Research Article Cite This: ACS Sustainable Chem. Eng. XXXX, XXX, XXX−XXX
pubs.acs.org/journal/ascecg
Profitable Mass-Production of Acid-Modified Recovered Resins for Value-Added Mechanical Recycling as a Compatibilizer for Composites Yuta Sunaga,† Shinji Ogoe,‡ Kenji Aoki,*,§ Hirokazu Ito,*,∥ and Yoshikuni Teramoto*,⊥,# †
Kayaku Akzo Corporation, 2935 Kori, Sanyo-Onoda, Yamaguchi 7570002, Japan Toclas Corporation, 1370 Nishiyama-cho, Hamamatsu, Shizuoka 4328001, Japan § Department of Environment and Forest Resources Science, Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 4228529, Japan ∥ Research Institute for Sustainable Chemistry, Department of Materials and Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 7370046, Japan ⊥ Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 5011193, Japan # Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 5011193, Japan
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S Supporting Information *
ABSTRACT: To realize upgrade recycling of commodity-type polyolefin resins, acid modification with maleic anhydride (MAH) and organic peroxide was applied to polypropylene (PP)-rich commercial recovered resins provided by different manufacturers. Modification conditions were established in advance to achieve high MAH grafting level as well as thermal fluidity using a laboratory scale batch kneader. Mass production prototyping with a view of productivity of 100 kg/h was carried out using an anisotropic twin-screw extruder. Transmission electron microscopy demonstrated that different domain structures of the original recovered resins were homogenized by the acid modification process. To evaluate the performance of the obtained acid-modified recovered resins as a compatibilizer, wood/plastic composite (WPC) compounds were prepared by kneading together with wood flour and PP and examined for their mechanical properties. As a result, the bending and impact strengths improved 1.5 times and the tensile strength increased 1.3 times in comparison with those of the composites containing no compatibilizer. We also conducted in 1t/day mass production prototyping of the WPC compounds using an existing commercial production facility. By estimating the manufacturing costs of the acid-modified recovered resins, the profitability of the production was confirmed. KEYWORDS: Recovered plastic containers and packaging, Upgrade recycling, Acid modification, Biomass, compatibilizer, composite materials
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INTRODUCTION Polyolefin resins such as polypropylene (PP) and polyethylene (PE) have not only good physical properties as generalpurpose plastics but also mechanical (material) recycling capability. In environmentally advanced countries, the mechanically recycling rate of plastics other than synthetic fibers has increased linearly since 1980 and currently reaches 25% (Japan and China) and 30% (Europe).1 However, the collection and sorting costs of waste plastics are still big issues.2−6 In recent years, the problem of ocean plastic waste has also become recognized as very important worldwide.7 Alternatively, the use of mechanically recycled plastics is usually a substitute for virgin resins, and it is generally difficult to find their additional values.3 From the viewpoints of quality and performance, however, recovered plastics are not equivalent to virgin resins;3 we must consider the resin heterogeneities including not only resin types but also © XXXX American Chemical Society
differences in molecular weight and molecular structures such as branching and stereochemistry even from the same monomers. Possible resin degradation (decrease in molecular weight) due to the use history such as the influence of heat and UV also causes heterogeneities and mechanical strength deterioration. At present, in environmentally advanced countries, the mechanical recycling systems based on the law structures are functioning smoothly, but if the recovery and sorting costs further increase in the future, there is concern that problems will arise in terms of profitability, merely by use as a replacement of existing resins. Herein, to accomplish an upgrade mechanical recycling of plastic wastes, we aim to propose the use of recovered Received: May 26, 2018 Revised: July 2, 2018
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DOI: 10.1021/acssuschemeng.8b02431 ACS Sustainable Chem. Eng. XXXX, XXX, XXX−XXX
Research Article
ACS Sustainable Chemistry & Engineering
Table 1. Nominal Values of the Component Composition and Physical Properties of the Commercial Recovered PP Resins Used in this Studya compositions in wt %
physical properties
type of polymersb
mechanical propertiese
sample code
PP
PE
PS
other solid contaminants
chlorine
moisture
MFRd (g/10 min)
flexural strength (MPa)
flexural modulus (MPa)
Izod impact strength (kJ/m2)
PPGL PPHRC
>85 68.7
n.e. 24.3
n.e. 3.7
n.e. 3.3c
