The potential for reuse of plastics recovered from solid wastes

Abstract

Plastics in solid wastes is a problem of growing concern. Recycling of wastes is currently believed to be the most acceptable form of disposal in the long run; however, this route is known to be especially difficult for plastics. Recycling would be easier if the various generic types present in solid wastes, mainly polyethylene, polystyrene and poly (vinyl chloride), could be isolated; however, this would be very difficult and expensive. This is a first report on research aimed at evaluating the potential of recycling plastics as a polymer blend of the various generic types. This approach suffers from the difficulty that the different plastics are incompatible and the blend has poor mechanical properties. The extent of this problem is documented with data on many ternary blends employing virgin polyethylene, polystyrene and poly (vinyl chloride) of numerous grades likely to be found in solid wastes. Property degradation was found to be more severe as the complexity of the blend increased, indicating that general municipal wastes could be reused only in very low grade applications, whereas certain commercial wastes might have brighter prospects. Strategies for improving blend properties are outlined.

Recycling of Mixed Plastics Waste Containing Polyethylene, Polyvinylchloride and Polyethylene Terephthalate

“…A substantial part of public solid waste (MSW) streams is composed of mixed polymers. Polyethylene (PE), polypropylene (PP) , polyvinyl chloride (PVC) and Polyethylene terephthalate (PET) are among the most common plastics waste, since they are the most frequently used commercial plastics in our daily lives as well as in industries [1]. A number of approaches are currently being investigated for dealing with post consumer resin.…”

Mechanical Properties of Ternary Blends of ABS + HIPS + PETG

“…The reprocessing of such factory scrap as a blend of the component polymers can be considered provided the mixture exhibits acceptable physical properties [2,4]. Unfortunately immiscibility is the rule for most polymer pairs and this inevitably leads to phase separation, poor interfacial adhesion and brittle materials [5,6].…”

“…However, nonlinear property improvements are possible in "compatible" phase-separated blends [6,7,9]. The term "compatibility" is used in technological literature when the blend has acceptable mechanical properties [4]. Compatibilization can be effected by the addition of small amounts of a third polymer, e.g.…”

“…Compatibilization can be effected by the addition of small amounts of a third polymer, e.g. a graft or block copolymer of the two constituent polymers [4,11,7,8,9,12]. This improves interfacial adhesion and allows the achievement of a finer dispersion of phases [4,9].…”

“…a graft or block copolymer of the two constituent polymers [4,11,7,8,9,12]. This improves interfacial adhesion and allows the achievement of a finer dispersion of phases [4,9]. For example, poly(ethy1ene terephthalate) (PET) blends with poly(acrylonitrile-butadiene-styrene) (ABS) are stabilized by adding maleic anhydride grafted ABS as compatibilizer [8] and ABS/ poly(butylene terephthalate) blends are further toughened by poly(styrene-co-glycidyl methacrylate) [12].…”