Sections I, III, VIII, and XII of the BPV code for ferrous and nonferrous metals. The design of pressure vessels using reinforced plastics is described in ASME BPV Code Sec. X. 

Tables VII and VIII sumnarize present and future RIM engineering plastic developments. This is an emerging area for RIM processable materials part of which will be made possible by recent equipment developments such as hot RIM. Polyurethane materials which now exist in this hard segment range are plastics...

TABUS VIII. HX3NBBRINS PLASTICS (>65% HARD SEXMNT)... 

PVCH Blends With Hydrogenated SB Polymers. One early goal of this research was to find a polymer that could be blended with PVCH to give an impact resistant product. Conventional unsaturated rubbers were incompatible. We did find, however, that PVCH-containing copolymers were compatible with PVCH and could yield clear, tough plastic compositions as shown in Table VIII. To obtain transparency, a minimum of 15% of a 25% PVCH compolymer is required. Depending on the ratios of PVCH to the copolymer, tough heat-resistant products can be made. 

Plasmapheresis. The separation of plasma from whole blood by continuous membrane filtration represents an improvement over conventional centrifugation techniques in terms of efficiency, safety and cost. In the past, plasmapheresis was carried out with blood donors by collecting their whole blood in plastic bags which were then centrifuged to separate the red cells from the plasma. The supernatant plasma was then decanted and the red cells returned to the donorenabling plasma to be drawn from the same person as frequently as three times per week. Most of this plasma is then processed to yield purified components such as albumin or anti-hemophilic factor (Factor VIII). 

Reproduced with permission from P.S. Allan, M.J. Bevis, P. Chuah and C.J. May, Plastics Pipes VIII, Konigshof, The Netherlands, 1992, Paper No. E2/4, Figure 1. 1992, Institute of Materials, UK. 

W. Elzink and J. Molin. Presented at the PRI Plastics Pipes VIII Conference, Eindhoven, the Netherlands, 1992, Paper No.A2/1. 

Elastic Stress Analysis - Simplified Elastic-Plastic Method. This method may be used in the case where the method indicated above shows the Pr + Pb + Q stress limits are not satisfied, but indicates that the Pl + Pb + Q range and excluding thermal effects must be less than Sps- Additionally, the effective alternating equivalent stress amplitude must include the fatigue penalty factor, ICej, which is based off of the simplified elastic-plastic criteria from the pre-2007 Section VIII, Division 2. Finally, a thermal stress ratcheting assessment must be made. 

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