The dissolution/reprecipitation technique applied on high‐density polyethylene: I. Model recycling experiments

Abstract

A model dissolution/reprecipitation process is studied for the recycling of high‐density polyethylene (HDPE). The process proposed basically comprises dissolution of the plastic in an appropriate solvent, reprecipitation by using a nonsolvent, thorough washing of the material obtained, and drying. The solvent mixtures involved are separated by distillation for further reuse. Toluene/acetone was tried as a potential solvent/nonsolvent pair and proved to be very satisfactory, similarly to the case of recycling low‐density polyethylene. Further investigation was focused on the effect of sample history through successive recycling cycles. The recycled grades were evaluated in terms of the following properties: melt flow index (MFI), molecular weight, crystallinity, mechanical performance in tensile mode, and grain size analysis. In all cases the recycled polymer exhibited excellent retention of its properties. © 1995 John Wiley & Sons, Inc.

Chemical recycling of plastic wastes made from polyethylene (LDPE and HDPE) and polypropylene (PP)

“…Even more, there is a clear indication that after recycling the elastic modulus increases possibly due to the influence of the fractionation phenomena encountered during the dissolution/reprecipitation process (i.e. some lower molecular weight fractions may remain soluble in the solvent/non-solvent phase), as well as to the role of the additives initially contained in the starting material [12][13][14].…”

“…For this purpose, different solvents/non-solvents were examined at different weight percent amounts and temperatures using either model polymers as raw material or commercial waste products (packaging film, bags, pipes, food-retail products). This technique has been widely used by Papaspyrides et al [12][13][14] and other researchers [15]. Furthermore, catalytic pyrolysis was carried out in a laboratory fixed bed reactor using as raw materials either model LDPE, HDPE and PP or waste products based on these polymers.…”

Mechanical recycling of postused high-density polyethylene crates using the restabilization technique. I. Influence of reprocessing

“…About 70% of the total HDPE consumption enters the waste streams in less than 2 years, because the HDPE homopolymers are commonly used for film, bottle, and container applications. 2 A further stream of HDPE consists of well-defined long-term applications, such as crates, containers, automotive, and electrical parts. The mechanical recycling of this easily collected scrap is mandatory.…”

“…[1][2][3][4] In recent years, it has been accepted that material recycling is the most efficient and reliable method of dealing with plastic waste. Among the material recycling technologies that have already been developed, the remelting technique; that is, reprocessing in the melt phase, remains the most effective, popular, economical and easily applicable method.…”

Comparison of Various Plastics Wastes Using X-ray Fluorescence

“…LDPE, HDPE, and PP are the most type of thermoplastic used throughout the world for many applications such as bags, toys, containers, pipes (LDPE), housewares, industrial wrappings and film, gas pipes (HDPE), film, battery cases, automotive parts, electrical components (PP). In addition, polymers as polyethylene in contrast to condensation polymers as polyethylene terephthalate (PET) cannot be easily recycled using simple chemical methods [12], but the plastics can be recycled using either mechanical technique or chemical/feedstock recycling [13,14]. Therefore, the more reliable method has been used to reduce some amount of plastic waste.…”