Recycle high impact polystyrene

F. Vilaplana, A. Ribes-Greus, and S. Karlsson, Analytical strategies for the quality assessment of recycled high-impact polystyrene A combination of thermal analysis, vibrational spectroscopy, and chromatography, Anal Chim. Acta, 604(l) 18-28, November 2007. 

In the industrial field, this separation technique has been used for purposes as diverse as the analysis of odour and taste problems in high-density polyethylene [93], contaminants in recycled high-impact polystyrene [94], benzene residues in recycled polyethylene terephthalate [95] and denture adhesives [96], residual toluene in medical plasters [97], and lipstick (for assignation of products to manufacturers) [98,99]. 

Mural and co-workers [57] also optimised the mechanical properties of an rPP and recycled high impact polystyrene (rHIPS) blend at a composition of 70/30 wt%. Consequently, this composition was mixed with a styrene-ethylene-butylene-styrene (SEES) block copolymer triblock copolymer and Cloisite 20A OMMT. Using X-ray diffraction, the samples containing 3 wt% of nanoclay were found to lack the characteristic nanoclay peak, which indicated the mixed intercalated and exfoliated clay layers where the intercalated layers were further pushed toward the interphase [76]. The incorporation of a compatibiliser and nanoclay also improved the thermal stability of the PP/HIPS blend. SEES and nanoclay performed as an interfacial compatibiliser, which led to the reduction in particle size of rHIPS and the promotion of interfacial adhesion. 

Hamm, S., Strikkeling, M., Ranken, P. F., and Rothenbacher, K., Determination of polybrominated diphenyl ethers and PBDD/Fs during the recycling of high impact polystyrene containing decabromodiphenyl ether and antimony oxide, Chemosphere, 44, 1353-1360, 2001. 

GRT particles of sizes of lower than 500 xm and between 500-1000 trm were blended with a postconsumer PP and high impact polystyrene (HIPS) at ratios of 90/10 and 70/30 (Montagna and Santana, 2012). The rheological, physical, and mechanical properties of blends were measured. The addition of GRT reduced the mechanical properties with the reduction being dependent on the particle size. The incorporation of GRT particles into the recycled HIPS and PP matrix led to a decrease and an increase of viscosity, respectively. The extent of the effect was dependent on particle size. 

The Canadian Polystyrene Recycling Association (CPRA), with a plant in Mississauga, ON, accepts polystyrene from all over Canada. Over 95 percent of its revenue comes from the sale of recycled resins, mostly black high-impact polystyrene (HIPS). The remainder comes from member companies, representing manufacturers, distributors, and end users of polystyrene products. The plant, which has a capacity of 5000 tonnes of PS per year, accepts both food-service PS and cushioning materials. While it uses mostly postconsumer materials as feedstock, it also accepts obsolete PS materials from manufacturers, such as scrap from sign manufacturing. ... 

Types of plastic resins suitable for recycling include ABS, expanded polystyrene (EPS), HDPE, high-impact polystyrene (HIPS), PET, PP, PS and PVC. However, one of the problems currently being addressed in the move to extend plastics recycling is the requirement for a process to extract brominated flame retardants from waste plastics in order to leave an acceptable level in the plastics destined to be recycled. This is because the ban on the use of certain brominated flame retardants in new appliances will mean that plastic recyclates containing them cannot be used by the electronics sector, other applications will have to be found. 

Another type of linear flow reactor system for the synthesis of high-impact polystyrene is shown in Fig. 5 [1]. Here, the first-stage backmixed reactor (CSTR) is maintained just beyond the phase-inversion point (98 C, 14% solids) and the dissolved styrene reacts to form either a graft copolymer with the rubber or a homopolymer in the linear flow reactor train. Note that a portion of the effluent (130°C, 35% solids) from the second reactor is recycled to the first reactor. The temperature of the polymerizing mixture is gradually increased as it travels through the linear flow reactors and the final conversion of about 72% is achieved. 

Laboratory tests indicated that gamma radiation treatment and cross-linking using triaHylcyanurate or acetylene produced a flexible recycled plastic from mixtures of polyethylene, polypropylene, general-purpose polystyrene, and high impact grade PS (62). 

An easy recovery of a catalyst from a mixture of reagents/products as well as its simple handling and recycling are important problems in chemical synthesis. Consequently, new recoverable catalysts attract increasing attention and the use of polymeric supports became a common practice. Polystyrene [1] is one of the most popular polymer supports due to its availability, facile functionalization and chemical inertness. However, such organic polymers usually show a solvent swelling dependent performance, which impacts the catalytic activity of the supported species. Polysiloxanes, due to unusually high flexibility of the polymer chain and low barrier... 

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