Vol.:(0123456789) 1 3 J Polym Environ DOI 10.1007/s10924-017-1053-y ORIGINAL PAPER Eﬀect of Microstructure of High Density Polyethylene on Catalytic Degradation: A Comparison Between Nano Clay and FCC Abbas Kebritchi 1,2 · Mehdi Nekoomansh 1 · Fereidoon Mohammadi 1 · Hossein Ali Khonakdar 1,2 © Springer Science+Business Media, LLC 2017 (LLDPE) from its ﬁrst commercialization in the late 1970s has seen the fastest growth rate in usage of the three major polyethylene families—low density polyethylene (LDPE), LLDPE, and high density polyethylene (HDPE)—and now comprises approximately 25% of the annual production of polyethylene around the world approaching 13 million met- ric tons [2]. However polyoleﬁns (polyethylene and poly- propylene) amount almost to the half of plastic wastes [3]. Owing to the limited capacity of landﬁll sites, increasing disposal costs, the generation of greenhouse gases (such as methane) and poor biodegradability of plastic wastes the common practice of discarding plastic wastes to landﬁll is becoming undesirable [1, 4–6]. From another point of view, plastic waste can be regarded as a potentially cheap source of chemicals and energy [7–9]. Feedstock recycling as an attractive tech- nique has attracted much attention aiming to convert waste polymer materials into original monomers or into other val- uable chemicals [10–12]. It is certainly possible to develop commercial processes based on equilibrium ﬂuid catalytic cracking (FCC). Therefore, a more interesting approach is that of adding polymer waste into the FCC process, under suitable process conditions with the use of zero value of equilibrium FCC catalysts, a large number of waste plastics can be economically converted into valuable hydrocarbons. However, much less is known about the performance of FCC commercial catalysts on the degradation of polymer waste [13]. Fluid catalytic cracking (FCC) catalysts are made using zeolite particles dispersed on an amorphous silica–alumina matrix. Since 1960, the most used zeolite in this kind of catalysts is the Y zeolite [14]. The FCC catalysts have good product selectivity [15] and usually have faujasite struc- ture with a ratio of Si/Al greater than 1.5. This catalyst is formed by the arrangement of truncated octahedra forming Abstract The eﬀect of microstructure of high density polyethylene (HDPE) on catalytic degradation over ﬂuid catalytic cracking (FCC) catalyst and Nano clay is investi- gated. An ethylene/1-hexene copolymer (HDPE) was frac- tionated based on 1-hexene content to diﬀerent fractions using preparative temperature rising elution fractionation (P-TREF) method. The short chain branch (SCB) content of each fraction calculated based on 1 H NMR results. The homogenous SCB content fractions were subsequently ana- lyzed using TGA and thermal degradation behavior of sam- ples were compared with catalytic degradation. The results showed that FCC, in contrast to nano clay, is more sensitive to microstructure of HDPE during catalytic degradation. Therefore, linear chains can start degradation sooner on FCC than the branched chains. In comparison of nano clay and FCC it was found that the nano clay, reduces tempera- ture at maximum degradation rate (T max ), but FCC reduces the T 5% and T max signiﬁcantly. Keywords Microstructure · High density polyethylene · Catalytic degradation · FCC and nano clay Introduction Our modern society is unimaginable without plastics such as polyethylenes [1]. Linear low density polyethylene * Abbas Kebritchi a.kebritchi@ippi.ac.ir 1 Iran Polymer and Petrochemical Institute, 14965-115 Tehran, Iran 2 Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany