Recyclable Blends

The experiments were repeated with a mixture of 60% small-diameter pellets and 40% low-density GPPS recycle material. The bulk density for this feedstock was measured at 0.10 g/cm a bulk density that was about 40% less than that for the commercial pellet-low-density recycle blend. This relatively large difference in density was attributed to the variability of the recycle material density. As indicated by the data in Table 12.11, the rate with no ledge was 20 kg/h, a rate that was about 30% less than that for the commercial pellet blend. Like before, the rate difference is primarily due to the differences between the feedstock bulk densities. When the ledge plates were positioned in the equipment, the solids-conveying rate was about 75% of the original rate. This rate decrease is very similar to the rate decrease that was experienced with the 114 mm diameter commercial extruder. Recall that the commercial extruder was operating at the maximum screw speed and at a rate that was only about 60% of the expected rate. 

Fresh feed (pure ethanol) is blended with a recycle stream (95 mole% ethanol and 5% acetaldehyde), and the combined stream is heated and vaporized, entering the reactor at 280 C. Gases leaving the reactor are cooled to -40 C to condense the acetaldehyde and unreacted ethanol. Off-gas from the condenser is sent to a scrubber, where the uncondensed organic compounds are removed and hydrogen is recovered as a by-product. The condensate from the condenser, which is 45 mole% ethanol, is sent to a distillation column that produces a distillate containing 97 mole% acetaldehyde and a bottoms product that constitutes the recycle blended with fresh feed to the process. The production rate of the distillate is 1000 kg/h. The pressure throughout the process may be taken as 1 atm absolute. 

The calculated crude-oil transportation cost for the emulsion case was based on estimates of the required capital investments for emulsification and oil recovery facilities, operating costs including pipeline tariffs, surfactant costs, and water disposal. The costs for the recycle blend case included the normal pipeline operating costs plus the costs of separating and pumping the diluent back to the start of the pipeline. The costs assumed for the... 

LCP dispersed in either PEST, PC, PA or modified PPE replacements for fiber reinforced plastics — recyclable blends Tomitaefa/., 1993, 1994... 

PA with PA/LDPE, EGMA recyclable blends, good performance Timmermann et al., 1994... 

Frequently, the recycled blends must also be impact-modified. There are two reasons for this (i) contamination of the composition by other polymers, and (ii) degradation of the usually less stable compatibilizers and impact modifiers. 

Blends of PPE with SBS, and an antioxidant/ metal deactivator (di-octylamine) were developed [Richards and Kelly, 1992 1994 Richards and Pickett, 1995]. Subjected to recycling at temperatures T = 250-350°C (or to thermal aging at T = 50-200°C), the blends maintained excellent retention of impact strength. Similarly, recyclable blends were prepared in two steps (1) PPE was capped with salicyhc acid ester, then blended with... 

Thermoplastic elastomer (TPE) blends have been broadly studied as a new class of materials. TPEs offer various advantages and require no state-of-the-art processing machinery, while scrap and rejects are recyclable. Blends can be homogeneous, phase separated or both. TPEs are multi-phase polymer systems consisting of hard and soft domains that can be copolymers or mechanical blends. This phase separation leads to materials having unique and viable commercial physical properties. TPEs exhibit the thermoplastic characteristics of the hard thermoplastic phase, and resilience as a result of the rubbery domains. TPEs based on natural rubber (NR) and thermoplastic blends are known as thermoplastic natural rubber (TPNR) blends. There are two types of TPNR, namely thermoplastic polyolefin (TPO) and thermoplastic vulcanizate (TPV).3... 

The crystallinity of HOPE is reduced in the recycled blend but not in the virgin ones, while the glass transition temperature of PS increases only in the virgin blends. Some modeling of the system was proposed but the full explanation of this behavior is still under study. 

Retain Polyethylene/polystyrene-based recycled blends Dow Plastics... 

After carding, the fibers were drawn twice and then ring spun into yam. The spinning process was difficult because the yams frequently broke, as will be seen by comparing these results with those obtained when spinning the 80% new acrylic/20% recycled blend (not chemically treated) described earUer. The spinning performance of chemically treated materials compared to non-treated is shown in Table 10.5. 

PET, polycondensation, films, fibers, ttles, thermal properties, mechanical properties, chemical stability, processing, recycling, blends, nanocomposites, surface modification. 

Recyclable blends of syndiotactic polystyrene, sPS, were prepared by blending sPS with a copolymer of styrene with either maleic anhydride (MA), or with glycidyl methaciylate (GMA), and with an elastomer, e.g., SEES, SBS, SBR, EPDM. The compositions showed good impact resistance, elongation and retention of physical properties upon... 

FIGURE 4.75 Rectangular flotation unit with recycle pressurization (1) flash mixing and flocculation, (2) float discharge line, (3) float beach, (4) skimmer, (5) adjustable effluent weir, (6) effluent line, (7) recycled effluent, (8) recycle pump, (9) air-saturation tank, (10) air controls, (11) pressure-reduction valve, (12) settled solids removal and bottom solids discharge line, (13) influent and recycle blending and distribution system, and (14) influent. (Envirex.)... 

Table 5 Mechanical properties of compatibilized and uncompatibilized recycled blends...

Compatibilisers are commercially available for combining a range of materials and this technology can also be applied to recyclate blends. The advantages of this are the removal of the requirement for costly and/or difficult separation processes, and the production of commercially valuable materials. The compatibilisers can be added during reprocessing usually at levels of around 2-5%. The cost of the compatibiliser must be taken into account, but this can... 

Few existing plastic blends are recycled with the notable exceptions of TPO, TPE, SMA, and some ABS streams (e.g., ABS, PC/ABS, ABS/Acrylic). More complex recycle blends have not yet made a significant impact on the recycle market. The use of recycle materials from complex mixtures is currently... 

Interaction of the sulfur and phosphorus types of chemicals can be a problem in recycling. If it is suspected that these two different types of chemicals are present in a mixed recycling blend, additional secondary AO of one type should be added in excess to provide long environmental life without color formation. The same is true when using these systems as thermal stabilizers. 

If, however, the various recycled polymers dted above are blended as part of the recycling process, the damage to the mechanical (ultimate) properties of the products is considerably reduced. This is notably case in binary recycled blends of polyolefins with polystyrene or... 

---